Agda.Utils.List1

Non-empty lists.

Better name List1 for non-empty lists, plus missing functionality.

Import: @

{-# LANGUAGE PatternSynonyms #-}

import Agda.Utils.List1 (List1, pattern (:|)) import qualified Agda.Utils.List1 as List1

@

Documentation

type List1 = NonEmpty

type String1 = List1 Char

foldr :: (a -> b -> b) -> (a -> b) -> List1 a -> b

List foldr but with a base case for the singleton list.

union :: Eq a => List1 a -> List1 a -> List1 a

Like union. Duplicates in the first list are not removed. O(nm).

mapMaybe :: (a -> Maybe b) -> List1 a -> [b]

Like mapMaybe.

catMaybes :: List1 (Maybe a) -> [a]

Like catMaybes.

concat :: [List1 a] -> [a]

Concatenate one or more non-empty lists.

lefts :: List1 (Either a b) -> [a]

Like lefts.

rights :: List1 (Either a b) -> [b]

Like rights.

partitionEithers :: List1 (Either a b) -> ([a], [b])

Like partitionEithers.

find :: (a -> Bool) -> List1 a -> Maybe a

Like find.

unwords :: List1 String -> String

Like unwords.

zipWithM :: Applicative m => (a -> b -> m c) -> List1 a -> List1 b -> m (List1 c)

Like zipWithM.

zipWithM_ :: Applicative m => (a -> b -> m c) -> List1 a -> List1 b -> m ()

Like zipWithM.

snoc :: [a] -> a -> List1 a

Build a list with one element.

More precise type for snoc.

wordsBy :: (a -> Bool) -> [a] -> [List1 a]

Split a list into sublists. Generalisation of the prelude function words. Same as wordsBy and wordsBy, but with the non-emptyness guarantee on the chunks. O(n).

words xs == wordsBy isSpace xs

ifNull :: [a] -> b -> (List1 a -> b) -> b

initLast :: List1 a -> ([a], a)

Return the last element and the rest.

updateHead :: (a -> a) -> List1 a -> List1 a

Update the first element of a non-empty list. O(1).

updateLast :: (a -> a) -> List1 a -> List1 a

Update the last element of a non-empty list. O(n).

last2 :: List1 a -> Maybe (a, a)

Last two elements (safe). O(n).

ifNotNull :: [a] -> (List1 a -> b) -> b -> b

unlessNull :: Null m => [a] -> (List1 a -> m) -> m

liftList1 :: (List1 a -> List1 b) -> [a] -> [b]

Lift a function on non-empty lists to a function on lists.

This is in essence fmap for Maybe, if we take [a] = Maybe (List1 a).

breakAfter :: (a -> Bool) -> List1 a -> (List1 a, [a])

Breaks a list just after an element satisfying the predicate is found.

>>> breakAfter even [1,3,5,2,4,7,8]
(1 :| [3,5,2],[4,7,8])

allEqual :: Eq a => List1 a -> Bool

Checks if all the elements in the list are equal. Assumes that the Eq instance stands for an equivalence relation. O(n).

nubM :: Monad m => (a -> a -> m Bool) -> List1 a -> m (List1 a)

Non-efficient, monadic nub. O(n²).

toList' :: Maybe (List1 a) -> [a]

Lossless toList, opposite of nonEmpty.

fromListSafe

Arguments

:: List1 a

Default value if convertee is empty.

-> [a]

List to convert, supposedly non-empty.

-> List1 a

Converted list.

Safe version of fromList.

groupOn :: Ord b => (a -> b) -> [a] -> [List1 a]

groupOn f = groupBy ((==) `on` f) . sortBy (compare `on` f). O(n log n).

groupOn1 :: Ord b => (a -> b) -> List1 a -> List1 (List1 a)

groupBy' :: forall a. (a -> a -> Bool) -> [a] -> [List1 a]

More precise type for groupBy'.

A variant of groupBy which applies the predicate to consecutive pairs. O(n).

groupByFst :: forall a b. Eq a => [(a, b)] -> [(a, List1 b)]

Group consecutive items that share the same first component.

groupByFst1 :: forall a b. Eq a => List1 (a, b) -> List1 (a, List1 b)

Group consecutive items that share the same first component.

concatMap1 :: (a -> List1 b) -> List1 a -> List1 b

lensHead :: Functor f => (a -> f a) -> List1 a -> f (List1 a)

Focus on the first element of a non-empty list. O(1).

lensLast :: Functor f => (a -> f a) -> List1 a -> f (List1 a)

Focus on the last element of a non-empty list. O(n).

data NonEmpty a

Non-empty (and non-strict) list type.

Since: base-4.9.0.0

Constructors

a :| [a] infixr 5

Instances

NumHoles NameParts

Defined in Agda.Syntax.Concrete.Name

Methods

numHoles :: NameParts -> Int

FromJSON1 NonEmpty

Defined in Data.Aeson.Types.FromJSON

Methods

liftParseJSON :: Maybe a -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (NonEmpty a)

liftParseJSONList :: Maybe a -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [NonEmpty a]

liftOmittedField :: Maybe a -> Maybe (NonEmpty a)

ToJSON1 NonEmpty

Defined in Data.Aeson.Types.ToJSON

Methods

liftToJSON :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> NonEmpty a -> Value

liftToJSONList :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> [NonEmpty a] -> Value

liftToEncoding :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> NonEmpty a -> Encoding

liftToEncodingList :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> [NonEmpty a] -> Encoding

liftOmitField :: (a -> Bool) -> NonEmpty a -> Bool

MonadFix NonEmpty

Since: base-4.9.0.0

Defined in Control.Monad.Fix

Methods

mfix :: (a -> NonEmpty a) -> NonEmpty a

Foldable NonEmpty

Since: base-4.9.0.0

Defined in Data.Foldable

Methods

fold :: Monoid m => NonEmpty m -> m

foldMap :: Monoid m => (a -> m) -> NonEmpty a -> m

foldMap' :: Monoid m => (a -> m) -> NonEmpty a -> m

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

foldr' :: (a -> b -> b) -> b -> NonEmpty a -> b

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

foldl' :: (b -> a -> b) -> b -> NonEmpty a -> b

foldr1 :: (a -> a -> a) -> NonEmpty a -> a

foldl1 :: (a -> a -> a) -> NonEmpty a -> a

toList :: NonEmpty a -> [a]

null :: NonEmpty a -> Bool

length :: NonEmpty a -> Int

elem :: Eq a => a -> NonEmpty a -> Bool

maximum :: Ord a => NonEmpty a -> a

minimum :: Ord a => NonEmpty a -> a

sum :: Num a => NonEmpty a -> a

product :: Num a => NonEmpty a -> a

IsString String1

Defined in Agda.Utils.String

Methods

fromString :: String -> String1

Traversable NonEmpty

Since: base-4.9.0.0

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> NonEmpty a -> f (NonEmpty b)

sequenceA :: Applicative f => NonEmpty (f a) -> f (NonEmpty a)

mapM :: Monad m => (a -> m b) -> NonEmpty a -> m (NonEmpty b)

sequence :: Monad m => NonEmpty (m a) -> m (NonEmpty 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

Functor NonEmpty

Since: base-4.9.0.0

Defined in GHC.Base

Methods

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

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

Monad NonEmpty

Since: base-4.9.0.0

Defined in GHC.Base

Methods

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

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

return :: a -> NonEmpty a

NFData1 NonEmpty

Since: deepseq-1.4.3.0

Defined in Control.DeepSeq

Methods

liftRnf :: (a -> ()) -> NonEmpty a -> ()

Hashable1 NonEmpty

Since: hashable-1.3.1.0

Defined in Data.Hashable.Class

Methods

liftHashWithSalt :: (Int -> a -> Int) -> Int -> NonEmpty a -> Int

Generic1 NonEmpty

Defined in GHC.Generics

Associated Types

type Rep1 NonEmpty :: k -> Type

Methods

from1 :: forall (a :: k). NonEmpty a -> Rep1 NonEmpty a

to1 :: forall (a :: k). Rep1 NonEmpty a -> NonEmpty a

Singleton a (NonEmpty a)

Defined in Agda.Utils.Singleton

Methods

singleton :: a -> NonEmpty a

Lift a => Lift (NonEmpty a :: Type)

Since: template-haskell-2.15.0.0

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Quote m => NonEmpty a -> m Exp

liftTyped :: forall (m :: Type -> Type). Quote m => NonEmpty a -> Code m (NonEmpty a)

Pretty a => Pretties (List1 a)

Defined in Agda.Compiler.JS.Pretty

Methods

pretties :: (Nat, Bool, JSModuleStyle) -> List1 a -> [Doc]

SubstExpr a => SubstExpr (List1 a)

Defined in Agda.Syntax.Abstract

Methods

substExpr :: [(Name, Expr)] -> List1 a -> List1 a

DeclaredNames a => DeclaredNames (List1 a)

Defined in Agda.Syntax.Abstract.Views

Methods

declaredNames :: Collection KName m => List1 a -> m

ExprLike a => ExprLike (List1 a)

Defined in Agda.Syntax.Abstract.Views

Methods

recurseExpr :: RecurseExprFn m (List1 a)

foldExpr :: FoldExprFn m (List1 a)

traverseExpr :: TraverseExprFn m (List1 a)

mapExpr :: (Expr -> Expr) -> List1 a -> List1 a

Pretty a => Pretty (List1 a)

Defined in Agda.Syntax.Common.Pretty

Methods

pretty :: List1 a -> Doc

prettyPrec :: Int -> List1 a -> Doc

prettyList :: [List1 a] -> Doc

ExprLike a => ExprLike (List1 a)

Defined in Agda.Syntax.Concrete.Generic

Methods

mapExpr :: (Expr -> Expr) -> List1 a -> List1 a

foldExpr :: Monoid m => (Expr -> m) -> List1 a -> m

traverseExpr :: Monad m => (Expr -> m Expr) -> List1 a -> m (List1 a)

FoldDecl a => FoldDecl (List1 a)

Defined in Agda.Syntax.Concrete.Generic

Methods

foldDecl :: Monoid m => (Declaration -> m) -> List1 a -> m

TraverseDecl a => TraverseDecl (List1 a)

Defined in Agda.Syntax.Concrete.Generic

Methods

preTraverseDecl :: Monad m => (Declaration -> m Declaration) -> List1 a -> m (List1 a)

CPatternLike p => CPatternLike (List1 p)

Defined in Agda.Syntax.Concrete.Pattern

Methods

foldrCPattern :: Monoid m => (Pattern -> m -> m) -> List1 p -> m

traverseCPatternA :: (Applicative m, Functor m) => (Pattern -> m Pattern -> m Pattern) -> List1 p -> m (List1 p)

traverseCPatternM :: Monad m => (Pattern -> m Pattern) -> (Pattern -> m Pattern) -> List1 p -> m (List1 p)

NamesIn a => NamesIn (List1 a)

Defined in Agda.Syntax.Internal.Names

Methods

namesAndMetasIn' :: Monoid m => (Either QName MetaId -> m) -> List1 a -> m

HasRange a => HasRange (List1 a)

Precondition: The ranges of the list elements must point to the same file (or be empty).

Defined in Agda.Syntax.Position

Methods

getRange :: List1 a -> Range

KillRange a => KillRange (List1 a)

Defined in Agda.Syntax.Position

Methods

killRange :: KillRangeT (List1 a)

SetBindingSite a => SetBindingSite (List1 a)

Defined in Agda.Syntax.Scope.Base

Methods

setBindingSite :: Range -> List1 a -> List1 a

ToConcrete a => ToConcrete (List1 a)

Defined in Agda.Syntax.Translation.AbstractToConcrete

Associated Types

type ConOfAbs (List1 a)

Methods

toConcrete :: List1 a -> AbsToCon (ConOfAbs (List1 a))

bindToConcrete :: List1 a -> (ConOfAbs (List1 a) -> AbsToCon b) -> AbsToCon b

ToAbstract c => ToAbstract (List1 c)

Defined in Agda.Syntax.Translation.ConcreteToAbstract

Associated Types

type AbsOfCon (List1 c)

Methods

toAbstract :: List1 c -> ScopeM (AbsOfCon (List1 c))

ToAbstract (List1 (QNamed Clause))

Defined in Agda.Syntax.Translation.ReflectedToAbstract

Associated Types

type AbsOfRef (List1 (QNamed Clause))

Methods

toAbstract :: MonadReflectedToAbstract m => List1 (QNamed Clause) -> m (AbsOfRef (List1 (QNamed Clause)))

EmbPrj a => EmbPrj (List1 a)

Defined in Agda.TypeChecking.Serialise.Instances.Common

Methods

icode :: List1 a -> S Int32

icod_ :: List1 a -> S Int32

value :: Int32 -> R (List1 a)

Sized (List1 a)

Defined in Agda.Utils.Size

Methods

size :: List1 a -> Int

natSize :: List1 a -> Peano

FromJSON a => FromJSON (NonEmpty a)

Defined in Data.Aeson.Types.FromJSON

Methods

parseJSON :: Value -> Parser (NonEmpty a)

parseJSONList :: Value -> Parser [NonEmpty a]

omittedField :: Maybe (NonEmpty a)

ToJSON a => ToJSON (NonEmpty a)

Defined in Data.Aeson.Types.ToJSON

Methods

toJSON :: NonEmpty a -> Value

toEncoding :: NonEmpty a -> Encoding

toJSONList :: [NonEmpty a] -> Value

toEncodingList :: [NonEmpty a] -> Encoding

omitField :: NonEmpty a -> Bool

Semigroup (NonEmpty a)

Since: base-4.9.0.0

Defined in GHC.Base

Methods

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

sconcat :: NonEmpty (NonEmpty a) -> NonEmpty a

stimes :: Integral b => b -> NonEmpty a -> NonEmpty a

Generic (NonEmpty a)

Defined in GHC.Generics

Associated Types

type Rep (NonEmpty a) :: Type -> Type

Methods

from :: NonEmpty a -> Rep (NonEmpty a) x

to :: Rep (NonEmpty a) x -> NonEmpty a

IsList (NonEmpty a)

Since: base-4.9.0.0

Defined in GHC.IsList

Associated Types

type Item (NonEmpty a)

Methods

fromList :: [Item (NonEmpty a)] -> NonEmpty a

fromListN :: Int -> [Item (NonEmpty a)] -> NonEmpty a

toList :: NonEmpty a -> [Item (NonEmpty a)]

Read a => Read (NonEmpty a)

Since: base-4.11.0.0

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (NonEmpty a)

readList :: ReadS [NonEmpty a]

readPrec :: ReadPrec (NonEmpty a)

readListPrec :: ReadPrec [NonEmpty a]

Show a => Show (NonEmpty a)

Since: base-4.11.0.0

Defined in GHC.Show

Methods

showsPrec :: Int -> NonEmpty a -> ShowS

show :: NonEmpty a -> String

showList :: [NonEmpty a] -> ShowS

Binary a => Binary (NonEmpty a)

Since: binary-0.8.4.0

Defined in Data.Binary.Class

Methods

put :: NonEmpty a -> Put

get :: Get (NonEmpty a)

putList :: [NonEmpty a] -> Put

ToMarkup (NonEmpty Char)

Defined in Text.Blaze

Methods

toMarkup :: NonEmpty Char -> Markup

preEscapedToMarkup :: NonEmpty Char -> Markup

ToValue (NonEmpty Char)

Defined in Text.Blaze

Methods

toValue :: NonEmpty Char -> AttributeValue

preEscapedToValue :: NonEmpty Char -> AttributeValue

NFData a => NFData (NonEmpty a)

Since: deepseq-1.4.2.0

Defined in Control.DeepSeq

Methods

rnf :: NonEmpty a -> ()

Eq a => Eq (NonEmpty a)

Since: base-4.9.0.0

Defined in GHC.Base

Methods

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

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

Ord a => Ord (NonEmpty a)

Since: base-4.9.0.0

Defined in GHC.Base

Methods

compare :: NonEmpty a -> NonEmpty a -> Ordering

(<) :: NonEmpty a -> NonEmpty a -> Bool

(<=) :: NonEmpty a -> NonEmpty a -> Bool

(>) :: NonEmpty a -> NonEmpty a -> Bool

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

max :: NonEmpty a -> NonEmpty a -> NonEmpty a

min :: NonEmpty a -> NonEmpty a -> NonEmpty a

Hashable a => Hashable (NonEmpty a)

Defined in Data.Hashable.Class

Methods

hashWithSalt :: Int -> NonEmpty a -> Int

hash :: NonEmpty a -> Int

AddContext (List1 Name, Dom Type)

Defined in Agda.TypeChecking.Monad.Context

Methods

addContext :: MonadAddContext m => (List1 Name, Dom Type) -> m a -> m a

contextSize :: (List1 Name, Dom Type) -> Nat

AddContext (List1 (Arg Name), Type)

Defined in Agda.TypeChecking.Monad.Context

Methods

addContext :: MonadAddContext m => (List1 (Arg Name), Type) -> m a -> m a

contextSize :: (List1 (Arg Name), Type) -> Nat

AddContext (List1 (NamedArg Name), Type)

Defined in Agda.TypeChecking.Monad.Context

Methods

addContext :: MonadAddContext m => (List1 (NamedArg Name), Type) -> m a -> m a

contextSize :: (List1 (NamedArg Name), Type) -> Nat

AddContext (List1 (WithHiding Name), Dom Type)

Defined in Agda.TypeChecking.Monad.Context

Methods

addContext :: MonadAddContext m => (List1 (WithHiding Name), Dom Type) -> m a -> m a

contextSize :: (List1 (WithHiding Name), Dom Type) -> Nat

type Rep1 NonEmpty

Since: base-4.6.0.0

Defined in GHC.Generics

type Rep1 NonEmpty = D1 ('MetaData "NonEmpty" "GHC.Base" "base" 'False) (C1 ('MetaCons ":|" ('InfixI 'RightAssociative 5) 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1 :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 List)))

type ConOfAbs (List1 a)

Defined in Agda.Syntax.Translation.AbstractToConcrete

type ConOfAbs (List1 a) = List1 (ConOfAbs a)

type AbsOfCon (List1 c)

Defined in Agda.Syntax.Translation.ConcreteToAbstract

type AbsOfCon (List1 c) = List1 (AbsOfCon c)

type AbsOfRef (List1 (QNamed Clause))

Defined in Agda.Syntax.Translation.ReflectedToAbstract

type AbsOfRef (List1 (QNamed Clause)) = List1 Clause

type Rep (NonEmpty a)

Since: base-4.6.0.0

Defined in GHC.Generics

type Rep (NonEmpty a) = D1 ('MetaData "NonEmpty" "GHC.Base" "base" 'False) (C1 ('MetaCons ":|" ('InfixI 'RightAssociative 5) 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [a])))

type Item (NonEmpty a)

Defined in GHC.IsList

type Item (NonEmpty a) = a

sort :: Ord a => NonEmpty a -> NonEmpty a

Sort a stream.

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

Map a function over a NonEmpty stream.

singleton :: a -> NonEmpty a

Construct a NonEmpty list from a single element.

Since: base-4.15

insert :: (Foldable f, Ord a) => a -> f a -> NonEmpty a

insert x xs inserts x into the last position in xs where it is still less than or equal to the next element. In particular, if the list is sorted beforehand, the result will also be sorted.

filter :: (a -> Bool) -> NonEmpty a -> [a]

filter p xs removes any elements from xs that do not satisfy p.

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

The zipWith function generalizes zip. Rather than tupling the elements, the elements are combined using the function passed as the first argument.

sortBy :: (a -> a -> Ordering) -> NonEmpty a -> NonEmpty a

sortBy for NonEmpty, behaves the same as sortBy

length :: NonEmpty a -> Int

Number of elements in NonEmpty list.

head :: NonEmpty a -> a

Extract the first element of the stream.

group :: (Foldable f, Eq a) => f a -> [NonEmpty a]

The group function takes a stream and returns a list of streams such that flattening the resulting list is equal to the argument. Moreover, each stream in the resulting list contains only equal elements. For example, in list notation:

'group' $ 'cycle' "Mississippi"
  = "M" : "i" : "ss" : "i" : "ss" : "i" : "pp" : "i" : "M" : "i" : ...

groupBy :: Foldable f => (a -> a -> Bool) -> f a -> [NonEmpty a]

groupBy operates like group, but uses the provided equality predicate instead of ==.

unfoldr :: (a -> (b, Maybe a)) -> a -> NonEmpty b

The unfoldr function is analogous to Data.List's unfoldr operation.

transpose :: NonEmpty (NonEmpty a) -> NonEmpty (NonEmpty a)

transpose for NonEmpty, behaves the same as transpose The rows/columns need not be the same length, in which case > transpose . transpose /= id

cycle :: NonEmpty a -> NonEmpty a

cycle xs returns the infinite repetition of xs:

cycle (1 :| [2,3]) = 1 :| [2,3,1,2,3,...]

zip :: NonEmpty a -> NonEmpty b -> NonEmpty (a, b)

The zip function takes two streams and returns a stream of corresponding pairs.

uncons :: NonEmpty a -> (a, Maybe (NonEmpty a))

uncons produces the first element of the stream, and a stream of the remaining elements, if any.

tail :: NonEmpty a -> [a]

Extract the possibly-empty tail of the stream.

last :: NonEmpty a -> a

Extract the last element of the stream.

init :: NonEmpty a -> [a]

Extract everything except the last element of the stream.

scanl :: Foldable f => (b -> a -> b) -> b -> f a -> NonEmpty b

scanl is similar to foldl, but returns a stream 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.

scanl1 :: (a -> a -> a) -> NonEmpty a -> NonEmpty a

scanl1 is a variant of scanl that has no starting value argument:

scanl1 f [x1, x2, ...] == x1 :| [x1 `f` x2, x1 `f` (x2 `f` x3), ...]

scanr :: Foldable f => (a -> b -> b) -> b -> f a -> NonEmpty b

scanr is the right-to-left dual of scanl. Note that

head (scanr f z xs) == foldr f z xs.

scanr1 :: (a -> a -> a) -> NonEmpty a -> NonEmpty a

scanr1 is a variant of scanr that has no starting value argument.

iterate :: (a -> a) -> a -> NonEmpty a

iterate f x produces the infinite sequence of repeated applications of f to x.

iterate f x = x :| [f x, f (f x), ..]

repeat :: a -> NonEmpty a

repeat x returns a constant stream, where all elements are equal to x.

takeWhile :: (a -> Bool) -> NonEmpty a -> [a]

takeWhile p xs returns the longest prefix of the stream xs for which the predicate p holds.

dropWhile :: (a -> Bool) -> NonEmpty a -> [a]

dropWhile p xs returns the suffix remaining after takeWhile p xs.

take :: Int -> NonEmpty a -> [a]

take n xs returns the first n elements of xs.

drop :: Int -> NonEmpty a -> [a]

drop n xs drops the first n elements off the front of the sequence xs.

splitAt :: Int -> NonEmpty a -> ([a], [a])

splitAt n xs returns a pair consisting of the prefix of xs of length n and the remaining stream immediately following this prefix.

'splitAt' n xs == ('take' n xs, 'drop' n xs)
xs == ys ++ zs where (ys, zs) = 'splitAt' n xs

span :: (a -> Bool) -> NonEmpty a -> ([a], [a])

span p xs returns the longest prefix of xs that satisfies p, together with the remainder of the stream.

'span' p xs == ('takeWhile' p xs, 'dropWhile' p xs)
xs == ys ++ zs where (ys, zs) = 'span' p xs

break :: (a -> Bool) -> NonEmpty a -> ([a], [a])

The break p function is equivalent to span (not . p).

reverse :: NonEmpty a -> NonEmpty a

reverse a finite NonEmpty stream.

(!!) :: HasCallStack => NonEmpty a -> Int -> a infixl 9

xs !! n returns the element of the stream xs at index n. Note that the head of the stream has index 0.

Beware: a negative or out-of-bounds index will cause an error.

xor :: NonEmpty Bool -> Bool

Compute n-ary logic exclusive OR operation on NonEmpty list.

isPrefixOf :: Eq a => [a] -> NonEmpty a -> Bool

The isPrefixOf function returns True if the first argument is a prefix of the second.

nub :: Eq a => NonEmpty a -> NonEmpty a

The nub function removes duplicate elements from a list. In particular, it keeps only the first occurrence of each element. (The name nub means 'essence'.) It is a special case of nubBy, which allows the programmer to supply their own inequality test.

nubBy :: (a -> a -> Bool) -> NonEmpty a -> NonEmpty a

The nubBy function behaves just like nub, except it uses a user-supplied equality predicate instead of the overloaded == function.

intersperse :: a -> NonEmpty a -> NonEmpty a

'intersperse x xs' alternates elements of the list with copies of x.

intersperse 0 (1 :| [2,3]) == 1 :| [0,2,0,3]

partition :: (a -> Bool) -> NonEmpty a -> ([a], [a])

The partition function takes a predicate p and a stream xs, and returns a pair of lists. The first list corresponds to the elements of xs for which p holds; the second corresponds to the elements of xs for which p does not hold.

'partition' p xs = ('filter' p xs, 'filter' (not . p) xs)

inits :: Foldable f => f a -> NonEmpty [a]

The inits function takes a stream xs and returns all the finite prefixes of xs, starting with the shortest. The result is NonEmpty because the result always contains the empty list as the first element.

inits [1,2,3] == [] :| [[1], [1,2], [1,2,3]]
inits [1] == [] :| [[1]]
inits [] == [] :| []

tails :: Foldable f => f a -> NonEmpty [a]

The tails function takes a stream xs and returns all the suffixes of xs, starting with the longest. The result is NonEmpty because the result always contains the empty list as the last element.

tails [1,2,3] == [1,2,3] :| [[2,3], [3], []]
tails [1] == [1] :| [[]]
tails [] == [] :| []

unfold :: (a -> (b, Maybe a)) -> a -> NonEmpty b

unfold produces a new stream by repeatedly applying the unfolding function to the seed value to produce an element of type b and a new seed value. When the unfolding function returns Nothing instead of a new seed value, the stream ends.

nonEmpty :: [a] -> Maybe (NonEmpty a)

nonEmpty efficiently turns a normal list into a NonEmpty stream, producing Nothing if the input is empty.

(<|) :: a -> NonEmpty a -> NonEmpty a infixr 5

Prepend an element to the stream.

cons :: a -> NonEmpty a -> NonEmpty a

Synonym for <|.

inits1 :: NonEmpty a -> NonEmpty (NonEmpty a)

The inits1 function takes a NonEmpty stream xs and returns all the NonEmpty finite prefixes of xs, starting with the shortest.

inits1 (1 :| [2,3]) == (1 :| []) :| [1 :| [2], 1 :| [2,3]]
inits1 (1 :| []) == (1 :| []) :| []

Since: base-4.18

tails1 :: NonEmpty a -> NonEmpty (NonEmpty a)

The tails1 function takes a NonEmpty stream xs and returns all the non-empty suffixes of xs, starting with the longest.

tails1 (1 :| [2,3]) == (1 :| [2,3]) :| [2 :| [3], 3 :| []]
tails1 (1 :| []) == (1 :| []) :| []

Since: base-4.18

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

some1 x sequences x one or more times.

groupWith :: (Foldable f, Eq b) => (a -> b) -> f a -> [NonEmpty a]

groupWith operates like group, but uses the provided projection when comparing for equality

groupAllWith :: Ord b => (a -> b) -> [a] -> [NonEmpty a]

groupAllWith operates like groupWith, but sorts the list first so that each equivalence class has, at most, one list in the output

group1 :: Eq a => NonEmpty a -> NonEmpty (NonEmpty a)

group1 operates like group, but uses the knowledge that its input is non-empty to produce guaranteed non-empty output.

groupBy1 :: (a -> a -> Bool) -> NonEmpty a -> NonEmpty (NonEmpty a)

groupBy1 is to group1 as groupBy is to group.

groupWith1 :: Eq b => (a -> b) -> NonEmpty a -> NonEmpty (NonEmpty a)

groupWith1 is to group1 as groupWith is to group

groupAllWith1 :: Ord b => (a -> b) -> NonEmpty a -> NonEmpty (NonEmpty a)

groupAllWith1 is to groupWith1 as groupAllWith is to groupWith

sortWith :: Ord o => (a -> o) -> NonEmpty a -> NonEmpty a

sortWith for NonEmpty, behaves the same as:

sortBy . comparing

append :: NonEmpty a -> NonEmpty a -> NonEmpty a

A monomorphic version of <> for NonEmpty.

>>> append (1 :| []) (2 :| [3])
1 :| [2,3]

Since: base-4.16

appendList :: NonEmpty a -> [a] -> NonEmpty a

Attach a list at the end of a NonEmpty.

>>> appendList (1 :| [2,3]) []
1 :| [2,3]

>>> appendList (1 :| [2,3]) [4,5]
1 :| [2,3,4,5]

Since: base-4.16

prependList :: [a] -> NonEmpty a -> NonEmpty a

Attach a list at the beginning of a NonEmpty.

>>> prependList [] (1 :| [2,3])
1 :| [2,3]

>>> prependList [negate 1, 0] (1 :| [2, 3])
-1 :| [0,1,2,3]

Since: base-4.16

class IsList l where

The IsList class and its methods are intended to be used in conjunction with the OverloadedLists extension.

Since: base-4.7.0.0

Minimal complete definition

fromList, toList

Associated Types

type Item l

The Item type function returns the type of items of the structure l.

Methods

fromList :: [Item l] -> l

The fromList function constructs the structure l from the given list of Item l

fromListN :: Int -> [Item l] -> l

The fromListN function takes the input list's length and potentially uses it to construct the structure l more efficiently compared to fromList. If the given number does not equal to the input list's length the behaviour of fromListN is not specified.

fromListN (length xs) xs == fromList xs

toList :: l -> [Item l]

The toList function extracts a list of Item l from the structure l. It should satisfy fromList . toList = id.

Instances

IsList ByteArray

Since: base-4.17.0.0

Defined in Data.Array.Byte

Associated Types

type Item ByteArray

Methods

fromList :: [Item ByteArray] -> ByteArray

fromListN :: Int -> [Item ByteArray] -> ByteArray

toList :: ByteArray -> [Item ByteArray]

IsList Version

Since: base-4.8.0.0

Defined in GHC.IsList

Associated Types

type Item Version

Methods

fromList :: [Item Version] -> Version

fromListN :: Int -> [Item Version] -> Version

toList :: Version -> [Item Version]

IsList CallStack

Be aware that 'fromList . toList = id' only for unfrozen CallStacks, since toList removes frozenness information.

Since: base-4.9.0.0

Defined in GHC.IsList

Associated Types

type Item CallStack

Methods

fromList :: [Item CallStack] -> CallStack

fromListN :: Int -> [Item CallStack] -> CallStack

toList :: CallStack -> [Item CallStack]

IsList ByteString

Since: bytestring-0.10.12.0

Defined in Data.ByteString.Internal.Type

Associated Types

type Item ByteString

Methods

fromList :: [Item ByteString] -> ByteString

fromListN :: Int -> [Item ByteString] -> ByteString

toList :: ByteString -> [Item ByteString]

IsList ByteString

Since: bytestring-0.10.12.0

Defined in Data.ByteString.Lazy.Internal

Associated Types

type Item ByteString

Methods

fromList :: [Item ByteString] -> ByteString

fromListN :: Int -> [Item ByteString] -> ByteString

toList :: ByteString -> [Item ByteString]

IsList ShortByteString

Since: bytestring-0.10.12.0

Defined in Data.ByteString.Short.Internal

Associated Types

type Item ShortByteString

Methods

fromList :: [Item ShortByteString] -> ShortByteString

fromListN :: Int -> [Item ShortByteString] -> ShortByteString

toList :: ShortByteString -> [Item ShortByteString]

IsList IntSet

Since: containers-0.5.6.2

Defined in Data.IntSet.Internal

Associated Types

type Item IntSet

Methods

fromList :: [Item IntSet] -> IntSet

fromListN :: Int -> [Item IntSet] -> IntSet

toList :: IntSet -> [Item IntSet]

IsList ShortText

Note: Surrogate pairs ([U+D800 .. U+DFFF]) character literals are replaced by U+FFFD.

Since: text-short-0.1.2

Defined in Data.Text.Short.Internal

Associated Types

type Item ShortText

Methods

fromList :: [Item ShortText] -> ShortText

fromListN :: Int -> [Item ShortText] -> ShortText

toList :: ShortText -> [Item ShortText]

IsList (List2 a)

fromList is unsafe.

Defined in Agda.Utils.List2

Associated Types

type Item (List2 a)

Methods

fromList :: [Item (List2 a)] -> List2 a

fromListN :: Int -> [Item (List2 a)] -> List2 a

toList :: List2 a -> [Item (List2 a)]

IsList (KeyMap v)

Since: aeson-2.0.2.0

Defined in Data.Aeson.KeyMap

Associated Types

type Item (KeyMap v)

Methods

fromList :: [Item (KeyMap v)] -> KeyMap v

fromListN :: Int -> [Item (KeyMap v)] -> KeyMap v

toList :: KeyMap v -> [Item (KeyMap v)]

IsList (ZipList a)

Since: base-4.15.0.0

Defined in GHC.IsList

Associated Types

type Item (ZipList a)

Methods

fromList :: [Item (ZipList a)] -> ZipList a

fromListN :: Int -> [Item (ZipList a)] -> ZipList a

toList :: ZipList a -> [Item (ZipList a)]

IsList (NonEmpty a)

Since: base-4.9.0.0

Defined in GHC.IsList

Associated Types

type Item (NonEmpty a)

Methods

fromList :: [Item (NonEmpty a)] -> NonEmpty a

fromListN :: Int -> [Item (NonEmpty a)] -> NonEmpty a

toList :: NonEmpty a -> [Item (NonEmpty a)]

IsList (IntMap a)

Since: containers-0.5.6.2

Defined in Data.IntMap.Internal

Associated Types

type Item (IntMap a)

Methods

fromList :: [Item (IntMap a)] -> IntMap a

fromListN :: Int -> [Item (IntMap a)] -> IntMap a

toList :: IntMap a -> [Item (IntMap a)]

IsList (Seq a)

Defined in Data.Sequence.Internal

Associated Types

type Item (Seq a)

Methods

fromList :: [Item (Seq a)] -> Seq a

fromListN :: Int -> [Item (Seq a)] -> Seq a

toList :: Seq a -> [Item (Seq a)]

Ord a => IsList (Set a)

Since: containers-0.5.6.2

Defined in Data.Set.Internal

Associated Types

type Item (Set a)

Methods

fromList :: [Item (Set a)] -> Set a

fromListN :: Int -> [Item (Set a)] -> Set a

toList :: Set a -> [Item (Set a)]

IsList (DNonEmpty a)

Defined in Data.DList.DNonEmpty.Internal

Associated Types

type Item (DNonEmpty a)

Methods

fromList :: [Item (DNonEmpty a)] -> DNonEmpty a

fromListN :: Int -> [Item (DNonEmpty a)] -> DNonEmpty a

toList :: DNonEmpty a -> [Item (DNonEmpty a)]

IsList (DList a)

Defined in Data.DList.Internal

Associated Types

type Item (DList a)

Methods

fromList :: [Item (DList a)] -> DList a

fromListN :: Int -> [Item (DList a)] -> DList a

toList :: DList a -> [Item (DList a)]

IsList (Array a)

Defined in Data.Primitive.Array

Associated Types

type Item (Array a)

Methods

fromList :: [Item (Array a)] -> Array a

fromListN :: Int -> [Item (Array a)] -> Array a

toList :: Array a -> [Item (Array a)]

Prim a => IsList (PrimArray a)

Since: primitive-0.6.4.0

Defined in Data.Primitive.PrimArray

Associated Types

type Item (PrimArray a)

Methods

fromList :: [Item (PrimArray a)] -> PrimArray a

fromListN :: Int -> [Item (PrimArray a)] -> PrimArray a

toList :: PrimArray a -> [Item (PrimArray a)]

IsList (SmallArray a)

Defined in Data.Primitive.SmallArray

Associated Types

type Item (SmallArray a)

Methods

fromList :: [Item (SmallArray a)] -> SmallArray a

fromListN :: Int -> [Item (SmallArray a)] -> SmallArray a

toList :: SmallArray a -> [Item (SmallArray a)]

(Eq a, Hashable a) => IsList (HashSet a)

Defined in Data.HashSet.Internal

Associated Types

type Item (HashSet a)

Methods

fromList :: [Item (HashSet a)] -> HashSet a

fromListN :: Int -> [Item (HashSet a)] -> HashSet a

toList :: HashSet a -> [Item (HashSet a)]

IsList (Vector a)

Defined in Data.Vector

Associated Types

type Item (Vector a)

Methods

fromList :: [Item (Vector a)] -> Vector a

fromListN :: Int -> [Item (Vector a)] -> Vector a

toList :: Vector a -> [Item (Vector a)]

Prim a => IsList (Vector a)

Defined in Data.Vector.Primitive

Associated Types

type Item (Vector a)

Methods

fromList :: [Item (Vector a)] -> Vector a

fromListN :: Int -> [Item (Vector a)] -> Vector a

toList :: Vector a -> [Item (Vector a)]

Storable a => IsList (Vector a)

Defined in Data.Vector.Storable

Associated Types

type Item (Vector a)

Methods

fromList :: [Item (Vector a)] -> Vector a

fromListN :: Int -> [Item (Vector a)] -> Vector a

toList :: Vector a -> [Item (Vector a)]

IsList [a]

Since: base-4.7.0.0

Defined in GHC.IsList

Associated Types

type Item [a]

Methods

fromList :: [Item [a]] -> [a]

fromListN :: Int -> [Item [a]] -> [a]

toList :: [a] -> [Item [a]]

Ord k => IsList (Map k v)

Since: containers-0.5.6.2

Defined in Data.Map.Internal

Associated Types

type Item (Map k v)

Methods

fromList :: [Item (Map k v)] -> Map k v

fromListN :: Int -> [Item (Map k v)] -> Map k v

toList :: Map k v -> [Item (Map k v)]

(Eq k, Hashable k) => IsList (HashMap k v)

Defined in Data.HashMap.Internal

Associated Types

type Item (HashMap k v)

Methods

fromList :: [Item (HashMap k v)] -> HashMap k v

fromListN :: Int -> [Item (HashMap k v)] -> HashMap k v

toList :: HashMap k v -> [Item (HashMap k v)]

type family Item l

The Item type function returns the type of items of the structure l.

Instances

type Item ByteArray

Defined in Data.Array.Byte

type Item ByteArray = Word8

type Item Version

Defined in GHC.IsList

type Item Version = Int

type Item CallStack

Defined in GHC.IsList

type Item CallStack = (String, SrcLoc)

type Item ByteString

Defined in Data.ByteString.Internal.Type

type Item ByteString = Word8

type Item ByteString

Defined in Data.ByteString.Lazy.Internal

type Item ByteString = Word8

type Item ShortByteString

Defined in Data.ByteString.Short.Internal

type Item ShortByteString = Word8

type Item IntSet

Defined in Data.IntSet.Internal

type Item IntSet = Key

type Item Text

Defined in Data.Text

type Item Text = Char

type Item Text

Defined in Data.Text.Lazy

type Item Text = Char

type Item ShortText

Defined in Data.Text.Short.Internal

type Item ShortText = Char

type Item (List2 a)

Defined in Agda.Utils.List2

type Item (List2 a) = a

type Item (KeyMap v)

Defined in Data.Aeson.KeyMap

type Item (KeyMap v) = (Key, v)

type Item (ZipList a)

Defined in GHC.IsList

type Item (ZipList a) = a

type Item (NonEmpty a)

Defined in GHC.IsList

type Item (NonEmpty a) = a

type Item (IntMap a)

Defined in Data.IntMap.Internal

type Item (IntMap a) = (Key, a)

type Item (Seq a)

Defined in Data.Sequence.Internal

type Item (Seq a) = a

type Item (Set a)

Defined in Data.Set.Internal

type Item (Set a) = a

type Item (DNonEmpty a)

Defined in Data.DList.DNonEmpty.Internal

type Item (DNonEmpty a) = a

type Item (DList a)

Defined in Data.DList.Internal

type Item (DList a) = a

type Item (Array a)

Defined in Data.Primitive.Array

type Item (Array a) = a

type Item (PrimArray a)

Defined in Data.Primitive.PrimArray

type Item (PrimArray a) = a

type Item (SmallArray a)

Defined in Data.Primitive.SmallArray

type Item (SmallArray a) = a

type Item (HashSet a)

Defined in Data.HashSet.Internal

type Item (HashSet a) = a

type Item (Vector a)

Defined in Data.Vector

type Item (Vector a) = a

type Item (Vector a)

Defined in Data.Vector.Primitive

type Item (Vector a) = a

type Item (Vector a)

Defined in Data.Vector.Storable

type Item (Vector a) = a

type Item (Vector e)

Defined in Data.Vector.Unboxed

type Item (Vector e) = e

type Item [a]

Defined in GHC.IsList

type Item [a] = a

type Item (Map k v)

Defined in Data.Map.Internal

type Item (Map k v) = (k, v)

type Item (HashMap k v)

Defined in Data.HashMap.Internal

type Item (HashMap k v) = (k, v)

unzip :: Functor f => f (a, b) -> (f a, f b)

The unzip function is the inverse of the zip function.