Applicative

Applicative

class Functor f => Applicative (f :: * -> *) where

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:

• u *> v = (id <$ u) <*> v

• u <* v = liftA2 const u v

As a consequence of these laws, the Functor instance for f will satisfy

• fmap f x = pure f <*> x

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

• pure = return

• (<*>) = ap

• (*>) = (>>)

(which implies that pure and <*> satisfy the applicative functor laws).

Minimal complete definition

pure, ((<*>) | liftA2)

Methods

pure :: a -> f a

Lift a value.

(<*>) :: f (a -> b) -> f a -> f b infixl 4

Sequential application.

A few functors support an implementation of <*> that is more efficient than the default one.

liftA2 :: (a -> b -> c) -> f a -> f b -> f c

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 <*>.

(*>) :: f a -> f b -> f b infixl 4

Sequence actions, discarding the value of the first argument.

(<*) :: f a -> f b -> f a infixl 4

Sequence actions, discarding the value of the second argument.

Instances

Applicative []

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> [a]

(<*>) :: [a -> b] -> [a] -> [b]

liftA2 :: (a -> b -> c) -> [a] -> [b] -> [c]

(*>) :: [a] -> [b] -> [b]

(<*) :: [a] -> [b] -> [a]

Applicative Maybe

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> Maybe a

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

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

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

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

Applicative IO

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> IO a

(<*>) :: IO (a -> b) -> IO a -> IO b

liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c

(*>) :: IO a -> IO b -> IO b

(<*) :: IO a -> IO b -> IO a

Applicative Par1

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> Par1 a

(<*>) :: Par1 (a -> b) -> Par1 a -> Par1 b

liftA2 :: (a -> b -> c) -> Par1 a -> Par1 b -> Par1 c

(*>) :: Par1 a -> Par1 b -> Par1 b

(<*) :: Par1 a -> Par1 b -> Par1 a

Applicative Q

Defined in Language.Haskell.TH.Syntax

Methods

pure :: a -> Q a

(<*>) :: Q (a -> b) -> Q a -> Q b

liftA2 :: (a -> b -> c) -> Q a -> Q b -> Q c

(*>) :: Q a -> Q b -> Q b

(<*) :: Q a -> Q b -> Q a

Applicative IResult

Defined in Data.Aeson.Types.Internal

Methods

pure :: a -> IResult a

(<*>) :: IResult (a -> b) -> IResult a -> IResult b

liftA2 :: (a -> b -> c) -> IResult a -> IResult b -> IResult c

(*>) :: IResult a -> IResult b -> IResult b

(<*) :: IResult a -> IResult b -> IResult a

Applicative Result

Defined in Data.Aeson.Types.Internal

Methods

pure :: a -> Result a

(<*>) :: Result (a -> b) -> Result a -> Result b

liftA2 :: (a -> b -> c) -> Result a -> Result b -> Result c

(*>) :: Result a -> Result b -> Result b

(<*) :: Result a -> Result b -> Result a

Applicative Parser

Defined in Data.Aeson.Types.Internal

Methods

pure :: a -> Parser a

(<*>) :: Parser (a -> b) -> Parser a -> Parser b

liftA2 :: (a -> b -> c) -> Parser a -> Parser b -> Parser c

(*>) :: Parser a -> Parser b -> Parser b

(<*) :: Parser a -> Parser b -> Parser a

Applicative Approximate

Defined in Data.Approximate.Type

Methods

pure :: a -> Approximate a

(<*>) :: Approximate (a -> b) -> Approximate a -> Approximate b

liftA2 :: (a -> b -> c) -> Approximate a -> Approximate b -> Approximate c

(*>) :: Approximate a -> Approximate b -> Approximate b

(<*) :: Approximate a -> Approximate b -> Approximate a

Applicative Concurrently

Defined in Control.Concurrent.Async

Methods

pure :: a -> Concurrently a

(<*>) :: Concurrently (a -> b) -> Concurrently a -> Concurrently b

liftA2 :: (a -> b -> c) -> Concurrently a -> Concurrently b -> Concurrently c

(*>) :: Concurrently a -> Concurrently b -> Concurrently b

(<*) :: Concurrently a -> Concurrently b -> Concurrently a

Applicative Complex

Since: base-4.9.0.0

Defined in Data.Complex

Methods

pure :: a -> Complex a

(<*>) :: Complex (a -> b) -> Complex a -> Complex b

liftA2 :: (a -> b -> c) -> Complex a -> Complex b -> Complex c

(*>) :: Complex a -> Complex b -> Complex b

(<*) :: Complex a -> Complex b -> Complex a

Applicative Min

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Min a

(<*>) :: Min (a -> b) -> Min a -> Min b

liftA2 :: (a -> b -> c) -> Min a -> Min b -> Min c

(*>) :: Min a -> Min b -> Min b

(<*) :: Min a -> Min b -> Min a

Applicative Max

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Max a

(<*>) :: Max (a -> b) -> Max a -> Max b

liftA2 :: (a -> b -> c) -> Max a -> Max b -> Max c

(*>) :: Max a -> Max b -> Max b

(<*) :: Max a -> Max b -> Max a

Applicative First

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> First a

(<*>) :: First (a -> b) -> First a -> First b

liftA2 :: (a -> b -> c) -> First a -> First b -> First c

(*>) :: First a -> First b -> First b

(<*) :: First a -> First b -> First a

Applicative Last

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Last a

(<*>) :: Last (a -> b) -> Last a -> Last b

liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c

(*>) :: Last a -> Last b -> Last b

(<*) :: Last a -> Last b -> Last a

Applicative Option

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Option a

(<*>) :: Option (a -> b) -> Option a -> Option b

liftA2 :: (a -> b -> c) -> Option a -> Option b -> Option c

(*>) :: Option a -> Option b -> Option b

(<*) :: Option a -> Option b -> Option a

Applicative ZipList

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

Defined in Control.Applicative

Methods

pure :: a -> ZipList a

(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b

liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c

(*>) :: ZipList a -> ZipList b -> ZipList b

(<*) :: ZipList a -> ZipList b -> ZipList a

Applicative Identity

Since: base-4.8.0.0

Defined in Data.Functor.Identity

Methods

pure :: a -> Identity a

(<*>) :: Identity (a -> b) -> Identity a -> Identity b

liftA2 :: (a -> b -> c) -> Identity a -> Identity b -> Identity c

(*>) :: Identity a -> Identity b -> Identity b

(<*) :: Identity a -> Identity b -> Identity a

Applicative STM

Since: base-4.8.0.0

Defined in GHC.Conc.Sync

Methods

pure :: a -> STM a

(<*>) :: STM (a -> b) -> STM a -> STM b

liftA2 :: (a -> b -> c) -> STM a -> STM b -> STM c

(*>) :: STM a -> STM b -> STM b

(<*) :: STM a -> STM b -> STM a

Applicative First

Defined in Data.Monoid

Methods

pure :: a -> First a

(<*>) :: First (a -> b) -> First a -> First b

liftA2 :: (a -> b -> c) -> First a -> First b -> First c

(*>) :: First a -> First b -> First b

(<*) :: First a -> First b -> First a

Applicative Last

Defined in Data.Monoid

Methods

pure :: a -> Last a

(<*>) :: Last (a -> b) -> Last a -> Last b

liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c

(*>) :: Last a -> Last b -> Last b

(<*) :: Last a -> Last b -> Last a

Applicative Dual

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Dual a

(<*>) :: Dual (a -> b) -> Dual a -> Dual b

liftA2 :: (a -> b -> c) -> Dual a -> Dual b -> Dual c

(*>) :: Dual a -> Dual b -> Dual b

(<*) :: Dual a -> Dual b -> Dual a

Applicative Sum

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Sum a

(<*>) :: Sum (a -> b) -> Sum a -> Sum b

liftA2 :: (a -> b -> c) -> Sum a -> Sum b -> Sum c

(*>) :: Sum a -> Sum b -> Sum b

(<*) :: Sum a -> Sum b -> Sum a

Applicative Product

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Product a

(<*>) :: Product (a -> b) -> Product a -> Product b

liftA2 :: (a -> b -> c) -> Product a -> Product b -> Product c

(*>) :: Product a -> Product b -> Product b

(<*) :: Product a -> Product b -> Product a

Applicative Down

Since: base-4.11.0.0

Defined in Data.Ord

Methods

pure :: a -> Down a

(<*>) :: Down (a -> b) -> Down a -> Down b

liftA2 :: (a -> b -> c) -> Down a -> Down b -> Down c

(*>) :: Down a -> Down b -> Down b

(<*) :: Down a -> Down b -> Down a

Applicative ReadPrec

Since: base-4.6.0.0

Defined in Text.ParserCombinators.ReadPrec

Methods

pure :: a -> ReadPrec a

(<*>) :: ReadPrec (a -> b) -> ReadPrec a -> ReadPrec b

liftA2 :: (a -> b -> c) -> ReadPrec a -> ReadPrec b -> ReadPrec c

(*>) :: ReadPrec a -> ReadPrec b -> ReadPrec b

(<*) :: ReadPrec a -> ReadPrec b -> ReadPrec a

Applicative ReadP

Since: base-4.6.0.0

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> ReadP a

(<*>) :: ReadP (a -> b) -> ReadP a -> ReadP b

liftA2 :: (a -> b -> c) -> ReadP a -> ReadP b -> ReadP c

(*>) :: ReadP a -> ReadP b -> ReadP b

(<*) :: ReadP a -> ReadP b -> ReadP a

Applicative NonEmpty

Since: base-4.9.0.0

Defined in GHC.Base

Methods

pure :: a -> NonEmpty a

(<*>) :: NonEmpty (a -> b) -> NonEmpty a -> NonEmpty b

liftA2 :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c

(*>) :: NonEmpty a -> NonEmpty b -> NonEmpty b

(<*) :: NonEmpty a -> NonEmpty b -> NonEmpty a

Applicative Put

Defined in Data.ByteString.Builder.Internal

Methods

pure :: a -> Put a

(<*>) :: Put (a -> b) -> Put a -> Put b

liftA2 :: (a -> b -> c) -> Put a -> Put b -> Put c

(*>) :: Put a -> Put b -> Put b

(<*) :: Put a -> Put b -> Put a

Applicative Tree

Defined in Data.Tree

Methods

pure :: a -> Tree a

(<*>) :: Tree (a -> b) -> Tree a -> Tree b

liftA2 :: (a -> b -> c) -> Tree a -> Tree b -> Tree c

(*>) :: Tree a -> Tree b -> Tree b

(<*) :: Tree a -> Tree b -> Tree a

Applicative Seq

Since: containers-0.5.4

Defined in Data.Sequence.Internal

Methods

pure :: a -> Seq a

(<*>) :: Seq (a -> b) -> Seq a -> Seq b

liftA2 :: (a -> b -> c) -> Seq a -> Seq b -> Seq c

(*>) :: Seq a -> Seq b -> Seq b

(<*) :: Seq a -> Seq b -> Seq a

Applicative DList

Defined in Data.DList

Methods

pure :: a -> DList a

(<*>) :: DList (a -> b) -> DList a -> DList b

liftA2 :: (a -> b -> c) -> DList a -> DList b -> DList c

(*>) :: DList a -> DList b -> DList b

(<*) :: DList a -> DList b -> DList a

Applicative Eval

Defined in Control.Parallel.Strategies

Methods

pure :: a -> Eval a

(<*>) :: Eval (a -> b) -> Eval a -> Eval b

liftA2 :: (a -> b -> c) -> Eval a -> Eval b -> Eval c

(*>) :: Eval a -> Eval b -> Eval b

(<*) :: Eval a -> Eval b -> Eval a

Applicative Vector

Defined in Data.Vector

Methods

pure :: a -> Vector a

(<*>) :: Vector (a -> b) -> Vector a -> Vector b

liftA2 :: (a -> b -> c) -> Vector a -> Vector b -> Vector c

(*>) :: Vector a -> Vector b -> Vector b

(<*) :: Vector a -> Vector b -> Vector a

Applicative Log

Defined in Numeric.Log

Methods

pure :: a -> Log a

(<*>) :: Log (a -> b) -> Log a -> Log b

liftA2 :: (a -> b -> c) -> Log a -> Log b -> Log c

(*>) :: Log a -> Log b -> Log b

(<*) :: Log a -> Log b -> Log a

Applicative Managed

Defined in Control.Monad.Managed

Methods

pure :: a -> Managed a

(<*>) :: Managed (a -> b) -> Managed a -> Managed b

liftA2 :: (a -> b -> c) -> Managed a -> Managed b -> Managed c

(*>) :: Managed a -> Managed b -> Managed b

(<*) :: Managed a -> Managed b -> Managed a

Applicative ReadM

Defined in Options.Applicative.Types

Methods

pure :: a -> ReadM a

(<*>) :: ReadM (a -> b) -> ReadM a -> ReadM b

liftA2 :: (a -> b -> c) -> ReadM a -> ReadM b -> ReadM c

(*>) :: ReadM a -> ReadM b -> ReadM b

(<*) :: ReadM a -> ReadM b -> ReadM a

Applicative Parser

Defined in Options.Applicative.Types

Methods

pure :: a -> Parser a

(<*>) :: Parser (a -> b) -> Parser a -> Parser b

liftA2 :: (a -> b -> c) -> Parser a -> Parser b -> Parser c

(*>) :: Parser a -> Parser b -> Parser b

(<*) :: Parser a -> Parser b -> Parser a

Applicative ParserM

Defined in Options.Applicative.Types

Methods

pure :: a -> ParserM a

(<*>) :: ParserM (a -> b) -> ParserM a -> ParserM b

liftA2 :: (a -> b -> c) -> ParserM a -> ParserM b -> ParserM c

(*>) :: ParserM a -> ParserM b -> ParserM b

(<*) :: ParserM a -> ParserM b -> ParserM a

Applicative ParserResult

Defined in Options.Applicative.Types

Methods

pure :: a -> ParserResult a

(<*>) :: ParserResult (a -> b) -> ParserResult a -> ParserResult b

liftA2 :: (a -> b -> c) -> ParserResult a -> ParserResult b -> ParserResult c

(*>) :: ParserResult a -> ParserResult b -> ParserResult b

(<*) :: ParserResult a -> ParserResult b -> ParserResult a

Applicative SmallArray

Defined in Data.Primitive.SmallArray

Methods

pure :: a -> SmallArray a

(<*>) :: SmallArray (a -> b) -> SmallArray a -> SmallArray b

liftA2 :: (a -> b -> c) -> SmallArray a -> SmallArray b -> SmallArray c

(*>) :: SmallArray a -> SmallArray b -> SmallArray b

(<*) :: SmallArray a -> SmallArray b -> SmallArray a

Applicative Array

Defined in Data.Primitive.Array

Methods

pure :: a -> Array a

(<*>) :: Array (a -> b) -> Array a -> Array b

liftA2 :: (a -> b -> c) -> Array a -> Array b -> Array c

(*>) :: Array a -> Array b -> Array b

(<*) :: Array a -> Array b -> Array a

Applicative Behavior

The function pure returns a value that is constant in time. Semantically,

pure     :: a -> Behavior a
pure x    = \time -> x

The combinator <*> applies a time-varying function to a time-varying value.

(<*>)    :: Behavior (a -> b) -> Behavior a -> Behavior b
fx <*> bx = \time -> fx time $ bx time

Defined in Reactive.Banana.Types

Methods

pure :: a -> Behavior a

(<*>) :: Behavior (a -> b) -> Behavior a -> Behavior b

liftA2 :: (a -> b -> c) -> Behavior a -> Behavior b -> Behavior c

(*>) :: Behavior a -> Behavior b -> Behavior b

(<*) :: Behavior a -> Behavior b -> Behavior a

Applicative Future

Defined in Reactive.Banana.Types

Methods

pure :: a -> Future a

(<*>) :: Future (a -> b) -> Future a -> Future b

liftA2 :: (a -> b -> c) -> Future a -> Future b -> Future c

(*>) :: Future a -> Future b -> Future b

(<*) :: Future a -> Future b -> Future a

Applicative Moment

Defined in Reactive.Banana.Types

Methods

pure :: a -> Moment a

(<*>) :: Moment (a -> b) -> Moment a -> Moment b

liftA2 :: (a -> b -> c) -> Moment a -> Moment b -> Moment c

(*>) :: Moment a -> Moment b -> Moment b

(<*) :: Moment a -> Moment b -> Moment a

Applicative MomentIO

Defined in Reactive.Banana.Types

Methods

pure :: a -> MomentIO a

(<*>) :: MomentIO (a -> b) -> MomentIO a -> MomentIO b

liftA2 :: (a -> b -> c) -> MomentIO a -> MomentIO b -> MomentIO c

(*>) :: MomentIO a -> MomentIO b -> MomentIO b

(<*) :: MomentIO a -> MomentIO b -> MomentIO a

Applicative Cleanup

Defined in System.Process.Typed

Methods

pure :: a -> Cleanup a

(<*>) :: Cleanup (a -> b) -> Cleanup a -> Cleanup b

liftA2 :: (a -> b -> c) -> Cleanup a -> Cleanup b -> Cleanup c

(*>) :: Cleanup a -> Cleanup b -> Cleanup b

(<*) :: Cleanup a -> Cleanup b -> Cleanup a

Applicative Element

Defined in Control.Concurrent.Chan.Unagi.NoBlocking.Types

Methods

pure :: a -> Element a

(<*>) :: Element (a -> b) -> Element a -> Element b

liftA2 :: (a -> b -> c) -> Element a -> Element b -> Element c

(*>) :: Element a -> Element b -> Element b

(<*) :: Element a -> Element b -> Element a

Applicative Memoized

Defined in UnliftIO.Memoize

Methods

pure :: a -> Memoized a

(<*>) :: Memoized (a -> b) -> Memoized a -> Memoized b

liftA2 :: (a -> b -> c) -> Memoized a -> Memoized b -> Memoized c

(*>) :: Memoized a -> Memoized b -> Memoized b

(<*) :: Memoized a -> Memoized b -> Memoized a

Applicative P

Since: base-4.5.0.0

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> P a

(<*>) :: P (a -> b) -> P a -> P b

liftA2 :: (a -> b -> c) -> P a -> P b -> P c

(*>) :: P a -> P b -> P b

(<*) :: P a -> P b -> P a

() :=> (Applicative ((->) a :: * -> *))

Defined in Data.Constraint

Methods

ins :: () :- Applicative ((->) a)

() :=> (Applicative [])

Defined in Data.Constraint

Methods

ins :: () :- Applicative []

() :=> (Applicative Maybe)

Defined in Data.Constraint

Methods

ins :: () :- Applicative Maybe

() :=> (Applicative IO)

Defined in Data.Constraint

Methods

ins :: () :- Applicative IO

() :=> (Applicative (Either a))

Defined in Data.Constraint

Methods

ins :: () :- Applicative (Either a)

Applicative (Either e)

Since: base-3.0

Defined in Data.Either

Methods

pure :: a -> Either e a

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

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

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

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

Applicative (U1 :: * -> *)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> U1 a

(<*>) :: U1 (a -> b) -> U1 a -> U1 b

liftA2 :: (a -> b -> c) -> U1 a -> U1 b -> U1 c

(*>) :: U1 a -> U1 b -> U1 b

(<*) :: U1 a -> U1 b -> U1 a

Monoid a => Applicative ((,) a)

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

Defined in GHC.Base

Methods

pure :: a0 -> (a, a0)

(<*>) :: (a, a0 -> b) -> (a, a0) -> (a, b)

liftA2 :: (a0 -> b -> c) -> (a, a0) -> (a, b) -> (a, c)

(*>) :: (a, a0) -> (a, b) -> (a, b)

(<*) :: (a, a0) -> (a, b) -> (a, a0)

Applicative (ST s)

Since: base-4.4.0.0

Defined in GHC.ST

Methods

pure :: a -> ST s a

(<*>) :: ST s (a -> b) -> ST s a -> ST s b

liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c

(*>) :: ST s a -> ST s b -> ST s b

(<*) :: ST s a -> ST s b -> ST s a

Applicative (Results s)

Defined in Text.Earley.Parser.Internal

Methods

pure :: a -> Results s a

(<*>) :: Results s (a -> b) -> Results s a -> Results s b

liftA2 :: (a -> b -> c) -> Results s a -> Results s b -> Results s c

(*>) :: Results s a -> Results s b -> Results s b

(<*) :: Results s a -> Results s b -> Results s a

Applicative (Grammar r)

Defined in Text.Earley.Grammar

Methods

pure :: a -> Grammar r a

(<*>) :: Grammar r (a -> b) -> Grammar r a -> Grammar r b

liftA2 :: (a -> b -> c) -> Grammar r a -> Grammar r b -> Grammar r c

(*>) :: Grammar r a -> Grammar r b -> Grammar r b

(<*) :: Grammar r a -> Grammar r b -> Grammar r a

Representable f => Applicative (Co f)

Defined in Data.Functor.Rep

Methods

pure :: a -> Co f a

(<*>) :: Co f (a -> b) -> Co f a -> Co f b

liftA2 :: (a -> b -> c) -> Co f a -> Co f b -> Co f c

(*>) :: Co f a -> Co f b -> Co f b

(<*) :: Co f a -> Co f b -> Co f a

Monad m => Applicative (WrappedMonad m)

Since: base-2.1

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a

(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b

liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c

(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b

(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m a

Arrow a => Applicative (ArrowMonad a)

Since: base-4.6.0.0

Defined in Control.Arrow

Methods

pure :: a0 -> ArrowMonad a a0

(<*>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b

liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c

(*>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b

(<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0

Applicative (Proxy :: * -> *)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

pure :: a -> Proxy a

(<*>) :: Proxy (a -> b) -> Proxy a -> Proxy b

liftA2 :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c

(*>) :: Proxy a -> Proxy b -> Proxy b

(<*) :: Proxy a -> Proxy b -> Proxy a

(Functor m, Monad m) => Applicative (MaybeT m)

Defined in Control.Monad.Trans.Maybe

Methods

pure :: a -> MaybeT m a

(<*>) :: MaybeT m (a -> b) -> MaybeT m a -> MaybeT m b

liftA2 :: (a -> b -> c) -> MaybeT m a -> MaybeT m b -> MaybeT m c

(*>) :: MaybeT m a -> MaybeT m b -> MaybeT m b

(<*) :: MaybeT m a -> MaybeT m b -> MaybeT m a

Applicative (Fold a)

Defined in Control.Foldl

Methods

pure :: a0 -> Fold a a0

(<*>) :: Fold a (a0 -> b) -> Fold a a0 -> Fold a b

liftA2 :: (a0 -> b -> c) -> Fold a a0 -> Fold a b -> Fold a c

(*>) :: Fold a a0 -> Fold a b -> Fold a b

(<*) :: Fold a a0 -> Fold a b -> Fold a a0

Alternative f => Applicative (Cofree f)

Defined in Control.Comonad.Cofree

Methods

pure :: a -> Cofree f a

(<*>) :: Cofree f (a -> b) -> Cofree f a -> Cofree f b

liftA2 :: (a -> b -> c) -> Cofree f a -> Cofree f b -> Cofree f c

(*>) :: Cofree f a -> Cofree f b -> Cofree f b

(<*) :: Cofree f a -> Cofree f b -> Cofree f a

Functor f => Applicative (Free f)

Defined in Control.Monad.Free

Methods

pure :: a -> Free f a

(<*>) :: Free f (a -> b) -> Free f a -> Free f b

liftA2 :: (a -> b -> c) -> Free f a -> Free f b -> Free f c

(*>) :: Free f a -> Free f b -> Free f b

(<*) :: Free f a -> Free f b -> Free f a

Applicative (Ap f)

Defined in Control.Applicative.Free

Methods

pure :: a -> Ap f a

(<*>) :: Ap f (a -> b) -> Ap f a -> Ap f b

liftA2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c

(*>) :: Ap f a -> Ap f b -> Ap f b

(<*) :: Ap f a -> Ap f b -> Ap f a

Functor f => Applicative (Curried f)

Defined in Data.Generics.Internal.VL.Traversal

Methods

pure :: a -> Curried f a

(<*>) :: Curried f (a -> b) -> Curried f a -> Curried f b

liftA2 :: (a -> b -> c) -> Curried f a -> Curried f b -> Curried f c

(*>) :: Curried f a -> Curried f b -> Curried f b

(<*) :: Curried f a -> Curried f b -> Curried f a

Applicative f => Applicative (Yoneda f)

Defined in Data.Generics.Internal.VL.Traversal

Methods

pure :: a -> Yoneda f a

(<*>) :: Yoneda f (a -> b) -> Yoneda f a -> Yoneda f b

liftA2 :: (a -> b -> c) -> Yoneda f a -> Yoneda f b -> Yoneda f c

(*>) :: Yoneda f a -> Yoneda f b -> Yoneda f b

(<*) :: Yoneda f a -> Yoneda f b -> Yoneda f a

Applicative f => Applicative (Yoneda f)

Defined in Data.Functor.Yoneda

Methods

pure :: a -> Yoneda f a

(<*>) :: Yoneda f (a -> b) -> Yoneda f a -> Yoneda f b

liftA2 :: (a -> b -> c) -> Yoneda f a -> Yoneda f b -> Yoneda f c

(*>) :: Yoneda f a -> Yoneda f b -> Yoneda f b

(<*) :: Yoneda f a -> Yoneda f b -> Yoneda f a

Applicative (ReifiedGetter s)

Defined in Control.Lens.Reified

Methods

pure :: a -> ReifiedGetter s a

(<*>) :: ReifiedGetter s (a -> b) -> ReifiedGetter s a -> ReifiedGetter s b

liftA2 :: (a -> b -> c) -> ReifiedGetter s a -> ReifiedGetter s b -> ReifiedGetter s c

(*>) :: ReifiedGetter s a -> ReifiedGetter s b -> ReifiedGetter s b

(<*) :: ReifiedGetter s a -> ReifiedGetter s b -> ReifiedGetter s a

Applicative (ReifiedFold s)

Defined in Control.Lens.Reified

Methods

pure :: a -> ReifiedFold s a

(<*>) :: ReifiedFold s (a -> b) -> ReifiedFold s a -> ReifiedFold s b

liftA2 :: (a -> b -> c) -> ReifiedFold s a -> ReifiedFold s b -> ReifiedFold s c

(*>) :: ReifiedFold s a -> ReifiedFold s b -> ReifiedFold s b

(<*) :: ReifiedFold s a -> ReifiedFold s b -> ReifiedFold s a

Applicative f => Applicative (Indexing f)

Defined in Control.Lens.Internal.Indexed

Methods

pure :: a -> Indexing f a

(<*>) :: Indexing f (a -> b) -> Indexing f a -> Indexing f b

liftA2 :: (a -> b -> c) -> Indexing f a -> Indexing f b -> Indexing f c

(*>) :: Indexing f a -> Indexing f b -> Indexing f b

(<*) :: Indexing f a -> Indexing f b -> Indexing f a

Applicative f => Applicative (Indexing64 f)

Defined in Control.Lens.Internal.Indexed

Methods

pure :: a -> Indexing64 f a

(<*>) :: Indexing64 f (a -> b) -> Indexing64 f a -> Indexing64 f b

liftA2 :: (a -> b -> c) -> Indexing64 f a -> Indexing64 f b -> Indexing64 f c

(*>) :: Indexing64 f a -> Indexing64 f b -> Indexing64 f b

(<*) :: Indexing64 f a -> Indexing64 f b -> Indexing64 f a

Monad m => Applicative (ListT m)

Defined in List.Transformer

Methods

pure :: a -> ListT m a

(<*>) :: ListT m (a -> b) -> ListT m a -> ListT m b

liftA2 :: (a -> b -> c) -> ListT m a -> ListT m b -> ListT m c

(*>) :: ListT m a -> ListT m b -> ListT m b

(<*) :: ListT m a -> ListT m b -> ListT m a

Applicative (LogicT f)

Defined in Control.Monad.Logic

Methods

pure :: a -> LogicT f a

(<*>) :: LogicT f (a -> b) -> LogicT f a -> LogicT f b

liftA2 :: (a -> b -> c) -> LogicT f a -> LogicT f b -> LogicT f c

(*>) :: LogicT f a -> LogicT f b -> LogicT f b

(<*) :: LogicT f a -> LogicT f b -> LogicT f a

(Applicative (Rep p), Representable p) => Applicative (Prep p)

Defined in Data.Profunctor.Rep

Methods

pure :: a -> Prep p a

(<*>) :: Prep p (a -> b) -> Prep p a -> Prep p b

liftA2 :: (a -> b -> c) -> Prep p a -> Prep p b -> Prep p c

(*>) :: Prep p a -> Prep p b -> Prep p b

(<*) :: Prep p a -> Prep p b -> Prep p a

Applicative f => Applicative (WrappedApplicative f)

Defined in Data.Functor.Bind.Class

Methods

pure :: a -> WrappedApplicative f a

(<*>) :: WrappedApplicative f (a -> b) -> WrappedApplicative f a -> WrappedApplicative f b

liftA2 :: (a -> b -> c) -> WrappedApplicative f a -> WrappedApplicative f b -> WrappedApplicative f c

(*>) :: WrappedApplicative f a -> WrappedApplicative f b -> WrappedApplicative f b

(<*) :: WrappedApplicative f a -> WrappedApplicative f b -> WrappedApplicative f a

Apply f => Applicative (MaybeApply f)

Defined in Data.Functor.Bind.Class

Methods

pure :: a -> MaybeApply f a

(<*>) :: MaybeApply f (a -> b) -> MaybeApply f a -> MaybeApply f b

liftA2 :: (a -> b -> c) -> MaybeApply f a -> MaybeApply f b -> MaybeApply f c

(*>) :: MaybeApply f a -> MaybeApply f b -> MaybeApply f b

(<*) :: MaybeApply f a -> MaybeApply f b -> MaybeApply f a

Applicative (IParser t)

Defined in Data.Text.Internal.Read

Methods

pure :: a -> IParser t a

(<*>) :: IParser t (a -> b) -> IParser t a -> IParser t b

liftA2 :: (a -> b -> c) -> IParser t a -> IParser t b -> IParser t c

(*>) :: IParser t a -> IParser t b -> IParser t b

(<*) :: IParser t a -> IParser t b -> IParser t a

MonadUnliftIO m => Applicative (Concurrently m)

Since: unliftio-0.1.0.0

Defined in UnliftIO.Async

Methods

pure :: a -> Concurrently m a

(<*>) :: Concurrently m (a -> b) -> Concurrently m a -> Concurrently m b

liftA2 :: (a -> b -> c) -> Concurrently m a -> Concurrently m b -> Concurrently m c

(*>) :: Concurrently m a -> Concurrently m b -> Concurrently m b

(<*) :: Concurrently m a -> Concurrently m b -> Concurrently m a

Applicative f => Applicative (AltSum f)

Defined in Control.Compactable

Methods

pure :: a -> AltSum f a

(<*>) :: AltSum f (a -> b) -> AltSum f a -> AltSum f b

liftA2 :: (a -> b -> c) -> AltSum f a -> AltSum f b -> AltSum f c

(*>) :: AltSum f a -> AltSum f b -> AltSum f b

(<*) :: AltSum f a -> AltSum f b -> AltSum f a

Applicative (SetM s)

Defined in Data.Graph

Methods

pure :: a -> SetM s a

(<*>) :: SetM s (a -> b) -> SetM s a -> SetM s b

liftA2 :: (a -> b -> c) -> SetM s a -> SetM s b -> SetM s c

(*>) :: SetM s a -> SetM s b -> SetM s b

(<*) :: SetM s a -> SetM s b -> SetM s a

Applicative (SortedAp f)

Defined in Data.HashMap.Strict.InsOrd

Methods

pure :: a -> SortedAp f a

(<*>) :: SortedAp f (a -> b) -> SortedAp f a -> SortedAp f b

liftA2 :: (a -> b -> c) -> SortedAp f a -> SortedAp f b -> SortedAp f c

(*>) :: SortedAp f a -> SortedAp f b -> SortedAp f b

(<*) :: SortedAp f a -> SortedAp f b -> SortedAp f a

Applicative (IncrementalDecoder s)

Defined in Codec.CBOR.Read

Methods

pure :: a -> IncrementalDecoder s a

(<*>) :: IncrementalDecoder s (a -> b) -> IncrementalDecoder s a -> IncrementalDecoder s b

liftA2 :: (a -> b -> c) -> IncrementalDecoder s a -> IncrementalDecoder s b -> IncrementalDecoder s c

(*>) :: IncrementalDecoder s a -> IncrementalDecoder s b -> IncrementalDecoder s b

(<*) :: IncrementalDecoder s a -> IncrementalDecoder s b -> IncrementalDecoder s a

Class (Functor f) (Applicative f)

Defined in Data.Constraint

Methods

cls :: Applicative f :- Functor f

Class (Applicative f) (Monad f)

Defined in Data.Constraint

Methods

cls :: Monad f :- Applicative f

Class (Applicative f) (Alternative f)

Defined in Data.Constraint

Methods

cls :: Alternative f :- Applicative f

(Monad m) :=> (Applicative (WrappedMonad m))

Defined in Data.Constraint

Methods

ins :: Monad m :- Applicative (WrappedMonad m)

(Monoid a) :=> (Applicative ((,) a))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Applicative ((,) a)

(Monoid a) :=> (Applicative (Const a :: * -> *))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Applicative (Const a)

Applicative f => Applicative (Rec1 f)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> Rec1 f a

(<*>) :: Rec1 f (a -> b) -> Rec1 f a -> Rec1 f b

liftA2 :: (a -> b -> c) -> Rec1 f a -> Rec1 f b -> Rec1 f c

(*>) :: Rec1 f a -> Rec1 f b -> Rec1 f b

(<*) :: Rec1 f a -> Rec1 f b -> Rec1 f a

Applicative (Results s t)

Defined in Text.Earley.Generator.Internal

Methods

pure :: a -> Results s t a

(<*>) :: Results s t (a -> b) -> Results s t a -> Results s t b

liftA2 :: (a -> b -> c) -> Results s t a -> Results s t b -> Results s t c

(*>) :: Results s t a -> Results s t b -> Results s t b

(<*) :: Results s t a -> Results s t b -> Results s t a

Arrow a => Applicative (WrappedArrow a b)

Since: base-2.1

Defined in Control.Applicative

Methods

pure :: a0 -> WrappedArrow a b a0

(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0

liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c

(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0

(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0

Monoid m => Applicative (Const m :: * -> *)

Since: base-2.0.1

Defined in Data.Functor.Const

Methods

pure :: a -> Const m a

(<*>) :: Const m (a -> b) -> Const m a -> Const m b

liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c

(*>) :: Const m a -> Const m b -> Const m b

(<*) :: Const m a -> Const m b -> Const m a

Applicative f => Applicative (Alt f)

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Alt f a

(<*>) :: Alt f (a -> b) -> Alt f a -> Alt f b

liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c

(*>) :: Alt f a -> Alt f b -> Alt f b

(<*) :: Alt f a -> Alt f b -> Alt f a

Biapplicative p => Applicative (Join p)

Defined in Data.Bifunctor.Join

Methods

pure :: a -> Join p a

(<*>) :: Join p (a -> b) -> Join p a -> Join p b

liftA2 :: (a -> b -> c) -> Join p a -> Join p b -> Join p c

(*>) :: Join p a -> Join p b -> Join p b

(<*) :: Join p a -> Join p b -> Join p a

Biapplicative p => Applicative (Fix p)

Defined in Data.Bifunctor.Fix

Methods

pure :: a -> Fix p a

(<*>) :: Fix p (a -> b) -> Fix p a -> Fix p b

liftA2 :: (a -> b -> c) -> Fix p a -> Fix p b -> Fix p c

(*>) :: Fix p a -> Fix p b -> Fix p b

(<*) :: Fix p a -> Fix p b -> Fix p a

Applicative m => Applicative (IdentityT m)

Defined in Control.Monad.Trans.Identity

Methods

pure :: a -> IdentityT m a

(<*>) :: IdentityT m (a -> b) -> IdentityT m a -> IdentityT m b

liftA2 :: (a -> b -> c) -> IdentityT m a -> IdentityT m b -> IdentityT m c

(*>) :: IdentityT m a -> IdentityT m b -> IdentityT m b

(<*) :: IdentityT m a -> IdentityT m b -> IdentityT m a

(Applicative f, Monad f) => Applicative (WhenMissing f x)

Equivalent to ReaderT k (ReaderT x (MaybeT f)).

Since: containers-0.5.9

Defined in Data.IntMap.Internal

Methods

pure :: a -> WhenMissing f x a

(<*>) :: WhenMissing f x (a -> b) -> WhenMissing f x a -> WhenMissing f x b

liftA2 :: (a -> b -> c) -> WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x c

(*>) :: WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x b

(<*) :: WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x a

(Functor m, Monad m) => Applicative (ExceptT e m)

Defined in Control.Monad.Trans.Except

Methods

pure :: a -> ExceptT e m a

(<*>) :: ExceptT e m (a -> b) -> ExceptT e m a -> ExceptT e m b

liftA2 :: (a -> b -> c) -> ExceptT e m a -> ExceptT e m b -> ExceptT e m c

(*>) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m b

(<*) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m a

Monad m => Applicative (GT m g)

Defined in Data.Graph.Inductive.Query.Monad

Methods

pure :: a -> GT m g a

(<*>) :: GT m g (a -> b) -> GT m g a -> GT m g b

liftA2 :: (a -> b -> c) -> GT m g a -> GT m g b -> GT m g c

(*>) :: GT m g a -> GT m g b -> GT m g b

(<*) :: GT m g a -> GT m g b -> GT m g a

Monad m => Applicative (FoldM m a)

Defined in Control.Foldl

Methods

pure :: a0 -> FoldM m a a0

(<*>) :: FoldM m a (a0 -> b) -> FoldM m a a0 -> FoldM m a b

liftA2 :: (a0 -> b -> c) -> FoldM m a a0 -> FoldM m a b -> FoldM m a c

(*>) :: FoldM m a a0 -> FoldM m a b -> FoldM m a b

(<*) :: FoldM m a a0 -> FoldM m a b -> FoldM m a a0

(Functor f, Monad m) => Applicative (FreeT f m)

Defined in Control.Monad.Trans.Free

Methods

pure :: a -> FreeT f m a

(<*>) :: FreeT f m (a -> b) -> FreeT f m a -> FreeT f m b

liftA2 :: (a -> b -> c) -> FreeT f m a -> FreeT f m b -> FreeT f m c

(*>) :: FreeT f m a -> FreeT f m b -> FreeT f m b

(<*) :: FreeT f m a -> FreeT f m b -> FreeT f m a

(Alternative f, Applicative w) => Applicative (CofreeT f w)

Defined in Control.Comonad.Trans.Cofree

Methods

pure :: a -> CofreeT f w a

(<*>) :: CofreeT f w (a -> b) -> CofreeT f w a -> CofreeT f w b

liftA2 :: (a -> b -> c) -> CofreeT f w a -> CofreeT f w b -> CofreeT f w c

(*>) :: CofreeT f w a -> CofreeT f w b -> CofreeT f w b

(<*) :: CofreeT f w a -> CofreeT f w b -> CofreeT f w a

(Applicative f, Applicative g) => Applicative (Day f g)

Defined in Data.Functor.Day

Methods

pure :: a -> Day f g a

(<*>) :: Day f g (a -> b) -> Day f g a -> Day f g b

liftA2 :: (a -> b -> c) -> Day f g a -> Day f g b -> Day f g c

(*>) :: Day f g a -> Day f g b -> Day f g b

(<*) :: Day f g a -> Day f g b -> Day f g a

(Functor m, Monad m) => Applicative (ErrorT e m)

Defined in Control.Monad.Trans.Error

Methods

pure :: a -> ErrorT e m a

(<*>) :: ErrorT e m (a -> b) -> ErrorT e m a -> ErrorT e m b

liftA2 :: (a -> b -> c) -> ErrorT e m a -> ErrorT e m b -> ErrorT e m c

(*>) :: ErrorT e m a -> ErrorT e m b -> ErrorT e m b

(<*) :: ErrorT e m a -> ErrorT e m b -> ErrorT e m a

Applicative f => Applicative (Backwards f)

Apply f-actions in the reverse order.

Defined in Control.Applicative.Backwards

Methods

pure :: a -> Backwards f a

(<*>) :: Backwards f (a -> b) -> Backwards f a -> Backwards f b

liftA2 :: (a -> b -> c) -> Backwards f a -> Backwards f b -> Backwards f c

(*>) :: Backwards f a -> Backwards f b -> Backwards f b

(<*) :: Backwards f a -> Backwards f b -> Backwards f a

Applicative (Mafic a b)

Defined in Control.Lens.Internal.Magma

Methods

pure :: a0 -> Mafic a b a0

(<*>) :: Mafic a b (a0 -> b0) -> Mafic a b a0 -> Mafic a b b0

liftA2 :: (a0 -> b0 -> c) -> Mafic a b a0 -> Mafic a b b0 -> Mafic a b c

(*>) :: Mafic a b a0 -> Mafic a b b0 -> Mafic a b b0

(<*) :: Mafic a b a0 -> Mafic a b b0 -> Mafic a b a0

Applicative (Indexed i a)

Defined in Control.Lens.Internal.Indexed

Methods

pure :: a0 -> Indexed i a a0

(<*>) :: Indexed i a (a0 -> b) -> Indexed i a a0 -> Indexed i a b

liftA2 :: (a0 -> b -> c) -> Indexed i a a0 -> Indexed i a b -> Indexed i a c

(*>) :: Indexed i a a0 -> Indexed i a b -> Indexed i a b

(<*) :: Indexed i a a0 -> Indexed i a b -> Indexed i a a0

(Functor m, Monad m) => Applicative (StateT s m)

Defined in Control.Monad.Trans.State.Lazy

Methods

pure :: a -> StateT s m a

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b

liftA2 :: (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c

(*>) :: StateT s m a -> StateT s m b -> StateT s m b

(<*) :: StateT s m a -> StateT s m b -> StateT s m a

Applicative (STE e s)

Defined in Control.Monad.STE.Internal

Methods

pure :: a -> STE e s a

(<*>) :: STE e s (a -> b) -> STE e s a -> STE e s b

liftA2 :: (a -> b -> c) -> STE e s a -> STE e s b -> STE e s c

(*>) :: STE e s a -> STE e s b -> STE e s b

(<*) :: STE e s a -> STE e s b -> STE e s a

(Functor m, Monad m) => Applicative (StateT s m)

Defined in Control.Monad.Trans.State.Strict

Methods

pure :: a -> StateT s m a

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b

liftA2 :: (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c

(*>) :: StateT s m a -> StateT s m b -> StateT s m b

(<*) :: StateT s m a -> StateT s m b -> StateT s m a

(Profunctor p, Arrow p) => Applicative (Closure p a)

Defined in Data.Profunctor.Closed

Methods

pure :: a0 -> Closure p a a0

(<*>) :: Closure p a (a0 -> b) -> Closure p a a0 -> Closure p a b

liftA2 :: (a0 -> b -> c) -> Closure p a a0 -> Closure p a b -> Closure p a c

(*>) :: Closure p a a0 -> Closure p a b -> Closure p a b

(<*) :: Closure p a a0 -> Closure p a b -> Closure p a a0

(Profunctor p, Arrow p) => Applicative (Tambara p a)

Defined in Data.Profunctor.Strong

Methods

pure :: a0 -> Tambara p a a0

(<*>) :: Tambara p a (a0 -> b) -> Tambara p a a0 -> Tambara p a b

liftA2 :: (a0 -> b -> c) -> Tambara p a a0 -> Tambara p a b -> Tambara p a c

(*>) :: Tambara p a a0 -> Tambara p a b -> Tambara p a b

(<*) :: Tambara p a a0 -> Tambara p a b -> Tambara p a a0

Applicative f => Applicative (Star f a)

Defined in Data.Profunctor.Types

Methods

pure :: a0 -> Star f a a0

(<*>) :: Star f a (a0 -> b) -> Star f a a0 -> Star f a b

liftA2 :: (a0 -> b -> c) -> Star f a a0 -> Star f a b -> Star f a c

(*>) :: Star f a a0 -> Star f a b -> Star f a b

(<*) :: Star f a a0 -> Star f a b -> Star f a a0

Applicative (Costar f a)

Defined in Data.Profunctor.Types

Methods

pure :: a0 -> Costar f a a0

(<*>) :: Costar f a (a0 -> b) -> Costar f a a0 -> Costar f a b

liftA2 :: (a0 -> b -> c) -> Costar f a a0 -> Costar f a b -> Costar f a c

(*>) :: Costar f a a0 -> Costar f a b -> Costar f a b

(<*) :: Costar f a a0 -> Costar f a b -> Costar f a a0

Applicative f => Applicative (Static f a)

Defined in Data.Semigroupoid.Static

Methods

pure :: a0 -> Static f a a0

(<*>) :: Static f a (a0 -> b) -> Static f a a0 -> Static f a b

liftA2 :: (a0 -> b -> c) -> Static f a a0 -> Static f a b -> Static f a c

(*>) :: Static f a a0 -> Static f a b -> Static f a b

(<*) :: Static f a a0 -> Static f a b -> Static f a a0

Applicative (Tagged s)

Defined in Data.Tagged

Methods

pure :: a -> Tagged s a

(<*>) :: Tagged s (a -> b) -> Tagged s a -> Tagged s b

liftA2 :: (a -> b -> c) -> Tagged s a -> Tagged s b -> Tagged s c

(*>) :: Tagged s a -> Tagged s b -> Tagged s b

(<*) :: Tagged s a -> Tagged s b -> Tagged s a

(Functor m, Monad m) => Applicative (WriterT w m)

Defined in Control.Monad.Trans.Writer.CPS.Internal

Methods

pure :: a -> WriterT w m a

(<*>) :: WriterT w m (a -> b) -> WriterT w m a -> WriterT w m b

liftA2 :: (a -> b -> c) -> WriterT w m a -> WriterT w m b -> WriterT w m c

(*>) :: WriterT w m a -> WriterT w m b -> WriterT w m b

(<*) :: WriterT w m a -> WriterT w m b -> WriterT w m a

Monoid m => Applicative (Holes t m)

Defined in Control.Lens.Traversal

Methods

pure :: a -> Holes t m a

(<*>) :: Holes t m (a -> b) -> Holes t m a -> Holes t m b

liftA2 :: (a -> b -> c) -> Holes t m a -> Holes t m b -> Holes t m c

(*>) :: Holes t m a -> Holes t m b -> Holes t m b

(<*) :: Holes t m a -> Holes t m b -> Holes t m a

Applicative ((->) a :: * -> *)

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a0 -> a -> a0

(<*>) :: (a -> a0 -> b) -> (a -> a0) -> a -> b

liftA2 :: (a0 -> b -> c) -> (a -> a0) -> (a -> b) -> a -> c

(*>) :: (a -> a0) -> (a -> b) -> a -> b

(<*) :: (a -> a0) -> (a -> b) -> a -> a0

(Applicative f, Applicative g) => Applicative (f :*: g)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> (f :*: g) a

(<*>) :: (f :*: g) (a -> b) -> (f :*: g) a -> (f :*: g) b

liftA2 :: (a -> b -> c) -> (f :*: g) a -> (f :*: g) b -> (f :*: g) c

(*>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b

(<*) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) a

Applicative (Prod r e t)

Defined in Text.Earley.Grammar

Methods

pure :: a -> Prod r e t a

(<*>) :: Prod r e t (a -> b) -> Prod r e t a -> Prod r e t b

liftA2 :: (a -> b -> c) -> Prod r e t a -> Prod r e t b -> Prod r e t c

(*>) :: Prod r e t a -> Prod r e t b -> Prod r e t b

(<*) :: Prod r e t a -> Prod r e t b -> Prod r e t a

(Applicative f, Applicative g) => Applicative (Product f g)

Since: base-4.9.0.0

Defined in Data.Functor.Product

Methods

pure :: a -> Product f g a

(<*>) :: Product f g (a -> b) -> Product f g a -> Product f g b

liftA2 :: (a -> b -> c) -> Product f g a -> Product f g b -> Product f g c

(*>) :: Product f g a -> Product f g b -> Product f g b

(<*) :: Product f g a -> Product f g b -> Product f g a

Applicative (Cokleisli w a)

Defined in Control.Comonad

Methods

pure :: a0 -> Cokleisli w a a0

(<*>) :: Cokleisli w a (a0 -> b) -> Cokleisli w a a0 -> Cokleisli w a b

liftA2 :: (a0 -> b -> c) -> Cokleisli w a a0 -> Cokleisli w a b -> Cokleisli w a c

(*>) :: Cokleisli w a a0 -> Cokleisli w a b -> Cokleisli w a b

(<*) :: Cokleisli w a a0 -> Cokleisli w a b -> Cokleisli w a a0

(Monad f, Applicative f) => Applicative (WhenMatched f x y)

Equivalent to ReaderT Key (ReaderT x (ReaderT y (MaybeT f)))

Since: containers-0.5.9

Defined in Data.IntMap.Internal

Methods

pure :: a -> WhenMatched f x y a

(<*>) :: WhenMatched f x y (a -> b) -> WhenMatched f x y a -> WhenMatched f x y b

liftA2 :: (a -> b -> c) -> WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y c

(*>) :: WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y b

(<*) :: WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y a

(Applicative f, Monad f) => Applicative (WhenMissing f k x)

Equivalent to ReaderT k (ReaderT x (MaybeT f)) .

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

pure :: a -> WhenMissing f k x a

(<*>) :: WhenMissing f k x (a -> b) -> WhenMissing f k x a -> WhenMissing f k x b

liftA2 :: (a -> b -> c) -> WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x c

(*>) :: WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x b

(<*) :: WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x a

Applicative (Molten i a b)

Defined in Control.Lens.Internal.Magma

Methods

pure :: a0 -> Molten i a b a0

(<*>) :: Molten i a b (a0 -> b0) -> Molten i a b a0 -> Molten i a b b0

liftA2 :: (a0 -> b0 -> c) -> Molten i a b a0 -> Molten i a b b0 -> Molten i a b c

(*>) :: Molten i a b a0 -> Molten i a b b0 -> Molten i a b b0

(<*) :: Molten i a b a0 -> Molten i a b b0 -> Molten i a b a0

Applicative (Bazaar p a b)

Defined in Control.Lens.Internal.Bazaar

Methods

pure :: a0 -> Bazaar p a b a0

(<*>) :: Bazaar p a b (a0 -> b0) -> Bazaar p a b a0 -> Bazaar p a b b0

liftA2 :: (a0 -> b0 -> c) -> Bazaar p a b a0 -> Bazaar p a b b0 -> Bazaar p a b c

(*>) :: Bazaar p a b a0 -> Bazaar p a b b0 -> Bazaar p a b b0

(<*) :: Bazaar p a b a0 -> Bazaar p a b b0 -> Bazaar p a b a0

Applicative m => Applicative (ReaderT r m)

Defined in Control.Monad.Trans.Reader

Methods

pure :: a -> ReaderT r m a

(<*>) :: ReaderT r m (a -> b) -> ReaderT r m a -> ReaderT r m b

liftA2 :: (a -> b -> c) -> ReaderT r m a -> ReaderT r m b -> ReaderT r m c

(*>) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m b

(<*) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m a

Stream s => Applicative (ParsecT e s m)

pure returns a parser that succeeds without consuming input.

Defined in Text.Megaparsec.Internal

Methods

pure :: a -> ParsecT e s m a

(<*>) :: ParsecT e s m (a -> b) -> ParsecT e s m a -> ParsecT e s m b

liftA2 :: (a -> b -> c) -> ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m c

(*>) :: ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m b

(<*) :: ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m a

Applicative (ContT r m)

Defined in Control.Monad.Trans.Cont

Methods

pure :: a -> ContT r m a

(<*>) :: ContT r m (a -> b) -> ContT r m a -> ContT r m b

liftA2 :: (a -> b -> c) -> ContT r m a -> ContT r m b -> ContT r m c

(*>) :: ContT r m a -> ContT r m b -> ContT r m b

(<*) :: ContT r m a -> ContT r m b -> ContT r m a

Applicative f => Applicative (M1 i c f)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> M1 i c f a

(<*>) :: M1 i c f (a -> b) -> M1 i c f a -> M1 i c f b

liftA2 :: (a -> b -> c0) -> M1 i c f a -> M1 i c f b -> M1 i c f c0

(*>) :: M1 i c f a -> M1 i c f b -> M1 i c f b

(<*) :: M1 i c f a -> M1 i c f b -> M1 i c f a

(Applicative f, Applicative g) => Applicative (f :.: g)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> (f :.: g) a

(<*>) :: (f :.: g) (a -> b) -> (f :.: g) a -> (f :.: g) b

liftA2 :: (a -> b -> c) -> (f :.: g) a -> (f :.: g) b -> (f :.: g) c

(*>) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) b

(<*) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) a

(Applicative f, Applicative g) => Applicative (Compose f g)

Since: base-4.9.0.0

Defined in Data.Functor.Compose

Methods

pure :: a -> Compose f g a

(<*>) :: Compose f g (a -> b) -> Compose f g a -> Compose f g b

liftA2 :: (a -> b -> c) -> Compose f g a -> Compose f g b -> Compose f g c

(*>) :: Compose f g a -> Compose f g b -> Compose f g b

(<*) :: Compose f g a -> Compose f g b -> Compose f g a

(Monad f, Applicative f) => Applicative (WhenMatched f k x y)

Equivalent to ReaderT k (ReaderT x (ReaderT y (MaybeT f)))

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

pure :: a -> WhenMatched f k x y a

(<*>) :: WhenMatched f k x y (a -> b) -> WhenMatched f k x y a -> WhenMatched f k x y b

liftA2 :: (a -> b -> c) -> WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y c

(*>) :: WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y b

(<*) :: WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y a

Applicative (TakingWhile p f a b)

Defined in Control.Lens.Internal.Magma

Methods

pure :: a0 -> TakingWhile p f a b a0

(<*>) :: TakingWhile p f a b (a0 -> b0) -> TakingWhile p f a b a0 -> TakingWhile p f a b b0

liftA2 :: (a0 -> b0 -> c) -> TakingWhile p f a b a0 -> TakingWhile p f a b b0 -> TakingWhile p f a b c

(*>) :: TakingWhile p f a b a0 -> TakingWhile p f a b b0 -> TakingWhile p f a b b0

(<*) :: TakingWhile p f a b a0 -> TakingWhile p f a b b0 -> TakingWhile p f a b a0

Applicative (BazaarT p g a b)

Defined in Control.Lens.Internal.Bazaar

Methods

pure :: a0 -> BazaarT p g a b a0

(<*>) :: BazaarT p g a b (a0 -> b0) -> BazaarT p g a b a0 -> BazaarT p g a b b0

liftA2 :: (a0 -> b0 -> c) -> BazaarT p g a b a0 -> BazaarT p g a b b0 -> BazaarT p g a b c

(*>) :: BazaarT p g a b a0 -> BazaarT p g a b b0 -> BazaarT p g a b b0

(<*) :: BazaarT p g a b a0 -> BazaarT p g a b b0 -> BazaarT p g a b a0

Reifies s (ReifiedApplicative f) => Applicative (ReflectedApplicative f s)

Defined in Data.Reflection

Methods

pure :: a -> ReflectedApplicative f s a

(<*>) :: ReflectedApplicative f s (a -> b) -> ReflectedApplicative f s a -> ReflectedApplicative f s b

liftA2 :: (a -> b -> c) -> ReflectedApplicative f s a -> ReflectedApplicative f s b -> ReflectedApplicative f s c

(*>) :: ReflectedApplicative f s a -> ReflectedApplicative f s b -> ReflectedApplicative f s b

(<*) :: ReflectedApplicative f s a -> ReflectedApplicative f s b -> ReflectedApplicative f s a

between :: Applicative m => m open -> m close -> m a -> m a

between open close p parses open, followed by p and close. Returns the value returned by p.

braces = between (symbol "{") (symbol "}")

filterM :: Applicative m => (a -> m Bool) -> [a] -> m [a]

This generalizes the list-based filter function.

forever :: Applicative f => f a -> f b

forever act repeats the action infinitely.

liftA3 :: Applicative f => (a -> b -> c -> d) -> f a -> f b -> f c -> f d

Lift a ternary function to actions.

replicateM :: Applicative m => Int -> m a -> m [a]

replicateM n act performs the action n times, gathering the results.

replicateM_ :: Applicative m => Int -> m a -> m ()

Like replicateM, but discards the result.

unless :: Applicative f => Bool -> f () -> f ()

The reverse of when.

when :: Applicative f => Bool -> f () -> f ()

Conditional execution of Applicative expressions. For example,

when debug (putStrLn "Debugging")

will output the string Debugging if the Boolean value debug is True, and otherwise do nothing.

zipWithM :: Applicative m => (a -> b -> m c) -> [a] -> [b] -> m [c]

The zipWithM function generalizes zipWith to arbitrary applicative functors.

zipWithM_ :: Applicative m => (a -> b -> m c) -> [a] -> [b] -> m ()

zipWithM_ is the extension of zipWithM which ignores the final result.

Alternative

class Applicative f => Alternative (f :: * -> *) where

A monoid on applicative functors.

If defined, some and many should be the least solutions of the equations:

• some v = (:) <$> v <*> many v

• many v = some v <|> pure []

Minimal complete definition

empty, (<|>)

Methods

empty :: f a

The identity of <|>

(<|>) :: f a -> f a -> f a infixl 3

An associative binary operation

many :: f a -> f [a]

Zero or more.

Instances

Alternative []

Since: base-2.1

Defined in GHC.Base

Methods

empty :: [a]

(<|>) :: [a] -> [a] -> [a]

some :: [a] -> [[a]]

many :: [a] -> [[a]]

Alternative Maybe

Since: base-2.1

Defined in GHC.Base

Methods

empty :: Maybe a

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

some :: Maybe a -> Maybe [a]

many :: Maybe a -> Maybe [a]

Alternative IO

Since: base-4.9.0.0

Defined in GHC.Base

Methods

empty :: IO a

(<|>) :: IO a -> IO a -> IO a

some :: IO a -> IO [a]

many :: IO a -> IO [a]

Alternative IResult

Defined in Data.Aeson.Types.Internal

Methods

empty :: IResult a

(<|>) :: IResult a -> IResult a -> IResult a

some :: IResult a -> IResult [a]

many :: IResult a -> IResult [a]

Alternative Result

Defined in Data.Aeson.Types.Internal

Methods

empty :: Result a

(<|>) :: Result a -> Result a -> Result a

some :: Result a -> Result [a]

many :: Result a -> Result [a]

Alternative Parser

Defined in Data.Aeson.Types.Internal

Methods

empty :: Parser a

(<|>) :: Parser a -> Parser a -> Parser a

some :: Parser a -> Parser [a]

many :: Parser a -> Parser [a]

Alternative Concurrently

Defined in Control.Concurrent.Async

Methods

empty :: Concurrently a

(<|>) :: Concurrently a -> Concurrently a -> Concurrently a

some :: Concurrently a -> Concurrently [a]

many :: Concurrently a -> Concurrently [a]

Alternative Option

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

empty :: Option a

(<|>) :: Option a -> Option a -> Option a

some :: Option a -> Option [a]

many :: Option a -> Option [a]

Alternative ZipList

Since: base-4.11.0.0

Defined in Control.Applicative

Methods

empty :: ZipList a

(<|>) :: ZipList a -> ZipList a -> ZipList a

some :: ZipList a -> ZipList [a]

many :: ZipList a -> ZipList [a]

Alternative STM

Since: base-4.8.0.0

Defined in GHC.Conc.Sync

Methods

empty :: STM a

(<|>) :: STM a -> STM a -> STM a

some :: STM a -> STM [a]

many :: STM a -> STM [a]

Alternative ReadPrec

Since: base-4.6.0.0

Defined in Text.ParserCombinators.ReadPrec

Methods

empty :: ReadPrec a

(<|>) :: ReadPrec a -> ReadPrec a -> ReadPrec a

some :: ReadPrec a -> ReadPrec [a]

many :: ReadPrec a -> ReadPrec [a]

Alternative ReadP

Since: base-4.6.0.0

Defined in Text.ParserCombinators.ReadP

Methods

empty :: ReadP a

(<|>) :: ReadP a -> ReadP a -> ReadP a

some :: ReadP a -> ReadP [a]

many :: ReadP a -> ReadP [a]

Alternative Seq

Since: containers-0.5.4

Defined in Data.Sequence.Internal

Methods

empty :: Seq a

(<|>) :: Seq a -> Seq a -> Seq a

some :: Seq a -> Seq [a]

many :: Seq a -> Seq [a]

Alternative DList

Defined in Data.DList

Methods

empty :: DList a

(<|>) :: DList a -> DList a -> DList a

some :: DList a -> DList [a]

many :: DList a -> DList [a]

Alternative Vector

Defined in Data.Vector

Methods

empty :: Vector a

(<|>) :: Vector a -> Vector a -> Vector a

some :: Vector a -> Vector [a]

many :: Vector a -> Vector [a]

Alternative ReadM

Defined in Options.Applicative.Types

Methods

empty :: ReadM a

(<|>) :: ReadM a -> ReadM a -> ReadM a

some :: ReadM a -> ReadM [a]

many :: ReadM a -> ReadM [a]

Alternative Parser

Defined in Options.Applicative.Types

Methods

empty :: Parser a

(<|>) :: Parser a -> Parser a -> Parser a

some :: Parser a -> Parser [a]

many :: Parser a -> Parser [a]

Alternative SmallArray

Defined in Data.Primitive.SmallArray

Methods

empty :: SmallArray a

(<|>) :: SmallArray a -> SmallArray a -> SmallArray a

some :: SmallArray a -> SmallArray [a]

many :: SmallArray a -> SmallArray [a]

Alternative Array

Defined in Data.Primitive.Array

Methods

empty :: Array a

(<|>) :: Array a -> Array a -> Array a

some :: Array a -> Array [a]

many :: Array a -> Array [a]

Alternative Element

Defined in Control.Concurrent.Chan.Unagi.NoBlocking.Types

Methods

empty :: Element a

(<|>) :: Element a -> Element a -> Element a

some :: Element a -> Element [a]

many :: Element a -> Element [a]

Alternative P

Since: base-4.5.0.0

Defined in Text.ParserCombinators.ReadP

Methods

empty :: P a

(<|>) :: P a -> P a -> P a

some :: P a -> P [a]

many :: P a -> P [a]

() :=> (Alternative [])

Defined in Data.Constraint

Methods

ins :: () :- Alternative []

() :=> (Alternative Maybe)

Defined in Data.Constraint

Methods

ins :: () :- Alternative Maybe

Alternative (U1 :: * -> *)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

empty :: U1 a

(<|>) :: U1 a -> U1 a -> U1 a

some :: U1 a -> U1 [a]

many :: U1 a -> U1 [a]

Alternative (Results s)

Defined in Text.Earley.Parser.Internal

Methods

empty :: Results s a

(<|>) :: Results s a -> Results s a -> Results s a

some :: Results s a -> Results s [a]

many :: Results s a -> Results s [a]

MonadPlus m => Alternative (WrappedMonad m)

Since: base-2.1

Defined in Control.Applicative

Methods

empty :: WrappedMonad m a

(<|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a

some :: WrappedMonad m a -> WrappedMonad m [a]

many :: WrappedMonad m a -> WrappedMonad m [a]

ArrowPlus a => Alternative (ArrowMonad a)

Since: base-4.6.0.0

Defined in Control.Arrow

Methods

empty :: ArrowMonad a a0

(<|>) :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0

some :: ArrowMonad a a0 -> ArrowMonad a [a0]

many :: ArrowMonad a a0 -> ArrowMonad a [a0]

Alternative (Proxy :: * -> *)

Since: base-4.9.0.0

Defined in Data.Proxy

Methods

empty :: Proxy a

(<|>) :: Proxy a -> Proxy a -> Proxy a

some :: Proxy a -> Proxy [a]

many :: Proxy a -> Proxy [a]

(Functor m, Monad m) => Alternative (MaybeT m)

Defined in Control.Monad.Trans.Maybe

Methods

empty :: MaybeT m a

(<|>) :: MaybeT m a -> MaybeT m a -> MaybeT m a

some :: MaybeT m a -> MaybeT m [a]

many :: MaybeT m a -> MaybeT m [a]

Alternative v => Alternative (Free v)

This violates the Alternative laws, handle with care.

Defined in Control.Monad.Free

Methods

empty :: Free v a

(<|>) :: Free v a -> Free v a -> Free v a

some :: Free v a -> Free v [a]

many :: Free v a -> Free v [a]

Alternative f => Alternative (Yoneda f)

Defined in Data.Functor.Yoneda

Methods

empty :: Yoneda f a

(<|>) :: Yoneda f a -> Yoneda f a -> Yoneda f a

some :: Yoneda f a -> Yoneda f [a]

many :: Yoneda f a -> Yoneda f [a]

Alternative (ReifiedFold s)

Defined in Control.Lens.Reified

Methods

empty :: ReifiedFold s a

(<|>) :: ReifiedFold s a -> ReifiedFold s a -> ReifiedFold s a

some :: ReifiedFold s a -> ReifiedFold s [a]

many :: ReifiedFold s a -> ReifiedFold s [a]

Monad m => Alternative (ListT m)

Defined in List.Transformer

Methods

empty :: ListT m a

(<|>) :: ListT m a -> ListT m a -> ListT m a

some :: ListT m a -> ListT m [a]

many :: ListT m a -> ListT m [a]

Alternative (LogicT f)

Defined in Control.Monad.Logic

Methods

empty :: LogicT f a

(<|>) :: LogicT f a -> LogicT f a -> LogicT f a

some :: LogicT f a -> LogicT f [a]

many :: LogicT f a -> LogicT f [a]

Alternative f => Alternative (WrappedApplicative f)

Defined in Data.Functor.Bind.Class

Methods

empty :: WrappedApplicative f a

(<|>) :: WrappedApplicative f a -> WrappedApplicative f a -> WrappedApplicative f a

some :: WrappedApplicative f a -> WrappedApplicative f [a]

many :: WrappedApplicative f a -> WrappedApplicative f [a]

MonadUnliftIO m => Alternative (Concurrently m)

Since: unliftio-0.1.0.0

Defined in UnliftIO.Async

Methods

empty :: Concurrently m a

(<|>) :: Concurrently m a -> Concurrently m a -> Concurrently m a

some :: Concurrently m a -> Concurrently m [a]

many :: Concurrently m a -> Concurrently m [a]

Alternative f => Alternative (AltSum f)

Defined in Control.Compactable

Methods

empty :: AltSum f a

(<|>) :: AltSum f a -> AltSum f a -> AltSum f a

some :: AltSum f a -> AltSum f [a]

many :: AltSum f a -> AltSum f [a]

Class (Applicative f) (Alternative f)

Defined in Data.Constraint

Methods

cls :: Alternative f :- Applicative f

(MonadPlus m) :=> (Alternative (WrappedMonad m))

Defined in Data.Constraint

Methods

ins :: MonadPlus m :- Alternative (WrappedMonad m)

Alternative f => Alternative (Rec1 f)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

empty :: Rec1 f a

(<|>) :: Rec1 f a -> Rec1 f a -> Rec1 f a

some :: Rec1 f a -> Rec1 f [a]

many :: Rec1 f a -> Rec1 f [a]

Alternative (Results t s)

Defined in Text.Earley.Generator.Internal

Methods

empty :: Results t s a

(<|>) :: Results t s a -> Results t s a -> Results t s a

some :: Results t s a -> Results t s [a]

many :: Results t s a -> Results t s [a]

(ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b)

Since: base-2.1

Defined in Control.Applicative

Methods

empty :: WrappedArrow a b a0

(<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0

some :: WrappedArrow a b a0 -> WrappedArrow a b [a0]

many :: WrappedArrow a b a0 -> WrappedArrow a b [a0]

Alternative f => Alternative (Alt f)

Defined in Data.Semigroup.Internal

Methods

empty :: Alt f a

(<|>) :: Alt f a -> Alt f a -> Alt f a

some :: Alt f a -> Alt f [a]

many :: Alt f a -> Alt f [a]

Alternative m => Alternative (IdentityT m)

Defined in Control.Monad.Trans.Identity

Methods

empty :: IdentityT m a

(<|>) :: IdentityT m a -> IdentityT m a -> IdentityT m a

some :: IdentityT m a -> IdentityT m [a]

many :: IdentityT m a -> IdentityT m [a]

(Functor m, Monad m, Monoid e) => Alternative (ExceptT e m)

Defined in Control.Monad.Trans.Except

Methods

empty :: ExceptT e m a

(<|>) :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a

some :: ExceptT e m a -> ExceptT e m [a]

many :: ExceptT e m a -> ExceptT e m [a]

(Functor f, MonadPlus m) => Alternative (FreeT f m)

Defined in Control.Monad.Trans.Free

Methods

empty :: FreeT f m a

(<|>) :: FreeT f m a -> FreeT f m a -> FreeT f m a

some :: FreeT f m a -> FreeT f m [a]

many :: FreeT f m a -> FreeT f m [a]

(Functor m, Monad m, Error e) => Alternative (ErrorT e m)

Defined in Control.Monad.Trans.Error

Methods

empty :: ErrorT e m a

(<|>) :: ErrorT e m a -> ErrorT e m a -> ErrorT e m a

some :: ErrorT e m a -> ErrorT e m [a]

many :: ErrorT e m a -> ErrorT e m [a]

Alternative f => Alternative (Backwards f)

Try alternatives in the same order as f.

Defined in Control.Applicative.Backwards

Methods

empty :: Backwards f a

(<|>) :: Backwards f a -> Backwards f a -> Backwards f a

some :: Backwards f a -> Backwards f [a]

many :: Backwards f a -> Backwards f [a]

(Functor m, MonadPlus m) => Alternative (StateT s m)

Defined in Control.Monad.Trans.State.Lazy

Methods

empty :: StateT s m a

(<|>) :: StateT s m a -> StateT s m a -> StateT s m a

some :: StateT s m a -> StateT s m [a]

many :: StateT s m a -> StateT s m [a]

(Functor m, MonadPlus m) => Alternative (StateT s m)

Defined in Control.Monad.Trans.State.Strict

Methods

empty :: StateT s m a

(<|>) :: StateT s m a -> StateT s m a -> StateT s m a

some :: StateT s m a -> StateT s m [a]

many :: StateT s m a -> StateT s m [a]

(Profunctor p, ArrowPlus p) => Alternative (Closure p a)

Defined in Data.Profunctor.Closed

Methods

empty :: Closure p a a0

(<|>) :: Closure p a a0 -> Closure p a a0 -> Closure p a a0

some :: Closure p a a0 -> Closure p a [a0]

many :: Closure p a a0 -> Closure p a [a0]

(Profunctor p, ArrowPlus p) => Alternative (Tambara p a)

Defined in Data.Profunctor.Strong

Methods

empty :: Tambara p a a0

(<|>) :: Tambara p a a0 -> Tambara p a a0 -> Tambara p a a0

some :: Tambara p a a0 -> Tambara p a [a0]

many :: Tambara p a a0 -> Tambara p a [a0]

Alternative f => Alternative (Star f a)

Defined in Data.Profunctor.Types

Methods

empty :: Star f a a0

(<|>) :: Star f a a0 -> Star f a a0 -> Star f a a0

some :: Star f a a0 -> Star f a [a0]

many :: Star f a a0 -> Star f a [a0]

(Functor m, MonadPlus m) => Alternative (WriterT w m)

Defined in Control.Monad.Trans.Writer.CPS.Internal

Methods

empty :: WriterT w m a

(<|>) :: WriterT w m a -> WriterT w m a -> WriterT w m a

some :: WriterT w m a -> WriterT w m [a]

many :: WriterT w m a -> WriterT w m [a]

Class (Monad f, Alternative f) (MonadPlus f)

Defined in Data.Constraint

Methods

cls :: MonadPlus f :- (Monad f, Alternative f)

(Alternative f, Alternative g) => Alternative (f :*: g)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

empty :: (f :*: g) a

(<|>) :: (f :*: g) a -> (f :*: g) a -> (f :*: g) a

some :: (f :*: g) a -> (f :*: g) [a]

many :: (f :*: g) a -> (f :*: g) [a]

Alternative (Prod r e t)

Defined in Text.Earley.Grammar

Methods

empty :: Prod r e t a

(<|>) :: Prod r e t a -> Prod r e t a -> Prod r e t a

some :: Prod r e t a -> Prod r e t [a]

many :: Prod r e t a -> Prod r e t [a]

(Alternative f, Alternative g) => Alternative (Product f g)

Since: base-4.9.0.0

Defined in Data.Functor.Product

Methods

empty :: Product f g a

(<|>) :: Product f g a -> Product f g a -> Product f g a

some :: Product f g a -> Product f g [a]

many :: Product f g a -> Product f g [a]

Alternative m => Alternative (ReaderT r m)

Defined in Control.Monad.Trans.Reader

Methods

empty :: ReaderT r m a

(<|>) :: ReaderT r m a -> ReaderT r m a -> ReaderT r m a

some :: ReaderT r m a -> ReaderT r m [a]

many :: ReaderT r m a -> ReaderT r m [a]

(Ord e, Stream s) => Alternative (ParsecT e s m)

empty is a parser that fails without consuming input.

Defined in Text.Megaparsec.Internal

Methods

empty :: ParsecT e s m a

(<|>) :: ParsecT e s m a -> ParsecT e s m a -> ParsecT e s m a

some :: ParsecT e s m a -> ParsecT e s m [a]

many :: ParsecT e s m a -> ParsecT e s m [a]

Alternative f => Alternative (M1 i c f)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

empty :: M1 i c f a

(<|>) :: M1 i c f a -> M1 i c f a -> M1 i c f a

some :: M1 i c f a -> M1 i c f [a]

many :: M1 i c f a -> M1 i c f [a]

(Alternative f, Applicative g) => Alternative (f :.: g)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

empty :: (f :.: g) a

(<|>) :: (f :.: g) a -> (f :.: g) a -> (f :.: g) a

some :: (f :.: g) a -> (f :.: g) [a]

many :: (f :.: g) a -> (f :.: g) [a]

(Alternative f, Applicative g) => Alternative (Compose f g)

Since: base-4.9.0.0

Defined in Data.Functor.Compose

Methods

empty :: Compose f g a

(<|>) :: Compose f g a -> Compose f g a -> Compose f g a

some :: Compose f g a -> Compose f g [a]

many :: Compose f g a -> Compose f g [a]

endBy :: Alternative m => m a -> m sep -> m [a]

endBy p sep parses zero or more occurrences of p, separated and ended by sep. Returns a list of values returned by p.

cStatements = cStatement `endBy` semicolon

endBy1 :: Alternative m => m a -> m sep -> m (NonEmpty a)

endBy1 p sep parses one or more occurrences of p, separated and ended by sep. Returns a non-empty list of values returned by p.

guard :: Alternative f => Bool -> f ()

Conditional failure of Alternative computations. Defined by

guard True  = pure ()
guard False = empty

Examples

Common uses of guard include conditionally signaling an error in an error monad and conditionally rejecting the current choice in an Alternative-based parser.

As an example of signaling an error in the error monad Maybe, consider a safe division function safeDiv x y that returns Nothing when the denominator y is zero and Just (x `div` y) otherwise. For example:

>>> safeDiv 4 0
Nothing
>>> safeDiv 4 2
Just 2

A definition of safeDiv using guards, but not guard:

safeDiv :: Int -> Int -> Maybe Int
safeDiv x y | y /= 0    = Just (x `div` y)
            | otherwise = Nothing

A definition of safeDiv using guard and Monad do-notation:

safeDiv :: Int -> Int -> Maybe Int
safeDiv x y = do
  guard (y /= 0)
  return (x `div` y)

manyTill :: Alternative m => m a -> m end -> m [a]

manyTill p end applies parser p zero or more times until parser end succeeds. Returns the list of values returned by p.

See also: skipMany, skipManyTill.

optional :: (Alt f, Applicative f) => f a -> f (Maybe a)

One or none.

sepBy :: Alternative m => m a -> m sep -> m [a]

sepBy p sep parses zero or more occurrences of p, separated by sep. Returns a list of values returned by p.

commaSep p = p `sepBy` comma

sepEndBy :: Alternative m => m a -> m sep -> m [a]

sepEndBy p sep parses zero or more occurrences of p, separated and optionally ended by sep. Returns a list of values returned by p.

sepBy1 :: Alternative m => m a -> m sep -> m (NonEmpty a)

sepBy1 p sep parses one or more occurrences of p, separated by sep. Returns a non-empty list of values returned by p.

sepEndBy1 :: Alternative m => m a -> m sep -> m (NonEmpty a)

sepEndBy1 p sep parses one or more occurrences of p, separated and optionally ended by sep. Returns a non-empty list of values returned by p.

skipMany :: Alternative m => m a -> m ()

skipMany p applies the parser p zero or more times, skipping its result.

See also: manyTill, skipManyTill.

skipManyTill :: Alternative m => m a -> m end -> m end

skipManyTill p end applies the parser p zero or more times skipping results until parser end succeeds. Result parsed by end is then returned.

See also: manyTill, skipMany.

skipSome :: Alternative m => m a -> m ()

skipSome p applies the parser p one or more times, skipping its result.

See also: someTill, skipSomeTill.

skipSomeTill :: Alternative m => m a -> m end -> m end

skipSomeTill p end applies the parser p one or more times skipping results until parser end succeeds. Result parsed by end is then returned.

See also: someTill, skipSome.

some1 :: Alternative f => f a -> f (NonEmpty a)

some1 x sequences x one or more times.

someTill :: Alternative m => m a -> m end -> m (NonEmpty a)

someTill p end works similarly to manyTill p end, but p should succeed at least once.

See also: skipSome, skipSomeTill.

Newtypes

newtype Alt (f :: k -> *) (a :: k) :: forall k. (k -> *) -> k -> *

Monoid under <|>.

Since: base-4.8.0.0

Constructors

Alt

Fields

• getAlt :: f a

Instances

Generic1 (Alt f :: k -> *)

Defined in Data.Semigroup.Internal

Associated Types

type Rep1 (Alt f) :: k -> *

Methods

from1 :: Alt f a -> Rep1 (Alt f) a

to1 :: Rep1 (Alt f) a -> Alt f a

Monad f => Monad (Alt f)

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Alt f a -> (a -> Alt f b) -> Alt f b

(>>) :: Alt f a -> Alt f b -> Alt f b

return :: a -> Alt f a

fail :: String -> Alt f a

Functor f => Functor (Alt f)

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Alt f a -> Alt f b

(<$) :: a -> Alt f b -> Alt f a

MonadFix f => MonadFix (Alt f)

Since: base-4.8.0.0

Defined in Control.Monad.Fix

Methods

mfix :: (a -> Alt f a) -> Alt f a

Applicative f => Applicative (Alt f)

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Alt f a

(<*>) :: Alt f (a -> b) -> Alt f a -> Alt f b

liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c

(*>) :: Alt f a -> Alt f b -> Alt f b

(<*) :: Alt f a -> Alt f b -> Alt f a

Alternative f => Alternative (Alt f)

Defined in Data.Semigroup.Internal

Methods

empty :: Alt f a

(<|>) :: Alt f a -> Alt f a -> Alt f a

some :: Alt f a -> Alt f [a]

many :: Alt f a -> Alt f [a]

Contravariant f => Contravariant (Alt f)

Defined in Data.Functor.Contravariant

Methods

contramap :: (a -> b) -> Alt f b -> Alt f a

(>$) :: b -> Alt f b -> Alt f a

MonadPlus f => MonadPlus (Alt f)

Defined in Data.Semigroup.Internal

Methods

mzero :: Alt f a

mplus :: Alt f a -> Alt f a -> Alt f a

MonadZip f => MonadZip (Alt f)

Since: base-4.8.0.0

Defined in Control.Monad.Zip

Methods

mzip :: Alt f a -> Alt f b -> Alt f (a, b)

mzipWith :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c

munzip :: Alt f (a, b) -> (Alt f a, Alt f b)

Functor a => Compactable (Alt a)

Defined in Control.Compactable

Methods

compact :: Alt a (Maybe a0) -> Alt a a0

separate :: Alt a (Either l r) -> (Alt a l, Alt a r)

filter :: (a0 -> Bool) -> Alt a a0 -> Alt a a0

partition :: (a0 -> Bool) -> Alt a a0 -> (Alt a a0, Alt a a0)

fmapMaybe :: Functor (Alt a) => (a0 -> Maybe b) -> Alt a a0 -> Alt a b

fmapEither :: Functor (Alt a) => (a0 -> Either l r) -> Alt a a0 -> (Alt a l, Alt a r)

applyMaybe :: Applicative (Alt a) => Alt a (a0 -> Maybe b) -> Alt a a0 -> Alt a b

applyEither :: Applicative (Alt a) => Alt a (a0 -> Either l r) -> Alt a a0 -> (Alt a l, Alt a r)

bindMaybe :: Monad (Alt a) => Alt a a0 -> (a0 -> Alt a (Maybe b)) -> Alt a b

bindEither :: Monad (Alt a) => Alt a a0 -> (a0 -> Alt a (Either l r)) -> (Alt a l, Alt a r)

traverseMaybe :: (Applicative g, Traversable (Alt a)) => (a0 -> g (Maybe b)) -> Alt a a0 -> g (Alt a b)

traverseEither :: (Applicative g, Traversable (Alt a)) => (a0 -> g (Either l r)) -> Alt a a0 -> g (Alt a l, Alt a r)

(Alternative a, Monad a) => CompactFold (Alt a)

Defined in Control.Compactable

Methods

compactFold :: Foldable g => Alt a (g a0) -> Alt a a0

separateFold :: Bifoldable g => Alt a (g a0 b) -> (Alt a a0, Alt a b)

fmapFold :: (Functor (Alt a), Foldable g) => (a0 -> g b) -> Alt a a0 -> Alt a b

fmapBifold :: (Functor (Alt a), Bifoldable g) => (a0 -> g l r) -> Alt a a0 -> (Alt a l, Alt a r)

applyFold :: (Applicative (Alt a), Foldable g) => Alt a (a0 -> g b) -> Alt a a0 -> Alt a b

applyBifold :: (Applicative (Alt a), Bifoldable g) => Alt a (a0 -> g l r) -> Alt a a0 -> (Alt a l, Alt a r)

bindFold :: (Monad (Alt a), Foldable g) => Alt a a0 -> (a0 -> Alt a (g b)) -> Alt a b

bindBifold :: (Monad (Alt a), Bifoldable g) => Alt a a0 -> (a0 -> Alt a (g l r)) -> (Alt a l, Alt a r)

traverseFold :: (Applicative h, Foldable g, Traversable (Alt a)) => (a0 -> h (g b)) -> Alt a a0 -> h (Alt a b)

traverseBifold :: (Applicative h, Bifoldable g, Traversable (Alt a)) => (a0 -> h (g l r)) -> Alt a a0 -> h (Alt a l, Alt a r)

Divisible f => Divisible (Alt f)

Defined in Data.Functor.Contravariant.Divisible

Methods

divide :: (a -> (b, c)) -> Alt f b -> Alt f c -> Alt f a

conquer :: Alt f a

Decidable f => Decidable (Alt f)

Defined in Data.Functor.Contravariant.Divisible

Methods

lose :: (a -> Void) -> Alt f a

choose :: (a -> Either b c) -> Alt f b -> Alt f c -> Alt f a

Apply f => Apply (Alt f)

Defined in Data.Functor.Bind.Class

Methods

(<.>) :: Alt f (a -> b) -> Alt f a -> Alt f b

(.>) :: Alt f a -> Alt f b -> Alt f b

(<.) :: Alt f a -> Alt f b -> Alt f a

liftF2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c

Traversable1 f => Traversable1 (Alt f)

Defined in Data.Semigroup.Traversable.Class

Methods

traverse1 :: Apply f0 => (a -> f0 b) -> Alt f a -> f0 (Alt f b)

sequence1 :: Apply f0 => Alt f (f0 b) -> f0 (Alt f b)

Foldable1 f => Foldable1 (Alt f)

Defined in Data.Semigroup.Foldable.Class

Methods

fold1 :: Semigroup m => Alt f m -> m

foldMap1 :: Semigroup m => (a -> m) -> Alt f a -> m

toNonEmpty :: Alt f a -> NonEmpty a

Bind f => Bind (Alt f)

Defined in Data.Functor.Bind.Class

Methods

(>>-) :: Alt f a -> (a -> Alt f b) -> Alt f b

join :: Alt f (Alt f a) -> Alt f a

Extend f => Extend (Alt f)

Defined in Data.Functor.Extend

Methods

duplicated :: Alt f a -> Alt f (Alt f a)

extended :: (Alt f a -> b) -> Alt f a -> Alt f b

Enum (f a) => Enum (Alt f a)

Defined in Data.Semigroup.Internal

Methods

succ :: Alt f a -> Alt f a

pred :: Alt f a -> Alt f a

toEnum :: Int -> Alt f a

fromEnum :: Alt f a -> Int

enumFrom :: Alt f a -> [Alt f a]

enumFromThen :: Alt f a -> Alt f a -> [Alt f a]

enumFromTo :: Alt f a -> Alt f a -> [Alt f a]

enumFromThenTo :: Alt f a -> Alt f a -> Alt f a -> [Alt f a]

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

Defined in Data.Semigroup.Internal

Methods

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

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

(Data (f a), Data a, Typeable f) => Data (Alt f a)

Since: base-4.8.0.0

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt f a -> c (Alt f a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt f a)

toConstr :: Alt f a -> Constr

dataTypeOf :: Alt f a -> DataType

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

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

gmapT :: (forall b. Data b => b -> b) -> Alt f a -> Alt f a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt f a -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt f a -> r

gmapQ :: (forall d. Data d => d -> u) -> Alt f a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Alt f a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Alt f a -> m (Alt f a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Alt f a -> m (Alt f a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Alt f a -> m (Alt f a)

Num (f a) => Num (Alt f a)

Defined in Data.Semigroup.Internal

Methods

(+) :: Alt f a -> Alt f a -> Alt f a

(-) :: Alt f a -> Alt f a -> Alt f a

(*) :: Alt f a -> Alt f a -> Alt f a

negate :: Alt f a -> Alt f a

abs :: Alt f a -> Alt f a

signum :: Alt f a -> Alt f a

fromInteger :: Integer -> Alt f a

Ord (f a) => Ord (Alt f a)

Defined in Data.Semigroup.Internal

Methods

compare :: Alt f a -> Alt f a -> Ordering

(<) :: Alt f a -> Alt f a -> Bool

(<=) :: Alt f a -> Alt f a -> Bool

(>) :: Alt f a -> Alt f a -> Bool

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

max :: Alt f a -> Alt f a -> Alt f a

min :: Alt f a -> Alt f a -> Alt f a

Read (f a) => Read (Alt f a)

Defined in Data.Semigroup.Internal

Methods

readsPrec :: Int -> ReadS (Alt f a)

readList :: ReadS [Alt f a]

readPrec :: ReadPrec (Alt f a)

readListPrec :: ReadPrec [Alt f a]

Show (f a) => Show (Alt f a)

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Alt f a -> ShowS

show :: Alt f a -> String

showList :: [Alt f a] -> ShowS

Generic (Alt f a)

Defined in Data.Semigroup.Internal

Associated Types

type Rep (Alt f a) :: * -> *

Methods

from :: Alt f a -> Rep (Alt f a) x

to :: Rep (Alt f a) x -> Alt f a

Alternative f => Semigroup (Alt f a)

Since: base-4.9.0.0

Defined in Data.Semigroup.Internal

Methods

(<>) :: Alt f a -> Alt f a -> Alt f a

sconcat :: NonEmpty (Alt f a) -> Alt f a

stimes :: Integral b => b -> Alt f a -> Alt f a

Alternative f => Monoid (Alt f a)

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

mempty :: Alt f a

mappend :: Alt f a -> Alt f a -> Alt f a

mconcat :: [Alt f a] -> Alt f a

Wrapped (Alt f a)

Defined in Control.Lens.Wrapped

Associated Types

type Unwrapped (Alt f a) :: *

Methods

_Wrapped' :: Iso' (Alt f a) (Unwrapped (Alt f a))

Serialise (f a) => Serialise (Alt f a)

Since: serialise-0.2.0.0

Defined in Codec.Serialise.Class

Methods

encode :: Alt f a -> Encoding

decode :: Decoder s (Alt f a)

encodeList :: [Alt f a] -> Encoding

decodeList :: Decoder s [Alt f a]

t ~ Alt g b => Rewrapped (Alt f a) t

Defined in Control.Lens.Wrapped

type Rep1 (Alt f :: k -> *)

Defined in Data.Semigroup.Internal

type Rep1 (Alt f :: k -> *) = D1 (MetaData "Alt" "Data.Semigroup.Internal" "base" True) (C1 (MetaCons "Alt" PrefixI True) (S1 (MetaSel (Just "getAlt") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec1 f)))

type Rep (Alt f a)

Defined in Data.Semigroup.Internal

type Rep (Alt f a) = D1 (MetaData "Alt" "Data.Semigroup.Internal" "base" True) (C1 (MetaCons "Alt" PrefixI True) (S1 (MetaSel (Just "getAlt") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (f a))))

type Unwrapped (Alt f a)

Defined in Control.Lens.Wrapped

type Unwrapped (Alt f a) = f a

Free applicative

data Ap (f :: * -> *) a where

The free Applicative for a Functor f.

Constructors

Pure :: Ap f a

Ap :: Ap f a

Instances

Functor (Ap f)

Defined in Control.Applicative.Free

Methods

fmap :: (a -> b) -> Ap f a -> Ap f b

(<$) :: a -> Ap f b -> Ap f a

Applicative (Ap f)

Defined in Control.Applicative.Free

Methods

pure :: a -> Ap f a

(<*>) :: Ap f (a -> b) -> Ap f a -> Ap f b

liftA2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c

(*>) :: Ap f a -> Ap f b -> Ap f b

(<*) :: Ap f a -> Ap f b -> Ap f a

Comonad f => Comonad (Ap f)

Defined in Control.Applicative.Free

Methods

extract :: Ap f a -> a

duplicate :: Ap f a -> Ap f (Ap f a)

extend :: (Ap f a -> b) -> Ap f a -> Ap f b

Apply (Ap f)

Defined in Control.Applicative.Free

Methods

(<.>) :: Ap f (a -> b) -> Ap f a -> Ap f b

(.>) :: Ap f a -> Ap f b -> Ap f b

(<.) :: Ap f a -> Ap f b -> Ap f a

liftF2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c

runAp :: Applicative g => (forall x. f x -> g x) -> Ap f a -> g a

Given a natural transformation from f to g, this gives a canonical monoidal natural transformation from Ap f to g.

runAp t == retractApp . hoistApp t

runAp_ :: Monoid m => (forall a. f a -> m) -> Ap f b -> m

Perform a monoidal analysis over free applicative value.

Example:

count :: Ap f a -> Int
count = getSum . runAp_ (\_ -> Sum 1)

liftAp :: f a -> Ap f a

A version of lift that can be used with just a Functor for f.

iterAp :: Functor g => (g a -> a) -> Ap g a -> a

Tear down a free Applicative using iteration.

hoistAp :: (forall a. f a -> g a) -> Ap f b -> Ap g b

Given a natural transformation from f to g this gives a monoidal natural transformation from Ap f to Ap g.

retractAp :: Applicative f => Ap f a -> f a

Interprets the free applicative functor over f using the semantics for pure and <*> given by the Applicative instance for f.

retractApp == runAp id