base-4.19.1.0: Basic libraries
Copyright(c) The University of Glasgow 2001
LicenseBSD-style (see the file libraries/base/LICENSE)
Maintainerlibraries@haskell.org
Stabilitystable
Portabilityportable
Safe HaskellTrustworthy
LanguageHaskell2010

Prelude

Description

The Prelude: a standard module. The Prelude is imported by default into all Haskell modules unless either there is an explicit import statement for it, or the NoImplicitPrelude extension is enabled.

Synopsis

Standard types, classes and related functions

Basic data types

data Bool Source #

Constructors

False 
True 

Instances

Instances details
Data Bool Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Bool -> c Bool Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Bool Source #

toConstr :: Bool -> Constr Source #

dataTypeOf :: Bool -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Bool) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Bool) Source #

gmapT :: (forall b. Data b => b -> b) -> Bool -> Bool Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Bool -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Bool -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Bool -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Bool -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Bool -> m Bool Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Bool -> m Bool Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Bool -> m Bool Source #

Storable Bool Source #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Bits Bool Source #

Interpret Bool as 1-bit bit-field

Since: base-4.7.0.0

Instance details

Defined in GHC.Bits

FiniteBits Bool Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Bits

Bounded Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Generic Bool Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep Bool

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep Bool = D1 ('MetaData "Bool" "GHC.Types" "ghc-prim" 'False) (C1 ('MetaCons "False" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "True" 'PrefixI 'False) (U1 :: Type -> Type))

Methods

from :: Bool -> Rep Bool x Source #

to :: Rep Bool x -> Bool Source #

Ix Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Ix

Read Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Show Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Eq Bool 
Instance details

Defined in GHC.Classes

Methods

(==) :: Bool -> Bool -> Bool Source #

(/=) :: Bool -> Bool -> Bool Source #

Ord Bool 
Instance details

Defined in GHC.Classes

type Rep Bool Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep Bool = D1 ('MetaData "Bool" "GHC.Types" "ghc-prim" 'False) (C1 ('MetaCons "False" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "True" 'PrefixI 'False) (U1 :: Type -> Type))

(&&) :: Bool -> Bool -> Bool infixr 3 Source #

Boolean "and", lazy in the second argument

(||) :: Bool -> Bool -> Bool infixr 2 Source #

Boolean "or", lazy in the second argument

not :: Bool -> Bool Source #

Boolean "not"

otherwise :: Bool Source #

otherwise is defined as the value True. It helps to make guards more readable. eg.

 f x | x < 0     = ...
     | otherwise = ...

data Maybe a Source #

The Maybe type encapsulates an optional value. A value of type Maybe a either contains a value of type a (represented as Just a), or it is empty (represented as Nothing). Using Maybe is a good way to deal with errors or exceptional cases without resorting to drastic measures such as error.

The Maybe type is also a monad. It is a simple kind of error monad, where all errors are represented by Nothing. A richer error monad can be built using the Either type.

Constructors

Nothing 
Just a 

Instances

Instances details
MonadFail Maybe Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.Fail

Methods

fail :: String -> Maybe a Source #

MonadFix Maybe Source #

Since: base-2.1

Instance details

Defined in Control.Monad.Fix

Methods

mfix :: (a -> Maybe a) -> Maybe a Source #

MonadZip Maybe Source #

Since: base-4.8.0.0

Instance details

Defined in Control.Monad.Zip

Methods

mzip :: Maybe a -> Maybe b -> Maybe (a, b) Source #

mzipWith :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c Source #

munzip :: Maybe (a, b) -> (Maybe a, Maybe b) Source #

Foldable Maybe Source #

Since: base-2.1

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Maybe m -> m Source #

foldMap :: Monoid m => (a -> m) -> Maybe a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Maybe a -> m Source #

foldr :: (a -> b -> b) -> b -> Maybe a -> b Source #

foldr' :: (a -> b -> b) -> b -> Maybe a -> b Source #

foldl :: (b -> a -> b) -> b -> Maybe a -> b Source #

foldl' :: (b -> a -> b) -> b -> Maybe a -> b Source #

foldr1 :: (a -> a -> a) -> Maybe a -> a Source #

foldl1 :: (a -> a -> a) -> Maybe a -> a Source #

toList :: Maybe a -> [a] Source #

null :: Maybe a -> Bool Source #

length :: Maybe a -> Int Source #

elem :: Eq a => a -> Maybe a -> Bool Source #

maximum :: Ord a => Maybe a -> a Source #

minimum :: Ord a => Maybe a -> a Source #

sum :: Num a => Maybe a -> a Source #

product :: Num a => Maybe a -> a Source #

Eq1 Maybe Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftEq :: (a -> b -> Bool) -> Maybe a -> Maybe b -> Bool Source #

Ord1 Maybe Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftCompare :: (a -> b -> Ordering) -> Maybe a -> Maybe b -> Ordering Source #

Read1 Maybe Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Show1 Maybe Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Maybe a -> ShowS Source #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Maybe a] -> ShowS Source #

Traversable Maybe Source #

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Maybe a -> f (Maybe b) Source #

sequenceA :: Applicative f => Maybe (f a) -> f (Maybe a) Source #

mapM :: Monad m => (a -> m b) -> Maybe a -> m (Maybe b) Source #

sequence :: Monad m => Maybe (m a) -> m (Maybe a) Source #

Alternative Maybe Source #

Picks the leftmost Just value, or, alternatively, Nothing.

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

empty :: Maybe a Source #

(<|>) :: Maybe a -> Maybe a -> Maybe a Source #

some :: Maybe a -> Maybe [a] Source #

many :: Maybe a -> Maybe [a] Source #

Applicative Maybe Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> Maybe a Source #

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b Source #

liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c Source #

(*>) :: Maybe a -> Maybe b -> Maybe b Source #

(<*) :: Maybe a -> Maybe b -> Maybe a Source #

Functor Maybe Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> Maybe a -> Maybe b Source #

(<$) :: a -> Maybe b -> Maybe a Source #

Monad Maybe Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b Source #

(>>) :: Maybe a -> Maybe b -> Maybe b Source #

return :: a -> Maybe a Source #

MonadPlus Maybe Source #

Picks the leftmost Just value, or, alternatively, Nothing.

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mzero :: Maybe a Source #

mplus :: Maybe a -> Maybe a -> Maybe a Source #

Generic1 Maybe Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 Maybe

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep1 Maybe = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))

Methods

from1 :: Maybe a -> Rep1 Maybe a Source #

to1 :: Rep1 Maybe a -> Maybe a Source #

Data a => Data (Maybe a) Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Maybe a -> c (Maybe a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Maybe a) Source #

toConstr :: Maybe a -> Constr Source #

dataTypeOf :: Maybe a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Maybe a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Maybe a)) Source #

gmapT :: (forall b. Data b => b -> b) -> Maybe a -> Maybe a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Maybe a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Maybe a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Maybe a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Maybe a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Maybe a -> m (Maybe a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Maybe a -> m (Maybe a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Maybe a -> m (Maybe a) Source #

Semigroup a => Monoid (Maybe a) Source #

Lift a semigroup into Maybe forming a Monoid according to http://en.wikipedia.org/wiki/Monoid: "Any semigroup S may be turned into a monoid simply by adjoining an element e not in S and defining e*e = e and e*s = s = s*e for all s ∈ S."

Since 4.11.0: constraint on inner a value generalised from Monoid to Semigroup.

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: Maybe a Source #

mappend :: Maybe a -> Maybe a -> Maybe a Source #

mconcat :: [Maybe a] -> Maybe a Source #

Semigroup a => Semigroup (Maybe a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: Maybe a -> Maybe a -> Maybe a Source #

sconcat :: NonEmpty (Maybe a) -> Maybe a Source #

stimes :: Integral b => b -> Maybe a -> Maybe a Source #

Generic (Maybe a) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (Maybe a)

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep (Maybe a) = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

Methods

from :: Maybe a -> Rep (Maybe a) x Source #

to :: Rep (Maybe a) x -> Maybe a Source #

Read a => Read (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Show a => Show (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Eq a => Eq (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Maybe

Methods

(==) :: Maybe a -> Maybe a -> Bool Source #

(/=) :: Maybe a -> Maybe a -> Bool Source #

Ord a => Ord (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Maybe

Methods

compare :: Maybe a -> Maybe a -> Ordering Source #

(<) :: Maybe a -> Maybe a -> Bool Source #

(<=) :: Maybe a -> Maybe a -> Bool Source #

(>) :: Maybe a -> Maybe a -> Bool Source #

(>=) :: Maybe a -> Maybe a -> Bool Source #

max :: Maybe a -> Maybe a -> Maybe a Source #

min :: Maybe a -> Maybe a -> Maybe a Source #

type Rep1 Maybe Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep1 Maybe = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))
type Rep (Maybe a) Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep (Maybe a) = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

maybe :: b -> (a -> b) -> Maybe a -> b Source #

The maybe function takes a default value, a function, and a Maybe value. If the Maybe value is Nothing, the function returns the default value. Otherwise, it applies the function to the value inside the Just and returns the result.

Examples

Expand

Basic usage:

>>> maybe False odd (Just 3)
True
>>> maybe False odd Nothing
False

Read an integer from a string using readMaybe. If we succeed, return twice the integer; that is, apply (*2) to it. If instead we fail to parse an integer, return 0 by default:

>>> import Text.Read ( readMaybe )
>>> maybe 0 (*2) (readMaybe "5")
10
>>> maybe 0 (*2) (readMaybe "")
0

Apply show to a Maybe Int. If we have Just n, we want to show the underlying Int n. But if we have Nothing, we return the empty string instead of (for example) "Nothing":

>>> maybe "" show (Just 5)
"5"
>>> maybe "" show Nothing
""

data Either a b Source #

The Either type represents values with two possibilities: a value of type Either a b is either Left a or Right b.

The Either type is sometimes used to represent a value which is either correct or an error; by convention, the Left constructor is used to hold an error value and the Right constructor is used to hold a correct value (mnemonic: "right" also means "correct").

Examples

Expand

The type Either String Int is the type of values which can be either a String or an Int. The Left constructor can be used only on Strings, and the Right constructor can be used only on Ints:

>>> let s = Left "foo" :: Either String Int
>>> s
Left "foo"
>>> let n = Right 3 :: Either String Int
>>> n
Right 3
>>> :type s
s :: Either String Int
>>> :type n
n :: Either String Int

The fmap from our Functor instance will ignore Left values, but will apply the supplied function to values contained in a Right:

>>> let s = Left "foo" :: Either String Int
>>> let n = Right 3 :: Either String Int
>>> fmap (*2) s
Left "foo"
>>> fmap (*2) n
Right 6

The Monad instance for Either allows us to chain together multiple actions which may fail, and fail overall if any of the individual steps failed. First we'll write a function that can either parse an Int from a Char, or fail.

>>> import Data.Char ( digitToInt, isDigit )
>>> :{
    let parseEither :: Char -> Either String Int
        parseEither c
          | isDigit c = Right (digitToInt c)
          | otherwise = Left "parse error"
>>> :}

The following should work, since both '1' and '2' can be parsed as Ints.

>>> :{
    let parseMultiple :: Either String Int
        parseMultiple = do
          x <- parseEither '1'
          y <- parseEither '2'
          return (x + y)
>>> :}
>>> parseMultiple
Right 3

But the following should fail overall, since the first operation where we attempt to parse 'm' as an Int will fail:

>>> :{
    let parseMultiple :: Either String Int
        parseMultiple = do
          x <- parseEither 'm'
          y <- parseEither '2'
          return (x + y)
>>> :}
>>> parseMultiple
Left "parse error"

Constructors

Left a 
Right b 

Instances

Instances details
Bifoldable Either Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Bifoldable

Methods

bifold :: Monoid m => Either m m -> m Source #

bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> Either a b -> m Source #

bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> Either a b -> c Source #

bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> Either a b -> c Source #

Bifoldable1 Either Source # 
Instance details

Defined in Data.Bifoldable1

Methods

bifold1 :: Semigroup m => Either m m -> m Source #

bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> Either a b -> m Source #

Bifunctor Either Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> Either a c -> Either b d Source #

first :: (a -> b) -> Either a c -> Either b c Source #

second :: (b -> c) -> Either a b -> Either a c Source #

Bitraversable Either Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Bitraversable

Methods

bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> Either a b -> f (Either c d) Source #

Eq2 Either Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Either a c -> Either b d -> Bool Source #

Ord2 Either Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Either a c -> Either b d -> Ordering Source #

Read2 Either Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Either a b) Source #

liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Either a b] Source #

liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Either a b) Source #

liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Either a b] Source #

Show2 Either Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Either a b -> ShowS Source #

liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Either a b] -> ShowS Source #

Generic1 (Either a :: Type -> Type) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (Either a :: Type -> Type)

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Methods

from1 :: Either a a0 -> Rep1 (Either a) a0 Source #

to1 :: Rep1 (Either a) a0 -> Either a a0 Source #

MonadFix (Either e) Source #

Since: base-4.3.0.0

Instance details

Defined in Control.Monad.Fix

Methods

mfix :: (a -> Either e a) -> Either e a Source #

Foldable (Either a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Either a m -> m Source #

foldMap :: Monoid m => (a0 -> m) -> Either a a0 -> m Source #

foldMap' :: Monoid m => (a0 -> m) -> Either a a0 -> m Source #

foldr :: (a0 -> b -> b) -> b -> Either a a0 -> b Source #

foldr' :: (a0 -> b -> b) -> b -> Either a a0 -> b Source #

foldl :: (b -> a0 -> b) -> b -> Either a a0 -> b Source #

foldl' :: (b -> a0 -> b) -> b -> Either a a0 -> b Source #

foldr1 :: (a0 -> a0 -> a0) -> Either a a0 -> a0 Source #

foldl1 :: (a0 -> a0 -> a0) -> Either a a0 -> a0 Source #

toList :: Either a a0 -> [a0] Source #

null :: Either a a0 -> Bool Source #

length :: Either a a0 -> Int Source #

elem :: Eq a0 => a0 -> Either a a0 -> Bool Source #

maximum :: Ord a0 => Either a a0 -> a0 Source #

minimum :: Ord a0 => Either a a0 -> a0 Source #

sum :: Num a0 => Either a a0 -> a0 Source #

product :: Num a0 => Either a a0 -> a0 Source #

Eq a => Eq1 (Either a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftEq :: (a0 -> b -> Bool) -> Either a a0 -> Either a b -> Bool Source #

Ord a => Ord1 (Either a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftCompare :: (a0 -> b -> Ordering) -> Either a a0 -> Either a b -> Ordering Source #

Read a => Read1 (Either a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Either a a0) Source #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Either a a0] Source #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Either a a0) Source #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Either a a0] Source #

Show a => Show1 (Either a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Either a a0 -> ShowS Source #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Either a a0] -> ShowS Source #

Traversable (Either a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a0 -> f b) -> Either a a0 -> f (Either a b) Source #

sequenceA :: Applicative f => Either a (f a0) -> f (Either a a0) Source #

mapM :: Monad m => (a0 -> m b) -> Either a a0 -> m (Either a b) Source #

sequence :: Monad m => Either a (m a0) -> m (Either a a0) Source #

Applicative (Either e) Source #

Since: base-3.0

Instance details

Defined in Data.Either

Methods

pure :: a -> Either e a Source #

(<*>) :: Either e (a -> b) -> Either e a -> Either e b Source #

liftA2 :: (a -> b -> c) -> Either e a -> Either e b -> Either e c Source #

(*>) :: Either e a -> Either e b -> Either e b Source #

(<*) :: Either e a -> Either e b -> Either e a Source #

Functor (Either a) Source #

Since: base-3.0

Instance details

Defined in Data.Either

Methods

fmap :: (a0 -> b) -> Either a a0 -> Either a b Source #

(<$) :: a0 -> Either a b -> Either a a0 Source #

Monad (Either e) Source #

Since: base-4.4.0.0

Instance details

Defined in Data.Either

Methods

(>>=) :: Either e a -> (a -> Either e b) -> Either e b Source #

(>>) :: Either e a -> Either e b -> Either e b Source #

return :: a -> Either e a Source #

(Data a, Data b) => Data (Either a b) Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> Either a b -> c (Either a b) Source #

gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Either a b) Source #

toConstr :: Either a b -> Constr Source #

dataTypeOf :: Either a b -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Either a b)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Either a b)) Source #

gmapT :: (forall b0. Data b0 => b0 -> b0) -> Either a b -> Either a b Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Either a b -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Either a b -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Either a b -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Either a b -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Either a b -> m (Either a b) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Either a b -> m (Either a b) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Either a b -> m (Either a b) Source #

Semigroup (Either a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Either

Methods

(<>) :: Either a b -> Either a b -> Either a b Source #

sconcat :: NonEmpty (Either a b) -> Either a b Source #

stimes :: Integral b0 => b0 -> Either a b -> Either a b Source #

Generic (Either a b) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (Either a b)

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Methods

from :: Either a b -> Rep (Either a b) x Source #

to :: Rep (Either a b) x -> Either a b Source #

(Read a, Read b) => Read (Either a b) Source #

Since: base-3.0

Instance details

Defined in Data.Either

(Show a, Show b) => Show (Either a b) Source #

Since: base-3.0

Instance details

Defined in Data.Either

Methods

showsPrec :: Int -> Either a b -> ShowS Source #

show :: Either a b -> String Source #

showList :: [Either a b] -> ShowS Source #

(Eq a, Eq b) => Eq (Either a b) Source #

Since: base-2.1

Instance details

Defined in Data.Either

Methods

(==) :: Either a b -> Either a b -> Bool Source #

(/=) :: Either a b -> Either a b -> Bool Source #

(Ord a, Ord b) => Ord (Either a b) Source #

Since: base-2.1

Instance details

Defined in Data.Either

Methods

compare :: Either a b -> Either a b -> Ordering Source #

(<) :: Either a b -> Either a b -> Bool Source #

(<=) :: Either a b -> Either a b -> Bool Source #

(>) :: Either a b -> Either a b -> Bool Source #

(>=) :: Either a b -> Either a b -> Bool Source #

max :: Either a b -> Either a b -> Either a b Source #

min :: Either a b -> Either a b -> Either a b Source #

type Rep1 (Either a :: Type -> Type) Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep (Either a b) Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

either :: (a -> c) -> (b -> c) -> Either a b -> c Source #

Case analysis for the Either type. If the value is Left a, apply the first function to a; if it is Right b, apply the second function to b.

Examples

Expand

We create two values of type Either String Int, one using the Left constructor and another using the Right constructor. Then we apply "either" the length function (if we have a String) or the "times-two" function (if we have an Int):

>>> let s = Left "foo" :: Either String Int
>>> let n = Right 3 :: Either String Int
>>> either length (*2) s
3
>>> either length (*2) n
6

data Ordering Source #

Constructors

LT 
EQ 
GT 

Instances

Instances details
Data Ordering Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Ordering -> c Ordering Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Ordering Source #

toConstr :: Ordering -> Constr Source #

dataTypeOf :: Ordering -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Ordering) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Ordering) Source #

gmapT :: (forall b. Data b => b -> b) -> Ordering -> Ordering Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Ordering -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Ordering -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Ordering -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Ordering -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Ordering -> m Ordering Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Ordering -> m Ordering Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Ordering -> m Ordering Source #

Monoid Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Semigroup Ordering Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Bounded Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Generic Ordering Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep Ordering

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep Ordering = D1 ('MetaData "Ordering" "GHC.Types" "ghc-prim" 'False) (C1 ('MetaCons "LT" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "EQ" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "GT" 'PrefixI 'False) (U1 :: Type -> Type)))
Ix Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Ix

Read Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Show Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Eq Ordering 
Instance details

Defined in GHC.Classes

Ord Ordering 
Instance details

Defined in GHC.Classes

type Rep Ordering Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

type Rep Ordering = D1 ('MetaData "Ordering" "GHC.Types" "ghc-prim" 'False) (C1 ('MetaCons "LT" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "EQ" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "GT" 'PrefixI 'False) (U1 :: Type -> Type)))

data Char Source #

The character type Char represents Unicode codespace and its elements are code points as in definitions D9 and D10 of the Unicode Standard.

Character literals in Haskell are single-quoted: 'Q', 'Я' or 'Ω'. To represent a single quote itself use '\'', and to represent a backslash use '\\'. The full grammar can be found in the section 2.6 of the Haskell 2010 Language Report.

To specify a character by its code point one can use decimal, hexadecimal or octal notation: '\65', '\x41' and '\o101' are all alternative forms of 'A'. The largest code point is '\x10ffff'.

There is a special escape syntax for ASCII control characters:

EscapeAlternativesMeaning
'\NUL''\0'null character
'\SOH''\1'start of heading
'\STX''\2'start of text
'\ETX''\3'end of text
'\EOT''\4'end of transmission
'\ENQ''\5'enquiry
'\ACK''\6'acknowledge
'\BEL''\7', '\a'bell (alert)
'\BS''\8', '\b'backspace
'\HT''\9', '\t'horizontal tab
'\LF''\10', '\n'line feed (new line)
'\VT''\11', '\v'vertical tab
'\FF''\12', '\f'form feed
'\CR''\13', '\r'carriage return
'\SO''\14'shift out
'\SI''\15'shift in
'\DLE''\16'data link escape
'\DC1''\17'device control 1
'\DC2''\18'device control 2
'\DC3''\19'device control 3
'\DC4''\20'device control 4
'\NAK''\21'negative acknowledge
'\SYN''\22'synchronous idle
'\ETB''\23'end of transmission block
'\CAN''\24'cancel
'\EM''\25'end of medium
'\SUB''\26'substitute
'\ESC''\27'escape
'\FS''\28'file separator
'\GS''\29'group separator
'\RS''\30'record separator
'\US''\31'unit separator
'\SP''\32', ' 'space
'\DEL''\127'delete

Data.Char provides utilities to work with Char.

Instances

Instances details
Data Char Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Char -> c Char Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Char Source #

toConstr :: Char -> Constr Source #

dataTypeOf :: Char -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Char) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Char) Source #

gmapT :: (forall b. Data b => b -> b) -> Char -> Char Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Char -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Char -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Char -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Char -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Char -> m Char Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Char -> m Char Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Char -> m Char Source #

Storable Char Source #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Bounded Char Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Char Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Ix Char Source #

Since: base-2.1

Instance details

Defined in GHC.Ix

Read Char Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Show Char Source #

Since: base-2.1

Instance details

Defined in GHC.Show

IsChar Char Source #

Since: base-2.1

Instance details

Defined in Text.Printf

PrintfArg Char Source #

Since: base-2.1

Instance details

Defined in Text.Printf

Eq Char 
Instance details

Defined in GHC.Classes

Methods

(==) :: Char -> Char -> Bool Source #

(/=) :: Char -> Char -> Bool Source #

Ord Char 
Instance details

Defined in GHC.Classes

TestCoercion SChar Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.TypeLits

Methods

testCoercion :: forall (a :: Char) (b :: Char). SChar a -> SChar b -> Maybe (Coercion a b) Source #

TestEquality SChar Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.TypeLits

Methods

testEquality :: forall (a :: Char) (b :: Char). SChar a -> SChar b -> Maybe (a :~: b) Source #

Generic1 (URec Char :: k -> Type) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Char :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Char :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UChar" 'PrefixI 'True) (S1 ('MetaSel ('Just "uChar#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UChar :: k -> Type)))

Methods

from1 :: forall (a :: k). URec Char a -> Rep1 (URec Char :: k -> Type) a Source #

to1 :: forall (a :: k). Rep1 (URec Char :: k -> Type) a -> URec Char a Source #

Foldable (UChar :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UChar m -> m Source #

foldMap :: Monoid m => (a -> m) -> UChar a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UChar a -> m Source #

foldr :: (a -> b -> b) -> b -> UChar a -> b Source #

foldr' :: (a -> b -> b) -> b -> UChar a -> b Source #

foldl :: (b -> a -> b) -> b -> UChar a -> b Source #

foldl' :: (b -> a -> b) -> b -> UChar a -> b Source #

foldr1 :: (a -> a -> a) -> UChar a -> a Source #

foldl1 :: (a -> a -> a) -> UChar a -> a Source #

toList :: UChar a -> [a] Source #

null :: UChar a -> Bool Source #

length :: UChar a -> Int Source #

elem :: Eq a => a -> UChar a -> Bool Source #

maximum :: Ord a => UChar a -> a Source #

minimum :: Ord a => UChar a -> a Source #

sum :: Num a => UChar a -> a Source #

product :: Num a => UChar a -> a Source #

Traversable (UChar :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UChar a -> f (UChar b) Source #

sequenceA :: Applicative f => UChar (f a) -> f (UChar a) Source #

mapM :: Monad m => (a -> m b) -> UChar a -> m (UChar b) Source #

sequence :: Monad m => UChar (m a) -> m (UChar a) Source #

Functor (URec Char :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Char a -> URec Char b Source #

(<$) :: a -> URec Char b -> URec Char a Source #

Generic (URec Char p) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Char p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UChar" 'PrefixI 'True) (S1 ('MetaSel ('Just "uChar#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UChar :: Type -> Type)))

Methods

from :: URec Char p -> Rep (URec Char p) x Source #

to :: Rep (URec Char p) x -> URec Char p Source #

Show (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Char p -> URec Char p -> Bool Source #

(/=) :: URec Char p -> URec Char p -> Bool Source #

Ord (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec Char p -> URec Char p -> Ordering Source #

(<) :: URec Char p -> URec Char p -> Bool Source #

(<=) :: URec Char p -> URec Char p -> Bool Source #

(>) :: URec Char p -> URec Char p -> Bool Source #

(>=) :: URec Char p -> URec Char p -> Bool Source #

max :: URec Char p -> URec Char p -> URec Char p Source #

min :: URec Char p -> URec Char p -> URec Char p Source #

data URec Char (p :: k) Source #

Used for marking occurrences of Char#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Char (p :: k) = UChar {}
type Compare (a :: Char) (b :: Char) Source # 
Instance details

Defined in Data.Type.Ord

type Compare (a :: Char) (b :: Char) = CmpChar a b
type Rep1 (URec Char :: k -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Char :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UChar" 'PrefixI 'True) (S1 ('MetaSel ('Just "uChar#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UChar :: k -> Type)))
type Rep (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Char p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UChar" 'PrefixI 'True) (S1 ('MetaSel ('Just "uChar#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UChar :: Type -> Type)))

type String = [Char] Source #

String is an alias for a list of characters.

String constants in Haskell are values of type String. That means if you write a string literal like "hello world", it will have the type [Char], which is the same as String.

Note: You can ask the compiler to automatically infer different types with the -XOverloadedStrings language extension, for example "hello world" :: Text. See IsString for more information.

Because String is just a list of characters, you can use normal list functions to do basic string manipulation. See Data.List for operations on lists.

Performance considerations

Expand

[Char] is a relatively memory-inefficient type. It is a linked list of boxed word-size characters, internally it looks something like:

╭─────┬───┬──╮  ╭─────┬───┬──╮  ╭─────┬───┬──╮  ╭────╮
│ (:) │   │ ─┼─>│ (:) │   │ ─┼─>│ (:) │   │ ─┼─>│ [] │
╰─────┴─┼─┴──╯  ╰─────┴─┼─┴──╯  ╰─────┴─┼─┴──╯  ╰────╯
        v               v               v
       'a'             'b'             'c'

The String "abc" will use 5*3+1 = 16 (in general 5n+1) words of space in memory.

Furthermore, operations like (++) (string concatenation) are O(n) (in the left argument).

For historical reasons, the base library uses String in a lot of places for the conceptual simplicity, but library code dealing with user-data should use the text package for Unicode text, or the the bytestring package for binary data.

Tuples

fst :: (a, b) -> a Source #

Extract the first component of a pair.

snd :: (a, b) -> b Source #

Extract the second component of a pair.

curry :: ((a, b) -> c) -> a -> b -> c Source #

curry converts an uncurried function to a curried function.

Examples

Expand
>>> curry fst 1 2
1

uncurry :: (a -> b -> c) -> (a, b) -> c Source #

uncurry converts a curried function to a function on pairs.

Examples

Expand
>>> uncurry (+) (1,2)
3
>>> uncurry ($) (show, 1)
"1"
>>> map (uncurry max) [(1,2), (3,4), (6,8)]
[2,4,8]

Basic type classes

class Eq a where Source #

The Eq class defines equality (==) and inequality (/=). All the basic datatypes exported by the Prelude are instances of Eq, and Eq may be derived for any datatype whose constituents are also instances of Eq.

The Haskell Report defines no laws for Eq. However, instances are encouraged to follow these properties:

Reflexivity
x == x = True
Symmetry
x == y = y == x
Transitivity
if x == y && y == z = True, then x == z = True
Extensionality
if x == y = True and f is a function whose return type is an instance of Eq, then f x == f y = True
Negation
x /= y = not (x == y)

Minimal complete definition: either == or /=.

Minimal complete definition

(==) | (/=)

Methods

(==) :: a -> a -> Bool infix 4 Source #

(/=) :: a -> a -> Bool infix 4 Source #

Instances

Instances details
Eq ByteArray Source #

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Eq Constr Source #

Equality of constructors

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Eq ConstrRep Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Eq DataRep Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Eq Fixity Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Eq All Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: All -> All -> Bool Source #

(/=) :: All -> All -> Bool Source #

Eq Any Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: Any -> Any -> Bool Source #

(/=) :: Any -> Any -> Bool Source #

Eq SomeTypeRep Source # 
Instance details

Defined in Data.Typeable.Internal

Eq Unique Source # 
Instance details

Defined in Data.Unique

Eq Version Source #

Since: base-2.1

Instance details

Defined in Data.Version

Eq Errno Source #

Since: base-2.1

Instance details

Defined in Foreign.C.Error

Methods

(==) :: Errno -> Errno -> Bool Source #

(/=) :: Errno -> Errno -> Bool Source #

Eq CBool Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CBool -> CBool -> Bool Source #

(/=) :: CBool -> CBool -> Bool Source #

Eq CChar Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CChar -> CChar -> Bool Source #

(/=) :: CChar -> CChar -> Bool Source #

Eq CClock Source # 
Instance details

Defined in Foreign.C.Types

Eq CDouble Source # 
Instance details

Defined in Foreign.C.Types

Eq CFloat Source # 
Instance details

Defined in Foreign.C.Types

Eq CInt Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CInt -> CInt -> Bool Source #

(/=) :: CInt -> CInt -> Bool Source #

Eq CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Eq CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Eq CLLong Source # 
Instance details

Defined in Foreign.C.Types

Eq CLong Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CLong -> CLong -> Bool Source #

(/=) :: CLong -> CLong -> Bool Source #

Eq CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Eq CSChar Source # 
Instance details

Defined in Foreign.C.Types

Eq CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Eq CShort Source # 
Instance details

Defined in Foreign.C.Types

Eq CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Eq CSize Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CSize -> CSize -> Bool Source #

(/=) :: CSize -> CSize -> Bool Source #

Eq CTime Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CTime -> CTime -> Bool Source #

(/=) :: CTime -> CTime -> Bool Source #

Eq CUChar Source # 
Instance details

Defined in Foreign.C.Types

Eq CUInt Source # 
Instance details

Defined in Foreign.C.Types

Methods

(==) :: CUInt -> CUInt -> Bool Source #

(/=) :: CUInt -> CUInt -> Bool Source #

Eq CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Eq CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Eq CULLong Source # 
Instance details

Defined in Foreign.C.Types

Eq CULong Source # 
Instance details

Defined in Foreign.C.Types

Eq CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Eq CUShort Source # 
Instance details

Defined in Foreign.C.Types

Eq CWchar Source # 
Instance details

Defined in Foreign.C.Types

Eq IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Eq WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Eq Void Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Base

Methods

(==) :: Void -> Void -> Bool Source #

(/=) :: Void -> Void -> Bool Source #

Eq ByteOrder Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ByteOrder

Eq BlockReason Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Eq ThreadId Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.Conc.Sync

Eq ThreadStatus Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Eq Event Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Internal.Types

Methods

(==) :: Event -> Event -> Bool Source #

(/=) :: Event -> Event -> Bool Source #

Eq Lifetime Source #

Since: base-4.8.1.0

Instance details

Defined in GHC.Event.Internal.Types

Eq FdKey Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Manager

Methods

(==) :: FdKey -> FdKey -> Bool Source #

(/=) :: FdKey -> FdKey -> Bool Source #

Eq TimeoutKey Source # 
Instance details

Defined in GHC.Event.TimeOut

Eq ErrorCall Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Exception

Eq ArithException Source #

Since: base-3.0

Instance details

Defined in GHC.Exception.Type

Eq SpecConstrAnnotation Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Exts

Eq Fingerprint Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Fingerprint.Type

Eq Associativity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Eq DecidedStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq Fixity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Eq SourceStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq SourceUnpackedness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq MaskingState Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO

Eq BufferState Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Buffer

Eq IODeviceType Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Device

Eq SeekMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Device

Eq CodingProgress Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.IO.Encoding.Types

Eq ArrayException Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Exception

Eq AsyncException Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Exception

Eq ExitCode Source # 
Instance details

Defined in GHC.IO.Exception

Eq IOErrorType Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Eq IOException Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Eq HandlePosn Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle

Eq BufferMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Handle.Types

Eq Handle Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle.Types

Eq Newline Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Handle.Types

Eq NewlineMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Handle.Types

Eq IOMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.IOMode

Eq InfoProv Source # 
Instance details

Defined in GHC.InfoProv

Eq Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

(==) :: Int16 -> Int16 -> Bool Source #

(/=) :: Int16 -> Int16 -> Bool Source #

Eq Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

(==) :: Int32 -> Int32 -> Bool Source #

(/=) :: Int32 -> Int32 -> Bool Source #

Eq Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

(==) :: Int64 -> Int64 -> Bool Source #

(/=) :: Int64 -> Int64 -> Bool Source #

Eq Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

(==) :: Int8 -> Int8 -> Bool Source #

(/=) :: Int8 -> Int8 -> Bool Source #

Eq IoSubSystem Source # 
Instance details

Defined in GHC.RTS.Flags

Eq StackEntry Source # 
Instance details

Defined in GHC.Stack.CloneStack

Eq SrcLoc Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Stack.Types

Eq SomeChar Source # 
Instance details

Defined in GHC.TypeLits

Eq SomeSymbol Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeLits

Eq SomeNat Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeNats

Eq GeneralCategory Source #

Since: base-2.1

Instance details

Defined in GHC.Unicode

Eq Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Eq Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Eq Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Eq Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

(==) :: Word8 -> Word8 -> Bool Source #

(/=) :: Word8 -> Word8 -> Bool Source #

Eq CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Eq CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Eq CCc Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CCc -> CCc -> Bool Source #

(/=) :: CCc -> CCc -> Bool Source #

Eq CClockId Source # 
Instance details

Defined in System.Posix.Types

Eq CDev Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CDev -> CDev -> Bool Source #

(/=) :: CDev -> CDev -> Bool Source #

Eq CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Eq CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Eq CGid Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CGid -> CGid -> Bool Source #

(/=) :: CGid -> CGid -> Bool Source #

Eq CId Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CId -> CId -> Bool Source #

(/=) :: CId -> CId -> Bool Source #

Eq CIno Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CIno -> CIno -> Bool Source #

(/=) :: CIno -> CIno -> Bool Source #

Eq CKey Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CKey -> CKey -> Bool Source #

(/=) :: CKey -> CKey -> Bool Source #

Eq CMode Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CMode -> CMode -> Bool Source #

(/=) :: CMode -> CMode -> Bool Source #

Eq CNfds Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CNfds -> CNfds -> Bool Source #

(/=) :: CNfds -> CNfds -> Bool Source #

Eq CNlink Source # 
Instance details

Defined in System.Posix.Types

Eq COff Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: COff -> COff -> Bool Source #

(/=) :: COff -> COff -> Bool Source #

Eq CPid Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CPid -> CPid -> Bool Source #

(/=) :: CPid -> CPid -> Bool Source #

Eq CRLim Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CRLim -> CRLim -> Bool Source #

(/=) :: CRLim -> CRLim -> Bool Source #

Eq CSocklen Source # 
Instance details

Defined in System.Posix.Types

Eq CSpeed Source # 
Instance details

Defined in System.Posix.Types

Eq CSsize Source # 
Instance details

Defined in System.Posix.Types

Eq CTcflag Source # 
Instance details

Defined in System.Posix.Types

Eq CTimer Source # 
Instance details

Defined in System.Posix.Types

Eq CUid Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: CUid -> CUid -> Bool Source #

(/=) :: CUid -> CUid -> Bool Source #

Eq Fd Source # 
Instance details

Defined in System.Posix.Types

Methods

(==) :: Fd -> Fd -> Bool Source #

(/=) :: Fd -> Fd -> Bool Source #

Eq Timeout Source # 
Instance details

Defined in System.Timeout

Eq Lexeme Source #

Since: base-2.1

Instance details

Defined in Text.Read.Lex

Eq Number Source #

Since: base-4.6.0.0

Instance details

Defined in Text.Read.Lex

Eq BigNat 
Instance details

Defined in GHC.Num.BigNat

Eq Module 
Instance details

Defined in GHC.Classes

Eq Ordering 
Instance details

Defined in GHC.Classes

Eq TrName 
Instance details

Defined in GHC.Classes

Eq TyCon 
Instance details

Defined in GHC.Classes

Methods

(==) :: TyCon -> TyCon -> Bool Source #

(/=) :: TyCon -> TyCon -> Bool Source #

Eq Integer 
Instance details

Defined in GHC.Num.Integer

Eq Natural 
Instance details

Defined in GHC.Num.Natural

Eq () 
Instance details

Defined in GHC.Classes

Methods

(==) :: () -> () -> Bool Source #

(/=) :: () -> () -> Bool Source #

Eq Bool 
Instance details

Defined in GHC.Classes

Methods

(==) :: Bool -> Bool -> Bool Source #

(/=) :: Bool -> Bool -> Bool Source #

Eq Char 
Instance details

Defined in GHC.Classes

Methods

(==) :: Char -> Char -> Bool Source #

(/=) :: Char -> Char -> Bool Source #

Eq Double

Note that due to the presence of NaN, Double's Eq instance does not satisfy reflexivity.

>>> 0/0 == (0/0 :: Double)
False

Also note that Double's Eq instance does not satisfy substitutivity:

>>> 0 == (-0 :: Double)
True
>>> recip 0 == recip (-0 :: Double)
False
Instance details

Defined in GHC.Classes

Eq Float

Note that due to the presence of NaN, Float's Eq instance does not satisfy reflexivity.

>>> 0/0 == (0/0 :: Float)
False

Also note that Float's Eq instance does not satisfy extensionality:

>>> 0 == (-0 :: Float)
True
>>> recip 0 == recip (-0 :: Float)
False
Instance details

Defined in GHC.Classes

Methods

(==) :: Float -> Float -> Bool Source #

(/=) :: Float -> Float -> Bool Source #

Eq Int 
Instance details

Defined in GHC.Classes

Methods

(==) :: Int -> Int -> Bool Source #

(/=) :: Int -> Int -> Bool Source #

Eq Word 
Instance details

Defined in GHC.Classes

Methods

(==) :: Word -> Word -> Bool Source #

(/=) :: Word -> Word -> Bool Source #

Eq a => Eq (ZipList a) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Methods

(==) :: ZipList a -> ZipList a -> Bool Source #

(/=) :: ZipList a -> ZipList a -> Bool Source #

Eq (Chan a) Source #

Since: base-4.4.0.0

Instance details

Defined in Control.Concurrent.Chan

Methods

(==) :: Chan a -> Chan a -> Bool Source #

(/=) :: Chan a -> Chan a -> Bool Source #

Eq (MutableByteArray s) Source #

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Eq a => Eq (And a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(==) :: And a -> And a -> Bool Source #

(/=) :: And a -> And a -> Bool Source #

Eq a => Eq (Iff a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(==) :: Iff a -> Iff a -> Bool Source #

(/=) :: Iff a -> Iff a -> Bool Source #

Eq a => Eq (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(==) :: Ior a -> Ior a -> Bool Source #

(/=) :: Ior a -> Ior a -> Bool Source #

Eq a => Eq (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(==) :: Xor a -> Xor a -> Bool Source #

(/=) :: Xor a -> Xor a -> Bool Source #

Eq a => Eq (Complex a) Source #

Since: base-2.1

Instance details

Defined in Data.Complex

Methods

(==) :: Complex a -> Complex a -> Bool Source #

(/=) :: Complex a -> Complex a -> Bool Source #

Eq a => Eq (Identity a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Methods

(==) :: Identity a -> Identity a -> Bool Source #

(/=) :: Identity a -> Identity a -> Bool Source #

Eq a => Eq (First a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

(==) :: First a -> First a -> Bool Source #

(/=) :: First a -> First a -> Bool Source #

Eq a => Eq (Last a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

(==) :: Last a -> Last a -> Bool Source #

(/=) :: Last a -> Last a -> Bool Source #

Eq a => Eq (Down a) Source #

Since: base-4.6.0.0

Instance details

Defined in Data.Ord

Methods

(==) :: Down a -> Down a -> Bool Source #

(/=) :: Down a -> Down a -> Bool Source #

Eq a => Eq (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(==) :: First a -> First a -> Bool Source #

(/=) :: First a -> First a -> Bool Source #

Eq a => Eq (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(==) :: Last a -> Last a -> Bool Source #

(/=) :: Last a -> Last a -> Bool Source #

Eq a => Eq (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(==) :: Max a -> Max a -> Bool Source #

(/=) :: Max a -> Max a -> Bool Source #

Eq a => Eq (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(==) :: Min a -> Min a -> Bool Source #

(/=) :: Min a -> Min a -> Bool Source #

Eq m => Eq (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Eq a => Eq (Dual a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: Dual a -> Dual a -> Bool Source #

(/=) :: Dual a -> Dual a -> Bool Source #

Eq a => Eq (Product a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: Product a -> Product a -> Bool Source #

(/=) :: Product a -> Product a -> Bool Source #

Eq a => Eq (Sum a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: Sum a -> Sum a -> Bool Source #

(/=) :: Sum a -> Sum a -> Bool Source #

Eq (ConstPtr a) Source # 
Instance details

Defined in Foreign.C.ConstPtr

Methods

(==) :: ConstPtr a -> ConstPtr a -> Bool Source #

(/=) :: ConstPtr a -> ConstPtr a -> Bool Source #

Eq a => Eq (NonEmpty a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(==) :: NonEmpty a -> NonEmpty a -> Bool Source #

(/=) :: NonEmpty a -> NonEmpty a -> Bool Source #

Eq (TVar a) Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

(==) :: TVar a -> TVar a -> Bool Source #

(/=) :: TVar a -> TVar a -> Bool Source #

Eq (ForeignPtr a) Source #

Since: base-2.1

Instance details

Defined in GHC.ForeignPtr

Eq p => Eq (Par1 p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: Par1 p -> Par1 p -> Bool Source #

(/=) :: Par1 p -> Par1 p -> Bool Source #

Eq (IORef a) Source #

Pointer equality.

Since: base-4.0.0.0

Instance details

Defined in GHC.IORef

Methods

(==) :: IORef a -> IORef a -> Bool Source #

(/=) :: IORef a -> IORef a -> Bool Source #

Eq (MVar a) Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.MVar

Methods

(==) :: MVar a -> MVar a -> Bool Source #

(/=) :: MVar a -> MVar a -> Bool Source #

Eq (FunPtr a) Source # 
Instance details

Defined in GHC.Ptr

Methods

(==) :: FunPtr a -> FunPtr a -> Bool Source #

(/=) :: FunPtr a -> FunPtr a -> Bool Source #

Eq (Ptr a) Source #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

(==) :: Ptr a -> Ptr a -> Bool Source #

(/=) :: Ptr a -> Ptr a -> Bool Source #

Eq a => Eq (Ratio a) Source #

Since: base-2.1

Instance details

Defined in GHC.Real

Methods

(==) :: Ratio a -> Ratio a -> Bool Source #

(/=) :: Ratio a -> Ratio a -> Bool Source #

Eq (StablePtr a) Source #

Since: base-2.1

Instance details

Defined in GHC.Stable

Eq (StableName a) Source #

Since: base-2.1

Instance details

Defined in GHC.StableName

Eq (SChar c) Source #

Since: base-4.19.0.0

Instance details

Defined in GHC.TypeLits

Methods

(==) :: SChar c -> SChar c -> Bool Source #

(/=) :: SChar c -> SChar c -> Bool Source #

Eq (SSymbol s) Source #

Since: base-4.19.0.0

Instance details

Defined in GHC.TypeLits

Methods

(==) :: SSymbol s -> SSymbol s -> Bool Source #

(/=) :: SSymbol s -> SSymbol s -> Bool Source #

Eq (SNat n) Source #

Since: base-4.19.0.0

Instance details

Defined in GHC.TypeNats

Methods

(==) :: SNat n -> SNat n -> Bool Source #

(/=) :: SNat n -> SNat n -> Bool Source #

Eq a => Eq (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Maybe

Methods

(==) :: Maybe a -> Maybe a -> Bool Source #

(/=) :: Maybe a -> Maybe a -> Bool Source #

Eq a => Eq (Solo a) 
Instance details

Defined in GHC.Classes

Methods

(==) :: Solo a -> Solo a -> Bool Source #

(/=) :: Solo a -> Solo a -> Bool Source #

Eq a => Eq [a] 
Instance details

Defined in GHC.Classes

Methods

(==) :: [a] -> [a] -> Bool Source #

(/=) :: [a] -> [a] -> Bool Source #

(Eq a, Eq b) => Eq (Either a b) Source #

Since: base-2.1

Instance details

Defined in Data.Either

Methods

(==) :: Either a b -> Either a b -> Bool Source #

(/=) :: Either a b -> Either a b -> Bool Source #

Eq (Fixed a) Source #

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

(==) :: Fixed a -> Fixed a -> Bool Source #

(/=) :: Fixed a -> Fixed a -> Bool Source #

Eq (Proxy s) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

(==) :: Proxy s -> Proxy s -> Bool Source #

(/=) :: Proxy s -> Proxy s -> Bool Source #

Eq a => Eq (Arg a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(==) :: Arg a b -> Arg a b -> Bool Source #

(/=) :: Arg a b -> Arg a b -> Bool Source #

Eq (TypeRep a) Source #

Since: base-2.1

Instance details

Defined in Data.Typeable.Internal

Methods

(==) :: TypeRep a -> TypeRep a -> Bool Source #

(/=) :: TypeRep a -> TypeRep a -> Bool Source #

(Ix i, Eq e) => Eq (Array i e) Source #

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

(==) :: Array i e -> Array i e -> Bool Source #

(/=) :: Array i e -> Array i e -> Bool Source #

Eq (U1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: U1 p -> U1 p -> Bool Source #

(/=) :: U1 p -> U1 p -> Bool Source #

Eq (V1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: V1 p -> V1 p -> Bool Source #

(/=) :: V1 p -> V1 p -> Bool Source #

Eq (IOArray i e) Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IOArray

Methods

(==) :: IOArray i e -> IOArray i e -> Bool Source #

(/=) :: IOArray i e -> IOArray i e -> Bool Source #

Eq (STRef s a) Source #

Pointer equality.

Since: base-2.1

Instance details

Defined in GHC.STRef

Methods

(==) :: STRef s a -> STRef s a -> Bool Source #

(/=) :: STRef s a -> STRef s a -> Bool Source #

(Eq a, Eq b) => Eq (a, b) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b) -> (a, b) -> Bool Source #

(/=) :: (a, b) -> (a, b) -> Bool Source #

Eq a => Eq (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

(==) :: Const a b -> Const a b -> Bool Source #

(/=) :: Const a b -> Const a b -> Bool Source #

Eq (f a) => Eq (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

(==) :: Ap f a -> Ap f a -> Bool Source #

(/=) :: Ap f a -> Ap f a -> Bool Source #

Eq (f a) => Eq (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: Alt f a -> Alt f a -> Bool Source #

(/=) :: Alt f a -> Alt f a -> Bool Source #

Eq (Coercion a b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Coercion

Methods

(==) :: Coercion a b -> Coercion a b -> Bool Source #

(/=) :: Coercion a b -> Coercion a b -> Bool Source #

Eq (a :~: b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

(==) :: (a :~: b) -> (a :~: b) -> Bool Source #

(/=) :: (a :~: b) -> (a :~: b) -> Bool Source #

Eq (OrderingI a b) Source # 
Instance details

Defined in Data.Type.Ord

Methods

(==) :: OrderingI a b -> OrderingI a b -> Bool Source #

(/=) :: OrderingI a b -> OrderingI a b -> Bool Source #

Eq (STArray s i e) Source #

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

(==) :: STArray s i e -> STArray s i e -> Bool Source #

(/=) :: STArray s i e -> STArray s i e -> Bool Source #

(Generic1 f, Eq (Rep1 f a)) => Eq (Generically1 f a) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.Generics

Eq (f p) => Eq (Rec1 f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: Rec1 f p -> Rec1 f p -> Bool Source #

(/=) :: Rec1 f p -> Rec1 f p -> Bool Source #

Eq (URec (Ptr ()) p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(/=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

Eq (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Char p -> URec Char p -> Bool Source #

(/=) :: URec Char p -> URec Char p -> Bool Source #

Eq (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Double p -> URec Double p -> Bool Source #

(/=) :: URec Double p -> URec Double p -> Bool Source #

Eq (URec Float p) Source # 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Float p -> URec Float p -> Bool Source #

(/=) :: URec Float p -> URec Float p -> Bool Source #

Eq (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Int p -> URec Int p -> Bool Source #

(/=) :: URec Int p -> URec Int p -> Bool Source #

Eq (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Word p -> URec Word p -> Bool Source #

(/=) :: URec Word p -> URec Word p -> Bool Source #

(Eq a, Eq b, Eq c) => Eq (a, b, c) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c) -> (a, b, c) -> Bool Source #

(/=) :: (a, b, c) -> (a, b, c) -> Bool Source #

(Eq (f a), Eq (g a)) => Eq (Product f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Product

Methods

(==) :: Product f g a -> Product f g a -> Bool Source #

(/=) :: Product f g a -> Product f g a -> Bool Source #

(Eq (f a), Eq (g a)) => Eq (Sum f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Sum

Methods

(==) :: Sum f g a -> Sum f g a -> Bool Source #

(/=) :: Sum f g a -> Sum f g a -> Bool Source #

Eq (a :~~: b) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

(==) :: (a :~~: b) -> (a :~~: b) -> Bool Source #

(/=) :: (a :~~: b) -> (a :~~: b) -> Bool Source #

(Eq (f p), Eq (g p)) => Eq ((f :*: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: (f :*: g) p -> (f :*: g) p -> Bool Source #

(/=) :: (f :*: g) p -> (f :*: g) p -> Bool Source #

(Eq (f p), Eq (g p)) => Eq ((f :+: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: (f :+: g) p -> (f :+: g) p -> Bool Source #

(/=) :: (f :+: g) p -> (f :+: g) p -> Bool Source #

Eq c => Eq (K1 i c p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: K1 i c p -> K1 i c p -> Bool Source #

(/=) :: K1 i c p -> K1 i c p -> Bool Source #

(Eq a, Eq b, Eq c, Eq d) => Eq (a, b, c, d) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d) -> (a, b, c, d) -> Bool Source #

(/=) :: (a, b, c, d) -> (a, b, c, d) -> Bool Source #

Eq (f (g a)) => Eq (Compose f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Compose

Methods

(==) :: Compose f g a -> Compose f g a -> Bool Source #

(/=) :: Compose f g a -> Compose f g a -> Bool Source #

Eq (f (g p)) => Eq ((f :.: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: (f :.: g) p -> (f :.: g) p -> Bool Source #

(/=) :: (f :.: g) p -> (f :.: g) p -> Bool Source #

Eq (f p) => Eq (M1 i c f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: M1 i c f p -> M1 i c f p -> Bool Source #

(/=) :: M1 i c f p -> M1 i c f p -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e) => Eq (a, b, c, d, e) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool Source #

(/=) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f) => Eq (a, b, c, d, e, f) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool Source #

(/=) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g) => Eq (a, b, c, d, e, f, g) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h) => Eq (a, b, c, d, e, f, g, h) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i) => Eq (a, b, c, d, e, f, g, h, i) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j) => Eq (a, b, c, d, e, f, g, h, i, j) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k) => Eq (a, b, c, d, e, f, g, h, i, j, k) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l) => Eq (a, b, c, d, e, f, g, h, i, j, k, l) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m, Eq n) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool Source #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m, Eq n, Eq o) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool Source #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool Source #

class Eq a => Ord a where Source #

The Ord class is used for totally ordered datatypes.

Instances of Ord can be derived for any user-defined datatype whose constituent types are in Ord. The declared order of the constructors in the data declaration determines the ordering in derived Ord instances. The Ordering datatype allows a single comparison to determine the precise ordering of two objects.

Ord, as defined by the Haskell report, implements a total order and has the following properties:

Comparability
x <= y || y <= x = True
Transitivity
if x <= y && y <= z = True, then x <= z = True
Reflexivity
x <= x = True
Antisymmetry
if x <= y && y <= x = True, then x == y = True

The following operator interactions are expected to hold:

  1. x >= y = y <= x
  2. x < y = x <= y && x /= y
  3. x > y = y < x
  4. x < y = compare x y == LT
  5. x > y = compare x y == GT
  6. x == y = compare x y == EQ
  7. min x y == if x <= y then x else y = True
  8. max x y == if x >= y then x else y = True

Note that (7.) and (8.) do not require min and max to return either of their arguments. The result is merely required to equal one of the arguments in terms of (==).

Minimal complete definition: either compare or <=. Using compare can be more efficient for complex types.

Minimal complete definition

compare | (<=)

Methods

compare :: a -> a -> Ordering Source #

(<) :: a -> a -> Bool infix 4 Source #

(<=) :: a -> a -> Bool infix 4 Source #

(>) :: a -> a -> Bool infix 4 Source #

(>=) :: a -> a -> Bool infix 4 Source #

max :: a -> a -> a Source #

min :: a -> a -> a Source #

Instances

Instances details
Ord ByteArray Source #

Non-lexicographic ordering. This compares the lengths of the byte arrays first and uses a lexicographic ordering if the lengths are equal. Subject to change between major versions.

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Ord All Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: All -> All -> Ordering Source #

(<) :: All -> All -> Bool Source #

(<=) :: All -> All -> Bool Source #

(>) :: All -> All -> Bool Source #

(>=) :: All -> All -> Bool Source #

max :: All -> All -> All Source #

min :: All -> All -> All Source #

Ord Any Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Any -> Any -> Ordering Source #

(<) :: Any -> Any -> Bool Source #

(<=) :: Any -> Any -> Bool Source #

(>) :: Any -> Any -> Bool Source #

(>=) :: Any -> Any -> Bool Source #

max :: Any -> Any -> Any Source #

min :: Any -> Any -> Any Source #

Ord SomeTypeRep Source # 
Instance details

Defined in Data.Typeable.Internal

Ord Unique Source # 
Instance details

Defined in Data.Unique

Ord Version Source #

Since: base-2.1

Instance details

Defined in Data.Version

Ord CBool Source # 
Instance details

Defined in Foreign.C.Types

Ord CChar Source # 
Instance details

Defined in Foreign.C.Types

Ord CClock Source # 
Instance details

Defined in Foreign.C.Types

Ord CDouble Source # 
Instance details

Defined in Foreign.C.Types

Ord CFloat Source # 
Instance details

Defined in Foreign.C.Types

Ord CInt Source # 
Instance details

Defined in Foreign.C.Types

Ord CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Ord CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Ord CLLong Source # 
Instance details

Defined in Foreign.C.Types

Ord CLong Source # 
Instance details

Defined in Foreign.C.Types

Ord CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Ord CSChar Source # 
Instance details

Defined in Foreign.C.Types

Ord CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Ord CShort Source # 
Instance details

Defined in Foreign.C.Types

Ord CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Ord CSize Source # 
Instance details

Defined in Foreign.C.Types

Ord CTime Source # 
Instance details

Defined in Foreign.C.Types

Ord CUChar Source # 
Instance details

Defined in Foreign.C.Types

Ord CUInt Source # 
Instance details

Defined in Foreign.C.Types

Ord CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Ord CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Ord CULLong Source # 
Instance details

Defined in Foreign.C.Types

Ord CULong Source # 
Instance details

Defined in Foreign.C.Types

Ord CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Ord CUShort Source # 
Instance details

Defined in Foreign.C.Types

Ord CWchar Source # 
Instance details

Defined in Foreign.C.Types

Ord IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Ord WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Ord Void Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Base

Ord ByteOrder Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ByteOrder

Ord BlockReason Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Ord ThreadId Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.Conc.Sync

Ord ThreadStatus Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Ord TimeoutKey Source # 
Instance details

Defined in GHC.Event.TimeOut

Ord ErrorCall Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Exception

Ord ArithException Source #

Since: base-3.0

Instance details

Defined in GHC.Exception.Type

Ord Fingerprint Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Fingerprint.Type

Ord Associativity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Ord DecidedStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Ord Fixity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Ord SourceStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Ord SourceUnpackedness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Ord SeekMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Device

Ord ArrayException Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Exception

Ord AsyncException Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Exception

Ord ExitCode Source # 
Instance details

Defined in GHC.IO.Exception

Ord BufferMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Handle.Types

Ord Newline Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Handle.Types

Ord NewlineMode Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Handle.Types

Ord IOMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.IOMode

Ord Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Ord Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Ord Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Ord Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Ord SomeChar Source # 
Instance details

Defined in GHC.TypeLits

Ord SomeSymbol Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeLits

Ord SomeNat Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeNats

Ord GeneralCategory Source #

Since: base-2.1

Instance details

Defined in GHC.Unicode

Ord Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Ord Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Ord Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Ord Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Ord CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Ord CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Ord CCc Source # 
Instance details

Defined in System.Posix.Types

Methods

compare :: CCc -> CCc -> Ordering Source #

(<) :: CCc -> CCc -> Bool Source #

(<=) :: CCc -> CCc -> Bool Source #

(>) :: CCc -> CCc -> Bool Source #

(>=) :: CCc -> CCc -> Bool Source #

max :: CCc -> CCc -> CCc Source #

min :: CCc -> CCc -> CCc Source #

Ord CClockId Source # 
Instance details

Defined in System.Posix.Types

Ord CDev Source # 
Instance details

Defined in System.Posix.Types

Ord CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Ord CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Ord CGid Source # 
Instance details

Defined in System.Posix.Types

Ord CId Source # 
Instance details

Defined in System.Posix.Types

Methods

compare :: CId -> CId -> Ordering Source #

(<) :: CId -> CId -> Bool Source #

(<=) :: CId -> CId -> Bool Source #

(>) :: CId -> CId -> Bool Source #

(>=) :: CId -> CId -> Bool Source #

max :: CId -> CId -> CId Source #

min :: CId -> CId -> CId Source #

Ord CIno Source # 
Instance details

Defined in System.Posix.Types

Ord CKey Source # 
Instance details

Defined in System.Posix.Types

Ord CMode Source # 
Instance details

Defined in System.Posix.Types

Ord CNfds Source # 
Instance details

Defined in System.Posix.Types

Ord CNlink Source # 
Instance details

Defined in System.Posix.Types

Ord COff Source # 
Instance details

Defined in System.Posix.Types

Ord CPid Source # 
Instance details

Defined in System.Posix.Types

Ord CRLim Source # 
Instance details

Defined in System.Posix.Types

Ord CSocklen Source # 
Instance details

Defined in System.Posix.Types

Ord CSpeed Source # 
Instance details

Defined in System.Posix.Types

Ord CSsize Source # 
Instance details

Defined in System.Posix.Types

Ord CTcflag Source # 
Instance details

Defined in System.Posix.Types

Ord CTimer Source # 
Instance details

Defined in System.Posix.Types

Ord CUid Source # 
Instance details

Defined in System.Posix.Types

Ord Fd Source # 
Instance details

Defined in System.Posix.Types

Methods

compare :: Fd -> Fd -> Ordering Source #

(<) :: Fd -> Fd -> Bool Source #

(<=) :: Fd -> Fd -> Bool Source #

(>) :: Fd -> Fd -> Bool Source #

(>=) :: Fd -> Fd -> Bool Source #

max :: Fd -> Fd -> Fd Source #

min :: Fd -> Fd -> Fd Source #

Ord BigNat 
Instance details

Defined in GHC.Num.BigNat

Ord Ordering 
Instance details

Defined in GHC.Classes

Ord TyCon 
Instance details

Defined in GHC.Classes

Ord Integer 
Instance details

Defined in GHC.Num.Integer

Ord Natural 
Instance details

Defined in GHC.Num.Natural

Ord () 
Instance details

Defined in GHC.Classes

Methods

compare :: () -> () -> Ordering Source #

(<) :: () -> () -> Bool Source #

(<=) :: () -> () -> Bool Source #

(>) :: () -> () -> Bool Source #

(>=) :: () -> () -> Bool Source #

max :: () -> () -> () Source #

min :: () -> () -> () Source #

Ord Bool 
Instance details

Defined in GHC.Classes

Ord Char 
Instance details

Defined in GHC.Classes

Ord Double

IEEE 754 Double-precision type includes not only numbers, but also positive and negative infinities and a special element called NaN (which can be quiet or signal).

IEEE 754-2008, section 5.11 requires that if at least one of arguments of <=, <, >, >= is NaN then the result of the comparison is False, and instance Ord Double complies with this requirement. This violates the reflexivity: both NaN <= NaN and NaN >= NaN are False.

IEEE 754-2008, section 5.10 defines totalOrder predicate. Unfortunately, compare on Doubles violates the IEEE standard and does not define a total order. More specifically, both compare NaN x and compare x NaN always return GT.

Thus, users must be extremely cautious when using instance Ord Double. For instance, one should avoid ordered containers with keys represented by Double, because data loss and corruption may happen. An IEEE-compliant compare is available in fp-ieee package as TotallyOrdered newtype.

Moving further, the behaviour of min and max with regards to NaN is also non-compliant. IEEE 754-2008, section 5.3.1 defines that quiet NaN should be treated as a missing data by minNum and maxNum functions, for example, minNum(NaN, 1) = minNum(1, NaN) = 1. Some languages such as Java deviate from the standard implementing minNum(NaN, 1) = minNum(1, NaN) = NaN. However, min / max in base are even worse: min NaN 1 is 1, but min 1 NaN is NaN.

IEEE 754-2008 compliant min / max can be found in ieee754 package under minNum / maxNum names. Implementations compliant with minimumNumber / maximumNumber from a newer IEEE 754-2019, section 9.6 are available from fp-ieee package.

Instance details

Defined in GHC.Classes

Ord Float

See instance Ord Double for discussion of deviations from IEEE 754 standard.

Instance details

Defined in GHC.Classes

Ord Int 
Instance details

Defined in GHC.Classes

Methods

compare :: Int -> Int -> Ordering Source #

(<) :: Int -> Int -> Bool Source #

(<=) :: Int -> Int -> Bool Source #

(>) :: Int -> Int -> Bool Source #

(>=) :: Int -> Int -> Bool Source #

max :: Int -> Int -> Int Source #

min :: Int -> Int -> Int Source #

Ord Word 
Instance details

Defined in GHC.Classes

Ord a => Ord (ZipList a) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Ord a => Ord (Identity a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Ord a => Ord (First a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

compare :: First a -> First a -> Ordering Source #

(<) :: First a -> First a -> Bool Source #

(<=) :: First a -> First a -> Bool Source #

(>) :: First a -> First a -> Bool Source #

(>=) :: First a -> First a -> Bool Source #

max :: First a -> First a -> First a Source #

min :: First a -> First a -> First a Source #

Ord a => Ord (Last a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

compare :: Last a -> Last a -> Ordering Source #

(<) :: Last a -> Last a -> Bool Source #

(<=) :: Last a -> Last a -> Bool Source #

(>) :: Last a -> Last a -> Bool Source #

(>=) :: Last a -> Last a -> Bool Source #

max :: Last a -> Last a -> Last a Source #

min :: Last a -> Last a -> Last a Source #

Ord a => Ord (Down a) Source #

Since: base-4.6.0.0

Instance details

Defined in Data.Ord

Methods

compare :: Down a -> Down a -> Ordering Source #

(<) :: Down a -> Down a -> Bool Source #

(<=) :: Down a -> Down a -> Bool Source #

(>) :: Down a -> Down a -> Bool Source #

(>=) :: Down a -> Down a -> Bool Source #

max :: Down a -> Down a -> Down a Source #

min :: Down a -> Down a -> Down a Source #

Ord a => Ord (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

compare :: First a -> First a -> Ordering Source #

(<) :: First a -> First a -> Bool Source #

(<=) :: First a -> First a -> Bool Source #

(>) :: First a -> First a -> Bool Source #

(>=) :: First a -> First a -> Bool Source #

max :: First a -> First a -> First a Source #

min :: First a -> First a -> First a Source #

Ord a => Ord (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

compare :: Last a -> Last a -> Ordering Source #

(<) :: Last a -> Last a -> Bool Source #

(<=) :: Last a -> Last a -> Bool Source #

(>) :: Last a -> Last a -> Bool Source #

(>=) :: Last a -> Last a -> Bool Source #

max :: Last a -> Last a -> Last a Source #

min :: Last a -> Last a -> Last a Source #

Ord a => Ord (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

compare :: Max a -> Max a -> Ordering Source #

(<) :: Max a -> Max a -> Bool Source #

(<=) :: Max a -> Max a -> Bool Source #

(>) :: Max a -> Max a -> Bool Source #

(>=) :: Max a -> Max a -> Bool Source #

max :: Max a -> Max a -> Max a Source #

min :: Max a -> Max a -> Max a Source #

Ord a => Ord (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

compare :: Min a -> Min a -> Ordering Source #

(<) :: Min a -> Min a -> Bool Source #

(<=) :: Min a -> Min a -> Bool Source #

(>) :: Min a -> Min a -> Bool Source #

(>=) :: Min a -> Min a -> Bool Source #

max :: Min a -> Min a -> Min a Source #

min :: Min a -> Min a -> Min a Source #

Ord m => Ord (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Ord a => Ord (Dual a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Dual a -> Dual a -> Ordering Source #

(<) :: Dual a -> Dual a -> Bool Source #

(<=) :: Dual a -> Dual a -> Bool Source #

(>) :: Dual a -> Dual a -> Bool Source #

(>=) :: Dual a -> Dual a -> Bool Source #

max :: Dual a -> Dual a -> Dual a Source #

min :: Dual a -> Dual a -> Dual a Source #

Ord a => Ord (Product a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Ord a => Ord (Sum a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Sum a -> Sum a -> Ordering Source #

(<) :: Sum a -> Sum a -> Bool Source #

(<=) :: Sum a -> Sum a -> Bool Source #

(>) :: Sum a -> Sum a -> Bool Source #

(>=) :: Sum a -> Sum a -> Bool Source #

max :: Sum a -> Sum a -> Sum a Source #

min :: Sum a -> Sum a -> Sum a Source #

Ord (ConstPtr a) Source # 
Instance details

Defined in Foreign.C.ConstPtr

Ord a => Ord (NonEmpty a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Ord (ForeignPtr a) Source #

Since: base-2.1

Instance details

Defined in GHC.ForeignPtr

Ord p => Ord (Par1 p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: Par1 p -> Par1 p -> Ordering Source #

(<) :: Par1 p -> Par1 p -> Bool Source #

(<=) :: Par1 p -> Par1 p -> Bool Source #

(>) :: Par1 p -> Par1 p -> Bool Source #

(>=) :: Par1 p -> Par1 p -> Bool Source #

max :: Par1 p -> Par1 p -> Par1 p Source #

min :: Par1 p -> Par1 p -> Par1 p Source #

Ord (FunPtr a) Source # 
Instance details

Defined in GHC.Ptr

Methods

compare :: FunPtr a -> FunPtr a -> Ordering Source #

(<) :: FunPtr a -> FunPtr a -> Bool Source #

(<=) :: FunPtr a -> FunPtr a -> Bool Source #

(>) :: FunPtr a -> FunPtr a -> Bool Source #

(>=) :: FunPtr a -> FunPtr a -> Bool Source #

max :: FunPtr a -> FunPtr a -> FunPtr a Source #

min :: FunPtr a -> FunPtr a -> FunPtr a Source #

Ord (Ptr a) Source #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

compare :: Ptr a -> Ptr a -> Ordering Source #

(<) :: Ptr a -> Ptr a -> Bool Source #

(<=) :: Ptr a -> Ptr a -> Bool Source #

(>) :: Ptr a -> Ptr a -> Bool Source #

(>=) :: Ptr a -> Ptr a -> Bool Source #

max :: Ptr a -> Ptr a -> Ptr a Source #

min :: Ptr a -> Ptr a -> Ptr a Source #

Integral a => Ord (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

compare :: Ratio a -> Ratio a -> Ordering Source #

(<) :: Ratio a -> Ratio a -> Bool Source #

(<=) :: Ratio a -> Ratio a -> Bool Source #

(>) :: Ratio a -> Ratio a -> Bool Source #

(>=) :: Ratio a -> Ratio a -> Bool Source #

max :: Ratio a -> Ratio a -> Ratio a Source #

min :: Ratio a -> Ratio a -> Ratio a Source #

Ord (SChar c) Source #

Since: base-4.19.0.0

Instance details

Defined in GHC.TypeLits

Methods

compare :: SChar c -> SChar c -> Ordering Source #

(<) :: SChar c -> SChar c -> Bool Source #

(<=) :: SChar c -> SChar c -> Bool Source #

(>) :: SChar c -> SChar c -> Bool Source #

(>=) :: SChar c -> SChar c -> Bool Source #

max :: SChar c -> SChar c -> SChar c Source #

min :: SChar c -> SChar c -> SChar c Source #

Ord (SSymbol s) Source #

Since: base-4.19.0.0

Instance details

Defined in GHC.TypeLits

Ord (SNat n) Source #

Since: base-4.19.0.0

Instance details

Defined in GHC.TypeNats

Methods

compare :: SNat n -> SNat n -> Ordering Source #

(<) :: SNat n -> SNat n -> Bool Source #

(<=) :: SNat n -> SNat n -> Bool Source #

(>) :: SNat n -> SNat n -> Bool Source #

(>=) :: SNat n -> SNat n -> Bool Source #

max :: SNat n -> SNat n -> SNat n Source #

min :: SNat n -> SNat n -> SNat n Source #

Ord a => Ord (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Maybe

Methods

compare :: Maybe a -> Maybe a -> Ordering Source #

(<) :: Maybe a -> Maybe a -> Bool Source #

(<=) :: Maybe a -> Maybe a -> Bool Source #

(>) :: Maybe a -> Maybe a -> Bool Source #

(>=) :: Maybe a -> Maybe a -> Bool Source #

max :: Maybe a -> Maybe a -> Maybe a Source #

min :: Maybe a -> Maybe a -> Maybe a Source #

Ord a => Ord (Solo a) 
Instance details

Defined in GHC.Classes

Methods

compare :: Solo a -> Solo a -> Ordering Source #

(<) :: Solo a -> Solo a -> Bool Source #

(<=) :: Solo a -> Solo a -> Bool Source #

(>) :: Solo a -> Solo a -> Bool Source #

(>=) :: Solo a -> Solo a -> Bool Source #

max :: Solo a -> Solo a -> Solo a Source #

min :: Solo a -> Solo a -> Solo a Source #

Ord a => Ord [a] 
Instance details

Defined in GHC.Classes

Methods

compare :: [a] -> [a] -> Ordering Source #

(<) :: [a] -> [a] -> Bool Source #

(<=) :: [a] -> [a] -> Bool Source #

(>) :: [a] -> [a] -> Bool Source #

(>=) :: [a] -> [a] -> Bool Source #

max :: [a] -> [a] -> [a] Source #

min :: [a] -> [a] -> [a] Source #

(Ord a, Ord b) => Ord (Either a b) Source #

Since: base-2.1

Instance details

Defined in Data.Either

Methods

compare :: Either a b -> Either a b -> Ordering Source #

(<) :: Either a b -> Either a b -> Bool Source #

(<=) :: Either a b -> Either a b -> Bool Source #

(>) :: Either a b -> Either a b -> Bool Source #

(>=) :: Either a b -> Either a b -> Bool Source #

max :: Either a b -> Either a b -> Either a b Source #

min :: Either a b -> Either a b -> Either a b Source #

Ord (Fixed a) Source #

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

compare :: Fixed a -> Fixed a -> Ordering Source #

(<) :: Fixed a -> Fixed a -> Bool Source #

(<=) :: Fixed a -> Fixed a -> Bool Source #

(>) :: Fixed a -> Fixed a -> Bool Source #

(>=) :: Fixed a -> Fixed a -> Bool Source #

max :: Fixed a -> Fixed a -> Fixed a Source #

min :: Fixed a -> Fixed a -> Fixed a Source #

Ord (Proxy s) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

compare :: Proxy s -> Proxy s -> Ordering Source #

(<) :: Proxy s -> Proxy s -> Bool Source #

(<=) :: Proxy s -> Proxy s -> Bool Source #

(>) :: Proxy s -> Proxy s -> Bool Source #

(>=) :: Proxy s -> Proxy s -> Bool Source #

max :: Proxy s -> Proxy s -> Proxy s Source #

min :: Proxy s -> Proxy s -> Proxy s Source #

Ord a => Ord (Arg a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

compare :: Arg a b -> Arg a b -> Ordering Source #

(<) :: Arg a b -> Arg a b -> Bool Source #

(<=) :: Arg a b -> Arg a b -> Bool Source #

(>) :: Arg a b -> Arg a b -> Bool Source #

(>=) :: Arg a b -> Arg a b -> Bool Source #

max :: Arg a b -> Arg a b -> Arg a b Source #

min :: Arg a b -> Arg a b -> Arg a b Source #

Ord (TypeRep a) Source #

Since: base-4.4.0.0

Instance details

Defined in Data.Typeable.Internal

(Ix i, Ord e) => Ord (Array i e) Source #

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

compare :: Array i e -> Array i e -> Ordering Source #

(<) :: Array i e -> Array i e -> Bool Source #

(<=) :: Array i e -> Array i e -> Bool Source #

(>) :: Array i e -> Array i e -> Bool Source #

(>=) :: Array i e -> Array i e -> Bool Source #

max :: Array i e -> Array i e -> Array i e Source #

min :: Array i e -> Array i e -> Array i e Source #

Ord (U1 p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: U1 p -> U1 p -> Ordering Source #

(<) :: U1 p -> U1 p -> Bool Source #

(<=) :: U1 p -> U1 p -> Bool Source #

(>) :: U1 p -> U1 p -> Bool Source #

(>=) :: U1 p -> U1 p -> Bool Source #

max :: U1 p -> U1 p -> U1 p Source #

min :: U1 p -> U1 p -> U1 p Source #

Ord (V1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: V1 p -> V1 p -> Ordering Source #

(<) :: V1 p -> V1 p -> Bool Source #

(<=) :: V1 p -> V1 p -> Bool Source #

(>) :: V1 p -> V1 p -> Bool Source #

(>=) :: V1 p -> V1 p -> Bool Source #

max :: V1 p -> V1 p -> V1 p Source #

min :: V1 p -> V1 p -> V1 p Source #

(Ord a, Ord b) => Ord (a, b) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b) -> (a, b) -> Ordering Source #

(<) :: (a, b) -> (a, b) -> Bool Source #

(<=) :: (a, b) -> (a, b) -> Bool Source #

(>) :: (a, b) -> (a, b) -> Bool Source #

(>=) :: (a, b) -> (a, b) -> Bool Source #

max :: (a, b) -> (a, b) -> (a, b) Source #

min :: (a, b) -> (a, b) -> (a, b) Source #

Ord a => Ord (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

compare :: Const a b -> Const a b -> Ordering Source #

(<) :: Const a b -> Const a b -> Bool Source #

(<=) :: Const a b -> Const a b -> Bool Source #

(>) :: Const a b -> Const a b -> Bool Source #

(>=) :: Const a b -> Const a b -> Bool Source #

max :: Const a b -> Const a b -> Const a b Source #

min :: Const a b -> Const a b -> Const a b Source #

Ord (f a) => Ord (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

compare :: Ap f a -> Ap f a -> Ordering Source #

(<) :: Ap f a -> Ap f a -> Bool Source #

(<=) :: Ap f a -> Ap f a -> Bool Source #

(>) :: Ap f a -> Ap f a -> Bool Source #

(>=) :: Ap f a -> Ap f a -> Bool Source #

max :: Ap f a -> Ap f a -> Ap f a Source #

min :: Ap f a -> Ap f a -> Ap f a Source #

Ord (f a) => Ord (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Alt f a -> Alt f a -> Ordering Source #

(<) :: Alt f a -> Alt f a -> Bool Source #

(<=) :: Alt f a -> Alt f a -> Bool Source #

(>) :: Alt f a -> Alt f a -> Bool Source #

(>=) :: Alt f a -> Alt f a -> Bool Source #

max :: Alt f a -> Alt f a -> Alt f a Source #

min :: Alt f a -> Alt f a -> Alt f a Source #

Ord (Coercion a b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Coercion

Methods

compare :: Coercion a b -> Coercion a b -> Ordering Source #

(<) :: Coercion a b -> Coercion a b -> Bool Source #

(<=) :: Coercion a b -> Coercion a b -> Bool Source #

(>) :: Coercion a b -> Coercion a b -> Bool Source #

(>=) :: Coercion a b -> Coercion a b -> Bool Source #

max :: Coercion a b -> Coercion a b -> Coercion a b Source #

min :: Coercion a b -> Coercion a b -> Coercion a b Source #

Ord (a :~: b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

compare :: (a :~: b) -> (a :~: b) -> Ordering Source #

(<) :: (a :~: b) -> (a :~: b) -> Bool Source #

(<=) :: (a :~: b) -> (a :~: b) -> Bool Source #

(>) :: (a :~: b) -> (a :~: b) -> Bool Source #

(>=) :: (a :~: b) -> (a :~: b) -> Bool Source #

max :: (a :~: b) -> (a :~: b) -> a :~: b Source #

min :: (a :~: b) -> (a :~: b) -> a :~: b Source #

(Generic1 f, Ord (Rep1 f a)) => Ord (Generically1 f a) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.Generics

Ord (f p) => Ord (Rec1 f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: Rec1 f p -> Rec1 f p -> Ordering Source #

(<) :: Rec1 f p -> Rec1 f p -> Bool Source #

(<=) :: Rec1 f p -> Rec1 f p -> Bool Source #

(>) :: Rec1 f p -> Rec1 f p -> Bool Source #

(>=) :: Rec1 f p -> Rec1 f p -> Bool Source #

max :: Rec1 f p -> Rec1 f p -> Rec1 f p Source #

min :: Rec1 f p -> Rec1 f p -> Rec1 f p Source #

Ord (URec (Ptr ()) p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec (Ptr ()) p -> URec (Ptr ()) p -> Ordering Source #

(<) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(<=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(>) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(>=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

max :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p Source #

min :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p Source #

Ord (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec Char p -> URec Char p -> Ordering Source #

(<) :: URec Char p -> URec Char p -> Bool Source #

(<=) :: URec Char p -> URec Char p -> Bool Source #

(>) :: URec Char p -> URec Char p -> Bool Source #

(>=) :: URec Char p -> URec Char p -> Bool Source #

max :: URec Char p -> URec Char p -> URec Char p Source #

min :: URec Char p -> URec Char p -> URec Char p Source #

Ord (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Ord (URec Float p) Source # 
Instance details

Defined in GHC.Generics

Ord (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec Int p -> URec Int p -> Ordering Source #

(<) :: URec Int p -> URec Int p -> Bool Source #

(<=) :: URec Int p -> URec Int p -> Bool Source #

(>) :: URec Int p -> URec Int p -> Bool Source #

(>=) :: URec Int p -> URec Int p -> Bool Source #

max :: URec Int p -> URec Int p -> URec Int p Source #

min :: URec Int p -> URec Int p -> URec Int p Source #

Ord (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec Word p -> URec Word p -> Ordering Source #

(<) :: URec Word p -> URec Word p -> Bool Source #

(<=) :: URec Word p -> URec Word p -> Bool Source #

(>) :: URec Word p -> URec Word p -> Bool Source #

(>=) :: URec Word p -> URec Word p -> Bool Source #

max :: URec Word p -> URec Word p -> URec Word p Source #

min :: URec Word p -> URec Word p -> URec Word p Source #

(Ord a, Ord b, Ord c) => Ord (a, b, c) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c) -> (a, b, c) -> Ordering Source #

(<) :: (a, b, c) -> (a, b, c) -> Bool Source #

(<=) :: (a, b, c) -> (a, b, c) -> Bool Source #

(>) :: (a, b, c) -> (a, b, c) -> Bool Source #

(>=) :: (a, b, c) -> (a, b, c) -> Bool Source #

max :: (a, b, c) -> (a, b, c) -> (a, b, c) Source #

min :: (a, b, c) -> (a, b, c) -> (a, b, c) Source #

(Ord (f a), Ord (g a)) => Ord (Product f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Product

Methods

compare :: Product f g a -> Product f g a -> Ordering Source #

(<) :: Product f g a -> Product f g a -> Bool Source #

(<=) :: Product f g a -> Product f g a -> Bool Source #

(>) :: Product f g a -> Product f g a -> Bool Source #

(>=) :: Product f g a -> Product f g a -> Bool Source #

max :: Product f g a -> Product f g a -> Product f g a Source #

min :: Product f g a -> Product f g a -> Product f g a Source #

(Ord (f a), Ord (g a)) => Ord (Sum f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Sum

Methods

compare :: Sum f g a -> Sum f g a -> Ordering Source #

(<) :: Sum f g a -> Sum f g a -> Bool Source #

(<=) :: Sum f g a -> Sum f g a -> Bool Source #

(>) :: Sum f g a -> Sum f g a -> Bool Source #

(>=) :: Sum f g a -> Sum f g a -> Bool Source #

max :: Sum f g a -> Sum f g a -> Sum f g a Source #

min :: Sum f g a -> Sum f g a -> Sum f g a Source #

Ord (a :~~: b) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

compare :: (a :~~: b) -> (a :~~: b) -> Ordering Source #

(<) :: (a :~~: b) -> (a :~~: b) -> Bool Source #

(<=) :: (a :~~: b) -> (a :~~: b) -> Bool Source #

(>) :: (a :~~: b) -> (a :~~: b) -> Bool Source #

(>=) :: (a :~~: b) -> (a :~~: b) -> Bool Source #

max :: (a :~~: b) -> (a :~~: b) -> a :~~: b Source #

min :: (a :~~: b) -> (a :~~: b) -> a :~~: b Source #

(Ord (f p), Ord (g p)) => Ord ((f :*: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: (f :*: g) p -> (f :*: g) p -> Ordering Source #

(<) :: (f :*: g) p -> (f :*: g) p -> Bool Source #

(<=) :: (f :*: g) p -> (f :*: g) p -> Bool Source #

(>) :: (f :*: g) p -> (f :*: g) p -> Bool Source #

(>=) :: (f :*: g) p -> (f :*: g) p -> Bool Source #

max :: (f :*: g) p -> (f :*: g) p -> (f :*: g) p Source #

min :: (f :*: g) p -> (f :*: g) p -> (f :*: g) p Source #

(Ord (f p), Ord (g p)) => Ord ((f :+: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: (f :+: g) p -> (f :+: g) p -> Ordering Source #

(<) :: (f :+: g) p -> (f :+: g) p -> Bool Source #

(<=) :: (f :+: g) p -> (f :+: g) p -> Bool Source #

(>) :: (f :+: g) p -> (f :+: g) p -> Bool Source #

(>=) :: (f :+: g) p -> (f :+: g) p -> Bool Source #

max :: (f :+: g) p -> (f :+: g) p -> (f :+: g) p Source #

min :: (f :+: g) p -> (f :+: g) p -> (f :+: g) p Source #

Ord c => Ord (K1 i c p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: K1 i c p -> K1 i c p -> Ordering Source #

(<) :: K1 i c p -> K1 i c p -> Bool Source #

(<=) :: K1 i c p -> K1 i c p -> Bool Source #

(>) :: K1 i c p -> K1 i c p -> Bool Source #

(>=) :: K1 i c p -> K1 i c p -> Bool Source #

max :: K1 i c p -> K1 i c p -> K1 i c p Source #

min :: K1 i c p -> K1 i c p -> K1 i c p Source #

(Ord a, Ord b, Ord c, Ord d) => Ord (a, b, c, d) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d) -> (a, b, c, d) -> Ordering Source #

(<) :: (a, b, c, d) -> (a, b, c, d) -> Bool Source #

(<=) :: (a, b, c, d) -> (a, b, c, d) -> Bool Source #

(>) :: (a, b, c, d) -> (a, b, c, d) -> Bool Source #

(>=) :: (a, b, c, d) -> (a, b, c, d) -> Bool Source #

max :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) Source #

min :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) Source #

Ord (f (g a)) => Ord (Compose f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Compose

Methods

compare :: Compose f g a -> Compose f g a -> Ordering Source #

(<) :: Compose f g a -> Compose f g a -> Bool Source #

(<=) :: Compose f g a -> Compose f g a -> Bool Source #

(>) :: Compose f g a -> Compose f g a -> Bool Source #

(>=) :: Compose f g a -> Compose f g a -> Bool Source #

max :: Compose f g a -> Compose f g a -> Compose f g a Source #

min :: Compose f g a -> Compose f g a -> Compose f g a Source #

Ord (f (g p)) => Ord ((f :.: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: (f :.: g) p -> (f :.: g) p -> Ordering Source #

(<) :: (f :.: g) p -> (f :.: g) p -> Bool Source #

(<=) :: (f :.: g) p -> (f :.: g) p -> Bool Source #

(>) :: (f :.: g) p -> (f :.: g) p -> Bool Source #

(>=) :: (f :.: g) p -> (f :.: g) p -> Bool Source #

max :: (f :.: g) p -> (f :.: g) p -> (f :.: g) p Source #

min :: (f :.: g) p -> (f :.: g) p -> (f :.: g) p Source #

Ord (f p) => Ord (M1 i c f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: M1 i c f p -> M1 i c f p -> Ordering Source #

(<) :: M1 i c f p -> M1 i c f p -> Bool Source #

(<=) :: M1 i c f p -> M1 i c f p -> Bool Source #

(>) :: M1 i c f p -> M1 i c f p -> Bool Source #

(>=) :: M1 i c f p -> M1 i c f p -> Bool Source #

max :: M1 i c f p -> M1 i c f p -> M1 i c f p Source #

min :: M1 i c f p -> M1 i c f p -> M1 i c f p Source #

(Ord a, Ord b, Ord c, Ord d, Ord e) => Ord (a, b, c, d, e) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e) -> (a, b, c, d, e) -> Ordering Source #

(<) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool Source #

(<=) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool Source #

(>) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool Source #

(>=) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool Source #

max :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) Source #

min :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f) => Ord (a, b, c, d, e, f) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Ordering Source #

(<) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool Source #

(<=) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool Source #

(>) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool Source #

(>=) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool Source #

max :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> (a, b, c, d, e, f) Source #

min :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> (a, b, c, d, e, f) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g) => Ord (a, b, c, d, e, f, g) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool Source #

(>) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool Source #

max :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) Source #

min :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h) => Ord (a, b, c, d, e, f, g, h) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool Source #

max :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) Source #

min :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i) => Ord (a, b, c, d, e, f, g, h, i) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) Source #

min :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j) => Ord (a, b, c, d, e, f, g, h, i, j) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) Source #

min :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k) => Ord (a, b, c, d, e, f, g, h, i, j, k) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) Source #

min :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l) => Ord (a, b, c, d, e, f, g, h, i, j, k, l) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) Source #

min :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

min :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m, Ord n) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m, n) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

min :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m, Ord n, Ord o) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Ordering Source #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool Source #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool Source #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool Source #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool Source #

max :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

min :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

class Enum a where Source #

Class Enum defines operations on sequentially ordered types.

The enumFrom... methods are used in Haskell's translation of arithmetic sequences.

Instances of Enum may be derived for any enumeration type (types whose constructors have no fields). The nullary constructors are assumed to be numbered left-to-right by fromEnum from 0 through n-1. See Chapter 10 of the Haskell Report for more details.

For any type that is an instance of class Bounded as well as Enum, the following should hold:

   enumFrom     x   = enumFromTo     x maxBound
   enumFromThen x y = enumFromThenTo x y bound
     where
       bound | fromEnum y >= fromEnum x = maxBound
             | otherwise                = minBound

Minimal complete definition

toEnum, fromEnum

Methods

succ :: a -> a Source #

the successor of a value. For numeric types, succ adds 1.

pred :: a -> a Source #

the predecessor of a value. For numeric types, pred subtracts 1.

toEnum :: Int -> a Source #

Convert from an Int.

fromEnum :: a -> Int Source #

Convert to an Int. It is implementation-dependent what fromEnum returns when applied to a value that is too large to fit in an Int.

enumFrom :: a -> [a] Source #

Used in Haskell's translation of [n..] with [n..] = enumFrom n, a possible implementation being enumFrom n = n : enumFrom (succ n). For example:

  • enumFrom 4 :: [Integer] = [4,5,6,7,...]
  • enumFrom 6 :: [Int] = [6,7,8,9,...,maxBound :: Int]

enumFromThen :: a -> a -> [a] Source #

Used in Haskell's translation of [n,n'..] with [n,n'..] = enumFromThen n n', a possible implementation being enumFromThen n n' = n : n' : worker (f x) (f x n'), worker s v = v : worker s (s v), x = fromEnum n' - fromEnum n and f n y | n > 0 = f (n - 1) (succ y) | n < 0 = f (n + 1) (pred y) | otherwise = y For example:

  • enumFromThen 4 6 :: [Integer] = [4,6,8,10...]
  • enumFromThen 6 2 :: [Int] = [6,2,-2,-6,...,minBound :: Int]

enumFromTo :: a -> a -> [a] Source #

Used in Haskell's translation of [n..m] with [n..m] = enumFromTo n m, a possible implementation being enumFromTo n m | n <= m = n : enumFromTo (succ n) m | otherwise = []. For example:

  • enumFromTo 6 10 :: [Int] = [6,7,8,9,10]
  • enumFromTo 42 1 :: [Integer] = []

enumFromThenTo :: a -> a -> a -> [a] Source #

Used in Haskell's translation of [n,n'..m] with [n,n'..m] = enumFromThenTo n n' m, a possible implementation being enumFromThenTo n n' m = worker (f x) (c x) n m, x = fromEnum n' - fromEnum n, c x = bool (>=) ((x 0) f n y | n > 0 = f (n - 1) (succ y) | n < 0 = f (n + 1) (pred y) | otherwise = y and worker s c v m | c v m = v : worker s c (s v) m | otherwise = [] For example:

  • enumFromThenTo 4 2 -6 :: [Integer] = [4,2,0,-2,-4,-6]
  • enumFromThenTo 6 8 2 :: [Int] = []

Instances

Instances details
Enum CBool Source # 
Instance details

Defined in Foreign.C.Types

Enum CChar Source # 
Instance details

Defined in Foreign.C.Types

Enum CClock Source # 
Instance details

Defined in Foreign.C.Types

Enum CDouble Source # 
Instance details

Defined in Foreign.C.Types

Enum CFloat Source # 
Instance details

Defined in Foreign.C.Types

Enum CInt Source # 
Instance details

Defined in Foreign.C.Types

Enum CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Enum CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Enum CLLong Source # 
Instance details

Defined in Foreign.C.Types

Enum CLong Source # 
Instance details

Defined in Foreign.C.Types

Enum CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Enum CSChar Source # 
Instance details

Defined in Foreign.C.Types

Enum CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Enum CShort Source # 
Instance details

Defined in Foreign.C.Types

Enum CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Enum CSize Source # 
Instance details

Defined in Foreign.C.Types

Enum CTime Source # 
Instance details

Defined in Foreign.C.Types

Enum CUChar Source # 
Instance details

Defined in Foreign.C.Types

Enum CUInt Source # 
Instance details

Defined in Foreign.C.Types

Enum CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Enum CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Enum CULLong Source # 
Instance details

Defined in Foreign.C.Types

Enum CULong Source # 
Instance details

Defined in Foreign.C.Types

Enum CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Enum CUShort Source # 
Instance details

Defined in Foreign.C.Types

Enum CWchar Source # 
Instance details

Defined in Foreign.C.Types

Enum IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Enum WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Enum ByteOrder Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ByteOrder

Enum Associativity Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Enum DecidedStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Enum SourceStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Enum SourceUnpackedness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Enum SeekMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Device

Enum IOMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.IOMode

Enum Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Enum DoCostCentres Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Enum DoHeapProfile Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Enum DoTrace Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Enum GiveGCStats Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Enum IoSubSystem Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.RTS.Flags

Enum GeneralCategory Source #

Since: base-2.1

Instance details

Defined in GHC.Unicode

Enum Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Enum CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Enum CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Enum CCc Source # 
Instance details

Defined in System.Posix.Types

Enum CClockId Source # 
Instance details

Defined in System.Posix.Types

Enum CDev Source # 
Instance details

Defined in System.Posix.Types

Enum CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Enum CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Enum CGid Source # 
Instance details

Defined in System.Posix.Types

Enum CId Source # 
Instance details

Defined in System.Posix.Types

Enum CIno Source # 
Instance details

Defined in System.Posix.Types

Enum CKey Source # 
Instance details

Defined in System.Posix.Types

Enum CMode Source # 
Instance details

Defined in System.Posix.Types

Enum CNfds Source # 
Instance details

Defined in System.Posix.Types

Enum CNlink Source # 
Instance details

Defined in System.Posix.Types

Enum COff Source # 
Instance details

Defined in System.Posix.Types

Enum CPid Source # 
Instance details

Defined in System.Posix.Types

Enum CRLim Source # 
Instance details

Defined in System.Posix.Types

Enum CSocklen Source # 
Instance details

Defined in System.Posix.Types

Enum CSpeed Source # 
Instance details

Defined in System.Posix.Types

Enum CSsize Source # 
Instance details

Defined in System.Posix.Types

Enum CTcflag Source # 
Instance details

Defined in System.Posix.Types

Enum CUid Source # 
Instance details

Defined in System.Posix.Types

Enum Fd Source # 
Instance details

Defined in System.Posix.Types

Methods

succ :: Fd -> Fd Source #

pred :: Fd -> Fd Source #

toEnum :: Int -> Fd Source #

fromEnum :: Fd -> Int Source #

enumFrom :: Fd -> [Fd] Source #

enumFromThen :: Fd -> Fd -> [Fd] Source #

enumFromTo :: Fd -> Fd -> [Fd] Source #

enumFromThenTo :: Fd -> Fd -> Fd -> [Fd] Source #

Enum Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Natural Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Enum

Enum () Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: () -> () Source #

pred :: () -> () Source #

toEnum :: Int -> () Source #

fromEnum :: () -> Int Source #

enumFrom :: () -> [()] Source #

enumFromThen :: () -> () -> [()] Source #

enumFromTo :: () -> () -> [()] Source #

enumFromThenTo :: () -> () -> () -> [()] Source #

Enum Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Char Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Double Source #

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Float

Enum Float Source #

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5 :: Float]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Float

Enum Int Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Levity Source #

Since: base-4.16.0.0

Instance details

Defined in GHC.Enum

Enum VecCount Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Enum

Enum VecElem Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Enum

Enum Word Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum a => Enum (And a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

succ :: And a -> And a Source #

pred :: And a -> And a Source #

toEnum :: Int -> And a Source #

fromEnum :: And a -> Int Source #

enumFrom :: And a -> [And a] Source #

enumFromThen :: And a -> And a -> [And a] Source #

enumFromTo :: And a -> And a -> [And a] Source #

enumFromThenTo :: And a -> And a -> And a -> [And a] Source #

Enum a => Enum (Iff a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

succ :: Iff a -> Iff a Source #

pred :: Iff a -> Iff a Source #

toEnum :: Int -> Iff a Source #

fromEnum :: Iff a -> Int Source #

enumFrom :: Iff a -> [Iff a] Source #

enumFromThen :: Iff a -> Iff a -> [Iff a] Source #

enumFromTo :: Iff a -> Iff a -> [Iff a] Source #

enumFromThenTo :: Iff a -> Iff a -> Iff a -> [Iff a] Source #

Enum a => Enum (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

succ :: Ior a -> Ior a Source #

pred :: Ior a -> Ior a Source #

toEnum :: Int -> Ior a Source #

fromEnum :: Ior a -> Int Source #

enumFrom :: Ior a -> [Ior a] Source #

enumFromThen :: Ior a -> Ior a -> [Ior a] Source #

enumFromTo :: Ior a -> Ior a -> [Ior a] Source #

enumFromThenTo :: Ior a -> Ior a -> Ior a -> [Ior a] Source #

Enum a => Enum (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

succ :: Xor a -> Xor a Source #

pred :: Xor a -> Xor a Source #

toEnum :: Int -> Xor a Source #

fromEnum :: Xor a -> Int Source #

enumFrom :: Xor a -> [Xor a] Source #

enumFromThen :: Xor a -> Xor a -> [Xor a] Source #

enumFromTo :: Xor a -> Xor a -> [Xor a] Source #

enumFromThenTo :: Xor a -> Xor a -> Xor a -> [Xor a] Source #

Enum a => Enum (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

(Enum a, Bounded a, Eq a) => Enum (Down a) Source #

Swaps succ and pred of the underlying type.

Since: base-4.18.0.0

Instance details

Defined in Data.Ord

Methods

succ :: Down a -> Down a Source #

pred :: Down a -> Down a Source #

toEnum :: Int -> Down a Source #

fromEnum :: Down a -> Int Source #

enumFrom :: Down a -> [Down a] Source #

enumFromThen :: Down a -> Down a -> [Down a] Source #

enumFromTo :: Down a -> Down a -> [Down a] Source #

enumFromThenTo :: Down a -> Down a -> Down a -> [Down a] Source #

Enum a => Enum (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: First a -> First a Source #

pred :: First a -> First a Source #

toEnum :: Int -> First a Source #

fromEnum :: First a -> Int Source #

enumFrom :: First a -> [First a] Source #

enumFromThen :: First a -> First a -> [First a] Source #

enumFromTo :: First a -> First a -> [First a] Source #

enumFromThenTo :: First a -> First a -> First a -> [First a] Source #

Enum a => Enum (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Last a -> Last a Source #

pred :: Last a -> Last a Source #

toEnum :: Int -> Last a Source #

fromEnum :: Last a -> Int Source #

enumFrom :: Last a -> [Last a] Source #

enumFromThen :: Last a -> Last a -> [Last a] Source #

enumFromTo :: Last a -> Last a -> [Last a] Source #

enumFromThenTo :: Last a -> Last a -> Last a -> [Last a] Source #

Enum a => Enum (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Max a -> Max a Source #

pred :: Max a -> Max a Source #

toEnum :: Int -> Max a Source #

fromEnum :: Max a -> Int Source #

enumFrom :: Max a -> [Max a] Source #

enumFromThen :: Max a -> Max a -> [Max a] Source #

enumFromTo :: Max a -> Max a -> [Max a] Source #

enumFromThenTo :: Max a -> Max a -> Max a -> [Max a] Source #

Enum a => Enum (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Min a -> Min a Source #

pred :: Min a -> Min a Source #

toEnum :: Int -> Min a Source #

fromEnum :: Min a -> Int Source #

enumFrom :: Min a -> [Min a] Source #

enumFromThen :: Min a -> Min a -> [Min a] Source #

enumFromTo :: Min a -> Min a -> [Min a] Source #

enumFromThenTo :: Min a -> Min a -> Min a -> [Min a] Source #

Enum a => Enum (WrappedMonoid a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Integral a => Enum (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

succ :: Ratio a -> Ratio a Source #

pred :: Ratio a -> Ratio a Source #

toEnum :: Int -> Ratio a Source #

fromEnum :: Ratio a -> Int Source #

enumFrom :: Ratio a -> [Ratio a] Source #

enumFromThen :: Ratio a -> Ratio a -> [Ratio a] Source #

enumFromTo :: Ratio a -> Ratio a -> [Ratio a] Source #

enumFromThenTo :: Ratio a -> Ratio a -> Ratio a -> [Ratio a] Source #

Enum a => Enum (Solo a) Source # 
Instance details

Defined in GHC.Enum

Methods

succ :: Solo a -> Solo a Source #

pred :: Solo a -> Solo a Source #

toEnum :: Int -> Solo a Source #

fromEnum :: Solo a -> Int Source #

enumFrom :: Solo a -> [Solo a] Source #

enumFromThen :: Solo a -> Solo a -> [Solo a] Source #

enumFromTo :: Solo a -> Solo a -> [Solo a] Source #

enumFromThenTo :: Solo a -> Solo a -> Solo a -> [Solo a] Source #

Enum (Fixed a) Source #

Recall that, for numeric types, succ and pred typically add and subtract 1, respectively. This is not true in the case of Fixed, whose successor and predecessor functions intuitively return the "next" and "previous" values in the enumeration. The results of these functions thus depend on the resolution of the Fixed value. For example, when enumerating values of resolution 10^-3 of type Milli = Fixed E3,

  succ (0.000 :: Milli) == 0.001

and likewise

  pred (0.000 :: Milli) == -0.001

In other words, succ and pred increment and decrement a fixed-precision value by the least amount such that the value's resolution is unchanged. For example, 10^-12 is the smallest (positive) amount that can be added to a value of type Pico = Fixed E12 without changing its resolution, and so

  succ (0.000000000000 :: Pico) == 0.000000000001

and similarly

  pred (0.000000000000 :: Pico) == -0.000000000001

This is worth bearing in mind when defining Fixed arithmetic sequences. In particular, you may be forgiven for thinking the sequence

  [1..10] :: [Pico]

evaluates to [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] :: [Pico].

However, this is not true. On the contrary, similarly to the above implementations of succ and pred, enumFromTo :: Pico -> Pico -> [Pico] has a "step size" of 10^-12. Hence, the list [1..10] :: [Pico] has the form

  [1.000000000000, 1.00000000001, 1.00000000002, ..., 10.000000000000]

and contains 9 * 10^12 + 1 values.

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

succ :: Fixed a -> Fixed a Source #

pred :: Fixed a -> Fixed a Source #

toEnum :: Int -> Fixed a Source #

fromEnum :: Fixed a -> Int Source #

enumFrom :: Fixed a -> [Fixed a] Source #

enumFromThen :: Fixed a -> Fixed a -> [Fixed a] Source #

enumFromTo :: Fixed a -> Fixed a -> [Fixed a] Source #

enumFromThenTo :: Fixed a -> Fixed a -> Fixed a -> [Fixed a] Source #

Enum (Proxy s) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

succ :: Proxy s -> Proxy s Source #

pred :: Proxy s -> Proxy s Source #

toEnum :: Int -> Proxy s Source #

fromEnum :: Proxy s -> Int Source #

enumFrom :: Proxy s -> [Proxy s] Source #

enumFromThen :: Proxy s -> Proxy s -> [Proxy s] Source #

enumFromTo :: Proxy s -> Proxy s -> [Proxy s] Source #

enumFromThenTo :: Proxy s -> Proxy s -> Proxy s -> [Proxy s] Source #

Enum a => Enum (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

succ :: Const a b -> Const a b Source #

pred :: Const a b -> Const a b Source #

toEnum :: Int -> Const a b Source #

fromEnum :: Const a b -> Int Source #

enumFrom :: Const a b -> [Const a b] Source #

enumFromThen :: Const a b -> Const a b -> [Const a b] Source #

enumFromTo :: Const a b -> Const a b -> [Const a b] Source #

enumFromThenTo :: Const a b -> Const a b -> Const a b -> [Const a b] Source #

Enum (f a) => Enum (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

succ :: Ap f a -> Ap f a Source #

pred :: Ap f a -> Ap f a Source #

toEnum :: Int -> Ap f a Source #

fromEnum :: Ap f a -> Int Source #

enumFrom :: Ap f a -> [Ap f a] Source #

enumFromThen :: Ap f a -> Ap f a -> [Ap f a] Source #

enumFromTo :: Ap f a -> Ap f a -> [Ap f a] Source #

enumFromThenTo :: Ap f a -> Ap f a -> Ap f a -> [Ap f a] Source #

Enum (f a) => Enum (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

succ :: Alt f a -> Alt f a Source #

pred :: Alt f a -> Alt f a Source #

toEnum :: Int -> Alt f a Source #

fromEnum :: Alt f a -> Int Source #

enumFrom :: Alt f a -> [Alt f a] Source #

enumFromThen :: Alt f a -> Alt f a -> [Alt f a] Source #

enumFromTo :: Alt f a -> Alt f a -> [Alt f a] Source #

enumFromThenTo :: Alt f a -> Alt f a -> Alt f a -> [Alt f a] Source #

Coercible a b => Enum (Coercion a b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Coercion

Methods

succ :: Coercion a b -> Coercion a b Source #

pred :: Coercion a b -> Coercion a b Source #

toEnum :: Int -> Coercion a b Source #

fromEnum :: Coercion a b -> Int Source #

enumFrom :: Coercion a b -> [Coercion a b] Source #

enumFromThen :: Coercion a b -> Coercion a b -> [Coercion a b] Source #

enumFromTo :: Coercion a b -> Coercion a b -> [Coercion a b] Source #

enumFromThenTo :: Coercion a b -> Coercion a b -> Coercion a b -> [Coercion a b] Source #

a ~ b => Enum (a :~: b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

succ :: (a :~: b) -> a :~: b Source #

pred :: (a :~: b) -> a :~: b Source #

toEnum :: Int -> a :~: b Source #

fromEnum :: (a :~: b) -> Int Source #

enumFrom :: (a :~: b) -> [a :~: b] Source #

enumFromThen :: (a :~: b) -> (a :~: b) -> [a :~: b] Source #

enumFromTo :: (a :~: b) -> (a :~: b) -> [a :~: b] Source #

enumFromThenTo :: (a :~: b) -> (a :~: b) -> (a :~: b) -> [a :~: b] Source #

a ~~ b => Enum (a :~~: b) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

succ :: (a :~~: b) -> a :~~: b Source #

pred :: (a :~~: b) -> a :~~: b Source #

toEnum :: Int -> a :~~: b Source #

fromEnum :: (a :~~: b) -> Int Source #

enumFrom :: (a :~~: b) -> [a :~~: b] Source #

enumFromThen :: (a :~~: b) -> (a :~~: b) -> [a :~~: b] Source #

enumFromTo :: (a :~~: b) -> (a :~~: b) -> [a :~~: b] Source #

enumFromThenTo :: (a :~~: b) -> (a :~~: b) -> (a :~~: b) -> [a :~~: b] Source #

Enum (f (g a)) => Enum (Compose f g a) Source #

Since: base-4.19.0.0

Instance details

Defined in Data.Functor.Compose

Methods

succ :: Compose f g a -> Compose f g a Source #

pred :: Compose f g a -> Compose f g a Source #

toEnum :: Int -> Compose f g a Source #

fromEnum :: Compose f g a -> Int Source #

enumFrom :: Compose f g a -> [Compose f g a] Source #

enumFromThen :: Compose f g a -> Compose f g a -> [Compose f g a] Source #

enumFromTo :: Compose f g a -> Compose f g a -> [Compose f g a] Source #

enumFromThenTo :: Compose f g a -> Compose f g a -> Compose f g a -> [Compose f g a] Source #

class Bounded a where Source #

The Bounded class is used to name the upper and lower limits of a type. Ord is not a superclass of Bounded since types that are not totally ordered may also have upper and lower bounds.

The Bounded class may be derived for any enumeration type; minBound is the first constructor listed in the data declaration and maxBound is the last. Bounded may also be derived for single-constructor datatypes whose constituent types are in Bounded.

Methods

minBound :: a Source #

maxBound :: a Source #

Instances

Instances details
Bounded All Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Bounded Any Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Bounded CBool Source # 
Instance details

Defined in Foreign.C.Types

Bounded CChar Source # 
Instance details

Defined in Foreign.C.Types

Bounded CInt Source # 
Instance details

Defined in Foreign.C.Types

Bounded CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Bounded CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Bounded CLLong Source # 
Instance details

Defined in Foreign.C.Types

Bounded CLong Source # 
Instance details

Defined in Foreign.C.Types

Bounded CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Bounded CSChar Source # 
Instance details

Defined in Foreign.C.Types

Bounded CShort Source # 
Instance details

Defined in Foreign.C.Types

Bounded CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Bounded CSize Source # 
Instance details

Defined in Foreign.C.Types

Bounded CUChar Source # 
Instance details

Defined in Foreign.C.Types

Bounded CUInt Source # 
Instance details

Defined in Foreign.C.Types

Bounded CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Bounded CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Bounded CULLong Source # 
Instance details

Defined in Foreign.C.Types

Bounded CULong Source # 
Instance details

Defined in Foreign.C.Types

Bounded CUShort Source # 
Instance details

Defined in Foreign.C.Types

Bounded CWchar Source # 
Instance details

Defined in Foreign.C.Types

Bounded IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Bounded WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Bounded ByteOrder Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ByteOrder

Bounded Associativity Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Bounded DecidedStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Bounded SourceStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Bounded SourceUnpackedness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Bounded Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Bounded Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Bounded Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Bounded Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Bounded GeneralCategory Source #

Since: base-2.1

Instance details

Defined in GHC.Unicode

Bounded Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Bounded Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Bounded Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Bounded Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Bounded CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Bounded CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Bounded CClockId Source # 
Instance details

Defined in System.Posix.Types

Bounded CDev Source # 
Instance details

Defined in System.Posix.Types

Bounded CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Bounded CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Bounded CGid Source # 
Instance details

Defined in System.Posix.Types

Bounded CId Source # 
Instance details

Defined in System.Posix.Types

Bounded CIno Source # 
Instance details

Defined in System.Posix.Types

Bounded CKey Source # 
Instance details

Defined in System.Posix.Types

Bounded CMode Source # 
Instance details

Defined in System.Posix.Types

Bounded CNfds Source # 
Instance details

Defined in System.Posix.Types

Bounded CNlink Source # 
Instance details

Defined in System.Posix.Types

Bounded COff Source # 
Instance details

Defined in System.Posix.Types

Bounded CPid Source # 
Instance details

Defined in System.Posix.Types

Bounded CRLim Source # 
Instance details

Defined in System.Posix.Types

Bounded CSocklen Source # 
Instance details

Defined in System.Posix.Types

Bounded CSsize Source # 
Instance details

Defined in System.Posix.Types

Bounded CTcflag Source # 
Instance details

Defined in System.Posix.Types

Bounded CUid Source # 
Instance details

Defined in System.Posix.Types

Bounded Fd Source # 
Instance details

Defined in System.Posix.Types

Bounded Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Bounded () Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: () Source #

maxBound :: () Source #

Bounded Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Bounded Char Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Bounded Int Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Bounded Levity Source #

Since: base-4.16.0.0

Instance details

Defined in GHC.Enum

Bounded VecCount Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Enum

Bounded VecElem Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Enum

Bounded Word Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Bounded a => Bounded (And a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Bounded a => Bounded (Iff a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Bounded a => Bounded (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Bounded a => Bounded (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Bounded a => Bounded (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Bounded a => Bounded (Down a) Source #

Swaps minBound and maxBound of the underlying type.

Since: base-4.14.0.0

Instance details

Defined in Data.Ord

Bounded a => Bounded (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Bounded a => Bounded (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Bounded a => Bounded (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Bounded a => Bounded (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Bounded m => Bounded (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Bounded a => Bounded (Dual a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Bounded a => Bounded (Product a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Bounded a => Bounded (Sum a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Bounded a => Bounded (Solo a) Source # 
Instance details

Defined in GHC.Enum

Bounded (Proxy t) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

(Bounded a, Bounded b) => Bounded (a, b) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b) Source #

maxBound :: (a, b) Source #

Bounded a => Bounded (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

minBound :: Const a b Source #

maxBound :: Const a b Source #

(Applicative f, Bounded a) => Bounded (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

minBound :: Ap f a Source #

maxBound :: Ap f a Source #

Coercible a b => Bounded (Coercion a b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Coercion

a ~ b => Bounded (a :~: b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

minBound :: a :~: b Source #

maxBound :: a :~: b Source #

(Bounded a, Bounded b, Bounded c) => Bounded (a, b, c) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c) Source #

maxBound :: (a, b, c) Source #

a ~~ b => Bounded (a :~~: b) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

minBound :: a :~~: b Source #

maxBound :: a :~~: b Source #

(Bounded a, Bounded b, Bounded c, Bounded d) => Bounded (a, b, c, d) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d) Source #

maxBound :: (a, b, c, d) Source #

Bounded (f (g a)) => Bounded (Compose f g a) Source #

Since: base-4.19.0.0

Instance details

Defined in Data.Functor.Compose

Methods

minBound :: Compose f g a Source #

maxBound :: Compose f g a Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e) => Bounded (a, b, c, d, e) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e) Source #

maxBound :: (a, b, c, d, e) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f) => Bounded (a, b, c, d, e, f) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f) Source #

maxBound :: (a, b, c, d, e, f) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g) => Bounded (a, b, c, d, e, f, g) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g) Source #

maxBound :: (a, b, c, d, e, f, g) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h) => Bounded (a, b, c, d, e, f, g, h) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h) Source #

maxBound :: (a, b, c, d, e, f, g, h) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i) => Bounded (a, b, c, d, e, f, g, h, i) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i) Source #

maxBound :: (a, b, c, d, e, f, g, h, i) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j) => Bounded (a, b, c, d, e, f, g, h, i, j) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i, j) Source #

maxBound :: (a, b, c, d, e, f, g, h, i, j) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k) => Bounded (a, b, c, d, e, f, g, h, i, j, k) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i, j, k) Source #

maxBound :: (a, b, c, d, e, f, g, h, i, j, k) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i, j, k, l) Source #

maxBound :: (a, b, c, d, e, f, g, h, i, j, k, l) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l, Bounded m) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

maxBound :: (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l, Bounded m, Bounded n) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

maxBound :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

(Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l, Bounded m, Bounded n, Bounded o) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

maxBound :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

Numbers

Numeric types

data Int Source #

A fixed-precision integer type with at least the range [-2^29 .. 2^29-1]. The exact range for a given implementation can be determined by using minBound and maxBound from the Bounded class.

Instances

Instances details
Data Int Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Int -> c Int Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Int Source #

toConstr :: Int -> Constr Source #

dataTypeOf :: Int -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Int) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Int) Source #

gmapT :: (forall b. Data b => b -> b) -> Int -> Int Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Int -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Int -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Int -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Int -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Int -> m Int Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Int -> m Int Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Int -> m Int Source #

Storable Int Source #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Bits Int Source #

Since: base-2.1

Instance details

Defined in GHC.Bits

FiniteBits Int Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Bits

Bounded Int Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Int Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Ix Int Source #

Since: base-2.1

Instance details

Defined in GHC.Ix

Num Int Source #

Since: base-2.1

Instance details

Defined in GHC.Num

Read Int Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Integral Int Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

quot :: Int -> Int -> Int Source #

rem :: Int -> Int -> Int Source #

div :: Int -> Int -> Int Source #

mod :: Int -> Int -> Int Source #

quotRem :: Int -> Int -> (Int, Int) Source #

divMod :: Int -> Int -> (Int, Int) Source #

toInteger :: Int -> Integer Source #

Real Int Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Show Int Source #

Since: base-2.1

Instance details

Defined in GHC.Show

PrintfArg Int Source #

Since: base-2.1

Instance details

Defined in Text.Printf

Eq Int 
Instance details

Defined in GHC.Classes

Methods

(==) :: Int -> Int -> Bool Source #

(/=) :: Int -> Int -> Bool Source #

Ord Int 
Instance details

Defined in GHC.Classes

Methods

compare :: Int -> Int -> Ordering Source #

(<) :: Int -> Int -> Bool Source #

(<=) :: Int -> Int -> Bool Source #

(>) :: Int -> Int -> Bool Source #

(>=) :: Int -> Int -> Bool Source #

max :: Int -> Int -> Int Source #

min :: Int -> Int -> Int Source #

Generic1 (URec Int :: k -> Type) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Int :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Int :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UInt" 'PrefixI 'True) (S1 ('MetaSel ('Just "uInt#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UInt :: k -> Type)))

Methods

from1 :: forall (a :: k). URec Int a -> Rep1 (URec Int :: k -> Type) a Source #

to1 :: forall (a :: k). Rep1 (URec Int :: k -> Type) a -> URec Int a Source #

Foldable (UInt :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UInt m -> m Source #

foldMap :: Monoid m => (a -> m) -> UInt a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UInt a -> m Source #

foldr :: (a -> b -> b) -> b -> UInt a -> b Source #

foldr' :: (a -> b -> b) -> b -> UInt a -> b Source #

foldl :: (b -> a -> b) -> b -> UInt a -> b Source #

foldl' :: (b -> a -> b) -> b -> UInt a -> b Source #

foldr1 :: (a -> a -> a) -> UInt a -> a Source #

foldl1 :: (a -> a -> a) -> UInt a -> a Source #

toList :: UInt a -> [a] Source #

null :: UInt a -> Bool Source #

length :: UInt a -> Int Source #

elem :: Eq a => a -> UInt a -> Bool Source #

maximum :: Ord a => UInt a -> a Source #

minimum :: Ord a => UInt a -> a Source #

sum :: Num a => UInt a -> a Source #

product :: Num a => UInt a -> a Source #

Traversable (UInt :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UInt a -> f (UInt b) Source #

sequenceA :: Applicative f => UInt (f a) -> f (UInt a) Source #

mapM :: Monad m => (a -> m b) -> UInt a -> m (UInt b) Source #

sequence :: Monad m => UInt (m a) -> m (UInt a) Source #

Functor (URec Int :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Int a -> URec Int b Source #

(<$) :: a -> URec Int b -> URec Int a Source #

Generic (URec Int p) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Int p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Int p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UInt" 'PrefixI 'True) (S1 ('MetaSel ('Just "uInt#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UInt :: Type -> Type)))

Methods

from :: URec Int p -> Rep (URec Int p) x Source #

to :: Rep (URec Int p) x -> URec Int p Source #

Show (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Int p -> URec Int p -> Bool Source #

(/=) :: URec Int p -> URec Int p -> Bool Source #

Ord (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec Int p -> URec Int p -> Ordering Source #

(<) :: URec Int p -> URec Int p -> Bool Source #

(<=) :: URec Int p -> URec Int p -> Bool Source #

(>) :: URec Int p -> URec Int p -> Bool Source #

(>=) :: URec Int p -> URec Int p -> Bool Source #

max :: URec Int p -> URec Int p -> URec Int p Source #

min :: URec Int p -> URec Int p -> URec Int p Source #

data URec Int (p :: k) Source #

Used for marking occurrences of Int#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Int (p :: k) = UInt {}
type Rep1 (URec Int :: k -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Int :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UInt" 'PrefixI 'True) (S1 ('MetaSel ('Just "uInt#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UInt :: k -> Type)))
type Rep (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Int p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UInt" 'PrefixI 'True) (S1 ('MetaSel ('Just "uInt#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UInt :: Type -> Type)))

data Integer Source #

Arbitrary precision integers. In contrast with fixed-size integral types such as Int, the Integer type represents the entire infinite range of integers.

Integers are stored in a kind of sign-magnitude form, hence do not expect two's complement form when using bit operations.

If the value is small (fit into an Int), IS constructor is used. Otherwise IP and IN constructors are used to store a BigNat representing respectively the positive or the negative value magnitude.

Invariant: IP and IN are used iff value doesn't fit in IS

Instances

Instances details
Data Integer Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Integer -> c Integer Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Integer Source #

toConstr :: Integer -> Constr Source #

dataTypeOf :: Integer -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Integer) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Integer) Source #

gmapT :: (forall b. Data b => b -> b) -> Integer -> Integer Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Integer -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Integer -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Integer -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Integer -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Integer -> m Integer Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Integer -> m Integer Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Integer -> m Integer Source #

Bits Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Bits

Enum Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Ix Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Ix

Num Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Num

Read Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Integral Integer Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Real Integer Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Show Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Show

PrintfArg Integer Source #

Since: base-2.1

Instance details

Defined in Text.Printf

Eq Integer 
Instance details

Defined in GHC.Num.Integer

Ord Integer 
Instance details

Defined in GHC.Num.Integer

data Float Source #

Single-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE single-precision type.

Instances

Instances details
Data Float Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Float -> c Float Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Float Source #

toConstr :: Float -> Constr Source #

dataTypeOf :: Float -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Float) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Float) Source #

gmapT :: (forall b. Data b => b -> b) -> Float -> Float Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Float -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Float -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Float -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Float -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Float -> m Float Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Float -> m Float Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Float -> m Float Source #

Storable Float Source #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Enum Float Source #

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5 :: Float]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Float

Floating Float Source #

Since: base-2.1

Instance details

Defined in GHC.Float

RealFloat Float Source #

Since: base-2.1

Instance details

Defined in GHC.Float

Num Float Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:

>>> (0.1 + 0.1 :: Float) + 0.5 == 0.1 + (0.1 + 0.5)
False
>>> (0.1 + 0.2 :: Float) * 0.9 == 0.1 * 0.9 + 0.2 * 0.9
False
>>> (0.1 * 0.1 :: Float) * 0.9 == 0.1 * (0.1 * 0.9)
False

Since: base-2.1

Instance details

Defined in GHC.Float

Read Float Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Fractional Float Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.

>>> 0 == (-0 :: Float)
True
>>> recip 0 == recip (-0 :: Float)
False
>>> map (/ 0) [-1, 0, 1 :: Float]
[-Infinity,NaN,Infinity]
>>> map (* 0) $ map (/ 0) [-1, 0, 1 :: Float]
[NaN,NaN,NaN]

Since: base-2.1

Instance details

Defined in GHC.Float

Real Float Source #

Beware that toRational generates garbage for non-finite arguments:

>>> toRational (1/0 :: Float)
340282366920938463463374607431768211456 % 1
>>> toRational (0/0 :: Float)
510423550381407695195061911147652317184 % 1

Since: base-2.1

Instance details

Defined in GHC.Float

RealFrac Float Source #

Beware that results for non-finite arguments are garbage:

>>> [ f x | f <- [round, floor, ceiling], x <- [-1/0, 0/0, 1/0 :: Float] ] :: [Int]
[0,0,0,0,0,0,0,0,0]
>>> map properFraction [-1/0, 0/0, 1/0] :: [(Int, Float)]
[(0,0.0),(0,0.0),(0,0.0)]

and get even more non-sensical if you ask for Integer instead of Int.

Since: base-2.1

Instance details

Defined in GHC.Float

Methods

properFraction :: Integral b => Float -> (b, Float) Source #

truncate :: Integral b => Float -> b Source #

round :: Integral b => Float -> b Source #

ceiling :: Integral b => Float -> b Source #

floor :: Integral b => Float -> b Source #

Show Float Source #

Since: base-2.1

Instance details

Defined in GHC.Float

PrintfArg Float Source #

Since: base-2.1

Instance details

Defined in Text.Printf

Eq Float

Note that due to the presence of NaN, Float's Eq instance does not satisfy reflexivity.

>>> 0/0 == (0/0 :: Float)
False

Also note that Float's Eq instance does not satisfy extensionality:

>>> 0 == (-0 :: Float)
True
>>> recip 0 == recip (-0 :: Float)
False
Instance details

Defined in GHC.Classes

Methods

(==) :: Float -> Float -> Bool Source #

(/=) :: Float -> Float -> Bool Source #

Ord Float

See instance Ord Double for discussion of deviations from IEEE 754 standard.

Instance details

Defined in GHC.Classes

Generic1 (URec Float :: k -> Type) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Float :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Float :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: k -> Type)))

Methods

from1 :: forall (a :: k). URec Float a -> Rep1 (URec Float :: k -> Type) a Source #

to1 :: forall (a :: k). Rep1 (URec Float :: k -> Type) a -> URec Float a Source #

Foldable (UFloat :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UFloat m -> m Source #

foldMap :: Monoid m => (a -> m) -> UFloat a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UFloat a -> m Source #

foldr :: (a -> b -> b) -> b -> UFloat a -> b Source #

foldr' :: (a -> b -> b) -> b -> UFloat a -> b Source #

foldl :: (b -> a -> b) -> b -> UFloat a -> b Source #

foldl' :: (b -> a -> b) -> b -> UFloat a -> b Source #

foldr1 :: (a -> a -> a) -> UFloat a -> a Source #

foldl1 :: (a -> a -> a) -> UFloat a -> a Source #

toList :: UFloat a -> [a] Source #

null :: UFloat a -> Bool Source #

length :: UFloat a -> Int Source #

elem :: Eq a => a -> UFloat a -> Bool Source #

maximum :: Ord a => UFloat a -> a Source #

minimum :: Ord a => UFloat a -> a Source #

sum :: Num a => UFloat a -> a Source #

product :: Num a => UFloat a -> a Source #

Traversable (UFloat :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UFloat a -> f (UFloat b) Source #

sequenceA :: Applicative f => UFloat (f a) -> f (UFloat a) Source #

mapM :: Monad m => (a -> m b) -> UFloat a -> m (UFloat b) Source #

sequence :: Monad m => UFloat (m a) -> m (UFloat a) Source #

Functor (URec Float :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Float a -> URec Float b Source #

(<$) :: a -> URec Float b -> URec Float a Source #

Generic (URec Float p) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Float p) 
Instance details

Defined in GHC.Generics

type Rep (URec Float p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: Type -> Type)))

Methods

from :: URec Float p -> Rep (URec Float p) x Source #

to :: Rep (URec Float p) x -> URec Float p Source #

Show (URec Float p) Source # 
Instance details

Defined in GHC.Generics

Eq (URec Float p) Source # 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Float p -> URec Float p -> Bool Source #

(/=) :: URec Float p -> URec Float p -> Bool Source #

Ord (URec Float p) Source # 
Instance details

Defined in GHC.Generics

data URec Float (p :: k) Source #

Used for marking occurrences of Float#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Float (p :: k) = UFloat {}
type Rep1 (URec Float :: k -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Float :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: k -> Type)))
type Rep (URec Float p) Source # 
Instance details

Defined in GHC.Generics

type Rep (URec Float p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: Type -> Type)))

data Double Source #

Double-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE double-precision type.

Instances

Instances details
Data Double Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Double -> c Double Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Double Source #

toConstr :: Double -> Constr Source #

dataTypeOf :: Double -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Double) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Double) Source #

gmapT :: (forall b. Data b => b -> b) -> Double -> Double Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Double -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Double -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Double -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Double -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Double -> m Double Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Double -> m Double Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Double -> m Double Source #

Storable Double Source #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Enum Double Source #

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Float

Floating Double Source #

Since: base-2.1

Instance details

Defined in GHC.Float

RealFloat Double Source #

Since: base-2.1

Instance details

Defined in GHC.Float

Num Double Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:

>>> (0.1 + 0.1) + 0.4 == 0.1 + (0.1 + 0.4)
False
>>> (0.1 + 0.2) * 0.3 == 0.1 * 0.3 + 0.2 * 0.3
False
>>> (0.1 * 0.1) * 0.3 == 0.1 * (0.1 * 0.3)
False

Since: base-2.1

Instance details

Defined in GHC.Float

Read Double Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Fractional Double Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.

>>> 0 == (-0 :: Double)
True
>>> recip 0 == recip (-0 :: Double)
False
>>> map (/ 0) [-1, 0, 1]
[-Infinity,NaN,Infinity]
>>> map (* 0) $ map (/ 0) [-1, 0, 1]
[NaN,NaN,NaN]

Since: base-2.1

Instance details

Defined in GHC.Float

Real Double Source #

Beware that toRational generates garbage for non-finite arguments:

>>> toRational (1/0)
179769313 (and 300 more digits...) % 1
>>> toRational (0/0)
269653970 (and 300 more digits...) % 1

Since: base-2.1

Instance details

Defined in GHC.Float

RealFrac Double Source #

Beware that results for non-finite arguments are garbage:

>>> [ f x | f <- [round, floor, ceiling], x <- [-1/0, 0/0, 1/0] ] :: [Int]
[0,0,0,0,0,0,0,0,0]
>>> map properFraction [-1/0, 0/0, 1/0] :: [(Int, Double)]
[(0,0.0),(0,0.0),(0,0.0)]

and get even more non-sensical if you ask for Integer instead of Int.

Since: base-2.1

Instance details

Defined in GHC.Float

Show Double Source #

Since: base-2.1

Instance details

Defined in GHC.Float

PrintfArg Double Source #

Since: base-2.1

Instance details

Defined in Text.Printf

Eq Double

Note that due to the presence of NaN, Double's Eq instance does not satisfy reflexivity.

>>> 0/0 == (0/0 :: Double)
False

Also note that Double's Eq instance does not satisfy substitutivity:

>>> 0 == (-0 :: Double)
True
>>> recip 0 == recip (-0 :: Double)
False
Instance details

Defined in GHC.Classes

Ord Double

IEEE 754 Double-precision type includes not only numbers, but also positive and negative infinities and a special element called NaN (which can be quiet or signal).

IEEE 754-2008, section 5.11 requires that if at least one of arguments of <=, <, >, >= is NaN then the result of the comparison is False, and instance Ord Double complies with this requirement. This violates the reflexivity: both NaN <= NaN and NaN >= NaN are False.

IEEE 754-2008, section 5.10 defines totalOrder predicate. Unfortunately, compare on Doubles violates the IEEE standard and does not define a total order. More specifically, both compare NaN x and compare x NaN always return GT.

Thus, users must be extremely cautious when using instance Ord Double. For instance, one should avoid ordered containers with keys represented by Double, because data loss and corruption may happen. An IEEE-compliant compare is available in fp-ieee package as TotallyOrdered newtype.

Moving further, the behaviour of min and max with regards to NaN is also non-compliant. IEEE 754-2008, section 5.3.1 defines that quiet NaN should be treated as a missing data by minNum and maxNum functions, for example, minNum(NaN, 1) = minNum(1, NaN) = 1. Some languages such as Java deviate from the standard implementing minNum(NaN, 1) = minNum(1, NaN) = NaN. However, min / max in base are even worse: min NaN 1 is 1, but min 1 NaN is NaN.

IEEE 754-2008 compliant min / max can be found in ieee754 package under minNum / maxNum names. Implementations compliant with minimumNumber / maximumNumber from a newer IEEE 754-2019, section 9.6 are available from fp-ieee package.

Instance details

Defined in GHC.Classes

Generic1 (URec Double :: k -> Type) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Double :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Double :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UDouble" 'PrefixI 'True) (S1 ('MetaSel ('Just "uDouble#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UDouble :: k -> Type)))

Methods

from1 :: forall (a :: k). URec Double a -> Rep1 (URec Double :: k -> Type) a Source #

to1 :: forall (a :: k). Rep1 (URec Double :: k -> Type) a -> URec Double a Source #

Foldable (UDouble :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UDouble m -> m Source #

foldMap :: Monoid m => (a -> m) -> UDouble a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UDouble a -> m Source #

foldr :: (a -> b -> b) -> b -> UDouble a -> b Source #

foldr' :: (a -> b -> b) -> b -> UDouble a -> b Source #

foldl :: (b -> a -> b) -> b -> UDouble a -> b Source #

foldl' :: (b -> a -> b) -> b -> UDouble a -> b Source #

foldr1 :: (a -> a -> a) -> UDouble a -> a Source #

foldl1 :: (a -> a -> a) -> UDouble a -> a Source #

toList :: UDouble a -> [a] Source #

null :: UDouble a -> Bool Source #

length :: UDouble a -> Int Source #

elem :: Eq a => a -> UDouble a -> Bool Source #

maximum :: Ord a => UDouble a -> a Source #

minimum :: Ord a => UDouble a -> a Source #

sum :: Num a => UDouble a -> a Source #

product :: Num a => UDouble a -> a Source #

Traversable (UDouble :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UDouble a -> f (UDouble b) Source #

sequenceA :: Applicative f => UDouble (f a) -> f (UDouble a) Source #

mapM :: Monad m => (a -> m b) -> UDouble a -> m (UDouble b) Source #

sequence :: Monad m => UDouble (m a) -> m (UDouble a) Source #

Functor (URec Double :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Double a -> URec Double b Source #

(<$) :: a -> URec Double b -> URec Double a Source #

Generic (URec Double p) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Double p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UDouble" 'PrefixI 'True) (S1 ('MetaSel ('Just "uDouble#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UDouble :: Type -> Type)))

Methods

from :: URec Double p -> Rep (URec Double p) x Source #

to :: Rep (URec Double p) x -> URec Double p Source #

Show (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Double p -> URec Double p -> Bool Source #

(/=) :: URec Double p -> URec Double p -> Bool Source #

Ord (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Double (p :: k) Source #

Used for marking occurrences of Double#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Double (p :: k) = UDouble {}
type Rep1 (URec Double :: k -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Double :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UDouble" 'PrefixI 'True) (S1 ('MetaSel ('Just "uDouble#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UDouble :: k -> Type)))
type Rep (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Double p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UDouble" 'PrefixI 'True) (S1 ('MetaSel ('Just "uDouble#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UDouble :: Type -> Type)))

type Rational = Ratio Integer Source #

Arbitrary-precision rational numbers, represented as a ratio of two Integer values. A rational number may be constructed using the % operator.

data Word Source #

A Word is an unsigned integral type, with the same size as Int.

Instances

Instances details
Data Word Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Word -> c Word Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Word Source #

toConstr :: Word -> Constr Source #

dataTypeOf :: Word -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Word) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Word) Source #

gmapT :: (forall b. Data b => b -> b) -> Word -> Word Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Word -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Word -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Word -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Word -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Word -> m Word Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Word -> m Word Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Word -> m Word Source #

Storable Word Source #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Bits Word Source #

Since: base-2.1

Instance details

Defined in GHC.Bits

FiniteBits Word Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Bits

Bounded Word Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Word Source #

Since: base-2.1

Instance details

Defined in GHC.Enum

Ix Word Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Ix

Num Word Source #

Since: base-2.1

Instance details

Defined in GHC.Num

Read Word Source #

Since: base-4.5.0.0

Instance details

Defined in GHC.Read

Integral Word Source #

Since: base-2.1

Instance details

Defined in GHC.Real

Real Word Source #

Since: base-2.1

Instance details

Defined in GHC.Real

Show Word Source #

Since: base-2.1

Instance details

Defined in GHC.Show

PrintfArg Word Source #

Since: base-2.1

Instance details

Defined in Text.Printf

Eq Word 
Instance details

Defined in GHC.Classes

Methods

(==) :: Word -> Word -> Bool Source #

(/=) :: Word -> Word -> Bool Source #

Ord Word 
Instance details

Defined in GHC.Classes

Generic1 (URec Word :: k -> Type) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Word :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Word :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UWord" 'PrefixI 'True) (S1 ('MetaSel ('Just "uWord#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UWord :: k -> Type)))

Methods

from1 :: forall (a :: k). URec Word a -> Rep1 (URec Word :: k -> Type) a Source #

to1 :: forall (a :: k). Rep1 (URec Word :: k -> Type) a -> URec Word a Source #

Foldable (UWord :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UWord m -> m Source #

foldMap :: Monoid m => (a -> m) -> UWord a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UWord a -> m Source #

foldr :: (a -> b -> b) -> b -> UWord a -> b Source #

foldr' :: (a -> b -> b) -> b -> UWord a -> b Source #

foldl :: (b -> a -> b) -> b -> UWord a -> b Source #

foldl' :: (b -> a -> b) -> b -> UWord a -> b Source #

foldr1 :: (a -> a -> a) -> UWord a -> a Source #

foldl1 :: (a -> a -> a) -> UWord a -> a Source #

toList :: UWord a -> [a] Source #

null :: UWord a -> Bool Source #

length :: UWord a -> Int Source #

elem :: Eq a => a -> UWord a -> Bool Source #

maximum :: Ord a => UWord a -> a Source #

minimum :: Ord a => UWord a -> a Source #

sum :: Num a => UWord a -> a Source #

product :: Num a => UWord a -> a Source #

Traversable (UWord :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UWord a -> f (UWord b) Source #

sequenceA :: Applicative f => UWord (f a) -> f (UWord a) Source #

mapM :: Monad m => (a -> m b) -> UWord a -> m (UWord b) Source #

sequence :: Monad m => UWord (m a) -> m (UWord a) Source #

Functor (URec Word :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Word a -> URec Word b Source #

(<$) :: a -> URec Word b -> URec Word a Source #

Generic (URec Word p) Source # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Word p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Word p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UWord" 'PrefixI 'True) (S1 ('MetaSel ('Just "uWord#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UWord :: Type -> Type)))

Methods

from :: URec Word p -> Rep (URec Word p) x Source #

to :: Rep (URec Word p) x -> URec Word p Source #

Show (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Eq (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec Word p -> URec Word p -> Bool Source #

(/=) :: URec Word p -> URec Word p -> Bool Source #

Ord (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec Word p -> URec Word p -> Ordering Source #

(<) :: URec Word p -> URec Word p -> Bool Source #

(<=) :: URec Word p -> URec Word p -> Bool Source #

(>) :: URec Word p -> URec Word p -> Bool Source #

(>=) :: URec Word p -> URec Word p -> Bool Source #

max :: URec Word p -> URec Word p -> URec Word p Source #

min :: URec Word p -> URec Word p -> URec Word p Source #

data URec Word (p :: k) Source #

Used for marking occurrences of Word#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Word (p :: k) = UWord {}
type Rep1 (URec Word :: k -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec Word :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UWord" 'PrefixI 'True) (S1 ('MetaSel ('Just "uWord#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UWord :: k -> Type)))
type Rep (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec Word p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UWord" 'PrefixI 'True) (S1 ('MetaSel ('Just "uWord#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UWord :: Type -> Type)))

Numeric type classes

class Num a where Source #

Basic numeric class.

The Haskell Report defines no laws for Num. However, (+) and (*) are customarily expected to define a ring and have the following properties:

Associativity of (+)
(x + y) + z = x + (y + z)
Commutativity of (+)
x + y = y + x
fromInteger 0 is the additive identity
x + fromInteger 0 = x
negate gives the additive inverse
x + negate x = fromInteger 0
Associativity of (*)
(x * y) * z = x * (y * z)
fromInteger 1 is the multiplicative identity
x * fromInteger 1 = x and fromInteger 1 * x = x
Distributivity of (*) with respect to (+)
a * (b + c) = (a * b) + (a * c) and (b + c) * a = (b * a) + (c * a)
Coherence with toInteger
if the type also implements Integral, then fromInteger is a left inverse for toInteger, i.e. fromInteger (toInteger i) == i

Note that it isn't customarily expected that a type instance of both Num and Ord implement an ordered ring. Indeed, in base only Integer and Rational do.

Minimal complete definition

(+), (*), abs, signum, fromInteger, (negate | (-))

Methods

(+) :: a -> a -> a infixl 6 Source #

(-) :: a -> a -> a infixl 6 Source #

(*) :: a -> a -> a infixl 7 Source #

negate :: a -> a Source #

Unary negation.

abs :: a -> a Source #

Absolute value.

signum :: a -> a Source #

Sign of a number. The functions abs and signum should satisfy the law:

abs x * signum x == x

For real numbers, the signum is either -1 (negative), 0 (zero) or 1 (positive).

fromInteger :: Integer -> a Source #

Conversion from an Integer. An integer literal represents the application of the function fromInteger to the appropriate value of type Integer, so such literals have type (Num a) => a.

Instances

Instances details
Num CBool Source # 
Instance details

Defined in Foreign.C.Types

Num CChar Source # 
Instance details

Defined in Foreign.C.Types

Num CClock Source # 
Instance details

Defined in Foreign.C.Types

Num CDouble Source # 
Instance details

Defined in Foreign.C.Types

Num CFloat Source # 
Instance details

Defined in Foreign.C.Types

Num CInt Source # 
Instance details

Defined in Foreign.C.Types

Num CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Num CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Num CLLong Source # 
Instance details

Defined in Foreign.C.Types

Num CLong Source # 
Instance details

Defined in Foreign.C.Types

Num CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Num CSChar Source # 
Instance details

Defined in Foreign.C.Types

Num CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Num CShort Source # 
Instance details

Defined in Foreign.C.Types

Num CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Num CSize Source # 
Instance details

Defined in Foreign.C.Types

Num CTime Source # 
Instance details

Defined in Foreign.C.Types

Num CUChar Source # 
Instance details

Defined in Foreign.C.Types

Num CUInt Source # 
Instance details

Defined in Foreign.C.Types

Num CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Num CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Num CULLong Source # 
Instance details

Defined in Foreign.C.Types

Num CULong Source # 
Instance details

Defined in Foreign.C.Types

Num CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Num CUShort Source # 
Instance details

Defined in Foreign.C.Types

Num CWchar Source # 
Instance details

Defined in Foreign.C.Types

Num IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Num WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Num Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Num Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Num CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Num CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Num CCc Source # 
Instance details

Defined in System.Posix.Types

Num CClockId Source # 
Instance details

Defined in System.Posix.Types

Num CDev Source # 
Instance details

Defined in System.Posix.Types

Num CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Num CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Num CGid Source # 
Instance details

Defined in System.Posix.Types

Num CId Source # 
Instance details

Defined in System.Posix.Types

Num CIno Source # 
Instance details

Defined in System.Posix.Types

Num CKey Source # 
Instance details

Defined in System.Posix.Types

Num CMode Source # 
Instance details

Defined in System.Posix.Types

Num CNfds Source # 
Instance details

Defined in System.Posix.Types

Num CNlink Source # 
Instance details

Defined in System.Posix.Types

Num COff Source # 
Instance details

Defined in System.Posix.Types

Num CPid Source # 
Instance details

Defined in System.Posix.Types

Num CRLim Source # 
Instance details

Defined in System.Posix.Types

Num CSocklen Source # 
Instance details

Defined in System.Posix.Types

Num CSpeed Source # 
Instance details

Defined in System.Posix.Types

Num CSsize Source # 
Instance details

Defined in System.Posix.Types

Num CTcflag Source # 
Instance details

Defined in System.Posix.Types

Num CUid Source # 
Instance details

Defined in System.Posix.Types

Num Fd Source # 
Instance details

Defined in System.Posix.Types

Methods

(+) :: Fd -> Fd -> Fd Source #

(-) :: Fd -> Fd -> Fd Source #

(*) :: Fd -> Fd -> Fd Source #

negate :: Fd -> Fd Source #

abs :: Fd -> Fd Source #

signum :: Fd -> Fd Source #

fromInteger :: Integer -> Fd Source #

Num Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Num

Num Natural Source #

Note that Natural's Num instance isn't a ring: no element but 0 has an additive inverse. It is a semiring though.

Since: base-4.8.0.0

Instance details

Defined in GHC.Num

Num Double Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:

>>> (0.1 + 0.1) + 0.4 == 0.1 + (0.1 + 0.4)
False
>>> (0.1 + 0.2) * 0.3 == 0.1 * 0.3 + 0.2 * 0.3
False
>>> (0.1 * 0.1) * 0.3 == 0.1 * (0.1 * 0.3)
False

Since: base-2.1

Instance details

Defined in GHC.Float

Num Float Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:

>>> (0.1 + 0.1 :: Float) + 0.5 == 0.1 + (0.1 + 0.5)
False
>>> (0.1 + 0.2 :: Float) * 0.9 == 0.1 * 0.9 + 0.2 * 0.9
False
>>> (0.1 * 0.1 :: Float) * 0.9 == 0.1 * (0.1 * 0.9)
False

Since: base-2.1

Instance details

Defined in GHC.Float

Num Int Source #

Since: base-2.1

Instance details

Defined in GHC.Num

Num Word Source #

Since: base-2.1

Instance details

Defined in GHC.Num

RealFloat a => Num (Complex a) Source #

Since: base-2.1

Instance details

Defined in Data.Complex

Num a => Num (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Num a => Num (Down a) Source #

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

(+) :: Down a -> Down a -> Down a Source #

(-) :: Down a -> Down a -> Down a Source #

(*) :: Down a -> Down a -> Down a Source #

negate :: Down a -> Down a Source #

abs :: Down a -> Down a Source #

signum :: Down a -> Down a Source #

fromInteger :: Integer -> Down a Source #

Num a => Num (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(+) :: Max a -> Max a -> Max a Source #

(-) :: Max a -> Max a -> Max a Source #

(*) :: Max a -> Max a -> Max a Source #

negate :: Max a -> Max a Source #

abs :: Max a -> Max a Source #

signum :: Max a -> Max a Source #

fromInteger :: Integer -> Max a Source #

Num a => Num (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(+) :: Min a -> Min a -> Min a Source #

(-) :: Min a -> Min a -> Min a Source #

(*) :: Min a -> Min a -> Min a Source #

negate :: Min a -> Min a Source #

abs :: Min a -> Min a Source #

signum :: Min a -> Min a Source #

fromInteger :: Integer -> Min a Source #

Num a => Num (Product a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Semigroup.Internal

Num a => Num (Sum a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(+) :: Sum a -> Sum a -> Sum a Source #

(-) :: Sum a -> Sum a -> Sum a Source #

(*) :: Sum a -> Sum a -> Sum a Source #

negate :: Sum a -> Sum a Source #

abs :: Sum a -> Sum a Source #

signum :: Sum a -> Sum a Source #

fromInteger :: Integer -> Sum a Source #

Integral a => Num (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

(+) :: Ratio a -> Ratio a -> Ratio a Source #

(-) :: Ratio a -> Ratio a -> Ratio a Source #

(*) :: Ratio a -> Ratio a -> Ratio a Source #

negate :: Ratio a -> Ratio a Source #

abs :: Ratio a -> Ratio a Source #

signum :: Ratio a -> Ratio a Source #

fromInteger :: Integer -> Ratio a Source #

HasResolution a => Num (Fixed a) Source #

Multiplication is not associative or distributive:

>>> (0.2 * 0.6 :: Deci) * 0.9 == 0.2 * (0.6 * 0.9)
False
>>> (0.1 + 0.1 :: Deci) * 0.5 == 0.1 * 0.5 + 0.1 * 0.5
False

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

(+) :: Fixed a -> Fixed a -> Fixed a Source #

(-) :: Fixed a -> Fixed a -> Fixed a Source #

(*) :: Fixed a -> Fixed a -> Fixed a Source #

negate :: Fixed a -> Fixed a Source #

abs :: Fixed a -> Fixed a Source #

signum :: Fixed a -> Fixed a Source #

fromInteger :: Integer -> Fixed a Source #

Num a => Num (Op a b) Source # 
Instance details

Defined in Data.Functor.Contravariant

Methods

(+) :: Op a b -> Op a b -> Op a b Source #

(-) :: Op a b -> Op a b -> Op a b Source #

(*) :: Op a b -> Op a b -> Op a b Source #

negate :: Op a b -> Op a b Source #

abs :: Op a b -> Op a b Source #

signum :: Op a b -> Op a b Source #

fromInteger :: Integer -> Op a b Source #

Num a => Num (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

(+) :: Const a b -> Const a b -> Const a b Source #

(-) :: Const a b -> Const a b -> Const a b Source #

(*) :: Const a b -> Const a b -> Const a b Source #

negate :: Const a b -> Const a b Source #

abs :: Const a b -> Const a b Source #

signum :: Const a b -> Const a b Source #

fromInteger :: Integer -> Const a b Source #

(Applicative f, Num a) => Num (Ap f a) Source #

Note that even if the underlying Num and Applicative instances are lawful, for most Applicatives, this instance will not be lawful. If you use this instance with the list Applicative, the following customary laws will not hold:

Commutativity:

>>> Ap [10,20] + Ap [1,2]
Ap {getAp = [11,12,21,22]}
>>> Ap [1,2] + Ap [10,20]
Ap {getAp = [11,21,12,22]}

Additive inverse:

>>> Ap [] + negate (Ap [])
Ap {getAp = []}
>>> fromInteger 0 :: Ap [] Int
Ap {getAp = [0]}

Distributivity:

>>> Ap [1,2] * (3 + 4)
Ap {getAp = [7,14]}
>>> (Ap [1,2] * 3) + (Ap [1,2] * 4)
Ap {getAp = [7,11,10,14]}

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

(+) :: Ap f a -> Ap f a -> Ap f a Source #

(-) :: Ap f a -> Ap f a -> Ap f a Source #

(*) :: Ap f a -> Ap f a -> Ap f a Source #

negate :: Ap f a -> Ap f a Source #

abs :: Ap f a -> Ap f a Source #

signum :: Ap f a -> Ap f a Source #

fromInteger :: Integer -> Ap f a Source #

Num (f a) => Num (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(+) :: Alt f a -> Alt f a -> Alt f a Source #

(-) :: Alt f a -> Alt f a -> Alt f a Source #

(*) :: Alt f a -> Alt f a -> Alt f a Source #

negate :: Alt f a -> Alt f a Source #

abs :: Alt f a -> Alt f a Source #

signum :: Alt f a -> Alt f a Source #

fromInteger :: Integer -> Alt f a Source #

Num (f (g a)) => Num (Compose f g a) Source #

Since: base-4.19.0.0

Instance details

Defined in Data.Functor.Compose

Methods

(+) :: Compose f g a -> Compose f g a -> Compose f g a Source #

(-) :: Compose f g a -> Compose f g a -> Compose f g a Source #

(*) :: Compose f g a -> Compose f g a -> Compose f g a Source #

negate :: Compose f g a -> Compose f g a Source #

abs :: Compose f g a -> Compose f g a Source #

signum :: Compose f g a -> Compose f g a Source #

fromInteger :: Integer -> Compose f g a Source #

class (Num a, Ord a) => Real a where Source #

Real numbers.

The Haskell report defines no laws for Real, however Real instances are customarily expected to adhere to the following law:

Coherence with fromRational
if the type also implements Fractional, then fromRational is a left inverse for toRational, i.e. fromRational (toRational i) = i

The law does not hold for Float, Double, CFloat, CDouble, etc., because these types contain non-finite values, which cannot be roundtripped through Rational.

Methods

toRational :: a -> Rational Source #

the rational equivalent of its real argument with full precision

Instances

Instances details
Real CBool Source # 
Instance details

Defined in Foreign.C.Types

Real CChar Source # 
Instance details

Defined in Foreign.C.Types

Real CClock Source # 
Instance details

Defined in Foreign.C.Types

Real CDouble Source # 
Instance details

Defined in Foreign.C.Types

Real CFloat Source # 
Instance details

Defined in Foreign.C.Types

Real CInt Source # 
Instance details

Defined in Foreign.C.Types

Real CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Real CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Real CLLong Source # 
Instance details

Defined in Foreign.C.Types

Real CLong Source # 
Instance details

Defined in Foreign.C.Types

Real CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Real CSChar Source # 
Instance details

Defined in Foreign.C.Types

Real CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Real CShort Source # 
Instance details

Defined in Foreign.C.Types

Real CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Real CSize Source # 
Instance details

Defined in Foreign.C.Types

Real CTime Source # 
Instance details

Defined in Foreign.C.Types

Real CUChar Source # 
Instance details

Defined in Foreign.C.Types

Real CUInt Source # 
Instance details

Defined in Foreign.C.Types

Real CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Real CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Real CULLong Source # 
Instance details

Defined in Foreign.C.Types

Real CULong Source # 
Instance details

Defined in Foreign.C.Types

Real CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Real CUShort Source # 
Instance details

Defined in Foreign.C.Types

Real CWchar Source # 
Instance details

Defined in Foreign.C.Types

Real IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Real WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Real Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Real Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Real Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Real Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Real Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Real CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Real CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Real CCc Source # 
Instance details

Defined in System.Posix.Types

Real CClockId Source # 
Instance details

Defined in System.Posix.Types

Real CDev Source # 
Instance details

Defined in System.Posix.Types

Real CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Real CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Real CGid Source # 
Instance details

Defined in System.Posix.Types

Real CId Source # 
Instance details

Defined in System.Posix.Types

Real CIno Source # 
Instance details

Defined in System.Posix.Types

Real CKey Source # 
Instance details

Defined in System.Posix.Types

Real CMode Source # 
Instance details

Defined in System.Posix.Types

Real CNfds Source # 
Instance details

Defined in System.Posix.Types

Real CNlink Source # 
Instance details

Defined in System.Posix.Types

Real COff Source # 
Instance details

Defined in System.Posix.Types

Real CPid Source # 
Instance details

Defined in System.Posix.Types

Real CRLim Source # 
Instance details

Defined in System.Posix.Types

Real CSocklen Source # 
Instance details

Defined in System.Posix.Types

Real CSpeed Source # 
Instance details

Defined in System.Posix.Types

Real CSsize Source # 
Instance details

Defined in System.Posix.Types

Real CTcflag Source # 
Instance details

Defined in System.Posix.Types

Real CUid Source # 
Instance details

Defined in System.Posix.Types

Real Fd Source # 
Instance details

Defined in System.Posix.Types

Real Integer Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Real Natural Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Real

Real Double Source #

Beware that toRational generates garbage for non-finite arguments:

>>> toRational (1/0)
179769313 (and 300 more digits...) % 1
>>> toRational (0/0)
269653970 (and 300 more digits...) % 1

Since: base-2.1

Instance details

Defined in GHC.Float

Real Float Source #

Beware that toRational generates garbage for non-finite arguments:

>>> toRational (1/0 :: Float)
340282366920938463463374607431768211456 % 1
>>> toRational (0/0 :: Float)
510423550381407695195061911147652317184 % 1

Since: base-2.1

Instance details

Defined in GHC.Float

Real Int Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Real Word Source #

Since: base-2.1

Instance details

Defined in GHC.Real

Real a => Real (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Real a => Real (Down a) Source #

Since: base-4.14.0.0

Instance details

Defined in Data.Ord

Integral a => Real (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

HasResolution a => Real (Fixed a) Source #

Since: base-2.1

Instance details

Defined in Data.Fixed

Real a => Real (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

toRational :: Const a b -> Rational Source #

Real (f (g a)) => Real (Compose f g a) Source #

Since: base-4.19.0.0

Instance details

Defined in Data.Functor.Compose

Methods

toRational :: Compose f g a -> Rational Source #

class (Real a, Enum a) => Integral a where Source #

Integral numbers, supporting integer division.

The Haskell Report defines no laws for Integral. However, Integral instances are customarily expected to define a Euclidean domain and have the following properties for the div/mod and quot/rem pairs, given suitable Euclidean functions f and g:

  • x = y * quot x y + rem x y with rem x y = fromInteger 0 or g (rem x y) < g y
  • x = y * div x y + mod x y with mod x y = fromInteger 0 or f (mod x y) < f y

An example of a suitable Euclidean function, for Integer's instance, is abs.

In addition, toInteger should be total, and fromInteger should be a left inverse for it, i.e. fromInteger (toInteger i) = i.

Minimal complete definition

quotRem, toInteger

Methods

quot :: a -> a -> a infixl 7 Source #

integer division truncated toward zero

WARNING: This function is partial (because it throws when 0 is passed as the divisor) for all the integer types in base.

rem :: a -> a -> a infixl 7 Source #

integer remainder, satisfying

(x `quot` y)*y + (x `rem` y) == x

WARNING: This function is partial (because it throws when 0 is passed as the divisor) for all the integer types in base.

div :: a -> a -> a infixl 7 Source #

integer division truncated toward negative infinity

WARNING: This function is partial (because it throws when 0 is passed as the divisor) for all the integer types in base.

mod :: a -> a -> a infixl 7 Source #

integer modulus, satisfying

(x `div` y)*y + (x `mod` y) == x

WARNING: This function is partial (because it throws when 0 is passed as the divisor) for all the integer types in base.

quotRem :: a -> a -> (a, a) Source #

simultaneous quot and rem

WARNING: This function is partial (because it throws when 0 is passed as the divisor) for all the integer types in base.

divMod :: a -> a -> (a, a) Source #

simultaneous div and mod

WARNING: This function is partial (because it throws when 0 is passed as the divisor) for all the integer types in base.

toInteger :: a -> Integer Source #

conversion to Integer

Instances

Instances details
Integral CBool Source # 
Instance details

Defined in Foreign.C.Types

Integral CChar Source # 
Instance details

Defined in Foreign.C.Types

Integral CInt Source # 
Instance details

Defined in Foreign.C.Types

Integral CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Integral CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Integral CLLong Source # 
Instance details

Defined in Foreign.C.Types

Integral CLong Source # 
Instance details

Defined in Foreign.C.Types

Integral CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Integral CSChar Source # 
Instance details

Defined in Foreign.C.Types

Integral CShort Source # 
Instance details

Defined in Foreign.C.Types

Integral CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Integral CSize Source # 
Instance details

Defined in Foreign.C.Types

Integral CUChar Source # 
Instance details

Defined in Foreign.C.Types

Integral CUInt Source # 
Instance details

Defined in Foreign.C.Types

Integral CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Integral CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Integral CULLong Source # 
Instance details

Defined in Foreign.C.Types

Integral CULong Source # 
Instance details

Defined in Foreign.C.Types

Integral CUShort Source # 
Instance details

Defined in Foreign.C.Types

Integral CWchar Source # 
Instance details

Defined in Foreign.C.Types

Integral IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Integral WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Integral Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Integral Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Integral Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Integral Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Integral Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Integral Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Integral Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Integral Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Integral CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Integral CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Integral CClockId Source # 
Instance details

Defined in System.Posix.Types

Integral CDev Source # 
Instance details

Defined in System.Posix.Types

Integral CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Integral CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Integral CGid Source # 
Instance details

Defined in System.Posix.Types

Integral CId Source # 
Instance details

Defined in System.Posix.Types

Methods

quot :: CId -> CId -> CId Source #

rem :: CId -> CId -> CId Source #

div :: CId -> CId -> CId Source #

mod :: CId -> CId -> CId Source #

quotRem :: CId -> CId -> (CId, CId) Source #

divMod :: CId -> CId -> (CId, CId) Source #

toInteger :: CId -> Integer Source #

Integral CIno Source # 
Instance details

Defined in System.Posix.Types

Integral CKey Source # 
Instance details

Defined in System.Posix.Types

Integral CMode Source # 
Instance details

Defined in System.Posix.Types

Integral CNfds Source # 
Instance details

Defined in System.Posix.Types

Integral CNlink Source # 
Instance details

Defined in System.Posix.Types

Integral COff Source # 
Instance details

Defined in System.Posix.Types

Integral CPid Source # 
Instance details

Defined in System.Posix.Types

Integral CRLim Source # 
Instance details

Defined in System.Posix.Types

Integral CSocklen Source # 
Instance details

Defined in System.Posix.Types

Integral CSsize Source # 
Instance details

Defined in System.Posix.Types

Integral CTcflag Source # 
Instance details

Defined in System.Posix.Types

Integral CUid Source # 
Instance details

Defined in System.Posix.Types

Integral Fd Source # 
Instance details

Defined in System.Posix.Types

Methods

quot :: Fd -> Fd -> Fd Source #

rem :: Fd -> Fd -> Fd Source #

div :: Fd -> Fd -> Fd Source #

mod :: Fd -> Fd -> Fd Source #

quotRem :: Fd -> Fd -> (Fd, Fd) Source #

divMod :: Fd -> Fd -> (Fd, Fd) Source #

toInteger :: Fd -> Integer Source #

Integral Integer Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Integral Natural Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Real

Integral Int Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

quot :: Int -> Int -> Int Source #

rem :: Int -> Int -> Int Source #

div :: Int -> Int -> Int Source #

mod :: Int -> Int -> Int Source #

quotRem :: Int -> Int -> (Int, Int) Source #

divMod :: Int -> Int -> (Int, Int) Source #

toInteger :: Int -> Integer Source #

Integral Word Source #

Since: base-2.1

Instance details

Defined in GHC.Real

Integral a => Integral (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Integral a => Integral (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

quot :: Const a b -> Const a b -> Const a b Source #

rem :: Const a b -> Const a b -> Const a b Source #

div :: Const a b -> Const a b -> Const a b Source #

mod :: Const a b -> Const a b -> Const a b Source #

quotRem :: Const a b -> Const a b -> (Const a b, Const a b) Source #

divMod :: Const a b -> Const a b -> (Const a b, Const a b) Source #

toInteger :: Const a b -> Integer Source #

Integral (f (g a)) => Integral (Compose f g a) Source #

Since: base-4.19.0.0

Instance details

Defined in Data.Functor.Compose

Methods

quot :: Compose f g a -> Compose f g a -> Compose f g a Source #

rem :: Compose f g a -> Compose f g a -> Compose f g a Source #

div :: Compose f g a -> Compose f g a -> Compose f g a Source #

mod :: Compose f g a -> Compose f g a -> Compose f g a Source #

quotRem :: Compose f g a -> Compose f g a -> (Compose f g a, Compose f g a) Source #

divMod :: Compose f g a -> Compose f g a -> (Compose f g a, Compose f g a) Source #

toInteger :: Compose f g a -> Integer Source #

class Num a => Fractional a where Source #

Fractional numbers, supporting real division.

The Haskell Report defines no laws for Fractional. However, (+) and (*) are customarily expected to define a division ring and have the following properties:

recip gives the multiplicative inverse
x * recip x = recip x * x = fromInteger 1
Totality of toRational
toRational is total
Coherence with toRational
if the type also implements Real, then fromRational is a left inverse for toRational, i.e. fromRational (toRational i) = i

Note that it isn't customarily expected that a type instance of Fractional implement a field. However, all instances in base do.

Minimal complete definition

fromRational, (recip | (/))

Methods

(/) :: a -> a -> a infixl 7 Source #

Fractional division.

recip :: a -> a Source #

Reciprocal fraction.

fromRational :: Rational -> a Source #

Conversion from a Rational (that is Ratio Integer). A floating literal stands for an application of fromRational to a value of type Rational, so such literals have type (Fractional a) => a.

Instances

Instances details
Fractional CDouble Source # 
Instance details

Defined in Foreign.C.Types

Fractional CFloat Source # 
Instance details

Defined in Foreign.C.Types

Fractional Double Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.

>>> 0 == (-0 :: Double)
True
>>> recip 0 == recip (-0 :: Double)
False
>>> map (/ 0) [-1, 0, 1]
[-Infinity,NaN,Infinity]
>>> map (* 0) $ map (/ 0) [-1, 0, 1]
[NaN,NaN,NaN]

Since: base-2.1

Instance details

Defined in GHC.Float

Fractional Float Source #

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.

>>> 0 == (-0 :: Float)
True
>>> recip 0 == recip (-0 :: Float)
False
>>> map (/ 0) [-1, 0, 1 :: Float]
[-Infinity,NaN,Infinity]
>>> map (* 0) $ map (/ 0) [-1, 0, 1 :: Float]
[NaN,NaN,NaN]

Since: base-2.1

Instance details

Defined in GHC.Float

RealFloat a => Fractional (Complex a) Source #

Since: base-2.1

Instance details

Defined in Data.Complex

Fractional a => Fractional (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Fractional a => Fractional (Down a) Source #

Since: base-4.14.0.0

Instance details

Defined in Data.Ord

Methods

(/) :: Down a -> Down a -> Down a Source #

recip :: Down a -> Down a Source #

fromRational :: Rational -> Down a Source #

Integral a => Fractional (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

(/) :: Ratio a -> Ratio a -> Ratio a Source #

recip :: Ratio a -> Ratio a Source #

fromRational :: Rational -> Ratio a Source #

HasResolution a => Fractional (Fixed a) Source #

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

(/) :: Fixed a -> Fixed a -> Fixed a Source #

recip :: Fixed a -> Fixed a Source #

fromRational :: Rational -> Fixed a Source #

Fractional a => Fractional (Op a b) Source # 
Instance details

Defined in Data.Functor.Contravariant

Methods

(/) :: Op a b -> Op a b -> Op a b Source #

recip :: Op a b -> Op a b Source #

fromRational :: Rational -> Op a b Source #

Fractional a => Fractional (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

(/) :: Const a b -> Const a b -> Const a b Source #

recip :: Const a b -> Const a b Source #

fromRational :: Rational -> Const a b Source #

class Fractional a => Floating a where Source #

Trigonometric and hyperbolic functions and related functions.

The Haskell Report defines no laws for Floating. However, (+), (*) and exp are customarily expected to define an exponential field and have the following properties:

  • exp (a + b) = exp a * exp b
  • exp (fromInteger 0) = fromInteger 1

Minimal complete definition

pi, exp, log, sin, cos, asin, acos, atan, sinh, cosh, asinh, acosh, atanh

Methods

pi :: a Source #

exp :: a -> a Source #

log :: a -> a Source #

sqrt :: a -> a Source #

(**) :: a -> a -> a infixr 8 Source #

logBase :: a -> a -> a Source #

sin :: a -> a Source #

cos :: a -> a Source #

tan :: a -> a Source #

asin :: a -> a Source #

acos :: a -> a Source #

atan :: a -> a Source #

sinh :: a -> a Source #

cosh :: a -> a Source #

tanh :: a -> a Source #

asinh :: a -> a Source #

acosh :: a -> a Source #

atanh :: a -> a Source #

Instances

Instances details
Floating CDouble Source # 
Instance details

Defined in Foreign.C.Types

Floating CFloat Source # 
Instance details

Defined in Foreign.C.Types

Floating Double Source #

Since: base-2.1

Instance details

Defined in GHC.Float

Floating Float Source #

Since: base-2.1

Instance details

Defined in GHC.Float

RealFloat a => Floating (Complex a) Source #

Since: base-2.1

Instance details

Defined in Data.Complex

Floating a => Floating (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Floating a => Floating (Down a) Source #

Since: base-4.14.0.0

Instance details

Defined in Data.Ord

Methods

pi :: Down a Source #

exp :: Down a -> Down a Source #

log :: Down a -> Down a Source #

sqrt :: Down a -> Down a Source #

(**) :: Down a -> Down a -> Down a Source #

logBase :: Down a -> Down a -> Down a Source #

sin :: Down a -> Down a Source #

cos :: Down a -> Down a Source #

tan :: Down a -> Down a Source #

asin :: Down a -> Down a Source #

acos :: Down a -> Down a Source #

atan :: Down a -> Down a Source #

sinh :: Down a -> Down a Source #

cosh :: Down a -> Down a Source #

tanh :: Down a -> Down a Source #

asinh :: Down a -> Down a Source #

acosh :: Down a -> Down a Source #

atanh :: Down a -> Down a Source #

log1p :: Down a -> Down a Source #

expm1 :: Down a -> Down a Source #

log1pexp :: Down a -> Down a Source #

log1mexp :: Down a -> Down a Source #

Floating a => Floating (Op a b) Source # 
Instance details

Defined in Data.Functor.Contravariant

Methods

pi :: Op a b Source #

exp :: Op a b -> Op a b Source #

log :: Op a b -> Op a b Source #

sqrt :: Op a b -> Op a b Source #

(**) :: Op a b -> Op a b -> Op a b Source #

logBase :: Op a b -> Op a b -> Op a b Source #

sin :: Op a b -> Op a b Source #

cos :: Op a b -> Op a b Source #

tan :: Op a b -> Op a b Source #

asin :: Op a b -> Op a b Source #

acos :: Op a b -> Op a b Source #

atan :: Op a b -> Op a b Source #

sinh :: Op a b -> Op a b Source #

cosh :: Op a b -> Op a b Source #

tanh :: Op a b -> Op a b Source #

asinh :: Op a b -> Op a b Source #

acosh :: Op a b -> Op a b Source #

atanh :: Op a b -> Op a b Source #

log1p :: Op a b -> Op a b Source #

expm1 :: Op a b -> Op a b Source #

log1pexp :: Op a b -> Op a b Source #

log1mexp :: Op a b -> Op a b Source #

Floating a => Floating (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

pi :: Const a b Source #

exp :: Const a b -> Const a b Source #

log :: Const a b -> Const a b Source #

sqrt :: Const a b -> Const a b Source #

(**) :: Const a b -> Const a b -> Const a b Source #

logBase :: Const a b -> Const a b -> Const a b Source #

sin :: Const a b -> Const a b Source #

cos :: Const a b -> Const a b Source #

tan :: Const a b -> Const a b Source #

asin :: Const a b -> Const a b Source #

acos :: Const a b -> Const a b Source #

atan :: Const a b -> Const a b Source #

sinh :: Const a b -> Const a b Source #

cosh :: Const a b -> Const a b Source #

tanh :: Const a b -> Const a b Source #

asinh :: Const a b -> Const a b Source #

acosh :: Const a b -> Const a b Source #

atanh :: Const a b -> Const a b Source #

log1p :: Const a b -> Const a b Source #

expm1 :: Const a b -> Const a b Source #

log1pexp :: Const a b -> Const a b Source #

log1mexp :: Const a b -> Const a b Source #

class (Real a, Fractional a) => RealFrac a where Source #

Extracting components of fractions.

Minimal complete definition

properFraction

Methods

properFraction :: Integral b => a -> (b, a) Source #

The function properFraction takes a real fractional number x and returns a pair (n,f) such that x = n+f, and:

  • n is an integral number with the same sign as x; and
  • f is a fraction with the same type and sign as x, and with absolute value less than 1.

The default definitions of the ceiling, floor, truncate and round functions are in terms of properFraction.

truncate :: Integral b => a -> b Source #

truncate x returns the integer nearest x between zero and x

round :: Integral b => a -> b Source #

round x returns the nearest integer to x; the even integer if x is equidistant between two integers

ceiling :: Integral b => a -> b Source #

ceiling x returns the least integer not less than x

floor :: Integral b => a -> b Source #

floor x returns the greatest integer not greater than x

Instances

Instances details
RealFrac CDouble Source # 
Instance details

Defined in Foreign.C.Types

RealFrac CFloat Source # 
Instance details

Defined in Foreign.C.Types

RealFrac Double Source #

Beware that results for non-finite arguments are garbage:

>>> [ f x | f <- [round, floor, ceiling], x <- [-1/0, 0/0, 1/0] ] :: [Int]
[0,0,0,0,0,0,0,0,0]
>>> map properFraction [-1/0, 0/0, 1/0] :: [(Int, Double)]
[(0,0.0),(0,0.0),(0,0.0)]

and get even more non-sensical if you ask for Integer instead of Int.

Since: base-2.1

Instance details

Defined in GHC.Float

RealFrac Float Source #

Beware that results for non-finite arguments are garbage:

>>> [ f x | f <- [round, floor, ceiling], x <- [-1/0, 0/0, 1/0 :: Float] ] :: [Int]
[0,0,0,0,0,0,0,0,0]
>>> map properFraction [-1/0, 0/0, 1/0] :: [(Int, Float)]
[(0,0.0),(0,0.0),(0,0.0)]

and get even more non-sensical if you ask for Integer instead of Int.

Since: base-2.1

Instance details

Defined in GHC.Float

Methods

properFraction :: Integral b => Float -> (b, Float) Source #

truncate :: Integral b => Float -> b Source #

round :: Integral b => Float -> b Source #

ceiling :: Integral b => Float -> b Source #

floor :: Integral b => Float -> b Source #

RealFrac a => RealFrac (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Methods

properFraction :: Integral b => Identity a -> (b, Identity a) Source #

truncate :: Integral b => Identity a -> b Source #

round :: Integral b => Identity a -> b Source #

ceiling :: Integral b => Identity a -> b Source #

floor :: Integral b => Identity a -> b Source #

RealFrac a => RealFrac (Down a) Source #

Since: base-4.14.0.0

Instance details

Defined in Data.Ord

Methods

properFraction :: Integral b => Down a -> (b, Down a) Source #

truncate :: Integral b => Down a -> b Source #

round :: Integral b => Down a -> b Source #

ceiling :: Integral b => Down a -> b Source #

floor :: Integral b => Down a -> b Source #

Integral a => RealFrac (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

properFraction :: Integral b => Ratio a -> (b, Ratio a) Source #

truncate :: Integral b => Ratio a -> b Source #

round :: Integral b => Ratio a -> b Source #

ceiling :: Integral b => Ratio a -> b Source #

floor :: Integral b => Ratio a -> b Source #

HasResolution a => RealFrac (Fixed a) Source #

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

properFraction :: Integral b => Fixed a -> (b, Fixed a) Source #

truncate :: Integral b => Fixed a -> b Source #

round :: Integral b => Fixed a -> b Source #

ceiling :: Integral b => Fixed a -> b Source #

floor :: Integral b => Fixed a -> b Source #

RealFrac a => RealFrac (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

properFraction :: Integral b0 => Const a b -> (b0, Const a b) Source #

truncate :: Integral b0 => Const a b -> b0 Source #

round :: Integral b0 => Const a b -> b0 Source #

ceiling :: Integral b0 => Const a b -> b0 Source #

floor :: Integral b0 => Const a b -> b0 Source #

class (RealFrac a, Floating a) => RealFloat a where Source #

Efficient, machine-independent access to the components of a floating-point number.

Methods

floatRadix :: a -> Integer Source #

a constant function, returning the radix of the representation (often 2)

floatDigits :: a -> Int Source #

a constant function, returning the number of digits of floatRadix in the significand

floatRange :: a -> (Int, Int) Source #

a constant function, returning the lowest and highest values the exponent may assume

decodeFloat :: a -> (Integer, Int) Source #

The function decodeFloat applied to a real floating-point number returns the significand expressed as an Integer and an appropriately scaled exponent (an Int). If decodeFloat x yields (m,n), then x is equal in value to m*b^^n, where b is the floating-point radix, and furthermore, either m and n are both zero or else b^(d-1) <= abs m < b^d, where d is the value of floatDigits x. In particular, decodeFloat 0 = (0,0). If the type contains a negative zero, also decodeFloat (-0.0) = (0,0). The result of decodeFloat x is unspecified if either of isNaN x or isInfinite x is True.

encodeFloat :: Integer -> Int -> a Source #

encodeFloat performs the inverse of decodeFloat in the sense that for finite x with the exception of -0.0, uncurry encodeFloat (decodeFloat x) = x. encodeFloat m n is one of the two closest representable floating-point numbers to m*b^^n (or ±Infinity if overflow occurs); usually the closer, but if m contains too many bits, the result may be rounded in the wrong direction.

exponent :: a -> Int Source #

exponent corresponds to the second component of decodeFloat. exponent 0 = 0 and for finite nonzero x, exponent x = snd (decodeFloat x) + floatDigits x. If x is a finite floating-point number, it is equal in value to significand x * b ^^ exponent x, where b is the floating-point radix. The behaviour is unspecified on infinite or NaN values.

significand :: a -> a Source #

The first component of decodeFloat, scaled to lie in the open interval (-1,1), either 0.0 or of absolute value >= 1/b, where b is the floating-point radix. The behaviour is unspecified on infinite or NaN values.

scaleFloat :: Int -> a -> a Source #

multiplies a floating-point number by an integer power of the radix

isNaN :: a -> Bool Source #

True if the argument is an IEEE "not-a-number" (NaN) value

isInfinite :: a -> Bool Source #

True if the argument is an IEEE infinity or negative infinity

isDenormalized :: a -> Bool Source #

True if the argument is too small to be represented in normalized format

isNegativeZero :: a -> Bool Source #

True if the argument is an IEEE negative zero

isIEEE :: a -> Bool Source #

True if the argument is an IEEE floating point number

atan2 :: a -> a -> a Source #

a version of arctangent taking two real floating-point arguments. For real floating x and y, atan2 y x computes the angle (from the positive x-axis) of the vector from the origin to the point (x,y). atan2 y x returns a value in the range [-pi, pi]. It follows the Common Lisp semantics for the origin when signed zeroes are supported. atan2 y 1, with y in a type that is RealFloat, should return the same value as atan y. A default definition of atan2 is provided, but implementors can provide a more accurate implementation.

Instances

Instances details
RealFloat CDouble Source # 
Instance details

Defined in Foreign.C.Types

RealFloat CFloat Source # 
Instance details

Defined in Foreign.C.Types

RealFloat Double Source #

Since: base-2.1

Instance details

Defined in GHC.Float

RealFloat Float Source #

Since: base-2.1

Instance details

Defined in GHC.Float

RealFloat a => RealFloat (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

RealFloat a => RealFloat (Down a) Source #

Since: base-4.14.0.0

Instance details

Defined in Data.Ord

RealFloat a => RealFloat (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Numeric functions

subtract :: Num a => a -> a -> a Source #

the same as flip (-).

Because - is treated specially in the Haskell grammar, (- e) is not a section, but an application of prefix negation. However, (subtract exp) is equivalent to the disallowed section.

even :: Integral a => a -> Bool Source #

odd :: Integral a => a -> Bool Source #

gcd :: Integral a => a -> a -> a Source #

gcd x y is the non-negative factor of both x and y of which every common factor of x and y is also a factor; for example gcd 4 2 = 2, gcd (-4) 6 = 2, gcd 0 4 = 4. gcd 0 0 = 0. (That is, the common divisor that is "greatest" in the divisibility preordering.)

Note: Since for signed fixed-width integer types, abs minBound < 0, the result may be negative if one of the arguments is minBound (and necessarily is if the other is 0 or minBound) for such types.

lcm :: Integral a => a -> a -> a Source #

lcm x y is the smallest positive integer that both x and y divide.

(^) :: (Num a, Integral b) => a -> b -> a infixr 8 Source #

raise a number to a non-negative integral power

(^^) :: (Fractional a, Integral b) => a -> b -> a infixr 8 Source #

raise a number to an integral power

fromIntegral :: (Integral a, Num b) => a -> b Source #

General coercion from Integral types.

WARNING: This function performs silent truncation if the result type is not at least as big as the argument's type.

realToFrac :: (Real a, Fractional b) => a -> b Source #

General coercion to Fractional types.

WARNING: This function goes through the Rational type, which does not have values for NaN for example. This means it does not round-trip.

For Double it also behaves differently with or without -O0:

Prelude> realToFrac nan -- With -O0
-Infinity
Prelude> realToFrac nan
NaN

Semigroups and Monoids

class Semigroup a where Source #

The class of semigroups (types with an associative binary operation).

Instances should satisfy the following:

Associativity
x <> (y <> z) = (x <> y) <> z

You can alternatively define sconcat instead of (<>), in which case the laws are:

Unit
sconcat (pure x) = x
Multiplication
sconcat (join xss) = sconcat (fmap sconcat xss)

Since: base-4.9.0.0

Minimal complete definition

(<>) | sconcat

Methods

(<>) :: a -> a -> a infixr 6 Source #

An associative operation.

Examples

Expand
>>> [1,2,3] <> [4,5,6]
[1,2,3,4,5,6]
>>> Just [1, 2, 3] <> Just [4, 5, 6]
Just [1,2,3,4,5,6]
>>> putStr "Hello, " <> putStrLn "World!"
Hello, World!

Instances

Instances details
Semigroup ByteArray Source #

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Semigroup All Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: All -> All -> All Source #

sconcat :: NonEmpty All -> All Source #

stimes :: Integral b => b -> All -> All Source #

Semigroup Any Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Any -> Any -> Any Source #

sconcat :: NonEmpty Any -> Any Source #

stimes :: Integral b => b -> Any -> Any Source #

Semigroup Void Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Semigroup Event Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Event.Internal.Types

Semigroup Lifetime Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Event.Internal.Types

Semigroup Ordering Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Semigroup () Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: () -> () -> () Source #

sconcat :: NonEmpty () -> () Source #

stimes :: Integral b => b -> () -> () Source #

Bits a => Semigroup (And a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(<>) :: And a -> And a -> And a Source #

sconcat :: NonEmpty (And a) -> And a Source #

stimes :: Integral b => b -> And a -> And a Source #

FiniteBits a => Semigroup (Iff a) Source #

This constraint is arguably too strong. However, as some types (such as Natural) have undefined complement, this is the only safe choice.

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(<>) :: Iff a -> Iff a -> Iff a Source #

sconcat :: NonEmpty (Iff a) -> Iff a Source #

stimes :: Integral b => b -> Iff a -> Iff a Source #

Bits a => Semigroup (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(<>) :: Ior a -> Ior a -> Ior a Source #

sconcat :: NonEmpty (Ior a) -> Ior a Source #

stimes :: Integral b => b -> Ior a -> Ior a Source #

Bits a => Semigroup (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

(<>) :: Xor a -> Xor a -> Xor a Source #

sconcat :: NonEmpty (Xor a) -> Xor a Source #

stimes :: Integral b => b -> Xor a -> Xor a Source #

Semigroup (Comparison a) Source #

(<>) on comparisons combines results with (<>) @Ordering. Without newtypes this equals liftA2 (liftA2 (<>)).

(<>) :: Comparison a -> Comparison a -> Comparison a
Comparison cmp <> Comparison cmp' = Comparison a a' ->
  cmp a a' <> cmp a a'
Instance details

Defined in Data.Functor.Contravariant

Semigroup (Equivalence a) Source #

(<>) on equivalences uses logical conjunction (&&) on the results. Without newtypes this equals liftA2 (liftA2 (&&)).

(<>) :: Equivalence a -> Equivalence a -> Equivalence a
Equivalence equiv <> Equivalence equiv' = Equivalence a b ->
  equiv a b && equiv' a b
Instance details

Defined in Data.Functor.Contravariant

Semigroup (Predicate a) Source #

(<>) on predicates uses logical conjunction (&&) on the results. Without newtypes this equals liftA2 (&&).

(<>) :: Predicate a -> Predicate a -> Predicate a
Predicate pred <> Predicate pred' = Predicate a ->
  pred a && pred' a
Instance details

Defined in Data.Functor.Contravariant

Semigroup a => Semigroup (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Semigroup (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Monoid

Methods

(<>) :: First a -> First a -> First a Source #

sconcat :: NonEmpty (First a) -> First a Source #

stimes :: Integral b => b -> First a -> First a Source #

Semigroup (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Monoid

Methods

(<>) :: Last a -> Last a -> Last a Source #

sconcat :: NonEmpty (Last a) -> Last a Source #

stimes :: Integral b => b -> Last a -> Last a Source #

Semigroup a => Semigroup (Down a) Source #

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

(<>) :: Down a -> Down a -> Down a Source #

sconcat :: NonEmpty (Down a) -> Down a Source #

stimes :: Integral b => b -> Down a -> Down a Source #

Semigroup (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(<>) :: First a -> First a -> First a Source #

sconcat :: NonEmpty (First a) -> First a Source #

stimes :: Integral b => b -> First a -> First a Source #

Semigroup (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(<>) :: Last a -> Last a -> Last a Source #

sconcat :: NonEmpty (Last a) -> Last a Source #

stimes :: Integral b => b -> Last a -> Last a Source #

Ord a => Semigroup (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(<>) :: Max a -> Max a -> Max a Source #

sconcat :: NonEmpty (Max a) -> Max a Source #

stimes :: Integral b => b -> Max a -> Max a Source #

Ord a => Semigroup (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(<>) :: Min a -> Min a -> Min a Source #

sconcat :: NonEmpty (Min a) -> Min a Source #

stimes :: Integral b => b -> Min a -> Min a Source #

Monoid m => Semigroup (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Semigroup a => Semigroup (Dual a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Dual a -> Dual a -> Dual a Source #

sconcat :: NonEmpty (Dual a) -> Dual a Source #

stimes :: Integral b => b -> Dual a -> Dual a Source #

Semigroup (Endo a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Endo a -> Endo a -> Endo a Source #

sconcat :: NonEmpty (Endo a) -> Endo a Source #

stimes :: Integral b => b -> Endo a -> Endo a Source #

Num a => Semigroup (Product a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Product a -> Product a -> Product a Source #

sconcat :: NonEmpty (Product a) -> Product a Source #

stimes :: Integral b => b -> Product a -> Product a Source #

Num a => Semigroup (Sum a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Sum a -> Sum a -> Sum a Source #

sconcat :: NonEmpty (Sum a) -> Sum a Source #

stimes :: Integral b => b -> Sum a -> Sum a Source #

Semigroup (NonEmpty a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Semigroup a => Semigroup (STM a) Source #

Since: base-4.17.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

(<>) :: STM a -> STM a -> STM a Source #

sconcat :: NonEmpty (STM a) -> STM a Source #

stimes :: Integral b => b -> STM a -> STM a Source #

(Generic a, Semigroup (Rep a ())) => Semigroup (Generically a) Source #

Since: base-4.17.0.0

Instance details

Defined in GHC.Generics

Semigroup p => Semigroup (Par1 p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: Par1 p -> Par1 p -> Par1 p Source #

sconcat :: NonEmpty (Par1 p) -> Par1 p Source #

stimes :: Integral b => b -> Par1 p -> Par1 p Source #

Semigroup a => Semigroup (IO a) Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: IO a -> IO a -> IO a Source #

sconcat :: NonEmpty (IO a) -> IO a Source #

stimes :: Integral b => b -> IO a -> IO a Source #

Semigroup a => Semigroup (Maybe a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: Maybe a -> Maybe a -> Maybe a Source #

sconcat :: NonEmpty (Maybe a) -> Maybe a Source #

stimes :: Integral b => b -> Maybe a -> Maybe a Source #

Semigroup a => Semigroup (Solo a) Source #

Since: base-4.15

Instance details

Defined in GHC.Base

Methods

(<>) :: Solo a -> Solo a -> Solo a Source #

sconcat :: NonEmpty (Solo a) -> Solo a Source #

stimes :: Integral b => b -> Solo a -> Solo a Source #

Semigroup [a] Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: [a] -> [a] -> [a] Source #

sconcat :: NonEmpty [a] -> [a] Source #

stimes :: Integral b => b -> [a] -> [a] Source #

Semigroup (Either a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Either

Methods

(<>) :: Either a b -> Either a b -> Either a b Source #

sconcat :: NonEmpty (Either a b) -> Either a b Source #

stimes :: Integral b0 => b0 -> Either a b -> Either a b Source #

Semigroup a => Semigroup (Op a b) Source #

(<>) @(Op a b) without newtypes is (<>) @(b->a) = liftA2 (<>). This lifts the Semigroup operation (<>) over the output of a.

(<>) :: Op a b -> Op a b -> Op a b
Op f <> Op g = Op a -> f a <> g a
Instance details

Defined in Data.Functor.Contravariant

Methods

(<>) :: Op a b -> Op a b -> Op a b Source #

sconcat :: NonEmpty (Op a b) -> Op a b Source #

stimes :: Integral b0 => b0 -> Op a b -> Op a b Source #

Semigroup (Proxy s) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Proxy

Methods

(<>) :: Proxy s -> Proxy s -> Proxy s Source #

sconcat :: NonEmpty (Proxy s) -> Proxy s Source #

stimes :: Integral b => b -> Proxy s -> Proxy s Source #

Semigroup (U1 p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: U1 p -> U1 p -> U1 p Source #

sconcat :: NonEmpty (U1 p) -> U1 p Source #

stimes :: Integral b => b -> U1 p -> U1 p Source #

Semigroup (V1 p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: V1 p -> V1 p -> V1 p Source #

sconcat :: NonEmpty (V1 p) -> V1 p Source #

stimes :: Integral b => b -> V1 p -> V1 p Source #

Semigroup a => Semigroup (ST s a) Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ST

Methods

(<>) :: ST s a -> ST s a -> ST s a Source #

sconcat :: NonEmpty (ST s a) -> ST s a Source #

stimes :: Integral b => b -> ST s a -> ST s a Source #

(Semigroup a, Semigroup b) => Semigroup (a, b) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b) -> (a, b) -> (a, b) Source #

sconcat :: NonEmpty (a, b) -> (a, b) Source #

stimes :: Integral b0 => b0 -> (a, b) -> (a, b) Source #

Semigroup b => Semigroup (a -> b) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a -> b) -> (a -> b) -> a -> b Source #

sconcat :: NonEmpty (a -> b) -> a -> b Source #

stimes :: Integral b0 => b0 -> (a -> b) -> a -> b Source #

Semigroup a => Semigroup (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

(<>) :: Const a b -> Const a b -> Const a b Source #

sconcat :: NonEmpty (Const a b) -> Const a b Source #

stimes :: Integral b0 => b0 -> Const a b -> Const a b Source #

(Applicative f, Semigroup a) => Semigroup (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

(<>) :: Ap f a -> Ap f a -> Ap f a Source #

sconcat :: NonEmpty (Ap f a) -> Ap f a Source #

stimes :: Integral b => b -> Ap f a -> Ap f a Source #

Alternative f => Semigroup (Alt f a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Alt f a -> Alt f a -> Alt f a Source #

sconcat :: NonEmpty (Alt f a) -> Alt f a Source #

stimes :: Integral b => b -> Alt f a -> Alt f a Source #

Semigroup (f p) => Semigroup (Rec1 f p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: Rec1 f p -> Rec1 f p -> Rec1 f p Source #

sconcat :: NonEmpty (Rec1 f p) -> Rec1 f p Source #

stimes :: Integral b => b -> Rec1 f p -> Rec1 f p Source #

(Semigroup a, Semigroup b, Semigroup c) => Semigroup (a, b, c) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b, c) -> (a, b, c) -> (a, b, c) Source #

sconcat :: NonEmpty (a, b, c) -> (a, b, c) Source #

stimes :: Integral b0 => b0 -> (a, b, c) -> (a, b, c) Source #

(Semigroup (f a), Semigroup (g a)) => Semigroup (Product f g a) Source #

Since: base-4.16.0.0

Instance details

Defined in Data.Functor.Product

Methods

(<>) :: Product f g a -> Product f g a -> Product f g a Source #

sconcat :: NonEmpty (Product f g a) -> Product f g a Source #

stimes :: Integral b => b -> Product f g a -> Product f g a Source #

(Semigroup (f p), Semigroup (g p)) => Semigroup ((f :*: g) p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: (f :*: g) p -> (f :*: g) p -> (f :*: g) p Source #

sconcat :: NonEmpty ((f :*: g) p) -> (f :*: g) p Source #

stimes :: Integral b => b -> (f :*: g) p -> (f :*: g) p Source #

Semigroup c => Semigroup (K1 i c p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: K1 i c p -> K1 i c p -> K1 i c p Source #

sconcat :: NonEmpty (K1 i c p) -> K1 i c p Source #

stimes :: Integral b => b -> K1 i c p -> K1 i c p Source #

(Semigroup a, Semigroup b, Semigroup c, Semigroup d) => Semigroup (a, b, c, d) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) Source #

sconcat :: NonEmpty (a, b, c, d) -> (a, b, c, d) Source #

stimes :: Integral b0 => b0 -> (a, b, c, d) -> (a, b, c, d) Source #

Semigroup (f (g a)) => Semigroup (Compose f g a) Source #

Since: base-4.16.0.0

Instance details

Defined in Data.Functor.Compose

Methods

(<>) :: Compose f g a -> Compose f g a -> Compose f g a Source #

sconcat :: NonEmpty (Compose f g a) -> Compose f g a Source #

stimes :: Integral b => b -> Compose f g a -> Compose f g a Source #

Semigroup (f (g p)) => Semigroup ((f :.: g) p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: (f :.: g) p -> (f :.: g) p -> (f :.: g) p Source #

sconcat :: NonEmpty ((f :.: g) p) -> (f :.: g) p Source #

stimes :: Integral b => b -> (f :.: g) p -> (f :.: g) p Source #

Semigroup (f p) => Semigroup (M1 i c f p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

(<>) :: M1 i c f p -> M1 i c f p -> M1 i c f p Source #

sconcat :: NonEmpty (M1 i c f p) -> M1 i c f p Source #

stimes :: Integral b => b -> M1 i c f p -> M1 i c f p Source #

(Semigroup a, Semigroup b, Semigroup c, Semigroup d, Semigroup e) => Semigroup (a, b, c, d, e) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) Source #

sconcat :: NonEmpty (a, b, c, d, e) -> (a, b, c, d, e) Source #

stimes :: Integral b0 => b0 -> (a, b, c, d, e) -> (a, b, c, d, e) Source #

class Semigroup a => Monoid a where Source #

The class of monoids (types with an associative binary operation that has an identity). Instances should satisfy the following:

Right identity
x <> mempty = x
Left identity
mempty <> x = x
Associativity
x <> (y <> z) = (x <> y) <> z (Semigroup law)
Concatenation
mconcat = foldr (<>) mempty

You can alternatively define mconcat instead of mempty, in which case the laws are:

Unit
mconcat (pure x) = x
Multiplication
mconcat (join xss) = mconcat (fmap mconcat xss)
Subclass
mconcat (toList xs) = sconcat xs

The method names refer to the monoid of lists under concatenation, but there are many other instances.

Some types can be viewed as a monoid in more than one way, e.g. both addition and multiplication on numbers. In such cases we often define newtypes and make those instances of Monoid, e.g. Sum and Product.

NOTE: Semigroup is a superclass of Monoid since base-4.11.0.0.

Minimal complete definition

mempty | mconcat

Methods

mempty :: a Source #

Identity of mappend

Examples

Expand
>>> "Hello world" <> mempty
"Hello world"
>>> mempty <> [1, 2, 3]
[1,2,3]

mappend :: a -> a -> a Source #

An associative operation

NOTE: This method is redundant and has the default implementation mappend = (<>) since base-4.11.0.0. Should it be implemented manually, since mappend is a synonym for (<>), it is expected that the two functions are defined the same way. In a future GHC release mappend will be removed from Monoid.

mconcat :: [a] -> a Source #

Fold a list using the monoid.

For most types, the default definition for mconcat will be used, but the function is included in the class definition so that an optimized version can be provided for specific types.

>>> mconcat ["Hello", " ", "Haskell", "!"]
"Hello Haskell!"

Instances

Instances details
Monoid ByteArray Source #

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Monoid All Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Monoid Any Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Monoid Event Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Internal.Types

Monoid Lifetime Source #

mappend takes the longer of two lifetimes.

Since: base-4.8.0.0

Instance details

Defined in GHC.Event.Internal.Types

Monoid Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Monoid () Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: () Source #

mappend :: () -> () -> () Source #

mconcat :: [()] -> () Source #

FiniteBits a => Monoid (And a) Source #

This constraint is arguably too strong. However, as some types (such as Natural) have undefined complement, this is the only safe choice.

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

mempty :: And a Source #

mappend :: And a -> And a -> And a Source #

mconcat :: [And a] -> And a Source #

FiniteBits a => Monoid (Iff a) Source #

This constraint is arguably too strong. However, as some types (such as Natural) have undefined complement, this is the only safe choice.

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

mempty :: Iff a Source #

mappend :: Iff a -> Iff a -> Iff a Source #

mconcat :: [Iff a] -> Iff a Source #

Bits a => Monoid (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

mempty :: Ior a Source #

mappend :: Ior a -> Ior a -> Ior a Source #

mconcat :: [Ior a] -> Ior a Source #

Bits a => Monoid (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

mempty :: Xor a Source #

mappend :: Xor a -> Xor a -> Xor a Source #

mconcat :: [Xor a] -> Xor a Source #

Monoid (Comparison a) Source #

mempty on comparisons always returns EQ. Without newtypes this equals pure (pure EQ).

mempty :: Comparison a
mempty = Comparison _ _ -> EQ
Instance details

Defined in Data.Functor.Contravariant

Monoid (Equivalence a) Source #

mempty on equivalences always returns True. Without newtypes this equals pure (pure True).

mempty :: Equivalence a
mempty = Equivalence _ _ -> True
Instance details

Defined in Data.Functor.Contravariant

Monoid (Predicate a) Source #

mempty on predicates always returns True. Without newtypes this equals pure True.

mempty :: Predicate a
mempty = _ -> True
Instance details

Defined in Data.Functor.Contravariant

Monoid a => Monoid (Identity a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Identity

Monoid (First a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

mempty :: First a Source #

mappend :: First a -> First a -> First a Source #

mconcat :: [First a] -> First a Source #

Monoid (Last a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

mempty :: Last a Source #

mappend :: Last a -> Last a -> Last a Source #

mconcat :: [Last a] -> Last a Source #

Monoid a => Monoid (Down a) Source #

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

mempty :: Down a Source #

mappend :: Down a -> Down a -> Down a Source #

mconcat :: [Down a] -> Down a Source #

(Ord a, Bounded a) => Monoid (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

mempty :: Max a Source #

mappend :: Max a -> Max a -> Max a Source #

mconcat :: [Max a] -> Max a Source #

(Ord a, Bounded a) => Monoid (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

mempty :: Min a Source #

mappend :: Min a -> Min a -> Min a Source #

mconcat :: [Min a] -> Min a Source #

Monoid m => Monoid (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Monoid a => Monoid (Dual a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Dual a Source #

mappend :: Dual a -> Dual a -> Dual a Source #

mconcat :: [Dual a] -> Dual a Source #

Monoid (Endo a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Endo a Source #

mappend :: Endo a -> Endo a -> Endo a Source #

mconcat :: [Endo a] -> Endo a Source #

Num a => Monoid (Product a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Num a => Monoid (Sum a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Sum a Source #

mappend :: Sum a -> Sum a -> Sum a Source #

mconcat :: [Sum a] -> Sum a Source #

Monoid a => Monoid (STM a) Source #

Since: base-4.17.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

mempty :: STM a Source #

mappend :: STM a -> STM a -> STM a Source #

mconcat :: [STM a] -> STM a Source #

(Generic a, Monoid (Rep a ())) => Monoid (Generically a) Source #

Since: base-4.17.0.0

Instance details

Defined in GHC.Generics

Monoid p => Monoid (Par1 p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: Par1 p Source #

mappend :: Par1 p -> Par1 p -> Par1 p Source #

mconcat :: [Par1 p] -> Par1 p Source #

Monoid a => Monoid (IO a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

mempty :: IO a Source #

mappend :: IO a -> IO a -> IO a Source #

mconcat :: [IO a] -> IO a Source #

Semigroup a => Monoid (Maybe a) Source #

Lift a semigroup into Maybe forming a Monoid according to http://en.wikipedia.org/wiki/Monoid: "Any semigroup S may be turned into a monoid simply by adjoining an element e not in S and defining e*e = e and e*s = s = s*e for all s ∈ S."

Since 4.11.0: constraint on inner a value generalised from Monoid to Semigroup.

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: Maybe a Source #

mappend :: Maybe a -> Maybe a -> Maybe a Source #

mconcat :: [Maybe a] -> Maybe a Source #

Monoid a => Monoid (Solo a) Source #

Since: base-4.15

Instance details

Defined in GHC.Base

Methods

mempty :: Solo a Source #

mappend :: Solo a -> Solo a -> Solo a Source #

mconcat :: [Solo a] -> Solo a Source #

Monoid [a] Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: [a] Source #

mappend :: [a] -> [a] -> [a] Source #

mconcat :: [[a]] -> [a] Source #

Monoid a => Monoid (Op a b) Source #

mempty @(Op a b) without newtypes is mempty @(b->a) = _ -> mempty.

mempty :: Op a b
mempty = Op _ -> mempty
Instance details

Defined in Data.Functor.Contravariant

Methods

mempty :: Op a b Source #

mappend :: Op a b -> Op a b -> Op a b Source #

mconcat :: [Op a b] -> Op a b Source #

Monoid (Proxy s) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

mempty :: Proxy s Source #

mappend :: Proxy s -> Proxy s -> Proxy s Source #

mconcat :: [Proxy s] -> Proxy s Source #

Monoid (U1 p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: U1 p Source #

mappend :: U1 p -> U1 p -> U1 p Source #

mconcat :: [U1 p] -> U1 p Source #

Monoid a => Monoid (ST s a) Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ST

Methods

mempty :: ST s a Source #

mappend :: ST s a -> ST s a -> ST s a Source #

mconcat :: [ST s a] -> ST s a Source #

(Monoid a, Monoid b) => Monoid (a, b) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b) Source #

mappend :: (a, b) -> (a, b) -> (a, b) Source #

mconcat :: [(a, b)] -> (a, b) Source #

Monoid b => Monoid (a -> b) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: a -> b Source #

mappend :: (a -> b) -> (a -> b) -> a -> b Source #

mconcat :: [a -> b] -> a -> b Source #

Monoid a => Monoid (Const a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

mempty :: Const a b Source #

mappend :: Const a b -> Const a b -> Const a b Source #

mconcat :: [Const a b] -> Const a b Source #

(Applicative f, Monoid a) => Monoid (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

mempty :: Ap f a Source #

mappend :: Ap f a -> Ap f a -> Ap f a Source #

mconcat :: [Ap f a] -> Ap f a Source #

Alternative f => Monoid (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Alt f a Source #

mappend :: Alt f a -> Alt f a -> Alt f a Source #

mconcat :: [Alt f a] -> Alt f a Source #

Monoid (f p) => Monoid (Rec1 f p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: Rec1 f p Source #

mappend :: Rec1 f p -> Rec1 f p -> Rec1 f p Source #

mconcat :: [Rec1 f p] -> Rec1 f p Source #

(Monoid a, Monoid b, Monoid c) => Monoid (a, b, c) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b, c) Source #

mappend :: (a, b, c) -> (a, b, c) -> (a, b, c) Source #

mconcat :: [(a, b, c)] -> (a, b, c) Source #

(Monoid (f a), Monoid (g a)) => Monoid (Product f g a) Source #

Since: base-4.16.0.0

Instance details

Defined in Data.Functor.Product

Methods

mempty :: Product f g a Source #

mappend :: Product f g a -> Product f g a -> Product f g a Source #

mconcat :: [Product f g a] -> Product f g a Source #

(Monoid (f p), Monoid (g p)) => Monoid ((f :*: g) p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: (f :*: g) p Source #

mappend :: (f :*: g) p -> (f :*: g) p -> (f :*: g) p Source #

mconcat :: [(f :*: g) p] -> (f :*: g) p Source #

Monoid c => Monoid (K1 i c p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: K1 i c p Source #

mappend :: K1 i c p -> K1 i c p -> K1 i c p Source #

mconcat :: [K1 i c p] -> K1 i c p Source #

(Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b, c, d) Source #

mappend :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) Source #

mconcat :: [(a, b, c, d)] -> (a, b, c, d) Source #

Monoid (f (g a)) => Monoid (Compose f g a) Source #

Since: base-4.16.0.0

Instance details

Defined in Data.Functor.Compose

Methods

mempty :: Compose f g a Source #

mappend :: Compose f g a -> Compose f g a -> Compose f g a Source #

mconcat :: [Compose f g a] -> Compose f g a Source #

Monoid (f (g p)) => Monoid ((f :.: g) p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: (f :.: g) p Source #

mappend :: (f :.: g) p -> (f :.: g) p -> (f :.: g) p Source #

mconcat :: [(f :.: g) p] -> (f :.: g) p Source #

Monoid (f p) => Monoid (M1 i c f p) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

mempty :: M1 i c f p Source #

mappend :: M1 i c f p -> M1 i c f p -> M1 i c f p Source #

mconcat :: [M1 i c f p] -> M1 i c f p Source #

(Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b, c, d, e) Source #

mappend :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) Source #

mconcat :: [(a, b, c, d, e)] -> (a, b, c, d, e) Source #

Monads and functors

class Functor (f :: Type -> Type) where Source #

A type f is a Functor if it provides a function fmap which, given any types a and b lets you apply any function from (a -> b) to turn an f a into an f b, preserving the structure of f. Furthermore f needs to adhere to the following:

Identity
fmap id == id
Composition
fmap (f . g) == fmap f . fmap g

Note, that the second law follows from the free theorem of the type fmap and the first law, so you need only check that the former condition holds. See https://www.schoolofhaskell.com/user/edwardk/snippets/fmap or https://github.com/quchen/articles/blob/master/second_functor_law.md for an explanation.

Minimal complete definition

fmap

Methods

fmap :: (a -> b) -> f a -> f b Source #

fmap is used to apply a function of type (a -> b) to a value of type f a, where f is a functor, to produce a value of type f b. Note that for any type constructor with more than one parameter (e.g., Either), only the last type parameter can be modified with fmap (e.g., b in `Either a b`).

Some type constructors with two parameters or more have a Bifunctor instance that allows both the last and the penultimate parameters to be mapped over.

Examples

Expand

Convert from a Maybe Int to a Maybe String using show:

>>> fmap show Nothing
Nothing
>>> fmap show (Just 3)
Just "3"

Convert from an Either Int Int to an Either Int String using show:

>>> fmap show (Left 17)
Left 17
>>> fmap show (Right 17)
Right "17"

Double each element of a list:

>>> fmap (*2) [1,2,3]
[2,4,6]

Apply even to the second element of a pair:

>>> fmap even (2,2)
(2,True)

It may seem surprising that the function is only applied to the last element of the tuple compared to the list example above which applies it to every element in the list. To understand, remember that tuples are type constructors with multiple type parameters: a tuple of 3 elements (a,b,c) can also be written (,,) a b c and its Functor instance is defined for Functor ((,,) a b) (i.e., only the third parameter is free to be mapped over with fmap).

It explains why fmap can be used with tuples containing values of different types as in the following example:

>>> fmap even ("hello", 1.0, 4)
("hello",1.0,True)

(<$) :: a -> f b -> f a infixl 4 Source #

Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version.

Examples

Expand

Perform a computation with Maybe and replace the result with a constant value if it is Just:

>>> 'a' <$ Just 2
Just 'a'
>>> 'a' <$ Nothing
Nothing

Instances

Instances details
Functor ZipList Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

fmap :: (a -> b) -> ZipList a -> ZipList b Source #

(<$) :: a -> ZipList b -> ZipList a Source #

Functor Handler Source #

Since: base-4.6.0.0

Instance details

Defined in Control.Exception

Methods

fmap :: (a -> b) -> Handler a -> Handler b Source #

(<$) :: a -> Handler b -> Handler a Source #

Functor Complex Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

fmap :: (a -> b) -> Complex a -> Complex b Source #

(<$) :: a -> Complex b -> Complex a Source #

Functor Identity Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Methods

fmap :: (a -> b) -> Identity a -> Identity b Source #

(<$) :: a -> Identity b -> Identity a Source #

Functor First Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Monoid

Methods

fmap :: (a -> b) -> First a -> First b Source #

(<$) :: a -> First b -> First a Source #

Functor Last Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Monoid

Methods

fmap :: (a -> b) -> Last a -> Last b Source #

(<$) :: a -> Last b -> Last a Source #

Functor Down Source #

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

fmap :: (a -> b) -> Down a -> Down b Source #

(<$) :: a -> Down b -> Down a Source #

Functor First Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> First a -> First b Source #

(<$) :: a -> First b -> First a Source #

Functor Last Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Last a -> Last b Source #

(<$) :: a -> Last b -> Last a Source #

Functor Max Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Max a -> Max b Source #

(<$) :: a -> Max b -> Max a Source #

Functor Min Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Min a -> Min b Source #

(<$) :: a -> Min b -> Min a Source #

Functor Dual Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Dual a -> Dual b Source #

(<$) :: a -> Dual b -> Dual a Source #

Functor Product Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Product a -> Product b Source #

(<$) :: a -> Product b -> Product a Source #

Functor Sum Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Sum a -> Sum b Source #

(<$) :: a -> Sum b -> Sum a Source #

Functor NonEmpty Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> NonEmpty a -> NonEmpty b Source #

(<$) :: a -> NonEmpty b -> NonEmpty a Source #

Functor STM Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

fmap :: (a -> b) -> STM a -> STM b Source #

(<$) :: a -> STM b -> STM a Source #

Functor NoIO Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.GHCi

Methods

fmap :: (a -> b) -> NoIO a -> NoIO b Source #

(<$) :: a -> NoIO b -> NoIO a Source #

Functor Par1 Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> Par1 a -> Par1 b Source #

(<$) :: a -> Par1 b -> Par1 a Source #

Functor ArgDescr Source #

Since: base-4.7.0.0

Instance details

Defined in System.Console.GetOpt

Methods

fmap :: (a -> b) -> ArgDescr a -> ArgDescr b Source #

(<$) :: a -> ArgDescr b -> ArgDescr a Source #

Functor ArgOrder Source #

Since: base-4.7.0.0

Instance details

Defined in System.Console.GetOpt

Methods

fmap :: (a -> b) -> ArgOrder a -> ArgOrder b Source #

(<$) :: a -> ArgOrder b -> ArgOrder a Source #

Functor OptDescr Source #

Since: base-4.7.0.0

Instance details

Defined in System.Console.GetOpt

Methods

fmap :: (a -> b) -> OptDescr a -> OptDescr b Source #

(<$) :: a -> OptDescr b -> OptDescr a Source #

Functor ReadP Source #

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

fmap :: (a -> b) -> ReadP a -> ReadP b Source #

(<$) :: a -> ReadP b -> ReadP a Source #

Functor ReadPrec Source #

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

fmap :: (a -> b) -> ReadPrec a -> ReadPrec b Source #

(<$) :: a -> ReadPrec b -> ReadPrec a Source #

Functor IO Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> IO a -> IO b Source #

(<$) :: a -> IO b -> IO a Source #

Functor Maybe Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> Maybe a -> Maybe b Source #

(<$) :: a -> Maybe b -> Maybe a Source #

Functor Solo Source #

Since: base-4.15

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> Solo a -> Solo b Source #

(<$) :: a -> Solo b -> Solo a Source #

Functor [] Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> [a] -> [b] Source #

(<$) :: a -> [b] -> [a] Source #

Monad m => Functor (WrappedMonad m) Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

fmap :: (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #

(<$) :: a -> WrappedMonad m b -> WrappedMonad m a Source #

Arrow a => Functor (ArrowMonad a) Source #

Since: base-4.6.0.0

Instance details

Defined in Control.Arrow

Methods

fmap :: (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b Source #

(<$) :: a0 -> ArrowMonad a b -> ArrowMonad a a0 Source #

Functor (ST s) Source #

Since: base-2.1

Instance details

Defined in Control.Monad.ST.Lazy.Imp

Methods

fmap :: (a -> b) -> ST s a -> ST s b Source #

(<$) :: a -> ST s b -> ST s a Source #

Functor (Either a) Source #

Since: base-3.0

Instance details

Defined in Data.Either

Methods

fmap :: (a0 -> b) -> Either a a0 -> Either a b Source #

(<$) :: a0 -> Either a b -> Either a a0 Source #

Functor (Proxy :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

fmap :: (a -> b) -> Proxy a -> Proxy b Source #

(<$) :: a -> Proxy b -> Proxy a Source #

Functor (Arg a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a0 -> b) -> Arg a a0 -> Arg a b Source #

(<$) :: a0 -> Arg a b -> Arg a a0 Source #

Functor (Array i) Source #

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

fmap :: (a -> b) -> Array i a -> Array i b Source #

(<$) :: a -> Array i b -> Array i a Source #

Functor (U1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> U1 a -> U1 b Source #

(<$) :: a -> U1 b -> U1 a Source #

Functor (V1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> V1 a -> V1 b Source #

(<$) :: a -> V1 b -> V1 a Source #

Functor (ST s) Source #

Since: base-2.1

Instance details

Defined in GHC.ST

Methods

fmap :: (a -> b) -> ST s a -> ST s b Source #

(<$) :: a -> ST s b -> ST s a Source #

Functor ((,) a) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b) -> (a, a0) -> (a, b) Source #

(<$) :: a0 -> (a, b) -> (a, a0) Source #

Arrow a => Functor (WrappedArrow a b) Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

fmap :: (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source #

(<$) :: a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source #

Functor m => Functor (Kleisli m a) Source #

Since: base-4.14.0.0

Instance details

Defined in Control.Arrow

Methods

fmap :: (a0 -> b) -> Kleisli m a a0 -> Kleisli m a b Source #

(<$) :: a0 -> Kleisli m a b -> Kleisli m a a0 Source #

Functor (Const m :: Type -> Type) Source #

Since: base-2.1

Instance details

Defined in Data.Functor.Const

Methods

fmap :: (a -> b) -> Const m a -> Const m b Source #

(<$) :: a -> Const m b -> Const m a Source #

Functor f => Functor (Ap f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

fmap :: (a -> b) -> Ap f a -> Ap f b Source #

(<$) :: a -> Ap f b -> Ap f a Source #

Functor f => Functor (Alt f) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Alt f a -> Alt f b Source #

(<$) :: a -> Alt f b -> Alt f a Source #

(Generic1 f, Functor (Rep1 f)) => Functor (Generically1 f) Source #

Since: base-4.17.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> Generically1 f a -> Generically1 f b Source #

(<$) :: a -> Generically1 f b -> Generically1 f a Source #

Functor f => Functor (Rec1 f) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> Rec1 f a -> Rec1 f b Source #

(<$) :: a -> Rec1 f b -> Rec1 f a Source #

Functor (URec (Ptr ()) :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec (Ptr ()) a -> URec (Ptr ()) b Source #

(<$) :: a -> URec (Ptr ()) b -> URec (Ptr ()) a Source #

Functor (URec Char :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Char a -> URec Char b Source #

(<$) :: a -> URec Char b -> URec Char a Source #

Functor (URec Double :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Double a -> URec Double b Source #

(<$) :: a -> URec Double b -> URec Double a Source #

Functor (URec Float :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Float a -> URec Float b Source #

(<$) :: a -> URec Float b -> URec Float a Source #

Functor (URec Int :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Int a -> URec Int b Source #

(<$) :: a -> URec Int b -> URec Int a Source #

Functor (URec Word :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Word a -> URec Word b Source #

(<$) :: a -> URec Word b -> URec Word a Source #

Functor ((,,) a b) Source #

Since: base-4.14.0.0

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b0) -> (a, b, a0) -> (a, b, b0) Source #

(<$) :: a0 -> (a, b, b0) -> (a, b, a0) Source #

(Functor f, Functor g) => Functor (Product f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

fmap :: (a -> b) -> Product f g a -> Product f g b Source #

(<$) :: a -> Product f g b -> Product f g a Source #

(Functor f, Functor g) => Functor (Sum f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

fmap :: (a -> b) -> Sum f g a -> Sum f g b Source #

(<$) :: a -> Sum f g b -> Sum f g a Source #

(Functor f, Functor g) => Functor (f :*: g) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> (f :*: g) a -> (f :*: g) b Source #

(<$) :: a -> (f :*: g) b -> (f :*: g) a Source #

(Functor f, Functor g) => Functor (f :+: g) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> (f :+: g) a -> (f :+: g) b Source #

(<$) :: a -> (f :+: g) b -> (f :+: g) a Source #

Functor (K1 i c :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> K1 i c a -> K1 i c b Source #

(<$) :: a -> K1 i c b -> K1 i c a Source #

Functor ((,,,) a b c) Source #

Since: base-4.14.0.0

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b0) -> (a, b, c, a0) -> (a, b, c, b0) Source #

(<$) :: a0 -> (a, b, c, b0) -> (a, b, c, a0) Source #

Functor ((->) r) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> (r -> a) -> r -> b Source #

(<$) :: a -> (r -> b) -> r -> a Source #

(Functor f, Functor g) => Functor (Compose f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

fmap :: (a -> b) -> Compose f g a -> Compose f g b Source #

(<$) :: a -> Compose f g b -> Compose f g a Source #

(Functor f, Functor g) => Functor (f :.: g) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> (f :.: g) a -> (f :.: g) b Source #

(<$) :: a -> (f :.: g) b -> (f :.: g) a Source #

Functor f => Functor (M1 i c f) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> M1 i c f a -> M1 i c f b Source #

(<$) :: a -> M1 i c f b -> M1 i c f a Source #

Functor ((,,,,) a b c d) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b0) -> (a, b, c, d, a0) -> (a, b, c, d, b0) Source #

(<$) :: a0 -> (a, b, c, d, b0) -> (a, b, c, d, a0) Source #

Functor ((,,,,,) a b c d e) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b0) -> (a, b, c, d, e, a0) -> (a, b, c, d, e, b0) Source #

(<$) :: a0 -> (a, b, c, d, e, b0) -> (a, b, c, d, e, a0) Source #

Functor ((,,,,,,) a b c d e f) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b0) -> (a, b, c, d, e, f, a0) -> (a, b, c, d, e, f, b0) Source #

(<$) :: a0 -> (a, b, c, d, e, f, b0) -> (a, b, c, d, e, f, a0) Source #

(<$>) :: Functor f => (a -> b) -> f a -> f b infixl 4 Source #

An infix synonym for fmap.

The name of this operator is an allusion to $. Note the similarities between their types:

 ($)  ::              (a -> b) ->   a ->   b
(<$>) :: Functor f => (a -> b) -> f a -> f b

Whereas $ is function application, <$> is function application lifted over a Functor.

Examples

Expand

Convert from a Maybe Int to a Maybe String using show:

>>> show <$> Nothing
Nothing
>>> show <$> Just 3
Just "3"

Convert from an Either Int Int to an Either Int String using show:

>>> show <$> Left 17
Left 17
>>> show <$> Right 17
Right "17"

Double each element of a list:

>>> (*2) <$> [1,2,3]
[2,4,6]

Apply even to the second element of a pair:

>>> even <$> (2,2)
(2,True)

class Functor f => Applicative (f :: Type -> Type) where Source #

A functor with application, providing operations to

  • embed pure expressions (pure), and
  • sequence computations and combine their results (<*> and liftA2).

A minimal complete definition must include implementations of pure and of either <*> or liftA2. If it defines both, then they must behave the same as their default definitions:

(<*>) = liftA2 id
liftA2 f x y = f <$> x <*> y

Further, any definition must satisfy the following:

Identity
pure id <*> v = v
Composition
pure (.) <*> u <*> v <*> w = u <*> (v <*> w)
Homomorphism
pure f <*> pure x = pure (f x)
Interchange
u <*> pure y = pure ($ y) <*> u

The other methods have the following default definitions, which may be overridden with equivalent specialized implementations:

As a consequence of these laws, the Functor instance for f will satisfy

It may be useful to note that supposing

forall x y. p (q x y) = f x . g y

it follows from the above that

liftA2 p (liftA2 q u v) = liftA2 f u . liftA2 g v

If f is also a Monad, it should satisfy

(which implies that pure and <*> satisfy the applicative functor laws).

Minimal complete definition

pure, ((<*>) | liftA2)

Methods

pure :: a -> f a Source #

Lift a value.

(<*>) :: f (a -> b) -> f a -> f b infixl 4 Source #

Sequential application.

A few functors support an implementation of <*> that is more efficient than the default one.

Example

Expand

Used in combination with (<$>), (<*>) can be used to build a record.

>>> data MyState = MyState {arg1 :: Foo, arg2 :: Bar, arg3 :: Baz}
>>> produceFoo :: Applicative f => f Foo
>>> produceBar :: Applicative f => f Bar
>>> produceBaz :: Applicative f => f Baz
>>> mkState :: Applicative f => f MyState
>>> mkState = MyState <$> produceFoo <*> produceBar <*> produceBaz

liftA2 :: (a -> b -> c) -> f a -> f b -> f c Source #

Lift a binary function to actions.

Some functors support an implementation of liftA2 that is more efficient than the default one. In particular, if fmap is an expensive operation, it is likely better to use liftA2 than to fmap over the structure and then use <*>.

This became a typeclass method in 4.10.0.0. Prior to that, it was a function defined in terms of <*> and fmap.

Example

Expand
>>> liftA2 (,) (Just 3) (Just 5)
Just (3,5)

(*>) :: f a -> f b -> f b infixl 4 Source #

Sequence actions, discarding the value of the first argument.

Examples

Expand

If used in conjunction with the Applicative instance for Maybe, you can chain Maybe computations, with a possible "early return" in case of Nothing.

>>> Just 2 *> Just 3
Just 3
>>> Nothing *> Just 3
Nothing

Of course a more interesting use case would be to have effectful computations instead of just returning pure values.

>>> import Data.Char
>>> import Text.ParserCombinators.ReadP
>>> let p = string "my name is " *> munch1 isAlpha <* eof
>>> readP_to_S p "my name is Simon"
[("Simon","")]

(<*) :: f a -> f b -> f a infixl 4 Source #

Sequence actions, discarding the value of the second argument.

Instances

Instances details
Applicative ZipList Source #
f <$> ZipList xs1 <*> ... <*> ZipList xsN
    = ZipList (zipWithN f xs1 ... xsN)

where zipWithN refers to the zipWith function of the appropriate arity (zipWith, zipWith3, zipWith4, ...). For example:

(\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..]
    = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..])
    = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> ZipList a Source #

(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b Source #

liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c Source #

(*>) :: ZipList a -> ZipList b -> ZipList b Source #

(<*) :: ZipList a -> ZipList b -> ZipList a Source #

Applicative Complex Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

pure :: a -> Complex a Source #

(<*>) :: Complex (a -> b) -> Complex a -> Complex b Source #

liftA2 :: (a -> b -> c) -> Complex a -> Complex b -> Complex c Source #

(*>) :: Complex a -> Complex b -> Complex b Source #

(<*) :: Complex a -> Complex b -> Complex a Source #

Applicative Identity Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Methods

pure :: a -> Identity a Source #

(<*>) :: Identity (a -> b) -> Identity a -> Identity b Source #

liftA2 :: (a -> b -> c) -> Identity a -> Identity b -> Identity c Source #

(*>) :: Identity a -> Identity b -> Identity b Source #

(<*) :: Identity a -> Identity b -> Identity a Source #

Applicative First Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Monoid

Methods

pure :: a -> First a Source #

(<*>) :: First (a -> b) -> First a -> First b Source #

liftA2 :: (a -> b -> c) -> First a -> First b -> First c Source #

(*>) :: First a -> First b -> First b Source #

(<*) :: First a -> First b -> First a Source #

Applicative Last Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Monoid

Methods

pure :: a -> Last a Source #

(<*>) :: Last (a -> b) -> Last a -> Last b Source #

liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c Source #

(*>) :: Last a -> Last b -> Last b Source #

(<*) :: Last a -> Last b -> Last a Source #

Applicative Down Source #

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

pure :: a -> Down a Source #

(<*>) :: Down (a -> b) -> Down a -> Down b Source #

liftA2 :: (a -> b -> c) -> Down a -> Down b -> Down c Source #

(*>) :: Down a -> Down b -> Down b Source #

(<*) :: Down a -> Down b -> Down a Source #

Applicative First Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> First a Source #

(<*>) :: First (a -> b) -> First a -> First b Source #

liftA2 :: (a -> b -> c) -> First a -> First b -> First c Source #

(*>) :: First a -> First b -> First b Source #

(<*) :: First a -> First b -> First a Source #

Applicative Last Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Last a Source #

(<*>) :: Last (a -> b) -> Last a -> Last b Source #

liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c Source #

(*>) :: Last a -> Last b -> Last b Source #

(<*) :: Last a -> Last b -> Last a Source #

Applicative Max Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Max a Source #

(<*>) :: Max (a -> b) -> Max a -> Max b Source #

liftA2 :: (a -> b -> c) -> Max a -> Max b -> Max c Source #

(*>) :: Max a -> Max b -> Max b Source #

(<*) :: Max a -> Max b -> Max a Source #

Applicative Min Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Min a Source #

(<*>) :: Min (a -> b) -> Min a -> Min b Source #

liftA2 :: (a -> b -> c) -> Min a -> Min b -> Min c Source #

(*>) :: Min a -> Min b -> Min b Source #

(<*) :: Min a -> Min b -> Min a Source #

Applicative Dual Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Dual a Source #

(<*>) :: Dual (a -> b) -> Dual a -> Dual b Source #

liftA2 :: (a -> b -> c) -> Dual a -> Dual b -> Dual c Source #

(*>) :: Dual a -> Dual b -> Dual b Source #

(<*) :: Dual a -> Dual b -> Dual a Source #

Applicative Product Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Product a Source #

(<*>) :: Product (a -> b) -> Product a -> Product b Source #

liftA2 :: (a -> b -> c) -> Product a -> Product b -> Product c Source #

(*>) :: Product a -> Product b -> Product b Source #

(<*) :: Product a -> Product b -> Product a Source #

Applicative Sum Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Sum a Source #

(<*>) :: Sum (a -> b) -> Sum a -> Sum b Source #

liftA2 :: (a -> b -> c) -> Sum a -> Sum b -> Sum c Source #

(*>) :: Sum a -> Sum b -> Sum b Source #

(<*) :: Sum a -> Sum b -> Sum a Source #

Applicative NonEmpty Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

pure :: a -> NonEmpty a Source #

(<*>) :: NonEmpty (a -> b) -> NonEmpty a -> NonEmpty b Source #

liftA2 :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c Source #

(*>) :: NonEmpty a -> NonEmpty b -> NonEmpty b Source #

(<*) :: NonEmpty a -> NonEmpty b -> NonEmpty a Source #

Applicative STM Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

pure :: a -> STM a Source #

(<*>) :: STM (a -> b) -> STM a -> STM b Source #

liftA2 :: (a -> b -> c) -> STM a -> STM b -> STM c Source #

(*>) :: STM a -> STM b -> STM b Source #

(<*) :: STM a -> STM b -> STM a Source #

Applicative NoIO Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.GHCi

Methods

pure :: a -> NoIO a Source #

(<*>) :: NoIO (a -> b) -> NoIO a -> NoIO b Source #

liftA2 :: (a -> b -> c) -> NoIO a -> NoIO b -> NoIO c Source #

(*>) :: NoIO a -> NoIO b -> NoIO b Source #

(<*) :: NoIO a -> NoIO b -> NoIO a Source #

Applicative Par1 Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> Par1 a Source #

(<*>) :: Par1 (a -> b) -> Par1 a -> Par1 b Source #

liftA2 :: (a -> b -> c) -> Par1 a -> Par1 b -> Par1 c Source #

(*>) :: Par1 a -> Par1 b -> Par1 b Source #

(<*) :: Par1 a -> Par1 b -> Par1 a Source #

Applicative ReadP Source #

Since: base-4.6.0.0

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> ReadP a Source #

(<*>) :: ReadP (a -> b) -> ReadP a -> ReadP b Source #

liftA2 :: (a -> b -> c) -> ReadP a -> ReadP b -> ReadP c Source #

(*>) :: ReadP a -> ReadP b -> ReadP b Source #

(<*) :: ReadP a -> ReadP b -> ReadP a Source #

Applicative ReadPrec Source #

Since: base-4.6.0.0

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

pure :: a -> ReadPrec a Source #

(<*>) :: ReadPrec (a -> b) -> ReadPrec a -> ReadPrec b Source #

liftA2 :: (a -> b -> c) -> ReadPrec a -> ReadPrec b -> ReadPrec c Source #

(*>) :: ReadPrec a -> ReadPrec b -> ReadPrec b Source #

(<*) :: ReadPrec a -> ReadPrec b -> ReadPrec a Source #

Applicative IO Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> IO a Source #

(<*>) :: IO (a -> b) -> IO a -> IO b Source #

liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c Source #

(*>) :: IO a -> IO b -> IO b Source #

(<*) :: IO a -> IO b -> IO a Source #

Applicative Maybe Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> Maybe a Source #

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b Source #

liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c Source #

(*>) :: Maybe a -> Maybe b -> Maybe b Source #

(<*) :: Maybe a -> Maybe b -> Maybe a Source #

Applicative Solo Source #

Since: base-4.15

Instance details

Defined in GHC.Base

Methods

pure :: a -> Solo a Source #

(<*>) :: Solo (a -> b) -> Solo a -> Solo b Source #

liftA2 :: (a -> b -> c) -> Solo a -> Solo b -> Solo c Source #

(*>) :: Solo a -> Solo b -> Solo b Source #

(<*) :: Solo a -> Solo b -> Solo a Source #

Applicative [] Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> [a] Source #

(<*>) :: [a -> b] -> [a] -> [b] Source #

liftA2 :: (a -> b -> c) -> [a] -> [b] -> [c] Source #

(*>) :: [a] -> [b] -> [b] Source #

(<*) :: [a] -> [b] -> [a] Source #

Monad m => Applicative (WrappedMonad m) Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a Source #

(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #

liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c Source #

(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source #

(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m a Source #

Arrow a => Applicative (ArrowMonad a) Source #

Since: base-4.6.0.0

Instance details

Defined in Control.Arrow

Methods

pure :: a0 -> ArrowMonad a a0 Source #

(<*>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b Source #

liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c Source #

(*>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b Source #

(<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0 Source #

Applicative (ST s) Source #

Since: base-2.1

Instance details

Defined in Control.Monad.ST.Lazy.Imp

Methods

pure :: a -> ST s a Source #

(<*>) :: ST s (a -> b) -> ST s a -> ST s b Source #

liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c Source #

(*>) :: ST s a -> ST s b -> ST s b Source #

(<*) :: ST s a -> ST s b -> ST s a Source #

Applicative (Either e) Source #

Since: base-3.0

Instance details

Defined in Data.Either

Methods

pure :: a -> Either e a Source #

(<*>) :: Either e (a -> b) -> Either e a -> Either e b Source #

liftA2 :: (a -> b -> c) -> Either e a -> Either e b -> Either e c Source #

(*>) :: Either e a -> Either e b -> Either e b Source #

(<*) :: Either e a -> Either e b -> Either e a Source #

Applicative (Proxy :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

pure :: a -> Proxy a Source #

(<*>) :: Proxy (a -> b) -> Proxy a -> Proxy b Source #

liftA2 :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c Source #

(*>) :: Proxy a -> Proxy b -> Proxy b Source #

(<*) :: Proxy a -> Proxy b -> Proxy a Source #

Applicative (U1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> U1 a Source #

(<*>) :: U1 (a -> b) -> U1 a -> U1 b Source #

liftA2 :: (a -> b -> c) -> U1 a -> U1 b -> U1 c Source #

(*>) :: U1 a -> U1 b -> U1 b Source #

(<*) :: U1 a -> U1 b -> U1 a Source #

Applicative (ST s) Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.ST

Methods

pure :: a -> ST s a Source #

(<*>) :: ST s (a -> b) -> ST s a -> ST s b Source #

liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c Source #

(*>) :: ST s a -> ST s b -> ST s b Source #

(<*) :: ST s a -> ST s b -> ST s a Source #

Monoid a => Applicative ((,) a) Source #

For tuples, the Monoid constraint on a determines how the first values merge. For example, Strings concatenate:

("hello ", (+15)) <*> ("world!", 2002)
("hello world!",2017)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a0 -> (a, a0) Source #

(<*>) :: (a, a0 -> b) -> (a, a0) -> (a, b) Source #

liftA2 :: (a0 -> b -> c) -> (a, a0) -> (a, b) -> (a, c) Source #

(*>) :: (a, a0) -> (a, b) -> (a, b) Source #

(<*) :: (a, a0) -> (a, b) -> (a, a0) Source #

Arrow a => Applicative (WrappedArrow a b) Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a0 -> WrappedArrow a b a0 Source #

(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source #

liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c Source #

(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 Source #

(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source #

Applicative m => Applicative (Kleisli m a) Source #

Since: base-4.14.0.0

Instance details

Defined in Control.Arrow

Methods

pure :: a0 -> Kleisli m a a0 Source #

(<*>) :: Kleisli m a (a0 -> b) -> Kleisli m a a0 -> Kleisli m a b Source #

liftA2 :: (a0 -> b -> c) -> Kleisli m a a0 -> Kleisli m a b -> Kleisli m a c Source #

(*>) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a b Source #

(<*) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a a0 Source #

Monoid m => Applicative (Const m :: Type -> Type) Source #

Since: base-2.0.1

Instance details

Defined in Data.Functor.Const

Methods

pure :: a -> Const m a Source #

(<*>) :: Const m (a -> b) -> Const m a -> Const m b Source #

liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c Source #

(*>) :: Const m a -> Const m b -> Const m b Source #

(<*) :: Const m a -> Const m b -> Const m a Source #

Applicative f => Applicative (Ap f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

pure :: a -> Ap f a Source #

(<*>) :: Ap f (a -> b) -> Ap f a -> Ap f b Source #

liftA2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c Source #

(*>) :: Ap f a -> Ap f b -> Ap f b Source #

(<*) :: Ap f a -> Ap f b -> Ap f a Source #

Applicative f => Applicative (Alt f) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Alt f a Source #

(<*>) :: Alt f (a -> b) -> Alt f a -> Alt f b Source #

liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c Source #

(*>) :: Alt f a -> Alt f b -> Alt f b Source #

(<*) :: Alt f a -> Alt f b -> Alt f a Source #

(Generic1 f, Applicative (Rep1 f)) => Applicative (Generically1 f) Source #

Since: base-4.17.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> Generically1 f a Source #

(<*>) :: Generically1 f (a -> b) -> Generically1 f a -> Generically1 f b Source #

liftA2 :: (a -> b -> c) -> Generically1 f a -> Generically1 f b -> Generically1 f c Source #

(*>) :: Generically1 f a -> Generically1 f b -> Generically1 f b Source #

(<*) :: Generically1 f a -> Generically1 f b -> Generically1 f a Source #

Applicative f => Applicative (Rec1 f) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> Rec1 f a Source #

(<*>) :: Rec1 f (a -> b) -> Rec1 f a -> Rec1 f b Source #

liftA2 :: (a -> b -> c) -> Rec1 f a -> Rec1 f b -> Rec1 f c Source #

(*>) :: Rec1 f a -> Rec1 f b -> Rec1 f b Source #

(<*) :: Rec1 f a -> Rec1 f b -> Rec1 f a Source #

(Monoid a, Monoid b) => Applicative ((,,) a b) Source #

Since: base-4.14.0.0

Instance details

Defined in GHC.Base

Methods

pure :: a0 -> (a, b, a0) Source #

(<*>) :: (a, b, a0 -> b0) -> (a, b, a0) -> (a, b, b0) Source #

liftA2 :: (a0 -> b0 -> c) -> (a, b, a0) -> (a, b, b0) -> (a, b, c) Source #

(*>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0) Source #

(<*) :: (a, b, a0) -> (a, b, b0) -> (a, b, a0) Source #

(Applicative f, Applicative g) => Applicative (Product f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

pure :: a -> Product f g a Source #

(<*>) :: Product f g (a -> b) -> Product f g a -> Product f g b Source #

liftA2 :: (a -> b -> c) -> Product f g a -> Product f g b -> Product f g c Source #

(*>) :: Product f g a -> Product f g b -> Product f g b Source #

(<*) :: Product f g a -> Product f g b -> Product f g a Source #

(Applicative f, Applicative g) => Applicative (f :*: g) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> (f :*: g) a Source #

(<*>) :: (f :*: g) (a -> b) -> (f :*: g) a -> (f :*: g) b Source #

liftA2 :: (a -> b -> c) -> (f :*: g) a -> (f :*: g) b -> (f :*: g) c Source #

(*>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b Source #

(<*) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) a Source #

Monoid c => Applicative (K1 i c :: Type -> Type) Source #

Since: base-4.12.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> K1 i c a Source #

(<*>) :: K1 i c (a -> b) -> K1 i c a -> K1 i c b Source #

liftA2 :: (a -> b -> c0) -> K1 i c a -> K1 i c b -> K1 i c c0 Source #

(*>) :: K1 i c a -> K1 i c b -> K1 i c b Source #

(<*) :: K1 i c a -> K1 i c b -> K1 i c a Source #

(Monoid a, Monoid b, Monoid c) => Applicative ((,,,) a b c) Source #

Since: base-4.14.0.0

Instance details

Defined in GHC.Base

Methods

pure :: a0 -> (a, b, c, a0) Source #

(<*>) :: (a, b, c, a0 -> b0) -> (a, b, c, a0) -> (a, b, c, b0) Source #

liftA2 :: (a0 -> b0 -> c0) -> (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, c0) Source #

(*>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0) Source #

(<*) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, a0) Source #

Applicative ((->) r) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> r -> a Source #

(<*>) :: (r -> (a -> b)) -> (r -> a) -> r -> b Source #

liftA2 :: (a -> b -> c) -> (r -> a) -> (r -> b) -> r -> c Source #

(*>) :: (r -> a) -> (r -> b) -> r -> b Source #

(<*) :: (r -> a) -> (r -> b) -> r -> a Source #

(Applicative f, Applicative g) => Applicative (Compose f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

pure :: a -> Compose f g a Source #

(<*>) :: Compose f g (a -> b) -> Compose f g a -> Compose f g b Source #

liftA2 :: (a -> b -> c) -> Compose f g a -> Compose f g b -> Compose f g c Source #

(*>) :: Compose f g a -> Compose f g b -> Compose f g b Source #

(<*) :: Compose f g a -> Compose f g b -> Compose f g a Source #

(Applicative f, Applicative g) => Applicative (f :.: g) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> (f :.: g) a Source #

(<*>) :: (f :.: g) (a -> b) -> (f :.: g) a -> (f :.: g) b Source #

liftA2 :: (a -> b -> c) -> (f :.: g) a -> (f :.: g) b -> (f :.: g) c Source #

(*>) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) b Source #

(<*) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) a Source #

Applicative f => Applicative (M1 i c f) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> M1 i c f a Source #

(<*>) :: M1 i c f (a -> b) -> M1 i c f a -> M1 i c f b Source #

liftA2 :: (a -> b -> c0) -> M1 i c f a -> M1 i c f b -> M1 i c f c0 Source #

(*>) :: M1 i c f a -> M1 i c f b -> M1 i c f b Source #

(<*) :: M1 i c f a -> M1 i c f b -> M1 i c f a Source #

class Applicative m => Monad (m :: Type -> Type) where Source #

The Monad class defines the basic operations over a monad, a concept from a branch of mathematics known as category theory. From the perspective of a Haskell programmer, however, it is best to think of a monad as an abstract datatype of actions. Haskell's do expressions provide a convenient syntax for writing monadic expressions.

Instances of Monad should satisfy the following:

Left identity
return a >>= k = k a
Right identity
m >>= return = m
Associativity
m >>= (\x -> k x >>= h) = (m >>= k) >>= h

Furthermore, the Monad and Applicative operations should relate as follows:

The above laws imply:

and that pure and (<*>) satisfy the applicative functor laws.

The instances of Monad for lists, Maybe and IO defined in the Prelude satisfy these laws.

Minimal complete definition

(>>=)

Methods

(>>=) :: m a -> (a -> m b) -> m b infixl 1 Source #

Sequentially compose two actions, passing any value produced by the first as an argument to the second.

'as >>= bs' can be understood as the do expression

do a <- as
   bs a

(>>) :: m a -> m b -> m b infixl 1 Source #

Sequentially compose two actions, discarding any value produced by the first, like sequencing operators (such as the semicolon) in imperative languages.

'as >> bs' can be understood as the do expression

do as
   bs

return :: a -> m a Source #

Inject a value into the monadic type.

Instances

Instances details
Monad Complex Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

(>>=) :: Complex a -> (a -> Complex b) -> Complex b Source #

(>>) :: Complex a -> Complex b -> Complex b Source #

return :: a -> Complex a Source #

Monad Identity Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Methods

(>>=) :: Identity a -> (a -> Identity b) -> Identity b Source #

(>>) :: Identity a -> Identity b -> Identity b Source #

return :: a -> Identity a Source #

Monad First Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Monoid

Methods

(>>=) :: First a -> (a -> First b) -> First b Source #

(>>) :: First a -> First b -> First b Source #

return :: a -> First a Source #

Monad Last Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Monoid

Methods

(>>=) :: Last a -> (a -> Last b) -> Last b Source #

(>>) :: Last a -> Last b -> Last b Source #

return :: a -> Last a Source #

Monad Down Source #

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

(>>=) :: Down a -> (a -> Down b) -> Down b Source #

(>>) :: Down a -> Down b -> Down b Source #

return :: a -> Down a Source #

Monad First Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: First a -> (a -> First b) -> First b Source #

(>>) :: First a -> First b -> First b Source #

return :: a -> First a Source #

Monad Last Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Last a -> (a -> Last b) -> Last b Source #

(>>) :: Last a -> Last b -> Last b Source #

return :: a -> Last a Source #

Monad Max Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Max a -> (a -> Max b) -> Max b Source #

(>>) :: Max a -> Max b -> Max b Source #

return :: a -> Max a Source #

Monad Min Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Min a -> (a -> Min b) -> Min b Source #

(>>) :: Min a -> Min b -> Min b Source #

return :: a -> Min a Source #

Monad Dual Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Dual a -> (a -> Dual b) -> Dual b Source #

(>>) :: Dual a -> Dual b -> Dual b Source #

return :: a -> Dual a Source #

Monad Product Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Product a -> (a -> Product b) -> Product b Source #

(>>) :: Product a -> Product b -> Product b Source #

return :: a -> Product a Source #

Monad Sum Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Sum a -> (a -> Sum b) -> Sum b Source #

(>>) :: Sum a -> Sum b -> Sum b Source #

return :: a -> Sum a Source #

Monad NonEmpty Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(>>=) :: NonEmpty a -> (a -> NonEmpty b) -> NonEmpty b Source #

(>>) :: NonEmpty a -> NonEmpty b -> NonEmpty b Source #

return :: a -> NonEmpty a Source #

Monad STM Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

(>>=) :: STM a -> (a -> STM b) -> STM b Source #

(>>) :: STM a -> STM b -> STM b Source #

return :: a -> STM a Source #

Monad NoIO Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.GHCi

Methods

(>>=) :: NoIO a -> (a -> NoIO b) -> NoIO b Source #

(>>) :: NoIO a -> NoIO b -> NoIO b Source #

return :: a -> NoIO a Source #

Monad Par1 Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: Par1 a -> (a -> Par1 b) -> Par1 b Source #

(>>) :: Par1 a -> Par1 b -> Par1 b Source #

return :: a -> Par1 a Source #

Monad ReadP Source #

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

(>>=) :: ReadP a -> (a -> ReadP b) -> ReadP b Source #

(>>) :: ReadP a -> ReadP b -> ReadP b Source #

return :: a -> ReadP a Source #

Monad ReadPrec Source #

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

(>>=) :: ReadPrec a -> (a -> ReadPrec b) -> ReadPrec b Source #

(>>) :: ReadPrec a -> ReadPrec b -> ReadPrec b Source #

return :: a -> ReadPrec a Source #

Monad IO Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: IO a -> (a -> IO b) -> IO b Source #

(>>) :: IO a -> IO b -> IO b Source #

return :: a -> IO a Source #

Monad Maybe Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b Source #

(>>) :: Maybe a -> Maybe b -> Maybe b Source #

return :: a -> Maybe a Source #

Monad Solo Source #

Since: base-4.15

Instance details

Defined in GHC.Base

Methods

(>>=) :: Solo a -> (a -> Solo b) -> Solo b Source #

(>>) :: Solo a -> Solo b -> Solo b Source #

return :: a -> Solo a Source #

Monad [] Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: [a] -> (a -> [b]) -> [b] Source #

(>>) :: [a] -> [b] -> [b] Source #

return :: a -> [a] Source #

Monad m => Monad (WrappedMonad m) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Methods

(>>=) :: WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b Source #

(>>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source #

return :: a -> WrappedMonad m a Source #

ArrowApply a => Monad (ArrowMonad a) Source #

Since: base-2.1

Instance details

Defined in Control.Arrow

Methods

(>>=) :: ArrowMonad a a0 -> (a0 -> ArrowMonad a b) -> ArrowMonad a b Source #

(>>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b Source #

return :: a0 -> ArrowMonad a a0 Source #

Monad (ST s) Source #

Since: base-2.1

Instance details

Defined in Control.Monad.ST.Lazy.Imp

Methods

(>>=) :: ST s a -> (a -> ST s b) -> ST s b Source #

(>>) :: ST s a -> ST s b -> ST s b Source #

return :: a -> ST s a Source #

Monad (Either e) Source #

Since: base-4.4.0.0

Instance details

Defined in Data.Either

Methods

(>>=) :: Either e a -> (a -> Either e b) -> Either e b Source #

(>>) :: Either e a -> Either e b -> Either e b Source #

return :: a -> Either e a Source #

Monad (Proxy :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

(>>=) :: Proxy a -> (a -> Proxy b) -> Proxy b Source #

(>>) :: Proxy a -> Proxy b -> Proxy b Source #

return :: a -> Proxy a Source #

Monad (U1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: U1 a -> (a -> U1 b) -> U1 b Source #

(>>) :: U1 a -> U1 b -> U1 b Source #

return :: a -> U1 a Source #

Monad (ST s) Source #

Since: base-2.1

Instance details

Defined in GHC.ST

Methods

(>>=) :: ST s a -> (a -> ST s b) -> ST s b Source #

(>>) :: ST s a -> ST s b -> ST s b Source #

return :: a -> ST s a Source #

Monoid a => Monad ((,) a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(>>=) :: (a, a0) -> (a0 -> (a, b)) -> (a, b) Source #

(>>) :: (a, a0) -> (a, b) -> (a, b) Source #

return :: a0 -> (a, a0) Source #

Monad m => Monad (Kleisli m a) Source #

Since: base-4.14.0.0

Instance details

Defined in Control.Arrow

Methods

(>>=) :: Kleisli m a a0 -> (a0 -> Kleisli m a b) -> Kleisli m a b Source #

(>>) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a b Source #

return :: a0 -> Kleisli m a a0 Source #

Monad f => Monad (Ap f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

(>>=) :: Ap f a -> (a -> Ap f b) -> Ap f b Source #

(>>) :: Ap f a -> Ap f b -> Ap f b Source #

return :: a -> Ap f a Source #

Monad f => Monad (Alt f) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Alt f a -> (a -> Alt f b) -> Alt f b Source #

(>>) :: Alt f a -> Alt f b -> Alt f b Source #

return :: a -> Alt f a Source #

Monad f => Monad (Rec1 f) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: Rec1 f a -> (a -> Rec1 f b) -> Rec1 f b Source #

(>>) :: Rec1 f a -> Rec1 f b -> Rec1 f b Source #

return :: a -> Rec1 f a Source #

(Monoid a, Monoid b) => Monad ((,,) a b) Source #

Since: base-4.14.0.0

Instance details

Defined in GHC.Base

Methods

(>>=) :: (a, b, a0) -> (a0 -> (a, b, b0)) -> (a, b, b0) Source #

(>>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0) Source #

return :: a0 -> (a, b, a0) Source #

(Monad f, Monad g) => Monad (Product f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

(>>=) :: Product f g a -> (a -> Product f g b) -> Product f g b Source #

(>>) :: Product f g a -> Product f g b -> Product f g b Source #

return :: a -> Product f g a Source #

(Monad f, Monad g) => Monad (f :*: g) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: (f :*: g) a -> (a -> (f :*: g) b) -> (f :*: g) b Source #

(>>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b Source #

return :: a -> (f :*: g) a Source #

(Monoid a, Monoid b, Monoid c) => Monad ((,,,) a b c) Source #

Since: base-4.14.0.0

Instance details

Defined in GHC.Base

Methods

(>>=) :: (a, b, c, a0) -> (a0 -> (a, b, c, b0)) -> (a, b, c, b0) Source #

(>>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0) Source #

return :: a0 -> (a, b, c, a0) Source #

Monad ((->) r) Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: (r -> a) -> (a -> r -> b) -> r -> b Source #

(>>) :: (r -> a) -> (r -> b) -> r -> b Source #

return :: a -> r -> a Source #

Monad f => Monad (M1 i c f) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: M1 i c f a -> (a -> M1 i c f b) -> M1 i c f b Source #

(>>) :: M1 i c f a -> M1 i c f b -> M1 i c f b Source #

return :: a -> M1 i c f a Source #

class Monad m => MonadFail (m :: Type -> Type) where Source #

When a value is bound in do-notation, the pattern on the left hand side of <- might not match. In this case, this class provides a function to recover.

A Monad without a MonadFail instance may only be used in conjunction with pattern that always match, such as newtypes, tuples, data types with only a single data constructor, and irrefutable patterns (~pat).

Instances of MonadFail should satisfy the following law: fail s should be a left zero for >>=,

fail s >>= f  =  fail s

If your Monad is also MonadPlus, a popular definition is

fail _ = mzero

fail s should be an action that runs in the monad itself, not an exception (except in instances of MonadIO). In particular, fail should not be implemented in terms of error.

Since: base-4.9.0.0

Methods

fail :: String -> m a Source #

Instances

Instances details
MonadFail ReadP Source #

Since: base-4.9.0.0

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

fail :: String -> ReadP a Source #

MonadFail ReadPrec Source #

Since: base-4.9.0.0

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

fail :: String -> ReadPrec a Source #

MonadFail IO Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.Fail

Methods

fail :: String -> IO a Source #

MonadFail Maybe Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.Fail

Methods

fail :: String -> Maybe a Source #

MonadFail [] Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.Fail

Methods

fail :: String -> [a] Source #

MonadFail f => MonadFail (Ap f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

fail :: String -> Ap f a Source #

mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m () Source #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM.

mapM_ is just like traverse_, but specialised to monadic actions.

sequence_ :: (Foldable t, Monad m) => t (m a) -> m () Source #

Evaluate each monadic action in the structure from left to right, and ignore the results. For a version that doesn't ignore the results see sequence.

sequence_ is just like sequenceA_, but specialised to monadic actions.

(=<<) :: Monad m => (a -> m b) -> m a -> m b infixr 1 Source #

Same as >>=, but with the arguments interchanged.

Folds and traversals

class Foldable (t :: Type -> Type) where Source #

The Foldable class represents data structures that can be reduced to a summary value one element at a time. Strict left-associative folds are a good fit for space-efficient reduction, while lazy right-associative folds are a good fit for corecursive iteration, or for folds that short-circuit after processing an initial subsequence of the structure's elements.

Instances can be derived automatically by enabling the DeriveFoldable extension. For example, a derived instance for a binary tree might be:

{-# LANGUAGE DeriveFoldable #-}
data Tree a = Empty
            | Leaf a
            | Node (Tree a) a (Tree a)
    deriving Foldable

A more detailed description can be found in the Overview section of Data.Foldable.

For the class laws see the Laws section of Data.Foldable.

Minimal complete definition

foldMap | foldr

Methods

foldMap :: Monoid m => (a -> m) -> t a -> m Source #

Map each element of the structure into a monoid, and combine the results with (<>). This fold is right-associative and lazy in the accumulator. For strict left-associative folds consider foldMap' instead.

Examples

Expand

Basic usage:

>>> foldMap Sum [1, 3, 5]
Sum {getSum = 9}
>>> foldMap Product [1, 3, 5]
Product {getProduct = 15}
>>> foldMap (replicate 3) [1, 2, 3]
[1,1,1,2,2,2,3,3,3]

When a Monoid's (<>) is lazy in its second argument, foldMap can return a result even from an unbounded structure. For example, lazy accumulation enables Data.ByteString.Builder to efficiently serialise large data structures and produce the output incrementally:

>>> import qualified Data.ByteString.Lazy as L
>>> import qualified Data.ByteString.Builder as B
>>> let bld :: Int -> B.Builder; bld i = B.intDec i <> B.word8 0x20
>>> let lbs = B.toLazyByteString $ foldMap bld [0..]
>>> L.take 64 lbs
"0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24"

foldr :: (a -> b -> b) -> b -> t a -> b Source #

Right-associative fold of a structure, lazy in the accumulator.

In the case of lists, foldr, when applied to a binary operator, a starting value (typically the right-identity of the operator), and a list, reduces the list using the binary operator, from right to left:

foldr f z [x1, x2, ..., xn] == x1 `f` (x2 `f` ... (xn `f` z)...)

Note that since the head of the resulting expression is produced by an application of the operator to the first element of the list, given an operator lazy in its right argument, foldr can produce a terminating expression from an unbounded list.

For a general Foldable structure this should be semantically identical to,

foldr f z = foldr f z . toList

Examples

Expand

Basic usage:

>>> foldr (||) False [False, True, False]
True
>>> foldr (||) False []
False
>>> foldr (\c acc -> acc ++ [c]) "foo" ['a', 'b', 'c', 'd']
"foodcba"
Infinite structures

⚠️ Applying foldr to infinite structures usually doesn't terminate.

It may still terminate under one of the following conditions:

  • the folding function is short-circuiting
  • the folding function is lazy on its second argument
Short-circuiting

(||) short-circuits on True values, so the following terminates because there is a True value finitely far from the left side:

>>> foldr (||) False (True : repeat False)
True

But the following doesn't terminate:

>>> foldr (||) False (repeat False ++ [True])
* Hangs forever *
Laziness in the second argument

Applying foldr to infinite structures terminates when the operator is lazy in its second argument (the initial accumulator is never used in this case, and so could be left undefined, but [] is more clear):

>>> take 5 $ foldr (\i acc -> i : fmap (+3) acc) [] (repeat 1)
[1,4,7,10,13]

foldl :: (b -> a -> b) -> b -> t a -> b Source #

Left-associative fold of a structure, lazy in the accumulator. This is rarely what you want, but can work well for structures with efficient right-to-left sequencing and an operator that is lazy in its left argument.

In the case of lists, foldl, when applied to a binary operator, a starting value (typically the left-identity of the operator), and a list, reduces the list using the binary operator, from left to right:

foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn

Note that to produce the outermost application of the operator the entire input list must be traversed. Like all left-associative folds, foldl will diverge if given an infinite list.

If you want an efficient strict left-fold, you probably want to use foldl' instead of foldl. The reason for this is that the latter does not force the inner results (e.g. z `f` x1 in the above example) before applying them to the operator (e.g. to (`f` x2)). This results in a thunk chain O(n) elements long, which then must be evaluated from the outside-in.

For a general Foldable structure this should be semantically identical to:

foldl f z = foldl f z . toList

Examples

Expand

The first example is a strict fold, which in practice is best performed with foldl'.

>>> foldl (+) 42 [1,2,3,4]
52

Though the result below is lazy, the input is reversed before prepending it to the initial accumulator, so corecursion begins only after traversing the entire input string.

>>> foldl (\acc c -> c : acc) "abcd" "efgh"
"hgfeabcd"

A left fold of a structure that is infinite on the right cannot terminate, even when for any finite input the fold just returns the initial accumulator:

>>> foldl (\a _ -> a) 0 $ repeat 1
* Hangs forever *

WARNING: When it comes to lists, you always want to use either foldl' or foldr instead.

foldr1 :: (a -> a -> a) -> t a -> a Source #

A variant of foldr that has no base case, and thus may only be applied to non-empty structures.

This function is non-total and will raise a runtime exception if the structure happens to be empty.

Examples

Expand

Basic usage:

>>> foldr1 (+) [1..4]
10
>>> foldr1 (+) []
Exception: Prelude.foldr1: empty list
>>> foldr1 (+) Nothing
*** Exception: foldr1: empty structure
>>> foldr1 (-) [1..4]
-2
>>> foldr1 (&&) [True, False, True, True]
False
>>> foldr1 (||) [False, False, True, True]
True
>>> foldr1 (+) [1..]
* Hangs forever *

foldl1 :: (a -> a -> a) -> t a -> a Source #

A variant of foldl that has no base case, and thus may only be applied to non-empty structures.

This function is non-total and will raise a runtime exception if the structure happens to be empty.

foldl1 f = foldl1 f . toList

Examples

Expand

Basic usage:

>>> foldl1 (+) [1..4]
10
>>> foldl1 (+) []
*** Exception: Prelude.foldl1: empty list
>>> foldl1 (+) Nothing
*** Exception: foldl1: empty structure
>>> foldl1 (-) [1..4]
-8
>>> foldl1 (&&) [True, False, True, True]
False
>>> foldl1 (||) [False, False, True, True]
True
>>> foldl1 (+) [1..]
* Hangs forever *

elem :: Eq a => a -> t a -> Bool infix 4 Source #

Does the element occur in the structure?

Note: elem is often used in infix form.

Examples

Expand

Basic usage:

>>> 3 `elem` []
False
>>> 3 `elem` [1,2]
False
>>> 3 `elem` [1,2,3,4,5]
True

For infinite structures, the default implementation of elem terminates if the sought-after value exists at a finite distance from the left side of the structure:

>>> 3 `elem` [1..]
True
>>> 3 `elem` ([4..] ++ [3])
* Hangs forever *

Since: base-4.8.0.0

maximum :: Ord a => t a -> a Source #

The largest element of a non-empty structure.

This function is non-total and will raise a runtime exception if the structure happens to be empty. A structure that supports random access and maintains its elements in order should provide a specialised implementation to return the maximum in faster than linear time.

Examples

Expand

Basic usage:

>>> maximum [1..10]
10
>>> maximum []
*** Exception: Prelude.maximum: empty list
>>> maximum Nothing
*** Exception: maximum: empty structure

WARNING: This function is partial for possibly-empty structures like lists.

Since: base-4.8.0.0

minimum :: Ord a => t a -> a Source #

The least element of a non-empty structure.

This function is non-total and will raise a runtime exception if the structure happens to be empty. A structure that supports random access and maintains its elements in order should provide a specialised implementation to return the minimum in faster than linear time.

Examples

Expand

Basic usage:

>>> minimum [1..10]
1
>>> minimum []
*** Exception: Prelude.minimum: empty list
>>> minimum Nothing
*** Exception: minimum: empty structure

WARNING: This function is partial for possibly-empty structures like lists.

Since: base-4.8.0.0

sum :: Num a => t a -> a Source #

The sum function computes the sum of the numbers of a structure.

Examples

Expand

Basic usage:

>>> sum []
0
>>> sum [42]
42
>>> sum [1..10]
55
>>> sum [4.1, 2.0, 1.7]
7.8
>>> sum [1..]
* Hangs forever *

Since: base-4.8.0.0

product :: Num a => t a -> a Source #

The product function computes the product of the numbers of a structure.

Examples

Expand

Basic usage:

>>> product []
1
>>> product [42]
42
>>> product [1..10]
3628800
>>> product [4.1, 2.0, 1.7]
13.939999999999998
>>> product [1..]
* Hangs forever *

Since: base-4.8.0.0

Instances

Instances details
Foldable ZipList Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Applicative

Methods

fold :: Monoid m => ZipList m -> m Source #

foldMap :: Monoid m => (a -> m) -> ZipList a -> m Source #

foldMap' :: Monoid m => (a -> m) -> ZipList a -> m Source #

foldr :: (a -> b -> b) -> b -> ZipList a -> b Source #

foldr' :: (a -> b -> b) -> b -> ZipList a -> b Source #

foldl :: (b -> a -> b) -> b -> ZipList a -> b Source #

foldl' :: (b -> a -> b) -> b -> ZipList a -> b Source #

foldr1 :: (a -> a -> a) -> ZipList a -> a Source #

foldl1 :: (a -> a -> a) -> ZipList a -> a Source #

toList :: ZipList a -> [a] Source #

null :: ZipList a -> Bool Source #

length :: ZipList a -> Int Source #

elem :: Eq a => a -> ZipList a -> Bool Source #

maximum :: Ord a => ZipList a -> a Source #

minimum :: Ord a => ZipList a -> a Source #

sum :: Num a => ZipList a -> a Source #

product :: Num a => ZipList a -> a Source #

Foldable Complex Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

fold :: Monoid m => Complex m -> m Source #

foldMap :: Monoid m => (a -> m) -> Complex a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Complex a -> m Source #

foldr :: (a -> b -> b) -> b -> Complex a -> b Source #

foldr' :: (a -> b -> b) -> b -> Complex a -> b Source #

foldl :: (b -> a -> b) -> b -> Complex a -> b Source #

foldl' :: (b -> a -> b) -> b -> Complex a -> b Source #

foldr1 :: (a -> a -> a) -> Complex a -> a Source #

foldl1 :: (a -> a -> a) -> Complex a -> a Source #

toList :: Complex a -> [a] Source #

null :: Complex a -> Bool Source #

length :: Complex a -> Int Source #

elem :: Eq a => a -> Complex a -> Bool Source #

maximum :: Ord a => Complex a -> a Source #

minimum :: Ord a => Complex a -> a Source #

sum :: Num a => Complex a -> a Source #

product :: Num a => Complex a -> a Source #

Foldable Identity Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Methods

fold :: Monoid m => Identity m -> m Source #

foldMap :: Monoid m => (a -> m) -> Identity a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Identity a -> m Source #

foldr :: (a -> b -> b) -> b -> Identity a -> b Source #

foldr' :: (a -> b -> b) -> b -> Identity a -> b Source #

foldl :: (b -> a -> b) -> b -> Identity a -> b Source #

foldl' :: (b -> a -> b) -> b -> Identity a -> b Source #

foldr1 :: (a -> a -> a) -> Identity a -> a Source #

foldl1 :: (a -> a -> a) -> Identity a -> a Source #

toList :: Identity a -> [a] Source #

null :: Identity a -> Bool Source #

length :: Identity a -> Int Source #

elem :: Eq a => a -> Identity a -> Bool Source #

maximum :: Ord a => Identity a -> a Source #

minimum :: Ord a => Identity a -> a Source #

sum :: Num a => Identity a -> a Source #

product :: Num a => Identity a -> a Source #

Foldable First Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => First m -> m Source #

foldMap :: Monoid m => (a -> m) -> First a -> m Source #

foldMap' :: Monoid m => (a -> m) -> First a -> m Source #

foldr :: (a -> b -> b) -> b -> First a -> b Source #

foldr' :: (a -> b -> b) -> b -> First a -> b Source #

foldl :: (b -> a -> b) -> b -> First a -> b Source #

foldl' :: (b -> a -> b) -> b -> First a -> b Source #

foldr1 :: (a -> a -> a) -> First a -> a Source #

foldl1 :: (a -> a -> a) -> First a -> a Source #

toList :: First a -> [a] Source #

null :: First a -> Bool Source #

length :: First a -> Int Source #

elem :: Eq a => a -> First a -> Bool Source #

maximum :: Ord a => First a -> a Source #

minimum :: Ord a => First a -> a Source #

sum :: Num a => First a -> a Source #

product :: Num a => First a -> a Source #

Foldable Last Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Last m -> m Source #

foldMap :: Monoid m => (a -> m) -> Last a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Last a -> m Source #

foldr :: (a -> b -> b) -> b -> Last a -> b Source #

foldr' :: (a -> b -> b) -> b -> Last a -> b Source #

foldl :: (b -> a -> b) -> b -> Last a -> b Source #

foldl' :: (b -> a -> b) -> b -> Last a -> b Source #

foldr1 :: (a -> a -> a) -> Last a -> a Source #

foldl1 :: (a -> a -> a) -> Last a -> a Source #

toList :: Last a -> [a] Source #

null :: Last a -> Bool Source #

length :: Last a -> Int Source #

elem :: Eq a => a -> Last a -> Bool Source #

maximum :: Ord a => Last a -> a Source #

minimum :: Ord a => Last a -> a Source #

sum :: Num a => Last a -> a Source #

product :: Num a => Last a -> a Source #

Foldable Down Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Down m -> m Source #

foldMap :: Monoid m => (a -> m) -> Down a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Down a -> m Source #

foldr :: (a -> b -> b) -> b -> Down a -> b Source #

foldr' :: (a -> b -> b) -> b -> Down a -> b Source #

foldl :: (b -> a -> b) -> b -> Down a -> b Source #

foldl' :: (b -> a -> b) -> b -> Down a -> b Source #

foldr1 :: (a -> a -> a) -> Down a -> a Source #

foldl1 :: (a -> a -> a) -> Down a -> a Source #

toList :: Down a -> [a] Source #

null :: Down a -> Bool Source #

length :: Down a -> Int Source #

elem :: Eq a => a -> Down a -> Bool Source #

maximum :: Ord a => Down a -> a Source #

minimum :: Ord a => Down a -> a Source #

sum :: Num a => Down a -> a Source #

product :: Num a => Down a -> a Source #

Foldable First Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => First m -> m Source #

foldMap :: Monoid m => (a -> m) -> First a -> m Source #

foldMap' :: Monoid m => (a -> m) -> First a -> m Source #

foldr :: (a -> b -> b) -> b -> First a -> b Source #

foldr' :: (a -> b -> b) -> b -> First a -> b Source #

foldl :: (b -> a -> b) -> b -> First a -> b Source #

foldl' :: (b -> a -> b) -> b -> First a -> b Source #

foldr1 :: (a -> a -> a) -> First a -> a Source #

foldl1 :: (a -> a -> a) -> First a -> a Source #

toList :: First a -> [a] Source #

null :: First a -> Bool Source #

length :: First a -> Int Source #

elem :: Eq a => a -> First a -> Bool Source #

maximum :: Ord a => First a -> a Source #

minimum :: Ord a => First a -> a Source #

sum :: Num a => First a -> a Source #

product :: Num a => First a -> a Source #

Foldable Last Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Last m -> m Source #

foldMap :: Monoid m => (a -> m) -> Last a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Last a -> m Source #

foldr :: (a -> b -> b) -> b -> Last a -> b Source #

foldr' :: (a -> b -> b) -> b -> Last a -> b Source #

foldl :: (b -> a -> b) -> b -> Last a -> b Source #

foldl' :: (b -> a -> b) -> b -> Last a -> b Source #

foldr1 :: (a -> a -> a) -> Last a -> a Source #

foldl1 :: (a -> a -> a) -> Last a -> a Source #

toList :: Last a -> [a] Source #

null :: Last a -> Bool Source #

length :: Last a -> Int Source #

elem :: Eq a => a -> Last a -> Bool Source #

maximum :: Ord a => Last a -> a Source #

minimum :: Ord a => Last a -> a Source #

sum :: Num a => Last a -> a Source #

product :: Num a => Last a -> a Source #

Foldable Max Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Max m -> m Source #

foldMap :: Monoid m => (a -> m) -> Max a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Max a -> m Source #

foldr :: (a -> b -> b) -> b -> Max a -> b Source #

foldr' :: (a -> b -> b) -> b -> Max a -> b Source #

foldl :: (b -> a -> b) -> b -> Max a -> b Source #

foldl' :: (b -> a -> b) -> b -> Max a -> b Source #

foldr1 :: (a -> a -> a) -> Max a -> a Source #

foldl1 :: (a -> a -> a) -> Max a -> a Source #

toList :: Max a -> [a] Source #

null :: Max a -> Bool Source #

length :: Max a -> Int Source #

elem :: Eq a => a -> Max a -> Bool Source #

maximum :: Ord a => Max a -> a Source #

minimum :: Ord a => Max a -> a Source #

sum :: Num a => Max a -> a Source #

product :: Num a => Max a -> a Source #

Foldable Min Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Min m -> m Source #

foldMap :: Monoid m => (a -> m) -> Min a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Min a -> m Source #

foldr :: (a -> b -> b) -> b -> Min a -> b Source #

foldr' :: (a -> b -> b) -> b -> Min a -> b Source #

foldl :: (b -> a -> b) -> b -> Min a -> b Source #

foldl' :: (b -> a -> b) -> b -> Min a -> b Source #

foldr1 :: (a -> a -> a) -> Min a -> a Source #

foldl1 :: (a -> a -> a) -> Min a -> a Source #

toList :: Min a -> [a] Source #

null :: Min a -> Bool Source #

length :: Min a -> Int Source #

elem :: Eq a => a -> Min a -> Bool Source #

maximum :: Ord a => Min a -> a Source #

minimum :: Ord a => Min a -> a Source #

sum :: Num a => Min a -> a Source #

product :: Num a => Min a -> a Source #

Foldable Dual Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Dual m -> m Source #

foldMap :: Monoid m => (a -> m) -> Dual a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Dual a -> m Source #

foldr :: (a -> b -> b) -> b -> Dual a -> b Source #

foldr' :: (a -> b -> b) -> b -> Dual a -> b Source #

foldl :: (b -> a -> b) -> b -> Dual a -> b Source #

foldl' :: (b -> a -> b) -> b -> Dual a -> b Source #

foldr1 :: (a -> a -> a) -> Dual a -> a Source #

foldl1 :: (a -> a -> a) -> Dual a -> a Source #

toList :: Dual a -> [a] Source #

null :: Dual a -> Bool Source #

length :: Dual a -> Int Source #

elem :: Eq a => a -> Dual a -> Bool Source #

maximum :: Ord a => Dual a -> a Source #

minimum :: Ord a => Dual a -> a Source #

sum :: Num a => Dual a -> a Source #

product :: Num a => Dual a -> a Source #

Foldable Product Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Product m -> m Source #

foldMap :: Monoid m => (a -> m) -> Product a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Product a -> m Source #

foldr :: (a -> b -> b) -> b -> Product a -> b Source #

foldr' :: (a -> b -> b) -> b -> Product a -> b Source #

foldl :: (b -> a -> b) -> b -> Product a -> b Source #

foldl' :: (b -> a -> b) -> b -> Product a -> b Source #

foldr1 :: (a -> a -> a) -> Product a -> a Source #

foldl1 :: (a -> a -> a) -> Product a -> a Source #

toList :: Product a -> [a] Source #

null :: Product a -> Bool Source #

length :: Product a -> Int Source #

elem :: Eq a => a -> Product a -> Bool Source #

maximum :: Ord a => Product a -> a Source #

minimum :: Ord a => Product a -> a Source #

sum :: Num a => Product a -> a Source #

product :: Num a => Product a -> a Source #

Foldable Sum Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Sum m -> m Source #

foldMap :: Monoid m => (a -> m) -> Sum a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Sum a -> m Source #

foldr :: (a -> b -> b) -> b -> Sum a -> b Source #

foldr' :: (a -> b -> b) -> b -> Sum a -> b Source #

foldl :: (b -> a -> b) -> b -> Sum a -> b Source #

foldl' :: (b -> a -> b) -> b -> Sum a -> b Source #

foldr1 :: (a -> a -> a) -> Sum a -> a Source #

foldl1 :: (a -> a -> a) -> Sum a -> a Source #

toList :: Sum a -> [a] Source #

null :: Sum a -> Bool Source #

length :: Sum a -> Int Source #

elem :: Eq a => a -> Sum a -> Bool Source #

maximum :: Ord a => Sum a -> a Source #

minimum :: Ord a => Sum a -> a Source #

sum :: Num a => Sum a -> a Source #

product :: Num a => Sum a -> a Source #

Foldable NonEmpty Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => NonEmpty m -> m Source #

foldMap :: Monoid m => (a -> m) -> NonEmpty a -> m Source #

foldMap' :: Monoid m => (a -> m) -> NonEmpty a -> m Source #

foldr :: (a -> b -> b) -> b -> NonEmpty a -> b Source #

foldr' :: (a -> b -> b) -> b -> NonEmpty a -> b Source #

foldl :: (b -> a -> b) -> b -> NonEmpty a -> b Source #

foldl' :: (b -> a -> b) -> b -> NonEmpty a -> b Source #

foldr1 :: (a -> a -> a) -> NonEmpty a -> a Source #

foldl1 :: (a -> a -> a) -> NonEmpty a -> a Source #

toList :: NonEmpty a -> [a] Source #

null :: NonEmpty a -> Bool Source #

length :: NonEmpty a -> Int Source #

elem :: Eq a => a -> NonEmpty a -> Bool Source #

maximum :: Ord a => NonEmpty a -> a Source #

minimum :: Ord a => NonEmpty a -> a Source #

sum :: Num a => NonEmpty a -> a Source #

product :: Num a => NonEmpty a -> a Source #

Foldable Par1 Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Par1 m -> m Source #

foldMap :: Monoid m => (a -> m) -> Par1 a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Par1 a -> m Source #

foldr :: (a -> b -> b) -> b -> Par1 a -> b Source #

foldr' :: (a -> b -> b) -> b -> Par1 a -> b Source #

foldl :: (b -> a -> b) -> b -> Par1 a -> b Source #

foldl' :: (b -> a -> b) -> b -> Par1 a -> b Source #

foldr1 :: (a -> a -> a) -> Par1 a -> a Source #

foldl1 :: (a -> a -> a) -> Par1 a -> a Source #

toList :: Par1 a -> [a] Source #

null :: Par1 a -> Bool Source #

length :: Par1 a -> Int Source #

elem :: Eq a => a -> Par1 a -> Bool Source #

maximum :: Ord a => Par1 a -> a Source #

minimum :: Ord a => Par1 a -> a Source #

sum :: Num a => Par1 a -> a Source #

product :: Num a => Par1 a -> a Source #

Foldable Maybe Source #

Since: base-2.1

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Maybe m -> m Source #

foldMap :: Monoid m => (a -> m) -> Maybe a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Maybe a -> m Source #

foldr :: (a -> b -> b) -> b -> Maybe a -> b Source #

foldr' :: (a -> b -> b) -> b -> Maybe a -> b Source #

foldl :: (b -> a -> b) -> b -> Maybe a -> b Source #

foldl' :: (b -> a -> b) -> b -> Maybe a -> b Source #

foldr1 :: (a -> a -> a) -> Maybe a -> a Source #

foldl1 :: (a -> a -> a) -> Maybe a -> a Source #

toList :: Maybe a -> [a] Source #

null :: Maybe a -> Bool Source #

length :: Maybe a -> Int Source #

elem :: Eq a => a -> Maybe a -> Bool Source #

maximum :: Ord a => Maybe a -> a Source #

minimum :: Ord a => Maybe a -> a Source #

sum :: Num a => Maybe a -> a Source #

product :: Num a => Maybe a -> a Source #

Foldable Solo Source #

Since: base-4.15

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Solo m -> m Source #

foldMap :: Monoid m => (a -> m) -> Solo a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Solo a -> m Source #

foldr :: (a -> b -> b) -> b -> Solo a -> b Source #

foldr' :: (a -> b -> b) -> b -> Solo a -> b Source #

foldl :: (b -> a -> b) -> b -> Solo a -> b Source #

foldl' :: (b -> a -> b) -> b -> Solo a -> b Source #

foldr1 :: (a -> a -> a) -> Solo a -> a Source #

foldl1 :: (a -> a -> a) -> Solo a -> a Source #

toList :: Solo a -> [a] Source #

null :: Solo a -> Bool Source #

length :: Solo a -> Int Source #

elem :: Eq a => a -> Solo a -> Bool Source #

maximum :: Ord a => Solo a -> a Source #

minimum :: Ord a => Solo a -> a Source #

sum :: Num a => Solo a -> a Source #

product :: Num a => Solo a -> a Source #

Foldable [] Source #

Since: base-2.1

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => [m] -> m Source #

foldMap :: Monoid m => (a -> m) -> [a] -> m Source #

foldMap' :: Monoid m => (a -> m) -> [a] -> m Source #

foldr :: (a -> b -> b) -> b -> [a] -> b Source #

foldr' :: (a -> b -> b) -> b -> [a] -> b Source #

foldl :: (b -> a -> b) -> b -> [a] -> b Source #

foldl' :: (b -> a -> b) -> b -> [a] -> b Source #

foldr1 :: (a -> a -> a) -> [a] -> a Source #

foldl1 :: (a -> a -> a) -> [a] -> a Source #

toList :: [a] -> [a] Source #

null :: [a] -> Bool Source #

length :: [a] -> Int Source #

elem :: Eq a => a -> [a] -> Bool Source #

maximum :: Ord a => [a] -> a Source #

minimum :: Ord a => [a] -> a Source #

sum :: Num a => [a] -> a Source #

product :: Num a => [a] -> a Source #

Foldable (Either a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Either a m -> m Source #

foldMap :: Monoid m => (a0 -> m) -> Either a a0 -> m Source #

foldMap' :: Monoid m => (a0 -> m) -> Either a a0 -> m Source #

foldr :: (a0 -> b -> b) -> b -> Either a a0 -> b Source #

foldr' :: (a0 -> b -> b) -> b -> Either a a0 -> b Source #

foldl :: (b -> a0 -> b) -> b -> Either a a0 -> b Source #

foldl' :: (b -> a0 -> b) -> b -> Either a a0 -> b Source #

foldr1 :: (a0 -> a0 -> a0) -> Either a a0 -> a0 Source #

foldl1 :: (a0 -> a0 -> a0) -> Either a a0 -> a0 Source #

toList :: Either a a0 -> [a0] Source #

null :: Either a a0 -> Bool Source #

length :: Either a a0 -> Int Source #

elem :: Eq a0 => a0 -> Either a a0 -> Bool Source #

maximum :: Ord a0 => Either a a0 -> a0 Source #

minimum :: Ord a0 => Either a a0 -> a0 Source #

sum :: Num a0 => Either a a0 -> a0 Source #

product :: Num a0 => Either a a0 -> a0 Source #

Foldable (Proxy :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Proxy m -> m Source #

foldMap :: Monoid m => (a -> m) -> Proxy a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Proxy a -> m Source #

foldr :: (a -> b -> b) -> b -> Proxy a -> b Source #

foldr' :: (a -> b -> b) -> b -> Proxy a -> b Source #

foldl :: (b -> a -> b) -> b -> Proxy a -> b Source #

foldl' :: (b -> a -> b) -> b -> Proxy a -> b Source #

foldr1 :: (a -> a -> a) -> Proxy a -> a Source #

foldl1 :: (a -> a -> a) -> Proxy a -> a Source #

toList :: Proxy a -> [a] Source #

null :: Proxy a -> Bool Source #

length :: Proxy a -> Int Source #

elem :: Eq a => a -> Proxy a -> Bool Source #

maximum :: Ord a => Proxy a -> a Source #

minimum :: Ord a => Proxy a -> a Source #

sum :: Num a => Proxy a -> a Source #

product :: Num a => Proxy a -> a Source #

Foldable (Arg a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Arg a m -> m Source #

foldMap :: Monoid m => (a0 -> m) -> Arg a a0 -> m Source #

foldMap' :: Monoid m => (a0 -> m) -> Arg a a0 -> m Source #

foldr :: (a0 -> b -> b) -> b -> Arg a a0 -> b Source #

foldr' :: (a0 -> b -> b) -> b -> Arg a a0 -> b Source #

foldl :: (b -> a0 -> b) -> b -> Arg a a0 -> b Source #

foldl' :: (b -> a0 -> b) -> b -> Arg a a0 -> b Source #

foldr1 :: (a0 -> a0 -> a0) -> Arg a a0 -> a0 Source #

foldl1 :: (a0 -> a0 -> a0) -> Arg a a0 -> a0 Source #

toList :: Arg a a0 -> [a0] Source #

null :: Arg a a0 -> Bool Source #

length :: Arg a a0 -> Int Source #

elem :: Eq a0 => a0 -> Arg a a0 -> Bool Source #

maximum :: Ord a0 => Arg a a0 -> a0 Source #

minimum :: Ord a0 => Arg a a0 -> a0 Source #

sum :: Num a0 => Arg a a0 -> a0 Source #

product :: Num a0 => Arg a a0 -> a0 Source #

Foldable (Array i) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Array i m -> m Source #

foldMap :: Monoid m => (a -> m) -> Array i a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Array i a -> m Source #

foldr :: (a -> b -> b) -> b -> Array i a -> b Source #

foldr' :: (a -> b -> b) -> b -> Array i a -> b Source #

foldl :: (b -> a -> b) -> b -> Array i a -> b Source #

foldl' :: (b -> a -> b) -> b -> Array i a -> b Source #

foldr1 :: (a -> a -> a) -> Array i a -> a Source #

foldl1 :: (a -> a -> a) -> Array i a -> a Source #

toList :: Array i a -> [a] Source #

null :: Array i a -> Bool Source #

length :: Array i a -> Int Source #

elem :: Eq a => a -> Array i a -> Bool Source #

maximum :: Ord a => Array i a -> a Source #

minimum :: Ord a => Array i a -> a Source #

sum :: Num a => Array i a -> a Source #

product :: Num a => Array i a -> a Source #

Foldable (U1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => U1 m -> m Source #

foldMap :: Monoid m => (a -> m) -> U1 a -> m Source #

foldMap' :: Monoid m => (a -> m) -> U1 a -> m Source #

foldr :: (a -> b -> b) -> b -> U1 a -> b Source #

foldr' :: (a -> b -> b) -> b -> U1 a -> b Source #

foldl :: (b -> a -> b) -> b -> U1 a -> b Source #

foldl' :: (b -> a -> b) -> b -> U1 a -> b Source #

foldr1 :: (a -> a -> a) -> U1 a -> a Source #

foldl1 :: (a -> a -> a) -> U1 a -> a Source #

toList :: U1 a -> [a] Source #

null :: U1 a -> Bool Source #

length :: U1 a -> Int Source #

elem :: Eq a => a -> U1 a -> Bool Source #

maximum :: Ord a => U1 a -> a Source #

minimum :: Ord a => U1 a -> a Source #

sum :: Num a => U1 a -> a Source #

product :: Num a => U1 a -> a Source #

Foldable (UAddr :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UAddr m -> m Source #

foldMap :: Monoid m => (a -> m) -> UAddr a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UAddr a -> m Source #

foldr :: (a -> b -> b) -> b -> UAddr a -> b Source #

foldr' :: (a -> b -> b) -> b -> UAddr a -> b Source #

foldl :: (b -> a -> b) -> b -> UAddr a -> b Source #

foldl' :: (b -> a -> b) -> b -> UAddr a -> b Source #

foldr1 :: (a -> a -> a) -> UAddr a -> a Source #

foldl1 :: (a -> a -> a) -> UAddr a -> a Source #

toList :: UAddr a -> [a] Source #

null :: UAddr a -> Bool Source #

length :: UAddr a -> Int Source #

elem :: Eq a => a -> UAddr a -> Bool Source #

maximum :: Ord a => UAddr a -> a Source #

minimum :: Ord a => UAddr a -> a Source #

sum :: Num a => UAddr a -> a Source #

product :: Num a => UAddr a -> a Source #

Foldable (UChar :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UChar m -> m Source #

foldMap :: Monoid m => (a -> m) -> UChar a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UChar a -> m Source #

foldr :: (a -> b -> b) -> b -> UChar a -> b Source #

foldr' :: (a -> b -> b) -> b -> UChar a -> b Source #

foldl :: (b -> a -> b) -> b -> UChar a -> b Source #

foldl' :: (b -> a -> b) -> b -> UChar a -> b Source #

foldr1 :: (a -> a -> a) -> UChar a -> a Source #

foldl1 :: (a -> a -> a) -> UChar a -> a Source #

toList :: UChar a -> [a] Source #

null :: UChar a -> Bool Source #

length :: UChar a -> Int Source #

elem :: Eq a => a -> UChar a -> Bool Source #

maximum :: Ord a => UChar a -> a Source #

minimum :: Ord a => UChar a -> a Source #

sum :: Num a => UChar a -> a Source #

product :: Num a => UChar a -> a Source #

Foldable (UDouble :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UDouble m -> m Source #

foldMap :: Monoid m => (a -> m) -> UDouble a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UDouble a -> m Source #

foldr :: (a -> b -> b) -> b -> UDouble a -> b Source #

foldr' :: (a -> b -> b) -> b -> UDouble a -> b Source #

foldl :: (b -> a -> b) -> b -> UDouble a -> b Source #

foldl' :: (b -> a -> b) -> b -> UDouble a -> b Source #

foldr1 :: (a -> a -> a) -> UDouble a -> a Source #

foldl1 :: (a -> a -> a) -> UDouble a -> a Source #

toList :: UDouble a -> [a] Source #

null :: UDouble a -> Bool Source #

length :: UDouble a -> Int Source #

elem :: Eq a => a -> UDouble a -> Bool Source #

maximum :: Ord a => UDouble a -> a Source #

minimum :: Ord a => UDouble a -> a Source #

sum :: Num a => UDouble a -> a Source #

product :: Num a => UDouble a -> a Source #

Foldable (UFloat :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UFloat m -> m Source #

foldMap :: Monoid m => (a -> m) -> UFloat a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UFloat a -> m Source #

foldr :: (a -> b -> b) -> b -> UFloat a -> b Source #

foldr' :: (a -> b -> b) -> b -> UFloat a -> b Source #

foldl :: (b -> a -> b) -> b -> UFloat a -> b Source #

foldl' :: (b -> a -> b) -> b -> UFloat a -> b Source #

foldr1 :: (a -> a -> a) -> UFloat a -> a Source #

foldl1 :: (a -> a -> a) -> UFloat a -> a Source #

toList :: UFloat a -> [a] Source #

null :: UFloat a -> Bool Source #

length :: UFloat a -> Int Source #

elem :: Eq a => a -> UFloat a -> Bool Source #

maximum :: Ord a => UFloat a -> a Source #

minimum :: Ord a => UFloat a -> a Source #

sum :: Num a => UFloat a -> a Source #

product :: Num a => UFloat a -> a Source #

Foldable (UInt :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UInt m -> m Source #

foldMap :: Monoid m => (a -> m) -> UInt a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UInt a -> m Source #

foldr :: (a -> b -> b) -> b -> UInt a -> b Source #

foldr' :: (a -> b -> b) -> b -> UInt a -> b Source #

foldl :: (b -> a -> b) -> b -> UInt a -> b Source #

foldl' :: (b -> a -> b) -> b -> UInt a -> b Source #

foldr1 :: (a -> a -> a) -> UInt a -> a Source #

foldl1 :: (a -> a -> a) -> UInt a -> a Source #

toList :: UInt a -> [a] Source #

null :: UInt a -> Bool Source #

length :: UInt a -> Int Source #

elem :: Eq a => a -> UInt a -> Bool Source #

maximum :: Ord a => UInt a -> a Source #

minimum :: Ord a => UInt a -> a Source #

sum :: Num a => UInt a -> a Source #

product :: Num a => UInt a -> a Source #

Foldable (UWord :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UWord m -> m Source #

foldMap :: Monoid m => (a -> m) -> UWord a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UWord a -> m Source #

foldr :: (a -> b -> b) -> b -> UWord a -> b Source #

foldr' :: (a -> b -> b) -> b -> UWord a -> b Source #

foldl :: (b -> a -> b) -> b -> UWord a -> b Source #

foldl' :: (b -> a -> b) -> b -> UWord a -> b Source #

foldr1 :: (a -> a -> a) -> UWord a -> a Source #

foldl1 :: (a -> a -> a) -> UWord a -> a Source #

toList :: UWord a -> [a] Source #

null :: UWord a -> Bool Source #

length :: UWord a -> Int Source #

elem :: Eq a => a -> UWord a -> Bool Source #

maximum :: Ord a => UWord a -> a Source #

minimum :: Ord a => UWord a -> a Source #

sum :: Num a => UWord a -> a Source #

product :: Num a => UWord a -> a Source #

Foldable (V1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => V1 m -> m Source #

foldMap :: Monoid m => (a -> m) -> V1 a -> m Source #

foldMap' :: Monoid m => (a -> m) -> V1 a -> m Source #

foldr :: (a -> b -> b) -> b -> V1 a -> b Source #

foldr' :: (a -> b -> b) -> b -> V1 a -> b Source #

foldl :: (b -> a -> b) -> b -> V1 a -> b Source #

foldl' :: (b -> a -> b) -> b -> V1 a -> b Source #

foldr1 :: (a -> a -> a) -> V1 a -> a Source #

foldl1 :: (a -> a -> a) -> V1 a -> a Source #

toList :: V1 a -> [a] Source #

null :: V1 a -> Bool Source #

length :: V1 a -> Int Source #

elem :: Eq a => a -> V1 a -> Bool Source #

maximum :: Ord a => V1 a -> a Source #

minimum :: Ord a => V1 a -> a Source #

sum :: Num a => V1 a -> a Source #

product :: Num a => V1 a -> a Source #

Foldable ((,) a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (a, m) -> m Source #

foldMap :: Monoid m => (a0 -> m) -> (a, a0) -> m Source #

foldMap' :: Monoid m => (a0 -> m) -> (a, a0) -> m Source #

foldr :: (a0 -> b -> b) -> b -> (a, a0) -> b Source #

foldr' :: (a0 -> b -> b) -> b -> (a, a0) -> b Source #

foldl :: (b -> a0 -> b) -> b -> (a, a0) -> b Source #

foldl' :: (b -> a0 -> b) -> b -> (a, a0) -> b Source #

foldr1 :: (a0 -> a0 -> a0) -> (a, a0) -> a0 Source #

foldl1 :: (a0 -> a0 -> a0) -> (a, a0) -> a0 Source #

toList :: (a, a0) -> [a0] Source #

null :: (a, a0) -> Bool Source #

length :: (a, a0) -> Int Source #

elem :: Eq a0 => a0 -> (a, a0) -> Bool Source #

maximum :: Ord a0 => (a, a0) -> a0 Source #

minimum :: Ord a0 => (a, a0) -> a0 Source #

sum :: Num a0 => (a, a0) -> a0 Source #

product :: Num a0 => (a, a0) -> a0 Source #

Foldable (Const m :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Functor.Const

Methods

fold :: Monoid m0 => Const m m0 -> m0 Source #

foldMap :: Monoid m0 => (a -> m0) -> Const m a -> m0 Source #

foldMap' :: Monoid m0 => (a -> m0) -> Const m a -> m0 Source #

foldr :: (a -> b -> b) -> b -> Const m a -> b Source #

foldr' :: (a -> b -> b) -> b -> Const m a -> b Source #

foldl :: (b -> a -> b) -> b -> Const m a -> b Source #

foldl' :: (b -> a -> b) -> b -> Const m a -> b Source #

foldr1 :: (a -> a -> a) -> Const m a -> a Source #

foldl1 :: (a -> a -> a) -> Const m a -> a Source #

toList :: Const m a -> [a] Source #

null :: Const m a -> Bool Source #

length :: Const m a -> Int Source #

elem :: Eq a => a -> Const m a -> Bool Source #

maximum :: Ord a => Const m a -> a Source #

minimum :: Ord a => Const m a -> a Source #

sum :: Num a => Const m a -> a Source #

product :: Num a => Const m a -> a Source #

Foldable f => Foldable (Ap f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Ap f m -> m Source #

foldMap :: Monoid m => (a -> m) -> Ap f a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Ap f a -> m Source #

foldr :: (a -> b -> b) -> b -> Ap f a -> b Source #

foldr' :: (a -> b -> b) -> b -> Ap f a -> b Source #

foldl :: (b -> a -> b) -> b -> Ap f a -> b Source #

foldl' :: (b -> a -> b) -> b -> Ap f a -> b Source #

foldr1 :: (a -> a -> a) -> Ap f a -> a Source #

foldl1 :: (a -> a -> a) -> Ap f a -> a Source #

toList :: Ap f a -> [a] Source #

null :: Ap f a -> Bool Source #

length :: Ap f a -> Int Source #

elem :: Eq a => a -> Ap f a -> Bool Source #

maximum :: Ord a => Ap f a -> a Source #

minimum :: Ord a => Ap f a -> a Source #

sum :: Num a => Ap f a -> a Source #

product :: Num a => Ap f a -> a Source #

Foldable f => Foldable (Alt f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Alt f m -> m Source #

foldMap :: Monoid m => (a -> m) -> Alt f a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Alt f a -> m Source #

foldr :: (a -> b -> b) -> b -> Alt f a -> b Source #

foldr' :: (a -> b -> b) -> b -> Alt f a -> b Source #

foldl :: (b -> a -> b) -> b -> Alt f a -> b Source #

foldl' :: (b -> a -> b) -> b -> Alt f a -> b Source #

foldr1 :: (a -> a -> a) -> Alt f a -> a Source #

foldl1 :: (a -> a -> a) -> Alt f a -> a Source #

toList :: Alt f a -> [a] Source #

null :: Alt f a -> Bool Source #

length :: Alt f a -> Int Source #

elem :: Eq a => a -> Alt f a -> Bool Source #

maximum :: Ord a => Alt f a -> a Source #

minimum :: Ord a => Alt f a -> a Source #

sum :: Num a => Alt f a -> a Source #

product :: Num a => Alt f a -> a Source #

Foldable f => Foldable (Rec1 f) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Rec1 f m -> m Source #

foldMap :: Monoid m => (a -> m) -> Rec1 f a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Rec1 f a -> m Source #

foldr :: (a -> b -> b) -> b -> Rec1 f a -> b Source #

foldr' :: (a -> b -> b) -> b -> Rec1 f a -> b Source #

foldl :: (b -> a -> b) -> b -> Rec1 f a -> b Source #

foldl' :: (b -> a -> b) -> b -> Rec1 f a -> b Source #

foldr1 :: (a -> a -> a) -> Rec1 f a -> a Source #

foldl1 :: (a -> a -> a) -> Rec1 f a -> a Source #

toList :: Rec1 f a -> [a] Source #

null :: Rec1 f a -> Bool Source #

length :: Rec1 f a -> Int Source #

elem :: Eq a => a -> Rec1 f a -> Bool Source #

maximum :: Ord a => Rec1 f a -> a Source #

minimum :: Ord a => Rec1 f a -> a Source #

sum :: Num a => Rec1 f a -> a Source #

product :: Num a => Rec1 f a -> a Source #

(Foldable f, Foldable g) => Foldable (Product f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

fold :: Monoid m => Product f g m -> m Source #

foldMap :: Monoid m => (a -> m) -> Product f g a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Product f g a -> m Source #

foldr :: (a -> b -> b) -> b -> Product f g a -> b Source #

foldr' :: (a -> b -> b) -> b -> Product f g a -> b Source #

foldl :: (b -> a -> b) -> b -> Product f g a -> b Source #

foldl' :: (b -> a -> b) -> b -> Product f g a -> b Source #

foldr1 :: (a -> a -> a) -> Product f g a -> a Source #

foldl1 :: (a -> a -> a) -> Product f g a -> a Source #

toList :: Product f g a -> [a] Source #

null :: Product f g a -> Bool Source #

length :: Product f g a -> Int Source #

elem :: Eq a => a -> Product f g a -> Bool Source #

maximum :: Ord a => Product f g a -> a Source #

minimum :: Ord a => Product f g a -> a Source #

sum :: Num a => Product f g a -> a Source #

product :: Num a => Product f g a -> a Source #

(Foldable f, Foldable g) => Foldable (Sum f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

fold :: Monoid m => Sum f g m -> m Source #

foldMap :: Monoid m => (a -> m) -> Sum f g a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Sum f g a -> m Source #

foldr :: (a -> b -> b) -> b -> Sum f g a -> b Source #

foldr' :: (a -> b -> b) -> b -> Sum f g a -> b Source #

foldl :: (b -> a -> b) -> b -> Sum f g a -> b Source #

foldl' :: (b -> a -> b) -> b -> Sum f g a -> b Source #

foldr1 :: (a -> a -> a) -> Sum f g a -> a Source #

foldl1 :: (a -> a -> a) -> Sum f g a -> a Source #

toList :: Sum f g a -> [a] Source #

null :: Sum f g a -> Bool Source #

length :: Sum f g a -> Int Source #

elem :: Eq a => a -> Sum f g a -> Bool Source #

maximum :: Ord a => Sum f g a -> a Source #

minimum :: Ord a => Sum f g a -> a Source #

sum :: Num a => Sum f g a -> a Source #

product :: Num a => Sum f g a -> a Source #

(Foldable f, Foldable g) => Foldable (f :*: g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (f :*: g) m -> m Source #

foldMap :: Monoid m => (a -> m) -> (f :*: g) a -> m Source #

foldMap' :: Monoid m => (a -> m) -> (f :*: g) a -> m Source #

foldr :: (a -> b -> b) -> b -> (f :*: g) a -> b Source #

foldr' :: (a -> b -> b) -> b -> (f :*: g) a -> b Source #

foldl :: (b -> a -> b) -> b -> (f :*: g) a -> b Source #

foldl' :: (b -> a -> b) -> b -> (f :*: g) a -> b Source #

foldr1 :: (a -> a -> a) -> (f :*: g) a -> a Source #

foldl1 :: (a -> a -> a) -> (f :*: g) a -> a Source #

toList :: (f :*: g) a -> [a] Source #

null :: (f :*: g) a -> Bool Source #

length :: (f :*: g) a -> Int Source #

elem :: Eq a => a -> (f :*: g) a -> Bool Source #

maximum :: Ord a => (f :*: g) a -> a Source #

minimum :: Ord a => (f :*: g) a -> a Source #

sum :: Num a => (f :*: g) a -> a Source #

product :: Num a => (f :*: g) a -> a Source #

(Foldable f, Foldable g) => Foldable (f :+: g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (f :+: g) m -> m Source #

foldMap :: Monoid m => (a -> m) -> (f :+: g) a -> m Source #

foldMap' :: Monoid m => (a -> m) -> (f :+: g) a -> m Source #

foldr :: (a -> b -> b) -> b -> (f :+: g) a -> b Source #

foldr' :: (a -> b -> b) -> b -> (f :+: g) a -> b Source #

foldl :: (b -> a -> b) -> b -> (f :+: g) a -> b Source #

foldl' :: (b -> a -> b) -> b -> (f :+: g) a -> b Source #

foldr1 :: (a -> a -> a) -> (f :+: g) a -> a Source #

foldl1 :: (a -> a -> a) -> (f :+: g) a -> a Source #

toList :: (f :+: g) a -> [a] Source #

null :: (f :+: g) a -> Bool Source #

length :: (f :+: g) a -> Int Source #

elem :: Eq a => a -> (f :+: g) a -> Bool Source #

maximum :: Ord a => (f :+: g) a -> a Source #

minimum :: Ord a => (f :+: g) a -> a Source #

sum :: Num a => (f :+: g) a -> a Source #

product :: Num a => (f :+: g) a -> a Source #

Foldable (K1 i c :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => K1 i c m -> m Source #

foldMap :: Monoid m => (a -> m) -> K1 i c a -> m Source #

foldMap' :: Monoid m => (a -> m) -> K1 i c a -> m Source #

foldr :: (a -> b -> b) -> b -> K1 i c a -> b Source #

foldr' :: (a -> b -> b) -> b -> K1 i c a -> b Source #

foldl :: (b -> a -> b) -> b -> K1 i c a -> b Source #

foldl' :: (b -> a -> b) -> b -> K1 i c a -> b Source #

foldr1 :: (a -> a -> a) -> K1 i c a -> a Source #

foldl1 :: (a -> a -> a) -> K1 i c a -> a Source #

toList :: K1 i c a -> [a] Source #

null :: K1 i c a -> Bool Source #

length :: K1 i c a -> Int Source #

elem :: Eq a => a -> K1 i c a -> Bool Source #

maximum :: Ord a => K1 i c a -> a Source #

minimum :: Ord a => K1 i c a -> a Source #

sum :: Num a => K1 i c a -> a Source #

product :: Num a => K1 i c a -> a Source #

(Foldable f, Foldable g) => Foldable (Compose f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

fold :: Monoid m => Compose f g m -> m Source #

foldMap :: Monoid m => (a -> m) -> Compose f g a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Compose f g a -> m Source #

foldr :: (a -> b -> b) -> b -> Compose f g a -> b Source #

foldr' :: (a -> b -> b) -> b -> Compose f g a -> b Source #

foldl :: (b -> a -> b) -> b -> Compose f g a -> b Source #

foldl' :: (b -> a -> b) -> b -> Compose f g a -> b Source #

foldr1 :: (a -> a -> a) -> Compose f g a -> a Source #

foldl1 :: (a -> a -> a) -> Compose f g a -> a Source #

toList :: Compose f g a -> [a] Source #

null :: Compose f g a -> Bool Source #

length :: Compose f g a -> Int Source #

elem :: Eq a => a -> Compose f g a -> Bool Source #

maximum :: Ord a => Compose f g a -> a Source #

minimum :: Ord a => Compose f g a -> a Source #

sum :: Num a => Compose f g a -> a Source #

product :: Num a => Compose f g a -> a Source #

(Foldable f, Foldable g) => Foldable (f :.: g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (f :.: g) m -> m Source #

foldMap :: Monoid m => (a -> m) -> (f :.: g) a -> m Source #

foldMap' :: Monoid m => (a -> m) -> (f :.: g) a -> m Source #

foldr :: (a -> b -> b) -> b -> (f :.: g) a -> b Source #

foldr' :: (a -> b -> b) -> b -> (f :.: g) a -> b Source #

foldl :: (b -> a -> b) -> b -> (f :.: g) a -> b Source #

foldl' :: (b -> a -> b) -> b -> (f :.: g) a -> b Source #

foldr1 :: (a -> a -> a) -> (f :.: g) a -> a Source #

foldl1 :: (a -> a -> a) -> (f :.: g) a -> a Source #

toList :: (f :.: g) a -> [a] Source #

null :: (f :.: g) a -> Bool Source #

length :: (f :.: g) a -> Int Source #

elem :: Eq a => a -> (f :.: g) a -> Bool Source #

maximum :: Ord a => (f :.: g) a -> a Source #

minimum :: Ord a => (f :.: g) a -> a Source #

sum :: Num a => (f :.: g) a -> a Source #

product :: Num a => (f :.: g) a -> a Source #

Foldable f => Foldable (M1 i c f) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => M1 i c f m -> m Source #

foldMap :: Monoid m => (a -> m) -> M1 i c f a -> m Source #

foldMap' :: Monoid m => (a -> m) -> M1 i c f a -> m Source #

foldr :: (a -> b -> b) -> b -> M1 i c f a -> b Source #

foldr' :: (a -> b -> b) -> b -> M1 i c f a -> b Source #

foldl :: (b -> a -> b) -> b -> M1 i c f a -> b Source #

foldl' :: (b -> a -> b) -> b -> M1 i c f a -> b Source #

foldr1 :: (a -> a -> a) -> M1 i c f a -> a Source #

foldl1 :: (a -> a -> a) -> M1 i c f a -> a Source #

toList :: M1 i c f a -> [a] Source #

null :: M1 i c f a -> Bool Source #

length :: M1 i c f a -> Int Source #

elem :: Eq a => a -> M1 i c f a -> Bool Source #

maximum :: Ord a => M1 i c f a -> a Source #

minimum :: Ord a => M1 i c f a -> a Source #

sum :: Num a => M1 i c f a -> a Source #

product :: Num a => M1 i c f a -> a Source #

class (Functor t, Foldable t) => Traversable (t :: Type -> Type) where Source #

Functors representing data structures that can be transformed to structures of the same shape by performing an Applicative (or, therefore, Monad) action on each element from left to right.

A more detailed description of what same shape means, the various methods, how traversals are constructed, and example advanced use-cases can be found in the Overview section of Data.Traversable.

For the class laws see the Laws section of Data.Traversable.

Minimal complete definition

traverse | sequenceA

Methods

traverse :: Applicative f => (a -> f b) -> t a -> f (t b) Source #

Map each element of a structure to an action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see traverse_.

Examples

Expand

Basic usage:

In the first two examples we show each evaluated action mapping to the output structure.

>>> traverse Just [1,2,3,4]
Just [1,2,3,4]
>>> traverse id [Right 1, Right 2, Right 3, Right 4]
Right [1,2,3,4]

In the next examples, we show that Nothing and Left values short circuit the created structure.

>>> traverse (const Nothing) [1,2,3,4]
Nothing
>>> traverse (\x -> if odd x then Just x else Nothing)  [1,2,3,4]
Nothing
>>> traverse id [Right 1, Right 2, Right 3, Right 4, Left 0]
Left 0

sequenceA :: Applicative f => t (f a) -> f (t a) Source #

Evaluate each action in the structure from left to right, and collect the results. For a version that ignores the results see sequenceA_.

Examples

Expand

Basic usage:

For the first two examples we show sequenceA fully evaluating a a structure and collecting the results.

>>> sequenceA [Just 1, Just 2, Just 3]
Just [1,2,3]
>>> sequenceA [Right 1, Right 2, Right 3]
Right [1,2,3]

The next two example show Nothing and Just will short circuit the resulting structure if present in the input. For more context, check the Traversable instances for Either and Maybe.

>>> sequenceA [Just 1, Just 2, Just 3, Nothing]
Nothing
>>> sequenceA [Right 1, Right 2, Right 3, Left 4]
Left 4

mapM :: Monad m => (a -> m b) -> t a -> m (t b) Source #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see mapM_.

Examples

Expand

mapM is literally a traverse with a type signature restricted to Monad. Its implementation may be more efficient due to additional power of Monad.

sequence :: Monad m => t (m a) -> m (t a) Source #

Evaluate each monadic action in the structure from left to right, and collect the results. For a version that ignores the results see sequence_.

Examples

Expand

Basic usage:

The first two examples are instances where the input and and output of sequence are isomorphic.

>>> sequence $ Right [1,2,3,4]
[Right 1,Right 2,Right 3,Right 4]
>>> sequence $ [Right 1,Right 2,Right 3,Right 4]
Right [1,2,3,4]

The following examples demonstrate short circuit behavior for sequence.

>>> sequence $ Left [1,2,3,4]
Left [1,2,3,4]
>>> sequence $ [Left 0, Right 1,Right 2,Right 3,Right 4]
Left 0

Instances

Instances details
Traversable ZipList Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> ZipList a -> f (ZipList b) Source #

sequenceA :: Applicative f => ZipList (f a) -> f (ZipList a) Source #

mapM :: Monad m => (a -> m b) -> ZipList a -> m (ZipList b) Source #

sequence :: Monad m => ZipList (m a) -> m (ZipList a) Source #

Traversable Complex Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

traverse :: Applicative f => (a -> f b) -> Complex a -> f (Complex b) Source #

sequenceA :: Applicative f => Complex (f a) -> f (Complex a) Source #

mapM :: Monad m => (a -> m b) -> Complex a -> m (Complex b) Source #

sequence :: Monad m => Complex (m a) -> m (Complex a) Source #

Traversable Identity Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Identity a -> f (Identity b) Source #

sequenceA :: Applicative f => Identity (f a) -> f (Identity a) Source #

mapM :: Monad m => (a -> m b) -> Identity a -> m (Identity b) Source #

sequence :: Monad m => Identity (m a) -> m (Identity a) Source #

Traversable First Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> First a -> f (First b) Source #

sequenceA :: Applicative f => First (f a) -> f (First a) Source #

mapM :: Monad m => (a -> m b) -> First a -> m (First b) Source #

sequence :: Monad m => First (m a) -> m (First a) Source #

Traversable Last Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Last a -> f (Last b) Source #

sequenceA :: Applicative f => Last (f a) -> f (Last a) Source #

mapM :: Monad m => (a -> m b) -> Last a -> m (Last b) Source #

sequence :: Monad m => Last (m a) -> m (Last a) Source #

Traversable Down Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Down a -> f (Down b) Source #

sequenceA :: Applicative f => Down (f a) -> f (Down a) Source #

mapM :: Monad m => (a -> m b) -> Down a -> m (Down b) Source #

sequence :: Monad m => Down (m a) -> m (Down a) Source #

Traversable First Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> First a -> f (First b) Source #

sequenceA :: Applicative f => First (f a) -> f (First a) Source #

mapM :: Monad m => (a -> m b) -> First a -> m (First b) Source #

sequence :: Monad m => First (m a) -> m (First a) Source #

Traversable Last Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Last a -> f (Last b) Source #

sequenceA :: Applicative f => Last (f a) -> f (Last a) Source #

mapM :: Monad m => (a -> m b) -> Last a -> m (Last b) Source #

sequence :: Monad m => Last (m a) -> m (Last a) Source #

Traversable Max Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Max a -> f (Max b) Source #

sequenceA :: Applicative f => Max (f a) -> f (Max a) Source #

mapM :: Monad m => (a -> m b) -> Max a -> m (Max b) Source #

sequence :: Monad m => Max (m a) -> m (Max a) Source #

Traversable Min Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Min a -> f (Min b) Source #

sequenceA :: Applicative f => Min (f a) -> f (Min a) Source #

mapM :: Monad m => (a -> m b) -> Min a -> m (Min b) Source #

sequence :: Monad m => Min (m a) -> m (Min a) Source #

Traversable Dual Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Dual a -> f (Dual b) Source #

sequenceA :: Applicative f => Dual (f a) -> f (Dual a) Source #

mapM :: Monad m => (a -> m b) -> Dual a -> m (Dual b) Source #

sequence :: Monad m => Dual (m a) -> m (Dual a) Source #

Traversable Product Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Product a -> f (Product b) Source #

sequenceA :: Applicative f => Product (f a) -> f (Product a) Source #

mapM :: Monad m => (a -> m b) -> Product a -> m (Product b) Source #

sequence :: Monad m => Product (m a) -> m (Product a) Source #

Traversable Sum Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Sum a -> f (Sum b) Source #

sequenceA :: Applicative f => Sum (f a) -> f (Sum a) Source #

mapM :: Monad m => (a -> m b) -> Sum a -> m (Sum b) Source #

sequence :: Monad m => Sum (m a) -> m (Sum a) Source #

Traversable NonEmpty Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> NonEmpty a -> f (NonEmpty b) Source #

sequenceA :: Applicative f => NonEmpty (f a) -> f (NonEmpty a) Source #

mapM :: Monad m => (a -> m b) -> NonEmpty a -> m (NonEmpty b) Source #

sequence :: Monad m => NonEmpty (m a) -> m (NonEmpty a) Source #

Traversable Par1 Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Par1 a -> f (Par1 b) Source #

sequenceA :: Applicative f => Par1 (f a) -> f (Par1 a) Source #

mapM :: Monad m => (a -> m b) -> Par1 a -> m (Par1 b) Source #

sequence :: Monad m => Par1 (m a) -> m (Par1 a) Source #

Traversable Maybe Source #

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Maybe a -> f (Maybe b) Source #

sequenceA :: Applicative f => Maybe (f a) -> f (Maybe a) Source #

mapM :: Monad m => (a -> m b) -> Maybe a -> m (Maybe b) Source #

sequence :: Monad m => Maybe (m a) -> m (Maybe a) Source #

Traversable Solo Source #

Since: base-4.15

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Solo a -> f (Solo b) Source #

sequenceA :: Applicative f => Solo (f a) -> f (Solo a) Source #

mapM :: Monad m => (a -> m b) -> Solo a -> m (Solo b) Source #

sequence :: Monad m => Solo (m a) -> m (Solo a) Source #

Traversable [] Source #

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> [a] -> f [b] Source #

sequenceA :: Applicative f => [f a] -> f [a] Source #

mapM :: Monad m => (a -> m b) -> [a] -> m [b] Source #

sequence :: Monad m => [m a] -> m [a] Source #

Traversable (Either a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a0 -> f b) -> Either a a0 -> f (Either a b) Source #

sequenceA :: Applicative f => Either a (f a0) -> f (Either a a0) Source #

mapM :: Monad m => (a0 -> m b) -> Either a a0 -> m (Either a b) Source #

sequence :: Monad m => Either a (m a0) -> m (Either a a0) Source #

Traversable (Proxy :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Proxy a -> f (Proxy b) Source #

sequenceA :: Applicative f => Proxy (f a) -> f (Proxy a) Source #

mapM :: Monad m => (a -> m b) -> Proxy a -> m (Proxy b) Source #

sequence :: Monad m => Proxy (m a) -> m (Proxy a) Source #

Traversable (Arg a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a0 -> f b) -> Arg a a0 -> f (Arg a b) Source #

sequenceA :: Applicative f => Arg a (f a0) -> f (Arg a a0) Source #

mapM :: Monad m => (a0 -> m b) -> Arg a a0 -> m (Arg a b) Source #

sequence :: Monad m => Arg a (m a0) -> m (Arg a a0) Source #

Ix i => Traversable (Array i) Source #

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Array i a -> f (Array i b) Source #

sequenceA :: Applicative f => Array i (f a) -> f (Array i a) Source #

mapM :: Monad m => (a -> m b) -> Array i a -> m (Array i b) Source #

sequence :: Monad m => Array i (m a) -> m (Array i a) Source #

Traversable (U1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> U1 a -> f (U1 b) Source #

sequenceA :: Applicative f => U1 (f a) -> f (U1 a) Source #

mapM :: Monad m => (a -> m b) -> U1 a -> m (U1 b) Source #

sequence :: Monad m => U1 (m a) -> m (U1 a) Source #

Traversable (UAddr :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UAddr a -> f (UAddr b) Source #

sequenceA :: Applicative f => UAddr (f a) -> f (UAddr a) Source #

mapM :: Monad m => (a -> m b) -> UAddr a -> m (UAddr b) Source #

sequence :: Monad m => UAddr (m a) -> m (UAddr a) Source #

Traversable (UChar :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UChar a -> f (UChar b) Source #

sequenceA :: Applicative f => UChar (f a) -> f (UChar a) Source #

mapM :: Monad m => (a -> m b) -> UChar a -> m (UChar b) Source #

sequence :: Monad m => UChar (m a) -> m (UChar a) Source #

Traversable (UDouble :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UDouble a -> f (UDouble b) Source #

sequenceA :: Applicative f => UDouble (f a) -> f (UDouble a) Source #

mapM :: Monad m => (a -> m b) -> UDouble a -> m (UDouble b) Source #

sequence :: Monad m => UDouble (m a) -> m (UDouble a) Source #

Traversable (UFloat :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UFloat a -> f (UFloat b) Source #

sequenceA :: Applicative f => UFloat (f a) -> f (UFloat a) Source #

mapM :: Monad m => (a -> m b) -> UFloat a -> m (UFloat b) Source #

sequence :: Monad m => UFloat (m a) -> m (UFloat a) Source #

Traversable (UInt :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UInt a -> f (UInt b) Source #

sequenceA :: Applicative f => UInt (f a) -> f (UInt a) Source #

mapM :: Monad m => (a -> m b) -> UInt a -> m (UInt b) Source #

sequence :: Monad m => UInt (m a) -> m (UInt a) Source #

Traversable (UWord :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UWord a -> f (UWord b) Source #

sequenceA :: Applicative f => UWord (f a) -> f (UWord a) Source #

mapM :: Monad m => (a -> m b) -> UWord a -> m (UWord b) Source #

sequence :: Monad m => UWord (m a) -> m (UWord a) Source #

Traversable (V1 :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> V1 a -> f (V1 b) Source #

sequenceA :: Applicative f => V1 (f a) -> f (V1 a) Source #

mapM :: Monad m => (a -> m b) -> V1 a -> m (V1 b) Source #

sequence :: Monad m => V1 (m a) -> m (V1 a) Source #

Traversable ((,) a) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a0 -> f b) -> (a, a0) -> f (a, b) Source #

sequenceA :: Applicative f => (a, f a0) -> f (a, a0) Source #

mapM :: Monad m => (a0 -> m b) -> (a, a0) -> m (a, b) Source #

sequence :: Monad m => (a, m a0) -> m (a, a0) Source #

Traversable (Const m :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Const m a -> f (Const m b) Source #

sequenceA :: Applicative f => Const m (f a) -> f (Const m a) Source #

mapM :: Monad m0 => (a -> m0 b) -> Const m a -> m0 (Const m b) Source #

sequence :: Monad m0 => Const m (m0 a) -> m0 (Const m a) Source #

Traversable f => Traversable (Ap f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Ap f a -> f0 (Ap f b) Source #

sequenceA :: Applicative f0 => Ap f (f0 a) -> f0 (Ap f a) Source #

mapM :: Monad m => (a -> m b) -> Ap f a -> m (Ap f b) Source #

sequence :: Monad m => Ap f (m a) -> m (Ap f a) Source #

Traversable f => Traversable (Alt f) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Alt f a -> f0 (Alt f b) Source #

sequenceA :: Applicative f0 => Alt f (f0 a) -> f0 (Alt f a) Source #

mapM :: Monad m => (a -> m b) -> Alt f a -> m (Alt f b) Source #

sequence :: Monad m => Alt f (m a) -> m (Alt f a) Source #

Traversable f => Traversable (Rec1 f) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Rec1 f a -> f0 (Rec1 f b) Source #

sequenceA :: Applicative f0 => Rec1 f (f0 a) -> f0 (Rec1 f a) Source #

mapM :: Monad m => (a -> m b) -> Rec1 f a -> m (Rec1 f b) Source #

sequence :: Monad m => Rec1 f (m a) -> m (Rec1 f a) Source #

(Traversable f, Traversable g) => Traversable (Product f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Product f g a -> f0 (Product f g b) Source #

sequenceA :: Applicative f0 => Product f g (f0 a) -> f0 (Product f g a) Source #

mapM :: Monad m => (a -> m b) -> Product f g a -> m (Product f g b) Source #

sequence :: Monad m => Product f g (m a) -> m (Product f g a) Source #

(Traversable f, Traversable g) => Traversable (Sum f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Sum f g a -> f0 (Sum f g b) Source #

sequenceA :: Applicative f0 => Sum f g (f0 a) -> f0 (Sum f g a) Source #

mapM :: Monad m => (a -> m b) -> Sum f g a -> m (Sum f g b) Source #

sequence :: Monad m => Sum f g (m a) -> m (Sum f g a) Source #

(Traversable f, Traversable g) => Traversable (f :*: g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :*: g) a -> f0 ((f :*: g) b) Source #

sequenceA :: Applicative f0 => (f :*: g) (f0 a) -> f0 ((f :*: g) a) Source #

mapM :: Monad m => (a -> m b) -> (f :*: g) a -> m ((f :*: g) b) Source #

sequence :: Monad m => (f :*: g) (m a) -> m ((f :*: g) a) Source #

(Traversable f, Traversable g) => Traversable (f :+: g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :+: g) a -> f0 ((f :+: g) b) Source #

sequenceA :: Applicative f0 => (f :+: g) (f0 a) -> f0 ((f :+: g) a) Source #

mapM :: Monad m => (a -> m b) -> (f :+: g) a -> m ((f :+: g) b) Source #

sequence :: Monad m => (f :+: g) (m a) -> m ((f :+: g) a) Source #

Traversable (K1 i c :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> K1 i c a -> f (K1 i c b) Source #

sequenceA :: Applicative f => K1 i c (f a) -> f (K1 i c a) Source #

mapM :: Monad m => (a -> m b) -> K1 i c a -> m (K1 i c b) Source #

sequence :: Monad m => K1 i c (m a) -> m (K1 i c a) Source #

(Traversable f, Traversable g) => Traversable (Compose f g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Compose f g a -> f0 (Compose f g b) Source #

sequenceA :: Applicative f0 => Compose f g (f0 a) -> f0 (Compose f g a) Source #

mapM :: Monad m => (a -> m b) -> Compose f g a -> m (Compose f g b) Source #

sequence :: Monad m => Compose f g (m a) -> m (Compose f g a) Source #

(Traversable f, Traversable g) => Traversable (f :.: g) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :.: g) a -> f0 ((f :.: g) b) Source #

sequenceA :: Applicative f0 => (f :.: g) (f0 a) -> f0 ((f :.: g) a) Source #

mapM :: Monad m => (a -> m b) -> (f :.: g) a -> m ((f :.: g) b) Source #

sequence :: Monad m => (f :.: g) (m a) -> m ((f :.: g) a) Source #

Traversable f => Traversable (M1 i c f) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> M1 i c f a -> f0 (M1 i c f b) Source #

sequenceA :: Applicative f0 => M1 i c f (f0 a) -> f0 (M1 i c f a) Source #

mapM :: Monad m => (a -> m b) -> M1 i c f a -> m (M1 i c f b) Source #

sequence :: Monad m => M1 i c f (m a) -> m (M1 i c f a) Source #

Miscellaneous functions

id :: a -> a Source #

Identity function.

id x = x

This function might seem useless at first glance, but it can be very useful in a higher order context.

Examples

Expand
>>> length $ filter id [True, True, False, True]
3
>>> Just (Just 3) >>= id
Just 3
>>> foldr id 0 [(^3), (*5), (+2)]
1000

const :: a -> b -> a Source #

const x y always evaluates to x, ignoring its second argument.

const x = \_ -> x

This function might seem useless at first glance, but it can be very useful in a higher order context.

Examples

Expand
>>> const 42 "hello"
42
>>> map (const 42) [0..3]
[42,42,42,42]

(.) :: (b -> c) -> (a -> b) -> a -> c infixr 9 Source #

Right to left function composition.

(f . g) x = f (g x)
f . id = f = id . f

Examples

Expand
>>> map ((*2) . length) [[], [0, 1, 2], [0]]
[0,6,2]
>>> foldr (.) id [(+1), (*3), (^3)] 2
25
>>> let (...) = (.).(.) in ((*2)...(+)) 5 10
30

flip :: (a -> b -> c) -> b -> a -> c Source #

flip f takes its (first) two arguments in the reverse order of f.

flip f x y = f y x
flip . flip = id

Examples

Expand
>>> flip (++) "hello" "world"
"worldhello"
>>> let (.>) = flip (.) in (+1) .> show $ 5
"6"

($) :: (a -> b) -> a -> b infixr 0 Source #

($) is the function application operator.

Applying ($) to a function f and an argument x gives the same result as applying f to x directly. The definition is akin to this:

($) :: (a -> b) -> a -> b
($) f x = f x

This is id specialized from a -> a to (a -> b) -> (a -> b) which by the associativity of (->) is the same as (a -> b) -> a -> b.

On the face of it, this may appear pointless! But it's actually one of the most useful and important operators in Haskell.

The order of operations is very different between ($) and normal function application. Normal function application has precedence 10 - higher than any operator - and associates to the left. So these two definitions are equivalent:

expr = min 5 1 + 5
expr = ((min 5) 1) + 5

($) has precedence 0 (the lowest) and associates to the right, so these are equivalent:

expr = min 5 $ 1 + 5
expr = (min 5) (1 + 5)

Examples

Expand

A common use cases of ($) is to avoid parentheses in complex expressions.

For example, instead of using nested parentheses in the following Haskell function:

-- | Sum numbers in a string: strSum "100  5 -7" == 98
strSum :: String -> Int
strSum s = sum (mapMaybe readMaybe (words s))

we can deploy the function application operator:

-- | Sum numbers in a string: strSum "100  5 -7" == 98
strSum :: String -> Int
strSum s = sum $ mapMaybe readMaybe $ words s

($) is also used as a section (a partially applied operator), in order to indicate that we wish to apply some yet-unspecified function to a given value. For example, to apply the argument 5 to a list of functions:

applyFive :: [Int]
applyFive = map ($ 5) [(+1), (2^)]
>>> [6, 32]

Technical Remark (Representation Polymorphism)

Expand

($) is fully representation-polymorphic. This allows it to also be used with arguments of unlifted and even unboxed kinds, such as unboxed integers:

fastMod :: Int -> Int -> Int
fastMod (I# x) (I# m) = I# $ remInt# x m

until :: (a -> Bool) -> (a -> a) -> a -> a Source #

until p f yields the result of applying f until p holds.

asTypeOf :: a -> a -> a Source #

asTypeOf is a type-restricted version of const. It is usually used as an infix operator, and its typing forces its first argument (which is usually overloaded) to have the same type as the second.

error :: HasCallStack => [Char] -> a Source #

error stops execution and displays an error message.

errorWithoutStackTrace :: [Char] -> a Source #

A variant of error that does not produce a stack trace.

Since: base-4.9.0.0

undefined :: HasCallStack => a Source #

A special case of error. It is expected that compilers will recognize this and insert error messages which are more appropriate to the context in which undefined appears.

seq :: a -> b -> b infixr 0 Source #

The value of seq a b is bottom if a is bottom, and otherwise equal to b. In other words, it evaluates the first argument a to weak head normal form (WHNF). seq is usually introduced to improve performance by avoiding unneeded laziness.

A note on evaluation order: the expression seq a b does not guarantee that a will be evaluated before b. The only guarantee given by seq is that the both a and b will be evaluated before seq returns a value. In particular, this means that b may be evaluated before a. If you need to guarantee a specific order of evaluation, you must use the function pseq from the "parallel" package.

($!) :: (a -> b) -> a -> b infixr 0 Source #

Strict (call-by-value) application operator. It takes a function and an argument, evaluates the argument to weak head normal form (WHNF), then calls the function with that value.

List operations

map :: (a -> b) -> [a] -> [b] Source #

\(\mathcal{O}(n)\). map f xs is the list obtained by applying f to each element of xs, i.e.,

map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
map f [x1, x2, ...] == [f x1, f x2, ...]

this means that map id == id

Examples

Expand
>>> map (+1) [1, 2, 3]
[2,3,4]
>>> map id [1, 2, 3]
[1,2,3]
>>> map (\n -> 3 * n + 1) [1, 2, 3]
[4,7,10]

(++) :: [a] -> [a] -> [a] infixr 5 Source #

(++) appends two lists, i.e.,

[x1, ..., xm] ++ [y1, ..., yn] == [x1, ..., xm, y1, ..., yn]
[x1, ..., xm] ++ [y1, ...] == [x1, ..., xm, y1, ...]

If the first list is not finite, the result is the first list.

Performance considerations

Expand

This function takes linear time in the number of elements of the first list. Thus it is better to associate repeated applications of (++) to the right (which is the default behaviour): xs ++ (ys ++ zs) or simply xs ++ ys ++ zs, but not (xs ++ ys) ++ zs. For the same reason concat = foldr (++) [] has linear performance, while foldl (++) [] is prone to quadratic slowdown

Examples

Expand
>>> [1, 2, 3] ++ [4, 5, 6]
[1,2,3,4,5,6]
>>> [] ++ [1, 2, 3]
[1,2,3]
>>> [3, 2, 1] ++ []
[3,2,1]

filter :: (a -> Bool) -> [a] -> [a] Source #

\(\mathcal{O}(n)\). filter, applied to a predicate and a list, returns the list of those elements that satisfy the predicate; i.e.,

filter p xs = [ x | x <- xs, p x]

Examples

Expand
>>> filter odd [1, 2, 3]
[1,3]
>>> filter (\l -> length l > 3) ["Hello", ", ", "World", "!"]
["Hello","World"]
>>> filter (/= 3) [1, 2, 3, 4, 3, 2, 1]
[1,2,4,2,1]

head :: HasCallStack => [a] -> a Source #

Warning: This is a partial function, it throws an error on empty lists. Use pattern matching or Data.List.uncons instead. Consider refactoring to use Data.List.NonEmpty.

\(\mathcal{O}(1)\). Extract the first element of a list, which must be non-empty.

Examples
Expand
>>> head [1, 2, 3]
1
>>> head [1..]
1
>>> head []
*** Exception: Prelude.head: empty list

last :: HasCallStack => [a] -> a Source #

\(\mathcal{O}(n)\). Extract the last element of a list, which must be finite and non-empty.

WARNING: This function is partial. Consider using unsnoc instead.

Examples

Expand
>>> last [1, 2, 3]
3
>>> last [1..]
* Hangs forever *
>>> last []
*** Exception: Prelude.last: empty list

tail :: HasCallStack => [a] -> [a] Source #

Warning: This is a partial function, it throws an error on empty lists. Replace it with drop 1, or use pattern matching or Data.List.uncons instead. Consider refactoring to use Data.List.NonEmpty.

\(\mathcal{O}(1)\). Extract the elements after the head of a list, which must be non-empty.

Examples

Expand
>>> tail [1, 2, 3]
[2,3]
>>> tail [1]
[]
>>> tail []
*** Exception: Prelude.tail: empty list

init :: HasCallStack => [a] -> [a] Source #

\(\mathcal{O}(n)\). Return all the elements of a list except the last one. The list must be non-empty.

WARNING: This function is partial. Consider using unsnoc instead.

Examples

Expand
>>> init [1, 2, 3]
[1,2]
>>> init [1]
[]
>>> init []
*** Exception: Prelude.init: empty list

(!!) :: HasCallStack => [a] -> Int -> a infixl 9 Source #

List index (subscript) operator, starting from 0. It is an instance of the more general genericIndex, which takes an index of any integral type.

WARNING: This function is partial, and should only be used if you are sure that the indexing will not fail. Otherwise, use !?.

WARNING: This function takes linear time in the index.

Examples

Expand
>>> ['a', 'b', 'c'] !! 0
'a'
>>> ['a', 'b', 'c'] !! 2
'c'
>>> ['a', 'b', 'c'] !! 3
*** Exception: Prelude.!!: index too large
>>> ['a', 'b', 'c'] !! (-1)
*** Exception: Prelude.!!: negative index

null :: Foldable t => t a -> Bool Source #

Test whether the structure is empty. The default implementation is Left-associative and lazy in both the initial element and the accumulator. Thus optimised for structures where the first element can be accessed in constant time. Structures where this is not the case should have a non-default implementation.

Examples

Expand

Basic usage:

>>> null []
True
>>> null [1]
False

null is expected to terminate even for infinite structures. The default implementation terminates provided the structure is bounded on the left (there is a leftmost element).

>>> null [1..]
False

Since: base-4.8.0.0

length :: Foldable t => t a -> Int Source #

Returns the size/length of a finite structure as an Int. The default implementation just counts elements starting with the leftmost. Instances for structures that can compute the element count faster than via element-by-element counting, should provide a specialised implementation.

Examples

Expand

Basic usage:

>>> length []
0
>>> length ['a', 'b', 'c']
3
>>> length [1..]
* Hangs forever *

Since: base-4.8.0.0

reverse :: [a] -> [a] Source #

\(\mathcal{O}(n)\). reverse xs returns the elements of xs in reverse order. xs must be finite.

Laziness

Expand

reverse is lazy in its elements.

>>> head (reverse [undefined, 1])
1
>>> reverse (1 : 2 : undefined)
*** Exception: Prelude.undefined

Examples

Expand
>>> reverse []
[]
>>> reverse [42]
[42]
>>> reverse [2,5,7]
[7,5,2]
>>> reverse [1..]
* Hangs forever *

Special folds

and :: Foldable t => t Bool -> Bool Source #

and returns the conjunction of a container of Bools. For the result to be True, the container must be finite; False, however, results from a False value finitely far from the left end.

Examples

Expand

Basic usage:

>>> and []
True
>>> and [True]
True
>>> and [False]
False
>>> and [True, True, False]
False
>>> and (False : repeat True) -- Infinite list [False,True,True,True,...
False
>>> and (repeat True)
* Hangs forever *

or :: Foldable t => t Bool -> Bool Source #

or returns the disjunction of a container of Bools. For the result to be False, the container must be finite; True, however, results from a True value finitely far from the left end.

Examples

Expand

Basic usage:

>>> or []
False
>>> or [True]
True
>>> or [False]
False
>>> or [True, True, False]
True
>>> or (True : repeat False) -- Infinite list [True,False,False,False,...
True
>>> or (repeat False)
* Hangs forever *

any :: Foldable t => (a -> Bool) -> t a -> Bool Source #

Determines whether any element of the structure satisfies the predicate.

Examples

Expand

Basic usage:

>>> any (> 3) []
False
>>> any (> 3) [1,2]
False
>>> any (> 3) [1,2,3,4,5]
True
>>> any (> 3) [1..]
True
>>> any (> 3) [0, -1..]
* Hangs forever *

all :: Foldable t => (a -> Bool) -> t a -> Bool Source #

Determines whether all elements of the structure satisfy the predicate.

Examples

Expand

Basic usage:

>>> all (> 3) []
True
>>> all (> 3) [1,2]
False
>>> all (> 3) [1,2,3,4,5]
False
>>> all (> 3) [1..]
False
>>> all (> 3) [4..]
* Hangs forever *

concat :: Foldable t => t [a] -> [a] Source #

The concatenation of all the elements of a container of lists.

Examples

Expand

Basic usage:

>>> concat (Just [1, 2, 3])
[1,2,3]
>>> concat (Left 42)
[]
>>> concat [[1, 2, 3], [4, 5], [6], []]
[1,2,3,4,5,6]

concatMap :: Foldable t => (a -> [b]) -> t a -> [b] Source #

Map a function over all the elements of a container and concatenate the resulting lists.

Examples

Expand

Basic usage:

>>> concatMap (take 3) [[1..], [10..], [100..], [1000..]]
[1,2,3,10,11,12,100,101,102,1000,1001,1002]
>>> concatMap (take 3) (Just [1..])
[1,2,3]

Building lists

Scans

scanl :: (b -> a -> b) -> b -> [a] -> [b] Source #

\(\mathcal{O}(n)\). scanl is similar to foldl, but returns a list of successive reduced values from the left:

scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]

Note that

last (scanl f z xs) == foldl f z xs

Examples

Expand
>>> scanl (+) 0 [1..4]
[0,1,3,6,10]
>>> scanl (+) 42 []
[42]
>>> scanl (-) 100 [1..4]
[100,99,97,94,90]
>>> scanl (\reversedString nextChar -> nextChar : reversedString) "foo" ['a', 'b', 'c', 'd']
["foo","afoo","bafoo","cbafoo","dcbafoo"]
>>> take 10 (scanl (+) 0 [1..])
[0,1,3,6,10,15,21,28,36,45]
>>> take 1 (scanl undefined 'a' undefined)
"a"

scanl1 :: (a -> a -> a) -> [a] -> [a] Source #

\(\mathcal{O}(n)\). scanl1 is a variant of scanl that has no starting value argument:

scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]

Examples

Expand
>>> scanl1 (+) [1..4]
[1,3,6,10]
>>> scanl1 (+) []
[]
>>> scanl1 (-) [1..4]
[1,-1,-4,-8]
>>> scanl1 (&&) [True, False, True, True]
[True,False,False,False]
>>> scanl1 (||) [False, False, True, True]
[False,False,True,True]
>>> take 10 (scanl1 (+) [1..])
[1,3,6,10,15,21,28,36,45,55]
>>> take 1 (scanl1 undefined ('a' : undefined))
"a"

scanr :: (a -> b -> b) -> b -> [a] -> [b] Source #

\(\mathcal{O}(n)\). scanr is the right-to-left dual of scanl. Note that the order of parameters on the accumulating function are reversed compared to scanl. Also note that

head (scanr f z xs) == foldr f z xs.

Examples

Expand
>>> scanr (+) 0 [1..4]
[10,9,7,4,0]
>>> scanr (+) 42 []
[42]
>>> scanr (-) 100 [1..4]
[98,-97,99,-96,100]
>>> scanr (\nextChar reversedString -> nextChar : reversedString) "foo" ['a', 'b', 'c', 'd']
["abcdfoo","bcdfoo","cdfoo","dfoo","foo"]
>>> force $ scanr (+) 0 [1..]
*** Exception: stack overflow

scanr1 :: (a -> a -> a) -> [a] -> [a] Source #

\(\mathcal{O}(n)\). scanr1 is a variant of scanr that has no starting value argument.

Examples

Expand
>>> scanr1 (+) [1..4]
[10,9,7,4]
>>> scanr1 (+) []
[]
>>> scanr1 (-) [1..4]
[-2,3,-1,4]
>>> scanr1 (&&) [True, False, True, True]
[False,False,True,True]
>>> scanr1 (||) [True, True, False, False]
[True,True,False,False]
>>> force $ scanr1 (+) [1..]
*** Exception: stack overflow

Infinite lists

iterate :: (a -> a) -> a -> [a] Source #

iterate f x returns an infinite list of repeated applications of f to x:

iterate f x == [x, f x, f (f x), ...]

Laziness

Expand

Note that iterate is lazy, potentially leading to thunk build-up if the consumer doesn't force each iterate. See iterate' for a strict variant of this function.

>>> take 1 $ iterate undefined 42
[42]

Examples

Expand
>>> take 10 $ iterate not True
[True,False,True,False,True,False,True,False,True,False]
>>> take 10 $ iterate (+3) 42
[42,45,48,51,54,57,60,63,66,69]

iterate id == repeat:

>>> take 10 $ iterate id 1
[1,1,1,1,1,1,1,1,1,1]

repeat :: a -> [a] Source #

repeat x is an infinite list, with x the value of every element.

Examples

Expand
>>> take 10 $ repeat 17
[17,17,17,17,17,17,17,17,17, 17]
>>> repeat undefined
[*** Exception: Prelude.undefined

replicate :: Int -> a -> [a] Source #

replicate n x is a list of length n with x the value of every element. It is an instance of the more general genericReplicate, in which n may be of any integral type.

Examples

Expand
>>> replicate 0 True
[]
>>> replicate (-1) True
[]
>>> replicate 4 True
[True,True,True,True]

cycle :: HasCallStack => [a] -> [a] Source #

cycle ties a finite list into a circular one, or equivalently, the infinite repetition of the original list. It is the identity on infinite lists.

Examples

Expand
>>> cycle []
*** Exception: Prelude.cycle: empty list
>>> take 10 (cycle [42])
[42,42,42,42,42,42,42,42,42,42]
>>> take 10 (cycle [2, 5, 7])
[2,5,7,2,5,7,2,5,7,2]
>>> take 1 (cycle (42 : undefined))
[42]

Sublists

take :: Int -> [a] -> [a] Source #

take n, applied to a list xs, returns the prefix of xs of length n, or xs itself if n >= length xs.

It is an instance of the more general genericTake, in which n may be of any integral type.

Laziness

Expand
>>> take 0 undefined
[]
>>> take 2 (1 : 2 : undefined)
[1,2]

Examples

Expand
>>> take 5 "Hello World!"
"Hello"
>>> take 3 [1,2,3,4,5]
[1,2,3]
>>> take 3 [1,2]
[1,2]
>>> take 3 []
[]
>>> take (-1) [1,2]
[]
>>> take 0 [1,2]
[]

drop :: Int -> [a] -> [a] Source #

drop n xs returns the suffix of xs after the first n elements, or [] if n >= length xs.

It is an instance of the more general genericDrop, in which n may be of any integral type.

Examples

Expand
>>> drop 6 "Hello World!"
"World!"
>>> drop 3 [1,2,3,4,5]
[4,5]
>>> drop 3 [1,2]
[]
>>> drop 3 []
[]
>>> drop (-1) [1,2]
[1,2]
>>> drop 0 [1,2]
[1,2]

takeWhile :: (a -> Bool) -> [a] -> [a] Source #

takeWhile, applied to a predicate p and a list xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p.

Laziness

Expand
>>> takeWhile (const False) undefined
*** Exception: Prelude.undefined
>>> takeWhile (const False) (undefined : undefined)
[]
>>> take 1 (takeWhile (const True) (1 : undefined))
[1]

Examples

Expand
>>> takeWhile (< 3) [1,2,3,4,1,2,3,4]
[1,2]
>>> takeWhile (< 9) [1,2,3]
[1,2,3]
>>> takeWhile (< 0) [1,2,3]
[]

dropWhile :: (a -> Bool) -> [a] -> [a] Source #

dropWhile p xs returns the suffix remaining after takeWhile p xs.

Examples

Expand
>>> dropWhile (< 3) [1,2,3,4,5,1,2,3]
[3,4,5,1,2,3]
>>> dropWhile (< 9) [1,2,3]
[]
>>> dropWhile (< 0) [1,2,3]
[1,2,3]

span :: (a -> Bool) -> [a] -> ([a], [a]) Source #

span, applied to a predicate p and a list xs, returns a tuple where first element is the longest prefix (possibly empty) of xs of elements that satisfy p and second element is the remainder of the list:

span p xs is equivalent to (takeWhile p xs, dropWhile p xs), even if p is _|_.

Laziness

Expand
>>> span undefined []
([],[])
>>> fst (span (const False) undefined)
*** Exception: Prelude.undefined
>>> fst (span (const False) (undefined : undefined))
[]
>>> take 1 (fst (span (const True) (1 : undefined)))
[1]

span produces the first component of the tuple lazily:

>>> take 10 (fst (span (const True) [1..]))
[1,2,3,4,5,6,7,8,9,10]

Examples

Expand
>>> span (< 3) [1,2,3,4,1,2,3,4]
([1,2],[3,4,1,2,3,4])
>>> span (< 9) [1,2,3]
([1,2,3],[])
>>> span (< 0) [1,2,3]
([],[1,2,3])

break :: (a -> Bool) -> [a] -> ([a], [a]) Source #

break, applied to a predicate p and a list xs, returns a tuple where first element is longest prefix (possibly empty) of xs of elements that do not satisfy p and second element is the remainder of the list:

break p is equivalent to span (not . p) and consequently to (takeWhile (not . p) xs, dropWhile (not . p) xs), even if p is _|_.

Laziness

Expand
>>> break undefined []
([],[])
>>> fst (break (const True) undefined)
*** Exception: Prelude.undefined
>>> fst (break (const True) (undefined : undefined))
[]
>>> take 1 (fst (break (const False) (1 : undefined)))
[1]

break produces the first component of the tuple lazily:

>>> take 10 (fst (break (const False) [1..]))
[1,2,3,4,5,6,7,8,9,10]

Examples

Expand
>>> break (> 3) [1,2,3,4,1,2,3,4]
([1,2,3],[4,1,2,3,4])
>>> break (< 9) [1,2,3]
([],[1,2,3])
>>> break (> 9) [1,2,3]
([1,2,3],[])

splitAt :: Int -> [a] -> ([a], [a]) Source #

splitAt n xs returns a tuple where first element is xs prefix of length n and second element is the remainder of the list:

splitAt is an instance of the more general genericSplitAt, in which n may be of any integral type.

Laziness

Expand

It is equivalent to (take n xs, drop n xs) unless n is _|_: splitAt _|_ xs = _|_, not (_|_, _|_)).

The first component of the tuple is produced lazily:

>>> fst (splitAt 0 undefined)
[]
>>> take 1 (fst (splitAt 10 (1 : undefined)))
[1]

Examples

Expand
>>> splitAt 6 "Hello World!"
("Hello ","World!")
>>> splitAt 3 [1,2,3,4,5]
([1,2,3],[4,5])
>>> splitAt 1 [1,2,3]
([1],[2,3])
>>> splitAt 3 [1,2,3]
([1,2,3],[])
>>> splitAt 4 [1,2,3]
([1,2,3],[])
>>> splitAt 0 [1,2,3]
([],[1,2,3])
>>> splitAt (-1) [1,2,3]
([],[1,2,3])

Searching lists

notElem :: (Foldable t, Eq a) => a -> t a -> Bool infix 4 Source #

notElem is the negation of elem.

Examples

Expand

Basic usage:

>>> 3 `notElem` []
True
>>> 3 `notElem` [1,2]
True
>>> 3 `notElem` [1,2,3,4,5]
False

For infinite structures, notElem terminates if the value exists at a finite distance from the left side of the structure:

>>> 3 `notElem` [1..]
False
>>> 3 `notElem` ([4..] ++ [3])
* Hangs forever *

lookup :: Eq a => a -> [(a, b)] -> Maybe b Source #

\(\mathcal{O}(n)\). lookup key assocs looks up a key in an association list. For the result to be Nothing, the list must be finite.

Examples

Expand
>>> lookup 2 []
Nothing
>>> lookup 2 [(1, "first")]
Nothing
>>> lookup 2 [(1, "first"), (2, "second"), (3, "third")]
Just "second"

Zipping and unzipping lists

zip :: [a] -> [b] -> [(a, b)] Source #

\(\mathcal{O}(\min(m,n))\). zip takes two lists and returns a list of corresponding pairs.

zip is right-lazy:

>>> zip [] undefined
[]
>>> zip undefined []
*** Exception: Prelude.undefined
...

zip is capable of list fusion, but it is restricted to its first list argument and its resulting list.

Examples

Expand
>>> zip [1, 2, 3] ['a', 'b', 'c']
[(1,'a'),(2,'b'),(3,'c')]

If one input list is shorter than the other, excess elements of the longer list are discarded, even if one of the lists is infinite:

>>> zip [1] ['a', 'b']
[(1,'a')]
>>> zip [1, 2] ['a']
[(1,'a')]
>>> zip [] [1..]
[]
>>> zip [1..] []
[]

zip3 :: [a] -> [b] -> [c] -> [(a, b, c)] Source #

zip3 takes three lists and returns a list of triples, analogous to zip. It is capable of list fusion, but it is restricted to its first list argument and its resulting list.

zipWith :: (a -> b -> c) -> [a] -> [b] -> [c] Source #

\(\mathcal{O}(\min(m,n))\). zipWith generalises zip by zipping with the function given as the first argument, instead of a tupling function.

zipWith (,) xs ys == zip xs ys
zipWith f [x1,x2,x3..] [y1,y2,y3..] == [f x1 y1, f x2 y2, f x3 y3..]

zipWith is right-lazy:

>>> let f = undefined
>>> zipWith f [] undefined
[]

zipWith is capable of list fusion, but it is restricted to its first list argument and its resulting list.

Examples

Expand

zipWith (+) can be applied to two lists to produce the list of corresponding sums:

>>> zipWith (+) [1, 2, 3] [4, 5, 6]
[5,7,9]
>>> zipWith (++) ["hello ", "foo"] ["world!", "bar"]
["hello world!","foobar"]

zipWith3 :: (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d] Source #

\(\mathcal{O}(\min(l,m,n))\). The zipWith3 function takes a function which combines three elements, as well as three lists and returns a list of the function applied to corresponding elements, analogous to zipWith. It is capable of list fusion, but it is restricted to its first list argument and its resulting list.

zipWith3 (,,) xs ys zs == zip3 xs ys zs
zipWith3 f [x1,x2,x3..] [y1,y2,y3..] [z1,z2,z3..] == [f x1 y1 z1, f x2 y2 z2, f x3 y3 z3..]

Examples

Expand
>>> zipWith3 (\x y z -> [x, y, z]) "123" "abc" "xyz"
["1ax","2by","3cz"]
>>> zipWith3 (\x y z -> (x * y) + z) [1, 2, 3] [4, 5, 6] [7, 8, 9]
[11,18,27]

unzip :: [(a, b)] -> ([a], [b]) Source #

unzip transforms a list of pairs into a list of first components and a list of second components.

Examples

Expand
>>> unzip []
([],[])
>>> unzip [(1, 'a'), (2, 'b')]
([1,2],"ab")

unzip3 :: [(a, b, c)] -> ([a], [b], [c]) Source #

The unzip3 function takes a list of triples and returns three lists of the respective components, analogous to unzip.

Examples

Expand
>>> unzip3 []
([],[],[])
>>> unzip3 [(1, 'a', True), (2, 'b', False)]
([1,2],"ab",[True,False])

Functions on strings

lines :: String -> [String] Source #

Splits the argument into a list of lines stripped of their terminating \n characters. The \n terminator is optional in a final non-empty line of the argument string.

When the argument string is empty, or ends in a \n character, it can be recovered by passing the result of lines to the unlines function. Otherwise, unlines appends the missing terminating \n. This makes unlines . lines idempotent:

(unlines . lines) . (unlines . lines) = (unlines . lines)

Examples

Expand
>>> lines ""           -- empty input contains no lines
[]
>>> lines "\n"         -- single empty line
[""]
>>> lines "one"        -- single unterminated line
["one"]
>>> lines "one\n"      -- single non-empty line
["one"]
>>> lines "one\n\n"    -- second line is empty
["one",""]
>>> lines "one\ntwo"   -- second line is unterminated
["one","two"]
>>> lines "one\ntwo\n" -- two non-empty lines
["one","two"]

words :: String -> [String] Source #

words breaks a string up into a list of words, which were delimited by white space (as defined by isSpace). This function trims any white spaces at the beginning and at the end.

Examples

Expand
>>> words "Lorem ipsum\ndolor"
["Lorem","ipsum","dolor"]
>>> words " foo bar "
["foo","bar"]

unlines :: [String] -> String Source #

Appends a \n character to each input string, then concatenates the results. Equivalent to foldMap (s -> s ++ "\n").

Examples

Expand
>>> unlines ["Hello", "World", "!"]
"Hello\nWorld\n!\n"

Note that unlines . lines /= id when the input is not \n-terminated:

>>> unlines . lines $ "foo\nbar"
"foo\nbar\n"

unwords :: [String] -> String Source #

unwords joins words with separating spaces (U+0020 SPACE).

unwords is neither left nor right inverse of words:

>>> words (unwords [" "])
[]
>>> unwords (words "foo\nbar")
"foo bar"

Examples

Expand
>>> unwords ["Lorem", "ipsum", "dolor"]
"Lorem ipsum dolor"
>>> unwords ["foo", "bar", "", "baz"]
"foo bar  baz"

Converting to and from String

Converting to String

type ShowS = String -> String Source #

The shows functions return a function that prepends the output String to an existing String. This allows constant-time concatenation of results using function composition.

class Show a where Source #

Conversion of values to readable Strings.

Derived instances of Show have the following properties, which are compatible with derived instances of Read:

  • The result of show is a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used.
  • If the constructor is defined to be an infix operator, then showsPrec will produce infix applications of the constructor.
  • the representation will be enclosed in parentheses if the precedence of the top-level constructor in x is less than d (associativity is ignored). Thus, if d is 0 then the result is never surrounded in parentheses; if d is 11 it is always surrounded in parentheses, unless it is an atomic expression.
  • If the constructor is defined using record syntax, then show will produce the record-syntax form, with the fields given in the same order as the original declaration.

For example, given the declarations

infixr 5 :^:
data Tree a =  Leaf a  |  Tree a :^: Tree a

the derived instance of Show is equivalent to

instance (Show a) => Show (Tree a) where

       showsPrec d (Leaf m) = showParen (d > app_prec) $
            showString "Leaf " . showsPrec (app_prec+1) m
         where app_prec = 10

       showsPrec d (u :^: v) = showParen (d > up_prec) $
            showsPrec (up_prec+1) u .
            showString " :^: "      .
            showsPrec (up_prec+1) v
         where up_prec = 5

Note that right-associativity of :^: is ignored. For example,

  • show (Leaf 1 :^: Leaf 2 :^: Leaf 3) produces the string "Leaf 1 :^: (Leaf 2 :^: Leaf 3)".

Minimal complete definition

showsPrec | show

Methods

showsPrec Source #

Arguments

:: Int

the operator precedence of the enclosing context (a number from 0 to 11). Function application has precedence 10.

-> a

the value to be converted to a String

-> ShowS 

Convert a value to a readable String.

showsPrec should satisfy the law

showsPrec d x r ++ s  ==  showsPrec d x (r ++ s)

Derived instances of Read and Show satisfy the following:

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

show :: a -> String Source #

A specialised variant of showsPrec, using precedence context zero, and returning an ordinary String.

showList :: [a] -> ShowS Source #

The method showList is provided to allow the programmer to give a specialised way of showing lists of values. For example, this is used by the predefined Show instance of the Char type, where values of type String should be shown in double quotes, rather than between square brackets.

Instances

Instances details
Show NestedAtomically Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show NoMatchingContinuationPrompt Source #

Since: base-4.18

Instance details

Defined in Control.Exception.Base

Show NoMethodError Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show NonTermination Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show PatternMatchFail Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show RecConError Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show RecSelError Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show RecUpdError Source #

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Show TypeError Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Exception.Base

Show ByteArray Source #

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Show Constr Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Show ConstrRep Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Show DataRep Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Show DataType Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Show Fixity Source #

Since: base-4.0.0.0

Instance details

Defined in Data.Data

Show Dynamic Source #

Since: base-2.1

Instance details

Defined in Data.Dynamic

Show All Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Show Any Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Show SomeTypeRep Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Typeable.Internal

Show Version Source #

Since: base-2.1

Instance details

Defined in Data.Version

Show CBool Source # 
Instance details

Defined in Foreign.C.Types

Show CChar Source # 
Instance details

Defined in Foreign.C.Types

Show CClock Source # 
Instance details

Defined in Foreign.C.Types

Show CDouble Source # 
Instance details

Defined in Foreign.C.Types

Show CFloat Source # 
Instance details

Defined in Foreign.C.Types

Show CInt Source # 
Instance details

Defined in Foreign.C.Types

Show CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Show CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Show CLLong Source # 
Instance details

Defined in Foreign.C.Types

Show CLong Source # 
Instance details

Defined in Foreign.C.Types

Show CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Show CSChar Source # 
Instance details

Defined in Foreign.C.Types

Show CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Show CShort Source # 
Instance details

Defined in Foreign.C.Types

Show CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Show CSize Source # 
Instance details

Defined in Foreign.C.Types

Show CTime Source # 
Instance details

Defined in Foreign.C.Types

Show CUChar Source # 
Instance details

Defined in Foreign.C.Types

Show CUInt Source # 
Instance details

Defined in Foreign.C.Types

Show CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Show CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Show CULLong Source # 
Instance details

Defined in Foreign.C.Types

Show CULong Source # 
Instance details

Defined in Foreign.C.Types

Show CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Show CUShort Source # 
Instance details

Defined in Foreign.C.Types

Show CWchar Source # 
Instance details

Defined in Foreign.C.Types

Show IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Show WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Show Void Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Show

Show ByteOrder Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ByteOrder

Show BlockReason Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Show ThreadId Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.Conc.Sync

Show ThreadStatus Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Show Event Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Internal.Types

Show Lifetime Source #

Since: base-4.8.1.0

Instance details

Defined in GHC.Event.Internal.Types

Show FdKey Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Manager

Show ErrorCall Source #

Since: base-4.0.0.0

Instance details

Defined in GHC.Exception

Show ArithException Source #

Since: base-4.0.0.0

Instance details

Defined in GHC.Exception.Type

Show SomeException Source #

Since: base-3.0

Instance details

Defined in GHC.Exception.Type

Show Fingerprint Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Fingerprint.Type

Show Associativity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Show DecidedStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Show Fixity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Show SourceStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Show SourceUnpackedness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Show MaskingState Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO

Show SeekMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Device

Show CodingFailureMode Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.IO.Encoding.Failure

Show CodingProgress Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.IO.Encoding.Types

Show TextEncoding Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Encoding.Types

Show AllocationLimitExceeded Source #

Since: base-4.7.1.0

Instance details

Defined in GHC.IO.Exception

Show ArrayException Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show AssertionFailed Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show AsyncException Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show BlockedIndefinitelyOnMVar Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show BlockedIndefinitelyOnSTM Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show CompactionFailed Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.IO.Exception

Show Deadlock Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show ExitCode Source # 
Instance details

Defined in GHC.IO.Exception

Show FixIOException Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.IO.Exception

Show IOErrorType Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show IOException Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show SomeAsyncException Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.IO.Exception

Show FD Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.FD

Show HandlePosn Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle

Show FileLockingNotSupported Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.IO.Handle.Lock.Common

Show BufferMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Handle.Types

Show Handle Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle.Types

Show HandleType Source #

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle.Types

Show Newline Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Handle.Types

Show NewlineMode Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Handle.Types

Show IOMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.IOMode

Show InfoProv Source # 
Instance details

Defined in GHC.InfoProv

Show Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Show Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Show Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Show Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Show CCFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show ConcFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show DebugFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show DoCostCentres Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show DoHeapProfile Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show DoTrace Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show GCFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show GiveGCStats Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show IoSubSystem Source # 
Instance details

Defined in GHC.RTS.Flags

Show MiscFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show ParFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show ProfFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show RTSFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show TickyFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show TraceFlags Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.RTS.Flags

Show FractionalExponentBase Source # 
Instance details

Defined in GHC.Real

Show StackEntry Source # 
Instance details

Defined in GHC.Stack.CloneStack

Show CallStack Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show SrcLoc Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show StaticPtrInfo Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.StaticPtr

Show GCDetails Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Stats

Show RTSStats Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Stats

Show SomeChar Source # 
Instance details

Defined in GHC.TypeLits

Show SomeSymbol Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeLits

Show SomeNat Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeNats

Show GeneralCategory Source #

Since: base-2.1

Instance details

Defined in GHC.Unicode

Show Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Show Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Show Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Show Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Word

Show CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Show CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Show CCc Source # 
Instance details

Defined in System.Posix.Types

Show CClockId Source # 
Instance details

Defined in System.Posix.Types

Show CDev Source # 
Instance details

Defined in System.Posix.Types

Show CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Show CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Show CGid Source # 
Instance details

Defined in System.Posix.Types

Show CId Source # 
Instance details

Defined in System.Posix.Types

Show CIno Source # 
Instance details

Defined in System.Posix.Types

Show CKey Source # 
Instance details

Defined in System.Posix.Types

Show CMode Source # 
Instance details

Defined in System.Posix.Types

Show CNfds Source # 
Instance details

Defined in System.Posix.Types

Show CNlink Source # 
Instance details

Defined in System.Posix.Types

Show COff Source # 
Instance details

Defined in System.Posix.Types

Show CPid Source # 
Instance details

Defined in System.Posix.Types

Show CRLim Source # 
Instance details

Defined in System.Posix.Types

Show CSocklen Source # 
Instance details

Defined in System.Posix.Types

Show CSpeed Source # 
Instance details

Defined in System.Posix.Types

Show CSsize Source # 
Instance details

Defined in System.Posix.Types

Show CTcflag Source # 
Instance details

Defined in System.Posix.Types

Show CTimer Source # 
Instance details

Defined in System.Posix.Types

Show CUid Source # 
Instance details

Defined in System.Posix.Types

Show Fd Source # 
Instance details

Defined in System.Posix.Types

Show Timeout Source #

Since: base-4.0

Instance details

Defined in System.Timeout

Show Lexeme Source #

Since: base-2.1

Instance details

Defined in Text.Read.Lex

Show Number Source #

Since: base-4.6.0.0

Instance details

Defined in Text.Read.Lex

Show KindRep Source # 
Instance details

Defined in GHC.Show

Show Module Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show TrName Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show TyCon Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show TypeLitSort Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.Show

Show Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show Natural Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Show

Show () Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> () -> ShowS Source #

show :: () -> String Source #

showList :: [()] -> ShowS Source #

Show Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show Char Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show Double Source #

Since: base-2.1

Instance details

Defined in GHC.Float

Show Float Source #

Since: base-2.1

Instance details

Defined in GHC.Float

Show Int Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show Levity Source #

Since: base-4.15.0.0

Instance details

Defined in GHC.Show

Show RuntimeRep Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.Show

Show VecCount Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.Show

Show VecElem Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.Show

Show Word Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show a => Show (ZipList a) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Show a => Show (And a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

showsPrec :: Int -> And a -> ShowS Source #

show :: And a -> String Source #

showList :: [And a] -> ShowS Source #

Show a => Show (Iff a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

showsPrec :: Int -> Iff a -> ShowS Source #

show :: Iff a -> String Source #

showList :: [Iff a] -> ShowS Source #

Show a => Show (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

showsPrec :: Int -> Ior a -> ShowS Source #

show :: Ior a -> String Source #

showList :: [Ior a] -> ShowS Source #

Show a => Show (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Methods

showsPrec :: Int -> Xor a -> ShowS Source #

show :: Xor a -> String Source #

showList :: [Xor a] -> ShowS Source #

Show a => Show (Complex a) Source #

Since: base-2.1

Instance details

Defined in Data.Complex

Show a => Show (Identity a) Source #

This instance would be equivalent to the derived instances of the Identity newtype if the runIdentity field were removed

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Show a => Show (First a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Show a => Show (Last a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

showsPrec :: Int -> Last a -> ShowS Source #

show :: Last a -> String Source #

showList :: [Last a] -> ShowS Source #

Show a => Show (Down a) Source #

This instance would be equivalent to the derived instances of the Down newtype if the getDown field were removed

Since: base-4.7.0.0

Instance details

Defined in Data.Ord

Methods

showsPrec :: Int -> Down a -> ShowS Source #

show :: Down a -> String Source #

showList :: [Down a] -> ShowS Source #

Show a => Show (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Show a => Show (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Last a -> ShowS Source #

show :: Last a -> String Source #

showList :: [Last a] -> ShowS Source #

Show a => Show (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Max a -> ShowS Source #

show :: Max a -> String Source #

showList :: [Max a] -> ShowS Source #

Show a => Show (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Min a -> ShowS Source #

show :: Min a -> String Source #

showList :: [Min a] -> ShowS Source #

Show m => Show (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Show a => Show (Dual a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Dual a -> ShowS Source #

show :: Dual a -> String Source #

showList :: [Dual a] -> ShowS Source #

Show a => Show (Product a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Show a => Show (Sum a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Sum a -> ShowS Source #

show :: Sum a -> String Source #

showList :: [Sum a] -> ShowS Source #

Show (ConstPtr a) Source # 
Instance details

Defined in Foreign.C.ConstPtr

Show a => Show (NonEmpty a) Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.Show

Show (ForeignPtr a) Source #

Since: base-2.1

Instance details

Defined in GHC.ForeignPtr

Show p => Show (Par1 p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> Par1 p -> ShowS Source #

show :: Par1 p -> String Source #

showList :: [Par1 p] -> ShowS Source #

Show (FunPtr a) Source #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Show (Ptr a) Source #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

showsPrec :: Int -> Ptr a -> ShowS Source #

show :: Ptr a -> String Source #

showList :: [Ptr a] -> ShowS Source #

Show a => Show (Ratio a) Source #

Since: base-2.0.1

Instance details

Defined in GHC.Real

Show (SChar c) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.TypeLits

Show (SSymbol s) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.TypeLits

Show (SNat n) Source #

Since: base-4.18.0.0

Instance details

Defined in GHC.TypeNats

Methods

showsPrec :: Int -> SNat n -> ShowS Source #

show :: SNat n -> String Source #

showList :: [SNat n] -> ShowS Source #

Show a => Show (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Show a => Show (Solo a) Source #

Since: base-4.15

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Solo a -> ShowS Source #

show :: Solo a -> String Source #

showList :: [Solo a] -> ShowS Source #

Show a => Show [a] Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> [a] -> ShowS Source #

show :: [a] -> String Source #

showList :: [[a]] -> ShowS Source #

(Show a, Show b) => Show (Either a b) Source #

Since: base-3.0

Instance details

Defined in Data.Either

Methods

showsPrec :: Int -> Either a b -> ShowS Source #

show :: Either a b -> String Source #

showList :: [Either a b] -> ShowS Source #

HasResolution a => Show (Fixed a) Source #

Since: base-2.1

Instance details

Defined in Data.Fixed

Show (Proxy s) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

(Show a, Show b) => Show (Arg a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Arg a b -> ShowS Source #

show :: Arg a b -> String Source #

showList :: [Arg a b] -> ShowS Source #

Show (TypeRep a) Source # 
Instance details

Defined in Data.Typeable.Internal

(Ix a, Show a, Show b) => Show (Array a b) Source #

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

showsPrec :: Int -> Array a b -> ShowS Source #

show :: Array a b -> String Source #

showList :: [Array a b] -> ShowS Source #

Show (U1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> U1 p -> ShowS Source #

show :: U1 p -> String Source #

showList :: [U1 p] -> ShowS Source #

Show (V1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> V1 p -> ShowS Source #

show :: V1 p -> String Source #

showList :: [V1 p] -> ShowS Source #

Show (ST s a) Source #

Since: base-2.1

Instance details

Defined in GHC.ST

Methods

showsPrec :: Int -> ST s a -> ShowS Source #

show :: ST s a -> String Source #

showList :: [ST s a] -> ShowS Source #

(Show a, Show b) => Show (a, b) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b) -> ShowS Source #

show :: (a, b) -> String Source #

showList :: [(a, b)] -> ShowS Source #

Show (a -> b) Source #

Since: base-2.1

Instance details

Defined in Text.Show.Functions

Methods

showsPrec :: Int -> (a -> b) -> ShowS Source #

show :: (a -> b) -> String Source #

showList :: [a -> b] -> ShowS Source #

Show a => Show (Const a b) Source #

This instance would be equivalent to the derived instances of the Const newtype if the getConst field were removed

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Const

Methods

showsPrec :: Int -> Const a b -> ShowS Source #

show :: Const a b -> String Source #

showList :: [Const a b] -> ShowS Source #

Show (f a) => Show (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Methods

showsPrec :: Int -> Ap f a -> ShowS Source #

show :: Ap f a -> String Source #

showList :: [Ap f a] -> ShowS Source #

Show (f a) => Show (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Alt f a -> ShowS Source #

show :: Alt f a -> String Source #

showList :: [Alt f a] -> ShowS Source #

Show (Coercion a b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Coercion

Show (a :~: b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

showsPrec :: Int -> (a :~: b) -> ShowS Source #

show :: (a :~: b) -> String Source #

showList :: [a :~: b] -> ShowS Source #

Show (OrderingI a b) Source # 
Instance details

Defined in Data.Type.Ord

Show (f p) => Show (Rec1 f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> Rec1 f p -> ShowS Source #

show :: Rec1 f p -> String Source #

showList :: [Rec1 f p] -> ShowS Source #

Show (URec Char p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Show (URec Double p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Show (URec Float p) Source # 
Instance details

Defined in GHC.Generics

Show (URec Int p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Show (URec Word p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

(Show a, Show b, Show c) => Show (a, b, c) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c) -> ShowS Source #

show :: (a, b, c) -> String Source #

showList :: [(a, b, c)] -> ShowS Source #

(Show (f a), Show (g a)) => Show (Product f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Product

Methods

showsPrec :: Int -> Product f g a -> ShowS Source #

show :: Product f g a -> String Source #

showList :: [Product f g a] -> ShowS Source #

(Show (f a), Show (g a)) => Show (Sum f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Sum

Methods

showsPrec :: Int -> Sum f g a -> ShowS Source #

show :: Sum f g a -> String Source #

showList :: [Sum f g a] -> ShowS Source #

Show (a :~~: b) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

showsPrec :: Int -> (a :~~: b) -> ShowS Source #

show :: (a :~~: b) -> String Source #

showList :: [a :~~: b] -> ShowS Source #

(Show (f p), Show (g p)) => Show ((f :*: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> (f :*: g) p -> ShowS Source #

show :: (f :*: g) p -> String Source #

showList :: [(f :*: g) p] -> ShowS Source #

(Show (f p), Show (g p)) => Show ((f :+: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> (f :+: g) p -> ShowS Source #

show :: (f :+: g) p -> String Source #

showList :: [(f :+: g) p] -> ShowS Source #

Show c => Show (K1 i c p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> K1 i c p -> ShowS Source #

show :: K1 i c p -> String Source #

showList :: [K1 i c p] -> ShowS Source #

(Show a, Show b, Show c, Show d) => Show (a, b, c, d) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d) -> ShowS Source #

show :: (a, b, c, d) -> String Source #

showList :: [(a, b, c, d)] -> ShowS Source #

Show (f (g a)) => Show (Compose f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Compose

Methods

showsPrec :: Int -> Compose f g a -> ShowS Source #

show :: Compose f g a -> String Source #

showList :: [Compose f g a] -> ShowS Source #

Show (f (g p)) => Show ((f :.: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> (f :.: g) p -> ShowS Source #

show :: (f :.: g) p -> String Source #

showList :: [(f :.: g) p] -> ShowS Source #

Show (f p) => Show (M1 i c f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> M1 i c f p -> ShowS Source #

show :: M1 i c f p -> String Source #

showList :: [M1 i c f p] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e) => Show (a, b, c, d, e) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e) -> ShowS Source #

show :: (a, b, c, d, e) -> String Source #

showList :: [(a, b, c, d, e)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f) => Show (a, b, c, d, e, f) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f) -> ShowS Source #

show :: (a, b, c, d, e, f) -> String Source #

showList :: [(a, b, c, d, e, f)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g) => Show (a, b, c, d, e, f, g) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g) -> ShowS Source #

show :: (a, b, c, d, e, f, g) -> String Source #

showList :: [(a, b, c, d, e, f, g)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h) => Show (a, b, c, d, e, f, g, h) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h) -> String Source #

showList :: [(a, b, c, d, e, f, g, h)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i) => Show (a, b, c, d, e, f, g, h, i) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j) => Show (a, b, c, d, e, f, g, h, i, j) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i, j) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i, j)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k) => Show (a, b, c, d, e, f, g, h, i, j, k) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i, j, k) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l) => Show (a, b, c, d, e, f, g, h, i, j, k, l) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i, j, k, l) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m, Show n) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m, Show n, Show o) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> ShowS Source #

show :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> String Source #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> ShowS Source #

shows :: Show a => a -> ShowS Source #

equivalent to showsPrec with a precedence of 0.

showChar :: Char -> ShowS Source #

utility function converting a Char to a show function that simply prepends the character unchanged.

showString :: String -> ShowS Source #

utility function converting a String to a show function that simply prepends the string unchanged.

showParen :: Bool -> ShowS -> ShowS Source #

utility function that surrounds the inner show function with parentheses when the Bool parameter is True.

Converting from String

type ReadS a = String -> [(a, String)] Source #

A parser for a type a, represented as a function that takes a String and returns a list of possible parses as (a,String) pairs.

Note that this kind of backtracking parser is very inefficient; reading a large structure may be quite slow (cf ReadP).

class Read a where Source #

Parsing of Strings, producing values.

Derived instances of Read make the following assumptions, which derived instances of Show obey:

  • If the constructor is defined to be an infix operator, then the derived Read instance will parse only infix applications of the constructor (not the prefix form).
  • Associativity is not used to reduce the occurrence of parentheses, although precedence may be.
  • If the constructor is defined using record syntax, the derived Read will parse only the record-syntax form, and furthermore, the fields must be given in the same order as the original declaration.
  • The derived Read instance allows arbitrary Haskell whitespace between tokens of the input string. Extra parentheses are also allowed.

For example, given the declarations

infixr 5 :^:
data Tree a =  Leaf a  |  Tree a :^: Tree a

the derived instance of Read in Haskell 2010 is equivalent to

instance (Read a) => Read (Tree a) where

        readsPrec d r =  readParen (d > app_prec)
                         (\r -> [(Leaf m,t) |
                                 ("Leaf",s) <- lex r,
                                 (m,t) <- readsPrec (app_prec+1) s]) r

                      ++ readParen (d > up_prec)
                         (\r -> [(u:^:v,w) |
                                 (u,s) <- readsPrec (up_prec+1) r,
                                 (":^:",t) <- lex s,
                                 (v,w) <- readsPrec (up_prec+1) t]) r

          where app_prec = 10
                up_prec = 5

Note that right-associativity of :^: is unused.

The derived instance in GHC is equivalent to

instance (Read a) => Read (Tree a) where

        readPrec = parens $ (prec app_prec $ do
                                 Ident "Leaf" <- lexP
                                 m <- step readPrec
                                 return (Leaf m))

                     +++ (prec up_prec $ do
                                 u <- step readPrec
                                 Symbol ":^:" <- lexP
                                 v <- step readPrec
                                 return (u :^: v))

          where app_prec = 10
                up_prec = 5

        readListPrec = readListPrecDefault

Why do both readsPrec and readPrec exist, and why does GHC opt to implement readPrec in derived Read instances instead of readsPrec? The reason is that readsPrec is based on the ReadS type, and although ReadS is mentioned in the Haskell 2010 Report, it is not a very efficient parser data structure.

readPrec, on the other hand, is based on a much more efficient ReadPrec datatype (a.k.a "new-style parsers"), but its definition relies on the use of the RankNTypes language extension. Therefore, readPrec (and its cousin, readListPrec) are marked as GHC-only. Nevertheless, it is recommended to use readPrec instead of readsPrec whenever possible for the efficiency improvements it brings.

As mentioned above, derived Read instances in GHC will implement readPrec instead of readsPrec. The default implementations of readsPrec (and its cousin, readList) will simply use readPrec under the hood. If you are writing a Read instance by hand, it is recommended to write it like so:

instance Read T where
  readPrec     = ...
  readListPrec = readListPrecDefault

Minimal complete definition

readsPrec | readPrec

Methods

readsPrec Source #

Arguments

:: Int

the operator precedence of the enclosing context (a number from 0 to 11). Function application has precedence 10.

-> ReadS a 

attempts to parse a value from the front of the string, returning a list of (parsed value, remaining string) pairs. If there is no successful parse, the returned list is empty.

Derived instances of Read and Show satisfy the following:

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

readList :: ReadS [a] Source #

The method readList is provided to allow the programmer to give a specialised way of parsing lists of values. For example, this is used by the predefined Read instance of the Char type, where values of type String are expected to use double quotes, rather than square brackets.

Instances

Instances details
Read All Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Read Any Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Read Version Source #

Since: base-2.1

Instance details

Defined in Data.Version

Read CBool Source # 
Instance details

Defined in Foreign.C.Types

Read CChar Source # 
Instance details

Defined in Foreign.C.Types

Read CClock Source # 
Instance details

Defined in Foreign.C.Types

Read CDouble Source # 
Instance details

Defined in Foreign.C.Types

Read CFloat Source # 
Instance details

Defined in Foreign.C.Types

Read CInt Source # 
Instance details

Defined in Foreign.C.Types

Read CIntMax Source # 
Instance details

Defined in Foreign.C.Types

Read CIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Read CLLong Source # 
Instance details

Defined in Foreign.C.Types

Read CLong Source # 
Instance details

Defined in Foreign.C.Types

Read CPtrdiff Source # 
Instance details

Defined in Foreign.C.Types

Read CSChar Source # 
Instance details

Defined in Foreign.C.Types

Read CSUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Read CShort Source # 
Instance details

Defined in Foreign.C.Types

Read CSigAtomic Source # 
Instance details

Defined in Foreign.C.Types

Read CSize Source # 
Instance details

Defined in Foreign.C.Types

Read CTime Source # 
Instance details

Defined in Foreign.C.Types

Read CUChar Source # 
Instance details

Defined in Foreign.C.Types

Read CUInt Source # 
Instance details

Defined in Foreign.C.Types

Read CUIntMax Source # 
Instance details

Defined in Foreign.C.Types

Read CUIntPtr Source # 
Instance details

Defined in Foreign.C.Types

Read CULLong Source # 
Instance details

Defined in Foreign.C.Types

Read CULong Source # 
Instance details

Defined in Foreign.C.Types

Read CUSeconds Source # 
Instance details

Defined in Foreign.C.Types

Read CUShort Source # 
Instance details

Defined in Foreign.C.Types

Read CWchar Source # 
Instance details

Defined in Foreign.C.Types

Read IntPtr Source # 
Instance details

Defined in Foreign.Ptr

Read WordPtr Source # 
Instance details

Defined in Foreign.Ptr

Read Void Source #

Reading a Void value is always a parse error, considering Void as a data type with no constructors.

Since: base-4.8.0.0

Instance details

Defined in GHC.Read

Read ByteOrder Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.ByteOrder

Read Associativity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Read DecidedStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read Fixity Source #

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Read SourceStrictness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read SourceUnpackedness Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read SeekMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Device

Read ExitCode Source # 
Instance details

Defined in GHC.IO.Exception

Read BufferMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.Handle.Types

Read Newline Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Handle.Types

Read NewlineMode Source #

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Handle.Types

Read IOMode Source #

Since: base-4.2.0.0

Instance details

Defined in GHC.IO.IOMode

Read Int16 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Read Int32 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Read Int64 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Read Int8 Source #

Since: base-2.1

Instance details

Defined in GHC.Int

Read GCDetails Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Stats

Read RTSStats Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Stats

Read SomeChar Source # 
Instance details

Defined in GHC.TypeLits

Read SomeSymbol Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeLits

Read SomeNat Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeNats

Read GeneralCategory Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word16 Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word32 Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word64 Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word8 Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read CBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Read CBlkSize Source # 
Instance details

Defined in System.Posix.Types

Read CCc Source # 
Instance details

Defined in System.Posix.Types

Read CClockId Source # 
Instance details

Defined in System.Posix.Types

Read CDev Source # 
Instance details

Defined in System.Posix.Types

Read CFsBlkCnt Source # 
Instance details

Defined in System.Posix.Types

Read CFsFilCnt Source # 
Instance details

Defined in System.Posix.Types

Read CGid Source # 
Instance details

Defined in System.Posix.Types

Read CId Source # 
Instance details

Defined in System.Posix.Types

Read CIno Source # 
Instance details

Defined in System.Posix.Types

Read CKey Source # 
Instance details

Defined in System.Posix.Types

Read CMode Source # 
Instance details

Defined in System.Posix.Types

Read CNfds Source # 
Instance details

Defined in System.Posix.Types

Read CNlink Source # 
Instance details

Defined in System.Posix.Types

Read COff Source # 
Instance details

Defined in System.Posix.Types

Read CPid Source # 
Instance details

Defined in System.Posix.Types

Read CRLim Source # 
Instance details

Defined in System.Posix.Types

Read CSocklen Source # 
Instance details

Defined in System.Posix.Types

Read CSpeed Source # 
Instance details

Defined in System.Posix.Types

Read CSsize Source # 
Instance details

Defined in System.Posix.Types

Read CTcflag Source # 
Instance details

Defined in System.Posix.Types

Read CUid Source # 
Instance details

Defined in System.Posix.Types

Read Fd Source # 
Instance details

Defined in System.Posix.Types

Read Lexeme Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Ordering Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Integer Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Natural Source #

Since: base-4.8.0.0

Instance details

Defined in GHC.Read

Read () Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Bool Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Char Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Double Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Float Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Int Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word Source #

Since: base-4.5.0.0

Instance details

Defined in GHC.Read

Read a => Read (ZipList a) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Read a => Read (And a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Read a => Read (Iff a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Read a => Read (Ior a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Read a => Read (Xor a) Source #

Since: base-4.16

Instance details

Defined in Data.Bits

Read a => Read (Complex a) Source #

Since: base-2.1

Instance details

Defined in Data.Complex

Read a => Read (Identity a) Source #

This instance would be equivalent to the derived instances of the Identity newtype if the runIdentity field were removed

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Identity

Read a => Read (First a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Read a => Read (Last a) Source #

Since: base-2.1

Instance details

Defined in Data.Monoid

Read a => Read (Down a) Source #

This instance would be equivalent to the derived instances of the Down newtype if the getDown field were removed

Since: base-4.7.0.0

Instance details

Defined in Data.Ord

Read a => Read (First a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Read a => Read (Last a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Read a => Read (Max a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Read a => Read (Min a) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Read m => Read (WrappedMonoid m) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Read a => Read (Dual a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Read a => Read (Product a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Read a => Read (Sum a) Source #

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Read a => Read (NonEmpty a) Source #

Since: base-4.11.0.0

Instance details

Defined in GHC.Read

Read p => Read (Par1 p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

(Integral a, Read a) => Read (Ratio a) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read a => Read (Maybe a) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read a => Read (Solo a) Source #

Since: base-4.15

Instance details

Defined in GHC.Read

Read a => Read [a] Source #

Since: base-2.1

Instance details

Defined in GHC.Read

(Read a, Read b) => Read (Either a b) Source #

Since: base-3.0

Instance details

Defined in Data.Either

HasResolution a => Read (Fixed a) Source #

Since: base-4.3.0.0

Instance details

Defined in Data.Fixed

Read (Proxy t) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

(Read a, Read b) => Read (Arg a b) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

(Ix a, Read a, Read b) => Read (Array a b) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Read (U1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read (V1 p) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

(Read a, Read b) => Read (a, b) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b) Source #

readList :: ReadS [(a, b)] Source #

readPrec :: ReadPrec (a, b) Source #

readListPrec :: ReadPrec [(a, b)] Source #

Read a => Read (Const a b) Source #

This instance would be equivalent to the derived instances of the Const newtype if the getConst field were removed

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Const

Read (f a) => Read (Ap f a) Source #

Since: base-4.12.0.0

Instance details

Defined in Data.Monoid

Read (f a) => Read (Alt f a) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Coercible a b => Read (Coercion a b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Coercion

a ~ b => Read (a :~: b) Source #

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Read (f p) => Read (Rec1 f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

(Read a, Read b, Read c) => Read (a, b, c) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c) Source #

readList :: ReadS [(a, b, c)] Source #

readPrec :: ReadPrec (a, b, c) Source #

readListPrec :: ReadPrec [(a, b, c)] Source #

(Read (f a), Read (g a)) => Read (Product f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Product

(Read (f a), Read (g a)) => Read (Sum f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Sum

Methods

readsPrec :: Int -> ReadS (Sum f g a) Source #

readList :: ReadS [Sum f g a] Source #

readPrec :: ReadPrec (Sum f g a) Source #

readListPrec :: ReadPrec [Sum f g a] Source #

a ~~ b => Read (a :~~: b) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

(Read (f p), Read (g p)) => Read ((f :*: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :*: g) p) Source #

readList :: ReadS [(f :*: g) p] Source #

readPrec :: ReadPrec ((f :*: g) p) Source #

readListPrec :: ReadPrec [(f :*: g) p] Source #

(Read (f p), Read (g p)) => Read ((f :+: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :+: g) p) Source #

readList :: ReadS [(f :+: g) p] Source #

readPrec :: ReadPrec ((f :+: g) p) Source #

readListPrec :: ReadPrec [(f :+: g) p] Source #

Read c => Read (K1 i c p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (K1 i c p) Source #

readList :: ReadS [K1 i c p] Source #

readPrec :: ReadPrec (K1 i c p) Source #

readListPrec :: ReadPrec [K1 i c p] Source #

(Read a, Read b, Read c, Read d) => Read (a, b, c, d) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d) Source #

readList :: ReadS [(a, b, c, d)] Source #

readPrec :: ReadPrec (a, b, c, d) Source #

readListPrec :: ReadPrec [(a, b, c, d)] Source #

Read (f (g a)) => Read (Compose f g a) Source #

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Compose

Read (f (g p)) => Read ((f :.: g) p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :.: g) p) Source #

readList :: ReadS [(f :.: g) p] Source #

readPrec :: ReadPrec ((f :.: g) p) Source #

readListPrec :: ReadPrec [(f :.: g) p] Source #

Read (f p) => Read (M1 i c f p) Source #

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (M1 i c f p) Source #

readList :: ReadS [M1 i c f p] Source #

readPrec :: ReadPrec (M1 i c f p) Source #

readListPrec :: ReadPrec [M1 i c f p] Source #

(Read a, Read b, Read c, Read d, Read e) => Read (a, b, c, d, e) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e) Source #

readList :: ReadS [(a, b, c, d, e)] Source #

readPrec :: ReadPrec (a, b, c, d, e) Source #

readListPrec :: ReadPrec [(a, b, c, d, e)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f) => Read (a, b, c, d, e, f) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f) Source #

readList :: ReadS [(a, b, c, d, e, f)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g) => Read (a, b, c, d, e, f, g) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g) Source #

readList :: ReadS [(a, b, c, d, e, f, g)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h) => Read (a, b, c, d, e, f, g, h) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i) => Read (a, b, c, d, e, f, g, h, i) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j) => Read (a, b, c, d, e, f, g, h, i, j) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k) => Read (a, b, c, d, e, f, g, h, i, j, k) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l) => Read (a, b, c, d, e, f, g, h, i, j, k, l) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m, Read n) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m, n) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] Source #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m, Read n, Read o) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] Source #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) Source #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] Source #

reads :: Read a => ReadS a Source #

equivalent to readsPrec with a precedence of 0.

readParen :: Bool -> ReadS a -> ReadS a Source #

readParen True p parses what p parses, but surrounded with parentheses.

readParen False p parses what p parses, but optionally surrounded with parentheses.

read :: Read a => String -> a Source #

The read function reads input from a string, which must be completely consumed by the input process. read fails with an error if the parse is unsuccessful, and it is therefore discouraged from being used in real applications. Use readMaybe or readEither for safe alternatives.

>>> read "123" :: Int
123
>>> read "hello" :: Int
*** Exception: Prelude.read: no parse

lex :: ReadS String Source #

The lex function reads a single lexeme from the input, discarding initial white space, and returning the characters that constitute the lexeme. If the input string contains only white space, lex returns a single successful `lexeme' consisting of the empty string. (Thus lex "" = [("","")].) If there is no legal lexeme at the beginning of the input string, lex fails (i.e. returns []).

This lexer is not completely faithful to the Haskell lexical syntax in the following respects:

  • Qualified names are not handled properly
  • Octal and hexadecimal numerics are not recognized as a single token
  • Comments are not treated properly

Basic Input and output

data IO a Source #

A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a.

There is really only one way to "perform" an I/O action: bind it to Main.main in your program. When your program is run, the I/O will be performed. It isn't possible to perform I/O from an arbitrary function, unless that function is itself in the IO monad and called at some point, directly or indirectly, from Main.main.

IO is a monad, so IO actions can be combined using either the do-notation or the >> and >>= operations from the Monad class.

Instances

Instances details
MonadFail IO Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.Fail

Methods

fail :: String -> IO a Source #

MonadFix IO Source #

Since: base-2.1

Instance details

Defined in Control.Monad.Fix

Methods

mfix :: (a -> IO a) -> IO a Source #

MonadIO IO Source #

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.IO.Class

Methods

liftIO :: IO a -> IO a Source #

Alternative IO Source #

Takes the first non-throwing IO action's result. empty throws an exception.

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

empty :: IO a Source #

(<|>) :: IO a -> IO a -> IO a Source #

some :: IO a -> IO [a] Source #

many :: IO a -> IO [a] Source #

Applicative IO Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> IO a Source #

(<*>) :: IO (a -> b) -> IO a -> IO b Source #

liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c Source #

(*>) :: IO a -> IO b -> IO b Source #

(<*) :: IO a -> IO b -> IO a Source #

Functor IO Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> IO a -> IO b Source #

(<$) :: a -> IO b -> IO a Source #

Monad IO Source #

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: IO a -> (a -> IO b) -> IO b Source #

(>>) :: IO a -> IO b -> IO b Source #

return :: a -> IO a Source #

MonadPlus IO Source #

Takes the first non-throwing IO action's result. mzero throws an exception.

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

mzero :: IO a Source #

mplus :: IO a -> IO a -> IO a Source #

GHCiSandboxIO IO Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.GHCi

Methods

ghciStepIO :: IO a -> IO a Source #

Monoid a => Monoid (IO a) Source #

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

mempty :: IO a Source #

mappend :: IO a -> IO a -> IO a Source #

mconcat :: [IO a] -> IO a Source #

Semigroup a => Semigroup (IO a) Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: IO a -> IO a -> IO a Source #

sconcat :: NonEmpty (IO a) -> IO a Source #

stimes :: Integral b => b -> IO a -> IO a Source #

a ~ () => HPrintfType (IO a) Source #

Since: base-4.7.0.0

Instance details

Defined in Text.Printf

Methods

hspr :: Handle -> String -> [UPrintf] -> IO a

a ~ () => PrintfType (IO a) Source #

Since: base-4.7.0.0

Instance details

Defined in Text.Printf

Methods

spr :: String -> [UPrintf] -> IO a

Simple I/O operations

Output functions

putChar :: Char -> IO () Source #

Write a character to the standard output device (same as hPutChar stdout).

putStr :: String -> IO () Source #

Write a string to the standard output device (same as hPutStr stdout).

putStrLn :: String -> IO () Source #

The same as putStr, but adds a newline character.

print :: Show a => a -> IO () Source #

The print function outputs a value of any printable type to the standard output device. Printable types are those that are instances of class Show; print converts values to strings for output using the show operation and adds a newline.

For example, a program to print the first 20 integers and their powers of 2 could be written as:

main = print ([(n, 2^n) | n <- [0..19]])

Input functions

getChar :: IO Char Source #

Read a character from the standard input device (same as hGetChar stdin).

getLine :: IO String Source #

Read a line from the standard input device (same as hGetLine stdin).

getContents :: IO String Source #

The getContents operation returns all user input as a single string, which is read lazily as it is needed (same as hGetContents stdin).

interact :: (String -> String) -> IO () Source #

The interact function takes a function of type String->String as its argument. The entire input from the standard input device is passed to this function as its argument, and the resulting string is output on the standard output device.

Files

type FilePath = String Source #

File and directory names are values of type String, whose precise meaning is operating system dependent. Files can be opened, yielding a handle which can then be used to operate on the contents of that file.

readFile :: FilePath -> IO String Source #

The readFile function reads a file and returns the contents of the file as a string. The file is read lazily, on demand, as with getContents.

writeFile :: FilePath -> String -> IO () Source #

The computation writeFile file str function writes the string str, to the file file.

appendFile :: FilePath -> String -> IO () Source #

The computation appendFile file str function appends the string str, to the file file.

Note that writeFile and appendFile write a literal string to a file. To write a value of any printable type, as with print, use the show function to convert the value to a string first.

main = appendFile "squares" (show [(x,x*x) | x <- [0,0.1..2]])

readIO :: Read a => String -> IO a Source #

The readIO function is similar to read except that it signals parse failure to the IO monad instead of terminating the program.

readLn :: Read a => IO a Source #

The readLn function combines getLine and readIO.

Exception handling in the I/O monad

type IOError = IOException Source #

The Haskell 2010 type for exceptions in the IO monad. Any I/O operation may raise an IOError instead of returning a result. For a more general type of exception, including also those that arise in pure code, see Exception.

In Haskell 2010, this is an opaque type.

ioError :: IOError -> IO a Source #

Raise an IOError in the IO monad.

userError :: String -> IOError Source #

Construct an IOError value with a string describing the error. The fail method of the IO instance of the Monad class raises a userError, thus:

instance Monad IO where
  ...
  fail s = ioError (userError s)

The equality types

class a ~# b => (a :: k) ~ (b :: k) infix 4 Source #

Lifted, homogeneous equality. By lifted, we mean that it can be bogus (deferred type error). By homogeneous, the two types a and b must have the same kinds.