| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
BasePrelude
Description
Reexports of most of the definitions from the "base" package, which it is a common practice to import unqualified.
For details check out the source.
Synopsis
- module Control.Applicative
- module Control.Category
- module Control.Concurrent
- module Control.Exception
- module Control.Monad
- module Control.Monad.Fail
- module Control.Monad.Fix
- module Control.Monad.IO.Class
- module Control.Monad.ST
- module Data.Bifunctor
- module Data.Bits
- module Data.Bool
- module Data.Char
- module Data.Coerce
- module Data.Complex
- module Data.Data
- module Data.Dynamic
- module Data.Either
- module Data.Fixed
- module Data.Functor.Classes
- module Data.Functor.Compose
- module Data.Functor.Contravariant
- module Data.Functor.Identity
- module Data.IORef
- module Data.Int
- module Data.Ix
- module Data.List
- module Data.Maybe
- module Data.Ord
- module Data.Proxy
- module Data.Ratio
- module Data.STRef
- module Data.Semigroup
- module Data.String
- module Data.Traversable
- module Data.Tuple
- module Data.Unique
- module Data.Version
- module Data.Void
- module Data.Word
- module Debug.Trace
- module Foreign.ForeignPtr
- module Foreign.Ptr
- module Foreign.StablePtr
- module Foreign.Storable
- module GHC.IO.Exception
- module GHC.OverloadedLabels
- module GHC.Records
- module Numeric
- module Numeric.Natural
- module System.Environment
- module System.Exit
- module System.IO
- module System.IO.Error
- module System.IO.Unsafe
- module System.Mem
- module System.Mem.StableName
- module System.Timeout
- module Unsafe.Coerce
- class Category a => Arrow (a :: Type -> Type -> Type) where
- const :: a -> b -> a
- closeFdWith :: (Fd -> IO ()) -> Fd -> IO ()
- class Foldable (t :: Type -> Type) where
- seq :: a -> b -> b
- lazy :: a -> a
- inline :: a -> a
- ($) :: (a -> b) -> a -> b
- class Num a where
- class Num a => Fractional a where
- (/) :: a -> a -> a
- recip :: a -> a
- fromRational :: Rational -> a
- class Enum a where
- succ :: a -> a
- pred :: a -> a
- toEnum :: Int -> a
- fromEnum :: a -> Int
- enumFrom :: a -> [a]
- enumFromThen :: a -> a -> [a]
- enumFromTo :: a -> a -> [a]
- enumFromThenTo :: a -> a -> a -> [a]
- class Eq a where
- class Arrow a => ArrowApply (a :: Type -> Type -> Type) where
- app :: a (a b c, b) c
- class Arrow a => ArrowChoice (a :: Type -> Type -> Type) where
- class Arrow a => ArrowLoop (a :: Type -> Type -> Type) where
- loop :: a (b, d) (c, d) -> a b c
- fromIntegral :: (Integral a, Num b) => a -> b
- realToFrac :: (Real a, Fractional b) => a -> b
- class (Real a, Enum a) => Integral a where
- class (Num a, Ord a) => Real a where
- toRational :: a -> Rational
- class IsList l where
- class Semigroup a => Monoid a where
- class Bounded a where
- class Read a where
- class (RealFrac a, Floating a) => RealFloat a where
- floatRadix :: a -> Integer
- floatDigits :: a -> Int
- floatRange :: a -> (Int, Int)
- decodeFloat :: a -> (Integer, Int)
- encodeFloat :: Integer -> Int -> a
- exponent :: a -> Int
- significand :: a -> a
- scaleFloat :: Int -> a -> a
- isNaN :: a -> Bool
- isInfinite :: a -> Bool
- isDenormalized :: a -> Bool
- isNegativeZero :: a -> Bool
- isIEEE :: a -> Bool
- atan2 :: a -> a -> a
- class (Real a, Fractional a) => RealFrac a where
- class Show a where
- class Generic a
- class Generic1 (f :: k -> Type)
- data Double
- data Float
- data Integer
- class a ~# b => (a :: k) ~ (b :: k)
- data NonEmpty a = a :| [a]
- (^) :: (Num a, Integral b) => a -> b -> a
- error :: HasCallStack => [Char] -> a
- errorWithoutStackTrace :: [Char] -> a
- undefined :: HasCallStack => a
- flip :: (a -> b -> c) -> b -> a -> c
- ($!) :: (a -> b) -> a -> b
- until :: (a -> Bool) -> (a -> a) -> a -> a
- asTypeOf :: a -> a -> a
- subtract :: Num a => a -> a -> a
- type ShowS = String -> String
- shows :: Show a => a -> ShowS
- showChar :: Char -> ShowS
- showString :: String -> ShowS
- showParen :: Bool -> ShowS -> ShowS
- even :: Integral a => a -> Bool
- odd :: Integral a => a -> Bool
- (^^) :: (Fractional a, Integral b) => a -> b -> a
- gcd :: Integral a => a -> a -> a
- lcm :: Integral a => a -> a -> a
- (<&>) :: Functor f => f a -> (a -> b) -> f b
- ($>) :: Functor f => f a -> b -> f b
- on :: (b -> b -> c) -> (a -> b) -> a -> a -> c
- (&) :: a -> (a -> b) -> b
- applyWhen :: Bool -> (a -> a) -> a -> a
- data ReadP a
- type ReadS a = String -> [(a, String)]
- readP_to_S :: ReadP a -> ReadS a
- readS_to_P :: ReadS a -> ReadP a
- lex :: ReadS String
- data ReadPrec a
- readPrec_to_P :: ReadPrec a -> Int -> ReadP a
- readP_to_Prec :: (Int -> ReadP a) -> ReadPrec a
- readPrec_to_S :: ReadPrec a -> Int -> ReadS a
- readS_to_Prec :: (Int -> ReadS a) -> ReadPrec a
- readParen :: Bool -> ReadS a -> ReadS a
- data ThreadStatus
- data BlockReason
- data TVar a = TVar (TVar# RealWorld a)
- pattern ThreadId :: ThreadId# -> ThreadId
- threadStatus :: ThreadId -> IO ThreadStatus
- data PrimMVar
- newStablePtrPrimMVar :: MVar a -> IO (StablePtr PrimMVar)
- reads :: Read a => ReadS a
- readEither :: Read a => String -> Either String a
- readMaybe :: Read a => String -> Maybe a
- read :: Read a => String -> a
- newtype Alt (f :: k -> Type) (a :: k) = Alt {
- getAlt :: f a
- newtype Ap (f :: k -> Type) (a :: k) = Ap {
- getAp :: f a
- foldrM :: (Foldable t, Monad m) => (a -> b -> m b) -> b -> t a -> m b
- foldlM :: (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b
- traverse_ :: (Foldable t, Applicative f) => (a -> f b) -> t a -> f ()
- for_ :: (Foldable t, Applicative f) => t a -> (a -> f b) -> f ()
- sequenceA_ :: (Foldable t, Applicative f) => t (f a) -> f ()
- newtype STM a = STM (State# RealWorld -> (# State# RealWorld, a #))
- reportHeapOverflow :: IO ()
- numCapabilities :: Int
- getNumProcessors :: IO Int
- numSparks :: IO Int
- childHandler :: SomeException -> IO ()
- labelThread :: ThreadId -> String -> IO ()
- pseq :: a -> b -> b
- par :: a -> b -> b
- runSparks :: IO ()
- listThreads :: IO [ThreadId]
- unsafeIOToSTM :: IO a -> STM a
- atomically :: STM a -> IO a
- retry :: STM a
- throwSTM :: Exception e => e -> STM a
- catchSTM :: Exception e => STM a -> (e -> STM a) -> STM a
- newTVar :: a -> STM (TVar a)
- newTVarIO :: a -> IO (TVar a)
- readTVarIO :: TVar a -> IO a
- readTVar :: TVar a -> STM a
- writeTVar :: TVar a -> a -> STM ()
- reportStackOverflow :: IO ()
- reportError :: SomeException -> IO ()
- setUncaughtExceptionHandler :: (SomeException -> IO ()) -> IO ()
- getUncaughtExceptionHandler :: IO (SomeException -> IO ())
- type HandlerFun = ForeignPtr Word8 -> IO ()
- type Signal = CInt
- setHandler :: Signal -> Maybe (HandlerFun, Dynamic) -> IO (Maybe (HandlerFun, Dynamic))
- runHandlers :: ForeignPtr Word8 -> Signal -> IO ()
- ensureIOManagerIsRunning :: IO ()
- ioManagerCapabilitiesChanged :: IO ()
- registerDelay :: Int -> IO (TVar Bool)
- type family Item l
- sortWith :: Ord b => (a -> b) -> [a] -> [a]
- groupWith :: Ord b => (a -> b) -> [a] -> [[a]]
- newtype ArrowMonad (a :: Type -> Type -> Type) b = ArrowMonad (a () b)
- class ArrowZero a => ArrowPlus (a :: Type -> Type -> Type) where
- (<+>) :: a b c -> a b c -> a b c
- class Arrow a => ArrowZero (a :: Type -> Type -> Type) where
- zeroArrow :: a b c
- newtype Kleisli (m :: Type -> Type) a b = Kleisli {
- runKleisli :: a -> m b
- returnA :: Arrow a => a b b
- (^>>) :: Arrow a => (b -> c) -> a c d -> a b d
- (>>^) :: Arrow a => a b c -> (c -> d) -> a b d
- (<<^) :: Arrow a => a c d -> (b -> c) -> a b d
- (^<<) :: Arrow a => (c -> d) -> a b c -> a b d
- leftApp :: ArrowApply a => a b c -> a (Either b d) (Either c d)
- printf :: PrintfType r => String -> r
- hPrintf :: HPrintfType r => Handle -> String -> r
Documentation
module Control.Applicative
module Control.Category
module Control.Concurrent
module Control.Exception
module Control.Monad
module Control.Monad.Fail
module Control.Monad.Fix
module Control.Monad.IO.Class
module Control.Monad.ST
module Data.Bifunctor
module Data.Bits
module Data.Bool
module Data.Char
module Data.Coerce
module Data.Complex
module Data.Data
module Data.Dynamic
module Data.Either
module Data.Fixed
module Data.Functor.Classes
module Data.Functor.Compose
module Data.Functor.Contravariant
module Data.Functor.Identity
module Data.IORef
module Data.Int
module Data.Ix
module Data.List
module Data.Maybe
module Data.Ord
module Data.Proxy
module Data.Ratio
module Data.STRef
module Data.Semigroup
module Data.String
module Data.Traversable
module Data.Tuple
module Data.Unique
module Data.Version
module Data.Void
module Data.Word
module Debug.Trace
module Foreign.ForeignPtr
module Foreign.Ptr
module Foreign.StablePtr
module Foreign.Storable
module GHC.IO.Exception
module GHC.OverloadedLabels
module GHC.Records
module Numeric
module Numeric.Natural
module System.Environment
module System.Exit
module System.IO
module System.IO.Error
module System.IO.Unsafe
module System.Mem
module System.Mem.StableName
module System.Timeout
module Unsafe.Coerce
class Category a => Arrow (a :: Type -> Type -> Type) where #
The basic arrow class.
Instances should satisfy the following laws:
arrid =idarr(f >>> g) =arrf >>>arrgfirst(arrf) =arr(firstf)first(f >>> g) =firstf >>>firstgfirstf >>>arrfst=arrfst>>> ffirstf >>>arr(id*** g) =arr(id*** g) >>>firstffirst(firstf) >>>arrassoc =arrassoc >>>firstf
where
assoc ((a,b),c) = (a,(b,c))
The other combinators have sensible default definitions, which may be overridden for efficiency.
Methods
Lift a function to an arrow.
(***) :: a b c -> a b' c' -> a (b, b') (c, c') infixr 3 #
Split the input between the two argument arrows and combine their output. Note that this is in general not a functor.
The default definition may be overridden with a more efficient version if desired.
(&&&) :: a b c -> a b c' -> a b (c, c') infixr 3 #
Fanout: send the input to both argument arrows and combine their output.
The default definition may be overridden with a more efficient version if desired.
Instances
| Monad m => Arrow (Kleisli m) | Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow | |
| Arrow (->) | Since: base-2.1 |
const x y always evaluates to x, ignoring its second argument.
const x = \_ -> x
This function might seem useless at first glance, but it can be very useful in a higher order context.
Examples
>>>const 42 "hello"42
>>>map (const 42) [0..3][42,42,42,42]
Arguments
| :: (Fd -> IO ()) | Low-level action that performs the real close. |
| -> Fd | File descriptor to close. |
| -> IO () |
Close a file descriptor in a concurrency-safe way (GHC only). If
you are using threadWaitRead or threadWaitWrite to perform
blocking I/O, you must use this function to close file
descriptors, or blocked threads may not be woken.
Any threads that are blocked on the file descriptor via
threadWaitRead or threadWaitWrite will be unblocked by having
IO exceptions thrown.
class Foldable (t :: Type -> Type) where #
The Foldable class represents data structures that can be reduced to a summary value one element at a time. Strict left-associative folds are a good fit for space-efficient reduction, while lazy right-associative folds are a good fit for corecursive iteration, or for folds that short-circuit after processing an initial subsequence of the structure's elements.
Instances can be derived automatically by enabling the DeriveFoldable
extension. For example, a derived instance for a binary tree might be:
{-# LANGUAGE DeriveFoldable #-}
data Tree a = Empty
| Leaf a
| Node (Tree a) a (Tree a)
deriving FoldableA more detailed description can be found in the Overview section of Data.Foldable.
For the class laws see the Laws section of Data.Foldable.
Methods
fold :: Monoid m => t m -> m #
Given a structure with elements whose type is a Monoid, combine them
via the monoid's ( operator. This fold is right-associative and
lazy in the accumulator. When you need a strict left-associative fold,
use <>)foldMap' instead, with id as the map.
Examples
Basic usage:
>>>fold [[1, 2, 3], [4, 5], [6], []][1,2,3,4,5,6]
>>>fold $ Node (Leaf (Sum 1)) (Sum 3) (Leaf (Sum 5))Sum {getSum = 9}
Folds of unbounded structures do not terminate when the monoid's
( operator is strict:<>)
>>>fold (repeat Nothing)* Hangs forever *
Lazy corecursive folds of unbounded structures are fine:
>>>take 12 $ fold $ map (\i -> [i..i+2]) [0..][0,1,2,1,2,3,2,3,4,3,4,5]>>>sum $ take 4000000 $ fold $ map (\i -> [i..i+2]) [0..]2666668666666
foldMap :: Monoid m => (a -> m) -> t a -> m #
Map each element of the structure into a monoid, and combine the
results with (. This fold is right-associative and lazy in the
accumulator. For strict left-associative folds consider <>)foldMap'
instead.
Examples
Basic usage:
>>>foldMap Sum [1, 3, 5]Sum {getSum = 9}
>>>foldMap Product [1, 3, 5]Product {getProduct = 15}
>>>foldMap (replicate 3) [1, 2, 3][1,1,1,2,2,2,3,3,3]
When a Monoid's ( is lazy in its second argument, <>)foldMap can
return a result even from an unbounded structure. For example, lazy
accumulation enables Data.ByteString.Builder to efficiently serialise
large data structures and produce the output incrementally:
>>>import qualified Data.ByteString.Lazy as L>>>import qualified Data.ByteString.Builder as B>>>let bld :: Int -> B.Builder; bld i = B.intDec i <> B.word8 0x20>>>let lbs = B.toLazyByteString $ foldMap bld [0..]>>>L.take 64 lbs"0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24"
foldMap' :: Monoid m => (a -> m) -> t a -> m #
A left-associative variant of foldMap that is strict in the
accumulator. Use this method for strict reduction when partial
results are merged via (.<>)
Examples
Define a Monoid over finite bit strings under xor. Use it to
strictly compute the xor of a list of Int values.
>>>:set -XGeneralizedNewtypeDeriving>>>import Data.Bits (Bits, FiniteBits, xor, zeroBits)>>>import Data.Foldable (foldMap')>>>import Numeric (showHex)>>>>>>newtype X a = X a deriving (Eq, Bounded, Enum, Bits, FiniteBits)>>>instance Bits a => Semigroup (X a) where X a <> X b = X (a `xor` b)>>>instance Bits a => Monoid (X a) where mempty = X zeroBits>>>>>>let bits :: [Int]; bits = [0xcafe, 0xfeed, 0xdeaf, 0xbeef, 0x5411]>>>(\ (X a) -> showString "0x" . showHex a $ "") $ foldMap' X bits"0x42"
Since: base-4.13.0.0
foldr' :: (a -> b -> b) -> b -> t a -> b #
foldr' is a variant of foldr that performs strict reduction from
right to left, i.e. starting with the right-most element. The input
structure must be finite, otherwise foldr' runs out of space
(diverges).
If you want a strict right fold in constant space, you need a structure
that supports faster than O(n) access to the right-most element, such
as Seq from the containers package.
This method does not run in constant space for structures such as lists
that don't support efficient right-to-left iteration and so require
O(n) space to perform right-to-left reduction. Use of this method
with such a structure is a hint that the chosen structure may be a poor
fit for the task at hand. If the order in which the elements are
combined is not important, use foldl' instead.
Since: base-4.6.0.0
Instances
| Foldable Complex | Since: base-4.9.0.0 |
Defined in Data.Complex Methods fold :: Monoid m => Complex m -> m # foldMap :: Monoid m => (a -> m) -> Complex a -> m # foldMap' :: Monoid m => (a -> m) -> Complex a -> m # foldr :: (a -> b -> b) -> b -> Complex a -> b # foldr' :: (a -> b -> b) -> b -> Complex a -> b # foldl :: (b -> a -> b) -> b -> Complex a -> b # foldl' :: (b -> a -> b) -> b -> Complex a -> b # foldr1 :: (a -> a -> a) -> Complex a -> a # foldl1 :: (a -> a -> a) -> Complex a -> a # elem :: Eq a => a -> Complex a -> Bool # maximum :: Ord a => Complex a -> a # minimum :: Ord a => Complex a -> a # | |
| Foldable First | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods fold :: Monoid m => First m -> m # foldMap :: Monoid m => (a -> m) -> First a -> m # foldMap' :: Monoid m => (a -> m) -> First a -> m # foldr :: (a -> b -> b) -> b -> First a -> b # foldr' :: (a -> b -> b) -> b -> First a -> b # foldl :: (b -> a -> b) -> b -> First a -> b # foldl' :: (b -> a -> b) -> b -> First a -> b # foldr1 :: (a -> a -> a) -> First a -> a # foldl1 :: (a -> a -> a) -> First a -> a # elem :: Eq a => a -> First a -> Bool # maximum :: Ord a => First a -> a # minimum :: Ord a => First a -> a # | |
| Foldable Last | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods fold :: Monoid m => Last m -> m # foldMap :: Monoid m => (a -> m) -> Last a -> m # foldMap' :: Monoid m => (a -> m) -> Last a -> m # foldr :: (a -> b -> b) -> b -> Last a -> b # foldr' :: (a -> b -> b) -> b -> Last a -> b # foldl :: (b -> a -> b) -> b -> Last a -> b # foldl' :: (b -> a -> b) -> b -> Last a -> b # foldr1 :: (a -> a -> a) -> Last a -> a # foldl1 :: (a -> a -> a) -> Last a -> a # elem :: Eq a => a -> Last a -> Bool # maximum :: Ord a => Last a -> a # | |
| Foldable Max | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods fold :: Monoid m => Max m -> m # foldMap :: Monoid m => (a -> m) -> Max a -> m # foldMap' :: Monoid m => (a -> m) -> Max a -> m # foldr :: (a -> b -> b) -> b -> Max a -> b # foldr' :: (a -> b -> b) -> b -> Max a -> b # foldl :: (b -> a -> b) -> b -> Max a -> b # foldl' :: (b -> a -> b) -> b -> Max a -> b # foldr1 :: (a -> a -> a) -> Max a -> a # foldl1 :: (a -> a -> a) -> Max a -> a # elem :: Eq a => a -> Max a -> Bool # maximum :: Ord a => Max a -> a # | |
| Foldable Min | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods fold :: Monoid m => Min m -> m # foldMap :: Monoid m => (a -> m) -> Min a -> m # foldMap' :: Monoid m => (a -> m) -> Min a -> m # foldr :: (a -> b -> b) -> b -> Min a -> b # foldr' :: (a -> b -> b) -> b -> Min a -> b # foldl :: (b -> a -> b) -> b -> Min a -> b # foldl' :: (b -> a -> b) -> b -> Min a -> b # foldr1 :: (a -> a -> a) -> Min a -> a # foldl1 :: (a -> a -> a) -> Min a -> a # elem :: Eq a => a -> Min a -> Bool # maximum :: Ord a => Min a -> a # | |
| Foldable NonEmpty | Since: base-4.9.0.0 |
Defined in GHC.Internal.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 # elem :: Eq a => a -> NonEmpty a -> Bool # maximum :: Ord a => NonEmpty a -> a # minimum :: Ord a => NonEmpty a -> a # | |
| Foldable Identity | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Functor.Identity Methods fold :: Monoid m => Identity m -> m # foldMap :: Monoid m => (a -> m) -> Identity a -> m # foldMap' :: Monoid m => (a -> m) -> Identity a -> m # foldr :: (a -> b -> b) -> b -> Identity a -> b # foldr' :: (a -> b -> b) -> b -> Identity a -> b # foldl :: (b -> a -> b) -> b -> Identity a -> b # foldl' :: (b -> a -> b) -> b -> Identity a -> b # foldr1 :: (a -> a -> a) -> Identity a -> a # foldl1 :: (a -> a -> a) -> Identity a -> a # elem :: Eq a => a -> Identity a -> Bool # maximum :: Ord a => Identity a -> a # minimum :: Ord a => Identity a -> a # | |
| Foldable First | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => First m -> m # foldMap :: Monoid m => (a -> m) -> First a -> m # foldMap' :: Monoid m => (a -> m) -> First a -> m # foldr :: (a -> b -> b) -> b -> First a -> b # foldr' :: (a -> b -> b) -> b -> First a -> b # foldl :: (b -> a -> b) -> b -> First a -> b # foldl' :: (b -> a -> b) -> b -> First a -> b # foldr1 :: (a -> a -> a) -> First a -> a # foldl1 :: (a -> a -> a) -> First a -> a # elem :: Eq a => a -> First a -> Bool # maximum :: Ord a => First a -> a # minimum :: Ord a => First a -> a # | |
| Foldable Last | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Last m -> m # foldMap :: Monoid m => (a -> m) -> Last a -> m # foldMap' :: Monoid m => (a -> m) -> Last a -> m # foldr :: (a -> b -> b) -> b -> Last a -> b # foldr' :: (a -> b -> b) -> b -> Last a -> b # foldl :: (b -> a -> b) -> b -> Last a -> b # foldl' :: (b -> a -> b) -> b -> Last a -> b # foldr1 :: (a -> a -> a) -> Last a -> a # foldl1 :: (a -> a -> a) -> Last a -> a # elem :: Eq a => a -> Last a -> Bool # maximum :: Ord a => Last a -> a # | |
| Foldable Down | Since: base-4.12.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Down m -> m # foldMap :: Monoid m => (a -> m) -> Down a -> m # foldMap' :: Monoid m => (a -> m) -> Down a -> m # foldr :: (a -> b -> b) -> b -> Down a -> b # foldr' :: (a -> b -> b) -> b -> Down a -> b # foldl :: (b -> a -> b) -> b -> Down a -> b # foldl' :: (b -> a -> b) -> b -> Down a -> b # foldr1 :: (a -> a -> a) -> Down a -> a # foldl1 :: (a -> a -> a) -> Down a -> a # elem :: Eq a => a -> Down a -> Bool # maximum :: Ord a => Down a -> a # | |
| Foldable Dual | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Dual m -> m # foldMap :: Monoid m => (a -> m) -> Dual a -> m # foldMap' :: Monoid m => (a -> m) -> Dual a -> m # foldr :: (a -> b -> b) -> b -> Dual a -> b # foldr' :: (a -> b -> b) -> b -> Dual a -> b # foldl :: (b -> a -> b) -> b -> Dual a -> b # foldl' :: (b -> a -> b) -> b -> Dual a -> b # foldr1 :: (a -> a -> a) -> Dual a -> a # foldl1 :: (a -> a -> a) -> Dual a -> a # elem :: Eq a => a -> Dual a -> Bool # maximum :: Ord a => Dual a -> a # | |
| Foldable Product | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Product m -> m # foldMap :: Monoid m => (a -> m) -> Product a -> m # foldMap' :: Monoid m => (a -> m) -> Product a -> m # foldr :: (a -> b -> b) -> b -> Product a -> b # foldr' :: (a -> b -> b) -> b -> Product a -> b # foldl :: (b -> a -> b) -> b -> Product a -> b # foldl' :: (b -> a -> b) -> b -> Product a -> b # foldr1 :: (a -> a -> a) -> Product a -> a # foldl1 :: (a -> a -> a) -> Product a -> a # elem :: Eq a => a -> Product a -> Bool # maximum :: Ord a => Product a -> a # minimum :: Ord a => Product a -> a # | |
| Foldable Sum | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Sum m -> m # foldMap :: Monoid m => (a -> m) -> Sum a -> m # foldMap' :: Monoid m => (a -> m) -> Sum a -> m # foldr :: (a -> b -> b) -> b -> Sum a -> b # foldr' :: (a -> b -> b) -> b -> Sum a -> b # foldl :: (b -> a -> b) -> b -> Sum a -> b # foldl' :: (b -> a -> b) -> b -> Sum a -> b # foldr1 :: (a -> a -> a) -> Sum a -> a # foldl1 :: (a -> a -> a) -> Sum a -> a # elem :: Eq a => a -> Sum a -> Bool # maximum :: Ord a => Sum a -> a # | |
| Foldable ZipList | Since: base-4.9.0.0 |
Defined in GHC.Internal.Functor.ZipList Methods fold :: Monoid m => ZipList m -> m # foldMap :: Monoid m => (a -> m) -> ZipList a -> m # foldMap' :: Monoid m => (a -> m) -> ZipList a -> m # foldr :: (a -> b -> b) -> b -> ZipList a -> b # foldr' :: (a -> b -> b) -> b -> ZipList a -> b # foldl :: (b -> a -> b) -> b -> ZipList a -> b # foldl' :: (b -> a -> b) -> b -> ZipList a -> b # foldr1 :: (a -> a -> a) -> ZipList a -> a # foldl1 :: (a -> a -> a) -> ZipList a -> a # elem :: Eq a => a -> ZipList a -> Bool # maximum :: Ord a => ZipList a -> a # minimum :: Ord a => ZipList a -> a # | |
| Foldable Par1 | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Par1 m -> m # foldMap :: Monoid m => (a -> m) -> Par1 a -> m # foldMap' :: Monoid m => (a -> m) -> Par1 a -> m # foldr :: (a -> b -> b) -> b -> Par1 a -> b # foldr' :: (a -> b -> b) -> b -> Par1 a -> b # foldl :: (b -> a -> b) -> b -> Par1 a -> b # foldl' :: (b -> a -> b) -> b -> Par1 a -> b # foldr1 :: (a -> a -> a) -> Par1 a -> a # foldl1 :: (a -> a -> a) -> Par1 a -> a # elem :: Eq a => a -> Par1 a -> Bool # maximum :: Ord a => Par1 a -> a # | |
| Foldable Maybe | Since: base-2.1 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Maybe m -> m # foldMap :: Monoid m => (a -> m) -> Maybe a -> m # foldMap' :: Monoid m => (a -> m) -> Maybe a -> m # foldr :: (a -> b -> b) -> b -> Maybe a -> b # foldr' :: (a -> b -> b) -> b -> Maybe a -> b # foldl :: (b -> a -> b) -> b -> Maybe a -> b # foldl' :: (b -> a -> b) -> b -> Maybe a -> b # foldr1 :: (a -> a -> a) -> Maybe a -> a # foldl1 :: (a -> a -> a) -> Maybe a -> a # elem :: Eq a => a -> Maybe a -> Bool # maximum :: Ord a => Maybe a -> a # minimum :: Ord a => Maybe a -> a # | |
| Foldable Solo | Since: base-4.15 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Solo m -> m # foldMap :: Monoid m => (a -> m) -> Solo a -> m # foldMap' :: Monoid m => (a -> m) -> Solo a -> m # foldr :: (a -> b -> b) -> b -> Solo a -> b # foldr' :: (a -> b -> b) -> b -> Solo a -> b # foldl :: (b -> a -> b) -> b -> Solo a -> b # foldl' :: (b -> a -> b) -> b -> Solo a -> b # foldr1 :: (a -> a -> a) -> Solo a -> a # foldl1 :: (a -> a -> a) -> Solo a -> a # elem :: Eq a => a -> Solo a -> Bool # maximum :: Ord a => Solo a -> a # | |
| Foldable [] | Since: base-2.1 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => [m] -> m # foldMap :: Monoid m => (a -> m) -> [a] -> m # foldMap' :: Monoid m => (a -> m) -> [a] -> m # foldr :: (a -> b -> b) -> b -> [a] -> b # foldr' :: (a -> b -> b) -> b -> [a] -> b # foldl :: (b -> a -> b) -> b -> [a] -> b # foldl' :: (b -> a -> b) -> b -> [a] -> b # foldr1 :: (a -> a -> a) -> [a] -> a # foldl1 :: (a -> a -> a) -> [a] -> a # elem :: Eq a => a -> [a] -> Bool # maximum :: Ord a => [a] -> a # | |
| Foldable (Arg a) | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods fold :: Monoid m => Arg a m -> m # foldMap :: Monoid m => (a0 -> m) -> Arg a a0 -> m # foldMap' :: Monoid m => (a0 -> m) -> Arg a a0 -> m # foldr :: (a0 -> b -> b) -> b -> Arg a a0 -> b # foldr' :: (a0 -> b -> b) -> b -> Arg a a0 -> b # foldl :: (b -> a0 -> b) -> b -> Arg a a0 -> b # foldl' :: (b -> a0 -> b) -> b -> Arg a a0 -> b # foldr1 :: (a0 -> a0 -> a0) -> Arg a a0 -> a0 # foldl1 :: (a0 -> a0 -> a0) -> Arg a a0 -> a0 # elem :: Eq a0 => a0 -> Arg a a0 -> Bool # maximum :: Ord a0 => Arg a a0 -> a0 # minimum :: Ord a0 => Arg a a0 -> a0 # | |
| Foldable (Array i) | Since: base-4.8.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Array i m -> m # foldMap :: Monoid m => (a -> m) -> Array i a -> m # foldMap' :: Monoid m => (a -> m) -> Array i a -> m # foldr :: (a -> b -> b) -> b -> Array i a -> b # foldr' :: (a -> b -> b) -> b -> Array i a -> b # foldl :: (b -> a -> b) -> b -> Array i a -> b # foldl' :: (b -> a -> b) -> b -> Array i a -> b # foldr1 :: (a -> a -> a) -> Array i a -> a # foldl1 :: (a -> a -> a) -> Array i a -> a # elem :: Eq a => a -> Array i a -> Bool # maximum :: Ord a => Array i a -> a # minimum :: Ord a => Array i a -> a # | |
| Foldable (Either a) | Since: base-4.7.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Either a m -> m # foldMap :: Monoid m => (a0 -> m) -> Either a a0 -> m # foldMap' :: Monoid m => (a0 -> m) -> Either a a0 -> m # foldr :: (a0 -> b -> b) -> b -> Either a a0 -> b # foldr' :: (a0 -> b -> b) -> b -> Either a a0 -> b # foldl :: (b -> a0 -> b) -> b -> Either a a0 -> b # foldl' :: (b -> a0 -> b) -> b -> Either a a0 -> b # foldr1 :: (a0 -> a0 -> a0) -> Either a a0 -> a0 # foldl1 :: (a0 -> a0 -> a0) -> Either a a0 -> a0 # toList :: Either a a0 -> [a0] # length :: Either a a0 -> Int # elem :: Eq a0 => a0 -> Either a a0 -> Bool # maximum :: Ord a0 => Either a a0 -> a0 # minimum :: Ord a0 => Either a a0 -> a0 # | |
| Foldable (Proxy :: Type -> Type) | Since: base-4.7.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Proxy m -> m # foldMap :: Monoid m => (a -> m) -> Proxy a -> m # foldMap' :: Monoid m => (a -> m) -> Proxy a -> m # foldr :: (a -> b -> b) -> b -> Proxy a -> b # foldr' :: (a -> b -> b) -> b -> Proxy a -> b # foldl :: (b -> a -> b) -> b -> Proxy a -> b # foldl' :: (b -> a -> b) -> b -> Proxy a -> b # foldr1 :: (a -> a -> a) -> Proxy a -> a # foldl1 :: (a -> a -> a) -> Proxy a -> a # elem :: Eq a => a -> Proxy a -> Bool # maximum :: Ord a => Proxy a -> a # minimum :: Ord a => Proxy a -> a # | |
| Foldable (U1 :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => U1 m -> m # foldMap :: Monoid m => (a -> m) -> U1 a -> m # foldMap' :: Monoid m => (a -> m) -> U1 a -> m # foldr :: (a -> b -> b) -> b -> U1 a -> b # foldr' :: (a -> b -> b) -> b -> U1 a -> b # foldl :: (b -> a -> b) -> b -> U1 a -> b # foldl' :: (b -> a -> b) -> b -> U1 a -> b # foldr1 :: (a -> a -> a) -> U1 a -> a # foldl1 :: (a -> a -> a) -> U1 a -> a # elem :: Eq a => a -> U1 a -> Bool # maximum :: Ord a => U1 a -> a # | |
| Foldable (UAddr :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UAddr m -> m # foldMap :: Monoid m => (a -> m) -> UAddr a -> m # foldMap' :: Monoid m => (a -> m) -> UAddr a -> m # foldr :: (a -> b -> b) -> b -> UAddr a -> b # foldr' :: (a -> b -> b) -> b -> UAddr a -> b # foldl :: (b -> a -> b) -> b -> UAddr a -> b # foldl' :: (b -> a -> b) -> b -> UAddr a -> b # foldr1 :: (a -> a -> a) -> UAddr a -> a # foldl1 :: (a -> a -> a) -> UAddr a -> a # elem :: Eq a => a -> UAddr a -> Bool # maximum :: Ord a => UAddr a -> a # minimum :: Ord a => UAddr a -> a # | |
| Foldable (UChar :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UChar m -> m # foldMap :: Monoid m => (a -> m) -> UChar a -> m # foldMap' :: Monoid m => (a -> m) -> UChar a -> m # foldr :: (a -> b -> b) -> b -> UChar a -> b # foldr' :: (a -> b -> b) -> b -> UChar a -> b # foldl :: (b -> a -> b) -> b -> UChar a -> b # foldl' :: (b -> a -> b) -> b -> UChar a -> b # foldr1 :: (a -> a -> a) -> UChar a -> a # foldl1 :: (a -> a -> a) -> UChar a -> a # elem :: Eq a => a -> UChar a -> Bool # maximum :: Ord a => UChar a -> a # minimum :: Ord a => UChar a -> a # | |
| Foldable (UDouble :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UDouble m -> m # foldMap :: Monoid m => (a -> m) -> UDouble a -> m # foldMap' :: Monoid m => (a -> m) -> UDouble a -> m # foldr :: (a -> b -> b) -> b -> UDouble a -> b # foldr' :: (a -> b -> b) -> b -> UDouble a -> b # foldl :: (b -> a -> b) -> b -> UDouble a -> b # foldl' :: (b -> a -> b) -> b -> UDouble a -> b # foldr1 :: (a -> a -> a) -> UDouble a -> a # foldl1 :: (a -> a -> a) -> UDouble a -> a # elem :: Eq a => a -> UDouble a -> Bool # maximum :: Ord a => UDouble a -> a # minimum :: Ord a => UDouble a -> a # | |
| Foldable (UFloat :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UFloat m -> m # foldMap :: Monoid m => (a -> m) -> UFloat a -> m # foldMap' :: Monoid m => (a -> m) -> UFloat a -> m # foldr :: (a -> b -> b) -> b -> UFloat a -> b # foldr' :: (a -> b -> b) -> b -> UFloat a -> b # foldl :: (b -> a -> b) -> b -> UFloat a -> b # foldl' :: (b -> a -> b) -> b -> UFloat a -> b # foldr1 :: (a -> a -> a) -> UFloat a -> a # foldl1 :: (a -> a -> a) -> UFloat a -> a # elem :: Eq a => a -> UFloat a -> Bool # maximum :: Ord a => UFloat a -> a # minimum :: Ord a => UFloat a -> a # | |
| Foldable (UInt :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UInt m -> m # foldMap :: Monoid m => (a -> m) -> UInt a -> m # foldMap' :: Monoid m => (a -> m) -> UInt a -> m # foldr :: (a -> b -> b) -> b -> UInt a -> b # foldr' :: (a -> b -> b) -> b -> UInt a -> b # foldl :: (b -> a -> b) -> b -> UInt a -> b # foldl' :: (b -> a -> b) -> b -> UInt a -> b # foldr1 :: (a -> a -> a) -> UInt a -> a # foldl1 :: (a -> a -> a) -> UInt a -> a # elem :: Eq a => a -> UInt a -> Bool # maximum :: Ord a => UInt a -> a # | |
| Foldable (UWord :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UWord m -> m # foldMap :: Monoid m => (a -> m) -> UWord a -> m # foldMap' :: Monoid m => (a -> m) -> UWord a -> m # foldr :: (a -> b -> b) -> b -> UWord a -> b # foldr' :: (a -> b -> b) -> b -> UWord a -> b # foldl :: (b -> a -> b) -> b -> UWord a -> b # foldl' :: (b -> a -> b) -> b -> UWord a -> b # foldr1 :: (a -> a -> a) -> UWord a -> a # foldl1 :: (a -> a -> a) -> UWord a -> a # elem :: Eq a => a -> UWord a -> Bool # maximum :: Ord a => UWord a -> a # minimum :: Ord a => UWord a -> a # | |
| Foldable (V1 :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => V1 m -> m # foldMap :: Monoid m => (a -> m) -> V1 a -> m # foldMap' :: Monoid m => (a -> m) -> V1 a -> m # foldr :: (a -> b -> b) -> b -> V1 a -> b # foldr' :: (a -> b -> b) -> b -> V1 a -> b # foldl :: (b -> a -> b) -> b -> V1 a -> b # foldl' :: (b -> a -> b) -> b -> V1 a -> b # foldr1 :: (a -> a -> a) -> V1 a -> a # foldl1 :: (a -> a -> a) -> V1 a -> a # elem :: Eq a => a -> V1 a -> Bool # maximum :: Ord a => V1 a -> a # | |
| Foldable ((,) a) | Since: base-4.7.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => (a, m) -> m # foldMap :: Monoid m => (a0 -> m) -> (a, a0) -> m # foldMap' :: Monoid m => (a0 -> m) -> (a, a0) -> m # foldr :: (a0 -> b -> b) -> b -> (a, a0) -> b # foldr' :: (a0 -> b -> b) -> b -> (a, a0) -> b # foldl :: (b -> a0 -> b) -> b -> (a, a0) -> b # foldl' :: (b -> a0 -> b) -> b -> (a, a0) -> b # foldr1 :: (a0 -> a0 -> a0) -> (a, a0) -> a0 # foldl1 :: (a0 -> a0 -> a0) -> (a, a0) -> a0 # elem :: Eq a0 => a0 -> (a, a0) -> Bool # maximum :: Ord a0 => (a, a0) -> a0 # minimum :: Ord a0 => (a, a0) -> a0 # | |
| Foldable (Const m :: Type -> Type) | Since: base-4.7.0.0 |
Defined in GHC.Internal.Data.Functor.Const Methods fold :: Monoid m0 => Const m m0 -> m0 # foldMap :: Monoid m0 => (a -> m0) -> Const m a -> m0 # foldMap' :: Monoid m0 => (a -> m0) -> Const m a -> m0 # foldr :: (a -> b -> b) -> b -> Const m a -> b # foldr' :: (a -> b -> b) -> b -> Const m a -> b # foldl :: (b -> a -> b) -> b -> Const m a -> b # foldl' :: (b -> a -> b) -> b -> Const m a -> b # foldr1 :: (a -> a -> a) -> Const m a -> a # foldl1 :: (a -> a -> a) -> Const m a -> a # elem :: Eq a => a -> Const m a -> Bool # maximum :: Ord a => Const m a -> a # minimum :: Ord a => Const m a -> a # | |
| Foldable f => Foldable (Ap f) | Since: base-4.12.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Ap f m -> m # foldMap :: Monoid m => (a -> m) -> Ap f a -> m # foldMap' :: Monoid m => (a -> m) -> Ap f a -> m # foldr :: (a -> b -> b) -> b -> Ap f a -> b # foldr' :: (a -> b -> b) -> b -> Ap f a -> b # foldl :: (b -> a -> b) -> b -> Ap f a -> b # foldl' :: (b -> a -> b) -> b -> Ap f a -> b # foldr1 :: (a -> a -> a) -> Ap f a -> a # foldl1 :: (a -> a -> a) -> Ap f a -> a # elem :: Eq a => a -> Ap f a -> Bool # maximum :: Ord a => Ap f a -> a # | |
| Foldable f => Foldable (Alt f) | Since: base-4.12.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Alt f m -> m # foldMap :: Monoid m => (a -> m) -> Alt f a -> m # foldMap' :: Monoid m => (a -> m) -> Alt f a -> m # foldr :: (a -> b -> b) -> b -> Alt f a -> b # foldr' :: (a -> b -> b) -> b -> Alt f a -> b # foldl :: (b -> a -> b) -> b -> Alt f a -> b # foldl' :: (b -> a -> b) -> b -> Alt f a -> b # foldr1 :: (a -> a -> a) -> Alt f a -> a # foldl1 :: (a -> a -> a) -> Alt f a -> a # elem :: Eq a => a -> Alt f a -> Bool # maximum :: Ord a => Alt f a -> a # minimum :: Ord a => Alt f a -> a # | |
| Foldable f => Foldable (Rec1 f) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Rec1 f m -> m # foldMap :: Monoid m => (a -> m) -> Rec1 f a -> m # foldMap' :: Monoid m => (a -> m) -> Rec1 f a -> m # foldr :: (a -> b -> b) -> b -> Rec1 f a -> b # foldr' :: (a -> b -> b) -> b -> Rec1 f a -> b # foldl :: (b -> a -> b) -> b -> Rec1 f a -> b # foldl' :: (b -> a -> b) -> b -> Rec1 f a -> b # foldr1 :: (a -> a -> a) -> Rec1 f a -> a # foldl1 :: (a -> a -> a) -> Rec1 f a -> a # elem :: Eq a => a -> Rec1 f a -> Bool # maximum :: Ord a => Rec1 f a -> a # minimum :: Ord a => Rec1 f a -> a # | |
| (Foldable f, Foldable g) => Foldable (Product f g) | Since: base-4.9.0.0 |
Defined in Data.Functor.Product Methods fold :: Monoid m => Product f g m -> m # foldMap :: Monoid m => (a -> m) -> Product f g a -> m # foldMap' :: Monoid m => (a -> m) -> Product f g a -> m # foldr :: (a -> b -> b) -> b -> Product f g a -> b # foldr' :: (a -> b -> b) -> b -> Product f g a -> b # foldl :: (b -> a -> b) -> b -> Product f g a -> b # foldl' :: (b -> a -> b) -> b -> Product f g a -> b # foldr1 :: (a -> a -> a) -> Product f g a -> a # foldl1 :: (a -> a -> a) -> Product f g a -> a # toList :: Product f g a -> [a] # null :: Product f g a -> Bool # length :: Product f g a -> Int # elem :: Eq a => a -> Product f g a -> Bool # maximum :: Ord a => Product f g a -> a # minimum :: Ord a => Product f g a -> a # | |
| (Foldable f, Foldable g) => Foldable (Sum f g) | Since: base-4.9.0.0 |
Defined in Data.Functor.Sum Methods fold :: Monoid m => Sum f g m -> m # foldMap :: Monoid m => (a -> m) -> Sum f g a -> m # foldMap' :: Monoid m => (a -> m) -> Sum f g a -> m # foldr :: (a -> b -> b) -> b -> Sum f g a -> b # foldr' :: (a -> b -> b) -> b -> Sum f g a -> b # foldl :: (b -> a -> b) -> b -> Sum f g a -> b # foldl' :: (b -> a -> b) -> b -> Sum f g a -> b # foldr1 :: (a -> a -> a) -> Sum f g a -> a # foldl1 :: (a -> a -> a) -> Sum f g a -> a # elem :: Eq a => a -> Sum f g a -> Bool # maximum :: Ord a => Sum f g a -> a # minimum :: Ord a => Sum f g a -> a # | |
| (Foldable f, Foldable g) => Foldable (f :*: g) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => (f :*: g) m -> m # foldMap :: Monoid m => (a -> m) -> (f :*: g) a -> m # foldMap' :: Monoid m => (a -> m) -> (f :*: g) a -> m # foldr :: (a -> b -> b) -> b -> (f :*: g) a -> b # foldr' :: (a -> b -> b) -> b -> (f :*: g) a -> b # foldl :: (b -> a -> b) -> b -> (f :*: g) a -> b # foldl' :: (b -> a -> b) -> b -> (f :*: g) a -> b # foldr1 :: (a -> a -> a) -> (f :*: g) a -> a # foldl1 :: (a -> a -> a) -> (f :*: g) a -> a # toList :: (f :*: g) a -> [a] # length :: (f :*: g) a -> Int # elem :: Eq a => a -> (f :*: g) a -> Bool # maximum :: Ord a => (f :*: g) a -> a # minimum :: Ord a => (f :*: g) a -> a # | |
| (Foldable f, Foldable g) => Foldable (f :+: g) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => (f :+: g) m -> m # foldMap :: Monoid m => (a -> m) -> (f :+: g) a -> m # foldMap' :: Monoid m => (a -> m) -> (f :+: g) a -> m # foldr :: (a -> b -> b) -> b -> (f :+: g) a -> b # foldr' :: (a -> b -> b) -> b -> (f :+: g) a -> b # foldl :: (b -> a -> b) -> b -> (f :+: g) a -> b # foldl' :: (b -> a -> b) -> b -> (f :+: g) a -> b # foldr1 :: (a -> a -> a) -> (f :+: g) a -> a # foldl1 :: (a -> a -> a) -> (f :+: g) a -> a # toList :: (f :+: g) a -> [a] # length :: (f :+: g) a -> Int # elem :: Eq a => a -> (f :+: g) a -> Bool # maximum :: Ord a => (f :+: g) a -> a # minimum :: Ord a => (f :+: g) a -> a # | |
| Foldable (K1 i c :: Type -> Type) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => K1 i c m -> m # foldMap :: Monoid m => (a -> m) -> K1 i c a -> m # foldMap' :: Monoid m => (a -> m) -> K1 i c a -> m # foldr :: (a -> b -> b) -> b -> K1 i c a -> b # foldr' :: (a -> b -> b) -> b -> K1 i c a -> b # foldl :: (b -> a -> b) -> b -> K1 i c a -> b # foldl' :: (b -> a -> b) -> b -> K1 i c a -> b # foldr1 :: (a -> a -> a) -> K1 i c a -> a # foldl1 :: (a -> a -> a) -> K1 i c a -> a # elem :: Eq a => a -> K1 i c a -> Bool # maximum :: Ord a => K1 i c a -> a # minimum :: Ord a => K1 i c a -> a # | |
| (Foldable f, Foldable g) => Foldable (Compose f g) | Since: base-4.9.0.0 |
Defined in Data.Functor.Compose Methods fold :: Monoid m => Compose f g m -> m # foldMap :: Monoid m => (a -> m) -> Compose f g a -> m # foldMap' :: Monoid m => (a -> m) -> Compose f g a -> m # foldr :: (a -> b -> b) -> b -> Compose f g a -> b # foldr' :: (a -> b -> b) -> b -> Compose f g a -> b # foldl :: (b -> a -> b) -> b -> Compose f g a -> b # foldl' :: (b -> a -> b) -> b -> Compose f g a -> b # foldr1 :: (a -> a -> a) -> Compose f g a -> a # foldl1 :: (a -> a -> a) -> Compose f g a -> a # toList :: Compose f g a -> [a] # null :: Compose f g a -> Bool # length :: Compose f g a -> Int # elem :: Eq a => a -> Compose f g a -> Bool # maximum :: Ord a => Compose f g a -> a # minimum :: Ord a => Compose f g a -> a # | |
| (Foldable f, Foldable g) => Foldable (f :.: g) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => (f :.: g) m -> m # foldMap :: Monoid m => (a -> m) -> (f :.: g) a -> m # foldMap' :: Monoid m => (a -> m) -> (f :.: g) a -> m # foldr :: (a -> b -> b) -> b -> (f :.: g) a -> b # foldr' :: (a -> b -> b) -> b -> (f :.: g) a -> b # foldl :: (b -> a -> b) -> b -> (f :.: g) a -> b # foldl' :: (b -> a -> b) -> b -> (f :.: g) a -> b # foldr1 :: (a -> a -> a) -> (f :.: g) a -> a # foldl1 :: (a -> a -> a) -> (f :.: g) a -> a # toList :: (f :.: g) a -> [a] # length :: (f :.: g) a -> Int # elem :: Eq a => a -> (f :.: g) a -> Bool # maximum :: Ord a => (f :.: g) a -> a # minimum :: Ord a => (f :.: g) a -> a # | |
| Foldable f => Foldable (M1 i c f) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => M1 i c f m -> m # foldMap :: Monoid m => (a -> m) -> M1 i c f a -> m # foldMap' :: Monoid m => (a -> m) -> M1 i c f a -> m # foldr :: (a -> b -> b) -> b -> M1 i c f a -> b # foldr' :: (a -> b -> b) -> b -> M1 i c f a -> b # foldl :: (b -> a -> b) -> b -> M1 i c f a -> b # foldl' :: (b -> a -> b) -> b -> M1 i c f a -> b # foldr1 :: (a -> a -> a) -> M1 i c f a -> a # foldl1 :: (a -> a -> a) -> M1 i c f a -> a # elem :: Eq a => a -> M1 i c f a -> Bool # maximum :: Ord a => M1 i c f a -> a # minimum :: Ord a => M1 i c f a -> a # | |
The value of is bottom if seq a ba is bottom, and
otherwise equal to b. In other words, it evaluates the first
argument a to weak head normal form (WHNF). seq is usually
introduced to improve performance by avoiding unneeded laziness.
A note on evaluation order: the expression does
not guarantee that seq a ba will be evaluated before b.
The only guarantee given by seq is that the both a
and b will be evaluated before seq returns a value.
In particular, this means that b may be evaluated before
a. If you need to guarantee a specific order of evaluation,
you must use the function pseq from the "parallel" package.
The lazy function restrains strictness analysis a little. The
call lazy e means the same as e, but lazy has a magical
property so far as strictness analysis is concerned: it is lazy in
its first argument, even though its semantics is strict. After
strictness analysis has run, calls to lazy are inlined to be the
identity function.
This behaviour is occasionally useful when controlling evaluation
order. Notably, lazy is used in the library definition of
par:
par :: a -> b -> b par x y = case (par# x) of _ -> lazy y
If lazy were not lazy, par would look strict in
y which would defeat the whole purpose of par.
The call inline f arranges that f is inlined, regardless of
its size. More precisely, the call inline f rewrites to the
right-hand side of f's definition. This allows the programmer to
control inlining from a particular call site rather than the
definition site of the function (c.f. INLINE pragmas).
This inlining occurs regardless of the argument to the call or the
size of f's definition; it is unconditional. The main caveat is
that f's definition must be visible to the compiler; it is
therefore recommended to mark the function with an INLINABLE
pragma at its definition so that GHC guarantees to record its
unfolding regardless of size.
If no inlining takes place, the inline function expands to the
identity function in Phase zero, so its use imposes no overhead.
($) :: (a -> b) -> a -> b infixr 0 #
is the function application operator.($)
Applying to a function ($)f and an argument x gives the same result as applying f to x directly. The definition is akin to this:
($) :: (a -> b) -> a -> b ($) f x = f x
This is specialized from ida -> a to (a -> b) -> (a -> b) which by the associativity of (->)
is the same as (a -> b) -> a -> b.
On the face of it, this may appear pointless! But it's actually one of the most useful and important operators in Haskell.
The order of operations is very different between ($) and normal function application. Normal function application has precedence 10 - higher than any operator - and associates to the left. So these two definitions are equivalent:
expr = min 5 1 + 5 expr = ((min 5) 1) + 5
($) has precedence 0 (the lowest) and associates to the right, so these are equivalent:
expr = min 5 $ 1 + 5 expr = (min 5) (1 + 5)
Examples
A common use cases of ($) is to avoid parentheses in complex expressions.
For example, instead of using nested parentheses in the following Haskell function:
-- | Sum numbers in a string: strSum "100 5 -7" == 98 strSum ::String->IntstrSum s =sum(mapMaybereadMaybe(wordss))
we can deploy the function application operator:
-- | Sum numbers in a string: strSum "100 5 -7" == 98 strSum ::String->IntstrSum s =sum$mapMaybereadMaybe$wordss
($) is also used as a section (a partially applied operator), in order to indicate that we wish to apply some yet-unspecified function to a given value. For example, to apply the argument 5 to a list of functions:
applyFive :: [Int] applyFive = map ($ 5) [(+1), (2^)] >>> [6, 32]
Technical Remark (Representation Polymorphism)
($) is fully representation-polymorphic. This allows it to also be used with arguments of unlifted and even unboxed kinds, such as unboxed integers:
fastMod :: Int -> Int -> Int fastMod (I# x) (I# m) = I# $ remInt# x m
Basic numeric class.
The Haskell Report defines no laws for Num. However, ( and +)( are
customarily expected to define a ring and have the following properties:*)
- Associativity of
(+) (x + y) + z=x + (y + z)- Commutativity of
(+) x + y=y + xis the additive identityfromInteger0x + fromInteger 0=xnegategives the additive inversex + negate x=fromInteger 0- Associativity of
(*) (x * y) * z=x * (y * z)is the multiplicative identityfromInteger1x * fromInteger 1=xandfromInteger 1 * x=x- Distributivity of
(with respect to*)(+) a * (b + c)=(a * b) + (a * c)and(b + c) * a=(b * a) + (c * a)- Coherence with
toInteger - if the type also implements
Integral, thenfromIntegeris a left inverse fortoInteger, i.e.fromInteger (toInteger i) == i
Note that it isn't customarily expected that a type instance of both Num
and Ord implement an ordered ring. Indeed, in base only Integer and
Rational do.
Methods
Unary negation.
Absolute value.
Sign of a number.
The functions abs and signum should satisfy the law:
abs x * signum x == x
For real numbers, the signum is either -1 (negative), 0 (zero)
or 1 (positive).
fromInteger :: Integer -> a #
Conversion from an Integer.
An integer literal represents the application of the function
fromInteger to the appropriate value of type Integer,
so such literals have type (.Num a) => a
Instances
| Num IntPtr | |
| Num WordPtr | |
| Num Int16 | Since: base-2.1 |
| Num Int32 | Since: base-2.1 |
| Num Int64 | Since: base-2.1 |
| Num Int8 | Since: base-2.1 |
| Num CBlkCnt | |
| Num CBlkSize | |
Defined in GHC.Internal.System.Posix.Types | |
| Num CCc | |
| Num CClockId | |
Defined in GHC.Internal.System.Posix.Types | |
| Num CDev | |
| Num CFsBlkCnt | |
Defined in GHC.Internal.System.Posix.Types | |
| Num CFsFilCnt | |
Defined in GHC.Internal.System.Posix.Types | |
| Num CGid | |
| Num CId | |
| Num CIno | |
| Num CKey | |
| Num CMode | |
| Num CNfds | |
| Num CNlink | |
| Num COff | |
| Num CPid | |
| Num CRLim | |
| Num CSocklen | |
Defined in GHC.Internal.System.Posix.Types | |
| Num CSpeed | |
| Num CSsize | |
| Num CTcflag | |
| Num CUid | |
| Num Fd | |
| Num Word16 | Since: base-2.1 |
| Num Word32 | Since: base-2.1 |
| Num Word64 | Since: base-2.1 |
| Num Word8 | Since: base-2.1 |
| Num Integer | Since: base-2.1 |
| Num Natural | Note that Since: base-4.8.0.0 |
| Num Double | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:
Since: base-2.1 |
| Num Float | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:
Since: base-2.1 |
| Num Int | Since: base-2.1 |
| Num Word | Since: base-2.1 |
| RealFloat a => Num (Complex a) | Since: base-2.1 |
| Num a => Num (Max a) | Since: base-4.9.0.0 |
| Num a => Num (Min a) | Since: base-4.9.0.0 |
| Num a => Num (Identity a) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Functor.Identity | |
| Num a => Num (Down a) | Since: base-4.11.0.0 |
| Num a => Num (Product a) | Since: base-4.7.0.0 |
Defined in GHC.Internal.Data.Semigroup.Internal | |
| Num a => Num (Sum a) | Since: base-4.7.0.0 |
| Integral a => Num (Ratio a) | Since: base-2.0.1 |
| HasResolution a => Num (Fixed a) | Multiplication is not associative or distributive:
Since: base-2.1 |
| Num a => Num (Op a b) | |
| Num a => Num (Const a b) | Since: base-4.9.0.0 |
Defined in GHC.Internal.Data.Functor.Const | |
| (Applicative f, Num a) => Num (Ap f a) | Note that even if the underlying Commutativity:
Additive inverse:
Distributivity:
Since: base-4.12.0.0 |
| Num (f a) => Num (Alt f a) | Since: base-4.8.0.0 |
| Num (f (g a)) => Num (Compose f g a) | Since: base-4.19.0.0 |
Defined in Data.Functor.Compose Methods (+) :: Compose f g a -> Compose f g a -> Compose f g a # (-) :: Compose f g a -> Compose f g a -> Compose f g a # (*) :: Compose f g a -> Compose f g a -> Compose f g a # negate :: Compose f g a -> Compose f g a # abs :: Compose f g a -> Compose f g a # signum :: Compose f g a -> Compose f g a # fromInteger :: Integer -> Compose f g a # | |
class Num a => Fractional a where #
Fractional numbers, supporting real division.
The Haskell Report defines no laws for Fractional. However, ( and
+)( are customarily expected to define a division ring and have the
following properties:*)
recipgives the multiplicative inversex * recip x=recip x * x=fromInteger 1- Totality of
toRational toRationalis total- Coherence with
toRational - if the type also implements
Real, thenfromRationalis a left inverse fortoRational, i.e.fromRational (toRational i) = i
Note that it isn't customarily expected that a type instance of
Fractional implement a field. However, all instances in base do.
Minimal complete definition
fromRational, (recip | (/))
Methods
Fractional division.
Reciprocal fraction.
fromRational :: Rational -> a #
Conversion from a Rational (that is ).
A floating literal stands for an application of Ratio IntegerfromRational
to a value of type Rational, so such literals have type
(.Fractional a) => a
Instances
| Fractional Double | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.
Since: base-2.1 |
| Fractional Float | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.
Since: base-2.1 |
| RealFloat a => Fractional (Complex a) | Since: base-2.1 |
| Fractional a => Fractional (Identity a) | Since: base-4.9.0.0 |
| Fractional a => Fractional (Down a) | Since: base-4.14.0.0 |
| Integral a => Fractional (Ratio a) | Since: base-2.0.1 |
| HasResolution a => Fractional (Fixed a) | Since: base-2.1 |
| Fractional a => Fractional (Op a b) | |
| Fractional a => Fractional (Const a b) | Since: base-4.9.0.0 |
| Fractional (f (g a)) => Fractional (Compose f g a) | Since: base-4.20.0.0 |
Class Enum defines operations on sequentially ordered types.
The enumFrom... methods are used in Haskell's translation of
arithmetic sequences.
Instances of Enum may be derived for any enumeration type (types
whose constructors have no fields). The nullary constructors are
assumed to be numbered left-to-right by fromEnum from 0 through n-1.
See Chapter 10 of the Haskell Report for more details.
For any type that is an instance of class Bounded as well as Enum,
the following should hold:
- The calls
andsuccmaxBoundshould result in a runtime error.predminBound fromEnumandtoEnumshould give a runtime error if the result value is not representable in the result type. For example,is an error.toEnum7 ::BoolenumFromandenumFromThenshould be defined with an implicit bound, thus:
enumFrom x = enumFromTo x maxBound
enumFromThen x y = enumFromThenTo x y bound
where
bound | fromEnum y >= fromEnum x = maxBound
| otherwise = minBoundMethods
Successor of a value. For numeric types, succ adds 1.
Predecessor of a value. For numeric types, pred subtracts 1.
Convert from an Int.
Convert to an Int.
It is implementation-dependent what fromEnum returns when
applied to a value that is too large to fit in an Int.
Used in Haskell's translation of [n..] with [n..] = enumFrom n,
a possible implementation being enumFrom n = n : enumFrom (succ n).
Examples
enumFrom 4 :: [Integer] = [4,5,6,7,...]
enumFrom 6 :: [Int] = [6,7,8,9,...,maxBound :: Int]
enumFromThen :: a -> a -> [a] #
Used in Haskell's translation of [n,n'..]
with [n,n'..] = enumFromThen n n', a possible implementation being
enumFromThen n n' = n : n' : worker (f x) (f x n'),
worker s v = v : worker s (s v), x = fromEnum n' - fromEnum n and
f n y
| n > 0 = f (n - 1) (succ y)
| n < 0 = f (n + 1) (pred y)
| otherwise = y
Examples
enumFromThen 4 6 :: [Integer] = [4,6,8,10...]
enumFromThen 6 2 :: [Int] = [6,2,-2,-6,...,minBound :: Int]
enumFromTo :: a -> a -> [a] #
Used in Haskell's translation of [n..m] with
[n..m] = enumFromTo n m, a possible implementation being
enumFromTo n m
| n <= m = n : enumFromTo (succ n) m
| otherwise = []
Examples
enumFromTo 6 10 :: [Int] = [6,7,8,9,10]
enumFromTo 42 1 :: [Integer] = []
enumFromThenTo :: a -> a -> a -> [a] #
Used in Haskell's translation of [n,n'..m] with
[n,n'..m] = enumFromThenTo n n' m, a possible implementation
being enumFromThenTo n n' m = worker (f x) (c x) n m,
x = fromEnum n' - fromEnum n, c x = bool (>=) ((x 0)
f n y
| n > 0 = f (n - 1) (succ y)
| n < 0 = f (n + 1) (pred y)
| otherwise = y
and
worker s c v m
| c v m = v : worker s c (s v) m
| otherwise = []
Examples
enumFromThenTo 4 2 -6 :: [Integer] = [4,2,0,-2,-4,-6]
enumFromThenTo 6 8 2 :: [Int] = []
Instances
The Eq class defines equality (==) and inequality (/=).
All the basic datatypes exported by the Prelude are instances of Eq,
and Eq may be derived for any datatype whose constituents are also
instances of Eq.
The Haskell Report defines no laws for Eq. However, instances are
encouraged to follow these properties:
Instances
| Eq ByteArray | Since: base-4.17.0.0 |
| Eq Timeout | |
| Eq BigNat | |
| Eq Void | Since: base-4.8.0.0 |
| Eq BlockReason | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync | |
| Eq ThreadId | Since: base-4.2.0.0 |
| Eq ThreadStatus | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync | |
| Eq Constr | Equality of constructors Since: base-4.0.0.0 |
| Eq ConstrRep | Since: base-4.0.0.0 |
| Eq DataRep | Since: base-4.0.0.0 |
| Eq Fixity | Since: base-4.0.0.0 |
| Eq All | Since: base-2.1 |
| Eq Any | Since: base-2.1 |
| Eq SomeTypeRep | |
Defined in GHC.Internal.Data.Typeable.Internal | |
| Eq Unique | |
| Eq Version | Since: base-2.1 |
| Eq ErrorCall | Since: base-4.7.0.0 |
| Eq ArithException | Since: base-3.0 |
Defined in GHC.Internal.Exception.Type Methods (==) :: ArithException -> ArithException -> Bool # (/=) :: ArithException -> ArithException -> Bool # | |
| Eq SpecConstrAnnotation | Since: base-4.3.0.0 |
Defined in GHC.Internal.Exts Methods (==) :: SpecConstrAnnotation -> SpecConstrAnnotation -> Bool # (/=) :: SpecConstrAnnotation -> SpecConstrAnnotation -> Bool # | |
| Eq IntPtr | |
| Eq WordPtr | |
| Eq Associativity | Since: base-4.6.0.0 |
Defined in GHC.Internal.Generics Methods (==) :: Associativity -> Associativity -> Bool # (/=) :: Associativity -> Associativity -> Bool # | |
| Eq DecidedStrictness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics Methods (==) :: DecidedStrictness -> DecidedStrictness -> Bool # (/=) :: DecidedStrictness -> DecidedStrictness -> Bool # | |
| Eq Fixity | Since: base-4.6.0.0 |
| Eq SourceStrictness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics Methods (==) :: SourceStrictness -> SourceStrictness -> Bool # (/=) :: SourceStrictness -> SourceStrictness -> Bool # | |
| Eq SourceUnpackedness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics Methods (==) :: SourceUnpackedness -> SourceUnpackedness -> Bool # (/=) :: SourceUnpackedness -> SourceUnpackedness -> Bool # | |
| Eq MaskingState | Since: base-4.3.0.0 |
Defined in GHC.Internal.IO | |
| Eq IODeviceType | Since: base-4.2.0.0 |
Defined in GHC.Internal.IO.Device | |
| Eq SeekMode | Since: base-4.2.0.0 |
| Eq CodingProgress | Since: base-4.4.0.0 |
Defined in GHC.Internal.IO.Encoding.Types Methods (==) :: CodingProgress -> CodingProgress -> Bool # (/=) :: CodingProgress -> CodingProgress -> Bool # | |
| Eq ArrayException | Since: base-4.2.0.0 |
Defined in GHC.Internal.IO.Exception Methods (==) :: ArrayException -> ArrayException -> Bool # (/=) :: ArrayException -> ArrayException -> Bool # | |
| Eq AsyncException | Since: base-4.2.0.0 |
Defined in GHC.Internal.IO.Exception Methods (==) :: AsyncException -> AsyncException -> Bool # (/=) :: AsyncException -> AsyncException -> Bool # | |
| Eq ExitCode | |
| Eq IOErrorType | Since: base-4.1.0.0 |
Defined in GHC.Internal.IO.Exception | |
| Eq IOException | Since: base-4.1.0.0 |
Defined in GHC.Internal.IO.Exception | |
| Eq HandlePosn | Since: base-4.1.0.0 |
Defined in GHC.Internal.IO.Handle | |
| Eq BufferMode | Since: base-4.2.0.0 |
Defined in GHC.Internal.IO.Handle.Types | |
| Eq Handle | Since: base-4.1.0.0 |
| Eq Newline | Since: base-4.2.0.0 |
| Eq NewlineMode | Since: base-4.2.0.0 |
Defined in GHC.Internal.IO.Handle.Types | |
| Eq IOMode | Since: base-4.2.0.0 |
| Eq Int16 | Since: base-2.1 |
| Eq Int32 | Since: base-2.1 |
| Eq Int64 | Since: base-2.1 |
| Eq Int8 | Since: base-2.1 |
| Eq SrcLoc | Since: base-4.9.0.0 |
| Eq CBlkCnt | |
| Eq CBlkSize | |
| Eq CCc | |
| Eq CClockId | |
| Eq CDev | |
| Eq CFsBlkCnt | |
| Eq CFsFilCnt | |
| Eq CGid | |
| Eq CId | |
| Eq CIno | |
| Eq CKey | |
| Eq CMode | |
| Eq CNfds | |
| Eq CNlink | |
| Eq COff | |
| Eq CPid | |
| Eq CRLim | |
| Eq CSocklen | |
| Eq CSpeed | |
| Eq CSsize | |
| Eq CTcflag | |
| Eq CTimer | |
| Eq CUid | |
| Eq Fd | |
| Eq GeneralCategory | Since: base-2.1 |
Defined in GHC.Internal.Unicode Methods (==) :: GeneralCategory -> GeneralCategory -> Bool # (/=) :: GeneralCategory -> GeneralCategory -> Bool # | |
| Eq Word16 | Since: base-2.1 |
| Eq Word32 | Since: base-2.1 |
| Eq Word64 | Since: base-2.1 |
| Eq Word8 | Since: base-2.1 |
| Eq Module | |
| Eq Ordering | |
| Eq TrName | |
| Eq TyCon | |
| Eq Integer | |
| Eq Natural | |
| Eq () | |
| Eq Bool | |
| Eq Char | |
| Eq Double | Note that due to the presence of
Also note that
|
| Eq Float | Note that due to the presence of
Also note that
|
| Eq Int | |
| Eq Word | |
| Eq (Chan a) | Since: base-4.4.0.0 |
| Eq (MutableByteArray s) | Since: base-4.17.0.0 |
Defined in Data.Array.Byte Methods (==) :: MutableByteArray s -> MutableByteArray s -> Bool # (/=) :: MutableByteArray s -> MutableByteArray s -> Bool # | |
| Eq a => Eq (Complex a) | Since: base-2.1 |
| Eq a => Eq (First a) | Since: base-4.9.0.0 |
| Eq a => Eq (Last a) | Since: base-4.9.0.0 |
| Eq a => Eq (Max a) | Since: base-4.9.0.0 |
| Eq a => Eq (Min a) | Since: base-4.9.0.0 |
| Eq m => Eq (WrappedMonoid m) | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods (==) :: WrappedMonoid m -> WrappedMonoid m -> Bool # (/=) :: WrappedMonoid m -> WrappedMonoid m -> Bool # | |
| Eq a => Eq (NonEmpty a) | Since: base-4.9.0.0 |
| Eq (TVar a) | Since: base-4.8.0.0 |
| Eq a => Eq (And a) | Since: base-4.16 |
| Eq a => Eq (Iff a) | Since: base-4.16 |
| Eq a => Eq (Ior a) | Since: base-4.16 |
| Eq a => Eq (Xor a) | Since: base-4.16 |
| Eq a => Eq (Identity a) | Since: base-4.8.0.0 |
| Eq a => Eq (First a) | Since: base-2.1 |
| Eq a => Eq (Last a) | Since: base-2.1 |
| Eq a => Eq (Down a) | Since: base-4.6.0.0 |
| Eq a => Eq (Dual a) | Since: base-2.1 |
| Eq a => Eq (Product a) | Since: base-2.1 |
| Eq a => Eq (Sum a) | Since: base-2.1 |
| Eq (ForeignPtr a) | Since: base-2.1 |
Defined in GHC.Internal.ForeignPtr | |
| Eq a => Eq (ZipList a) | Since: base-4.7.0.0 |
| Eq p => Eq (Par1 p) | Since: base-4.7.0.0 |
| Eq (IORef a) | Pointer equality. Since: base-4.0.0.0 |
| Eq (MVar a) | Compares the underlying pointers. Since: base-4.1.0.0 |
| Eq (FunPtr a) | |
| Eq (Ptr a) | Since: base-2.1 |
| Eq a => Eq (Ratio a) | Since: base-2.1 |
| Eq (StablePtr a) | Since: base-2.1 |
| Eq (StableName a) | Since: base-2.1 |
Defined in GHC.Internal.StableName | |
| Eq a => Eq (Maybe a) | Since: base-2.1 |
| Eq a => Eq (Solo a) | |
| Eq a => Eq [a] | |
| Eq (Fixed a) | Since: base-2.1 |
| Eq a => Eq (Arg a b) | Since: base-4.9.0.0 |
| (Eq a, Eq b) => Eq (Either a b) | Since: base-2.1 |
| Eq (Proxy s) | Since: base-4.7.0.0 |
| Eq (TypeRep a) | Since: base-2.1 |
| Eq (U1 p) | Since: base-4.9.0.0 |
| Eq (V1 p) | Since: base-4.9.0.0 |
| Eq (STRef s a) | Pointer equality. Since: base-2.1 |
| (Eq a, Eq b) => Eq (a, b) | |
| Eq a => Eq (Const a b) | Since: base-4.9.0.0 |
| Eq (f a) => Eq (Ap f a) | Since: base-4.12.0.0 |
| Eq (f a) => Eq (Alt f a) | Since: base-4.8.0.0 |
| Eq (a :~: b) | Since: base-4.7.0.0 |
| (Generic1 f, Eq (Rep1 f a)) => Eq (Generically1 f a) | Since: base-4.18.0.0 |
Defined in GHC.Internal.Generics Methods (==) :: Generically1 f a -> Generically1 f a -> Bool # (/=) :: Generically1 f a -> Generically1 f a -> Bool # | |
| Eq (f p) => Eq (Rec1 f p) | Since: base-4.7.0.0 |
| Eq (URec (Ptr ()) p) | Since: base-4.9.0.0 |
| Eq (URec Char p) | Since: base-4.9.0.0 |
| Eq (URec Double p) | Since: base-4.9.0.0 |
| Eq (URec Float p) | |
| Eq (URec Int p) | Since: base-4.9.0.0 |
| Eq (URec Word p) | Since: base-4.9.0.0 |
| (Eq a, Eq b, Eq c) => Eq (a, b, c) | |
| (Eq (f a), Eq (g a)) => Eq (Product f g a) | Since: base-4.18.0.0 |
| (Eq (f a), Eq (g a)) => Eq (Sum f g a) | Since: base-4.18.0.0 |
| Eq (a :~~: b) | Since: base-4.10.0.0 |
| (Eq (f p), Eq (g p)) => Eq ((f :*: g) p) | Since: base-4.7.0.0 |
| (Eq (f p), Eq (g p)) => Eq ((f :+: g) p) | Since: base-4.7.0.0 |
| Eq c => Eq (K1 i c p) | Since: base-4.7.0.0 |
| (Eq a, Eq b, Eq c, Eq d) => Eq (a, b, c, d) | |
| Eq (f (g a)) => Eq (Compose f g a) | Since: base-4.18.0.0 |
| Eq (f (g p)) => Eq ((f :.: g) p) | Since: base-4.7.0.0 |
| Eq (f p) => Eq (M1 i c f p) | Since: base-4.7.0.0 |
| (Eq a, Eq b, Eq c, Eq d, Eq e) => Eq (a, b, c, d, e) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f) => Eq (a, b, c, d, e, f) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g) => Eq (a, b, c, d, e, f, g) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h) => Eq (a, b, c, d, e, f, g, h) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i) => Eq (a, b, c, d, e, f, g, h, i) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j) => Eq (a, b, c, d, e, f, g, h, i, j) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k) => Eq (a, b, c, d, e, f, g, h, i, j, k) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l) => Eq (a, b, c, d, e, f, g, h, i, j, k, l) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m, Eq n) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n) | |
| (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m, Eq n, Eq o) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) | |
class Arrow a => ArrowApply (a :: Type -> Type -> Type) where #
Some arrows allow application of arrow inputs to other inputs. Instances should satisfy the following laws:
first(arr(\x ->arr(\y -> (x,y)))) >>>app=idfirst(arr(g >>>)) >>>app=secondg >>>appfirst(arr(>>> h)) >>>app=app>>> h
Such arrows are equivalent to monads (see ArrowMonad).
Instances
| Monad m => ArrowApply (Kleisli m) | Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow | |
| ArrowApply (->) | Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow | |
class Arrow a => ArrowChoice (a :: Type -> Type -> Type) where #
Choice, for arrows that support it. This class underlies the
if and case constructs in arrow notation.
Instances should satisfy the following laws:
left(arrf) =arr(leftf)left(f >>> g) =leftf >>>leftgf >>>
arrLeft=arrLeft>>>leftfleftf >>>arr(id+++ g) =arr(id+++ g) >>>leftfleft(leftf) >>>arrassocsum =arrassocsum >>>leftf
where
assocsum (Left (Left x)) = Left x assocsum (Left (Right y)) = Right (Left y) assocsum (Right z) = Right (Right z)
The other combinators have sensible default definitions, which may be overridden for efficiency.
Methods
left :: a b c -> a (Either b d) (Either c d) #
Feed marked inputs through the argument arrow, passing the rest through unchanged to the output.
right :: a b c -> a (Either d b) (Either d c) #
A mirror image of left.
The default definition may be overridden with a more efficient version if desired.
(+++) :: a b c -> a b' c' -> a (Either b b') (Either c c') infixr 2 #
Split the input between the two argument arrows, retagging and merging their outputs. Note that this is in general not a functor.
The default definition may be overridden with a more efficient version if desired.
(|||) :: a b d -> a c d -> a (Either b c) d infixr 2 #
Fanin: Split the input between the two argument arrows and merge their outputs.
The default definition may be overridden with a more efficient version if desired.
Instances
| Monad m => ArrowChoice (Kleisli m) | Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow | |
| ArrowChoice (->) | Since: base-2.1 |
class Arrow a => ArrowLoop (a :: Type -> Type -> Type) where #
The loop operator expresses computations in which an output value
is fed back as input, although the computation occurs only once.
It underlies the rec value recursion construct in arrow notation.
loop should satisfy the following laws:
- extension
loop(arrf) =arr(\ b ->fst(fix(\ (c,d) -> f (b,d))))- left tightening
loop(firsth >>> f) = h >>>loopf- right tightening
loop(f >>>firsth) =loopf >>> h- sliding
loop(f >>>arr(id*** k)) =loop(arr(id*** k) >>> f)- vanishing
loop(loopf) =loop(arrunassoc >>> f >>>arrassoc)- superposing
second(loopf) =loop(arrassoc >>>secondf >>>arrunassoc)
where
assoc ((a,b),c) = (a,(b,c)) unassoc (a,(b,c)) = ((a,b),c)
Instances
| MonadFix m => ArrowLoop (Kleisli m) | Beware that for many monads (those for which the Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow | |
| ArrowLoop (->) | Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow | |
fromIntegral :: (Integral a, Num b) => a -> b #
General coercion from Integral types.
WARNING: This function performs silent truncation if the result type is not at least as big as the argument's type.
realToFrac :: (Real a, Fractional b) => a -> b #
General coercion to Fractional types.
WARNING: This function goes through the Rational type, which does not have values for NaN for example.
This means it does not round-trip.
For Double it also behaves differently with or without -O0:
Prelude> realToFrac nan -- With -O0 -Infinity Prelude> realToFrac nan NaN
class (Real a, Enum a) => Integral a where #
Integral numbers, supporting integer division.
The Haskell Report defines no laws for Integral. However, Integral
instances are customarily expected to define a Euclidean domain and have the
following properties for the div/mod and quot/rem pairs, given
suitable Euclidean functions f and g:
x=y * quot x y + rem x ywithrem x y=fromInteger 0org (rem x y)<g yx=y * div x y + mod x ywithmod x y=fromInteger 0orf (mod x y)<f y
An example of a suitable Euclidean function, for Integer's instance, is
abs.
In addition, toInteger should be total, and fromInteger should be a left
inverse for it, i.e. fromInteger (toInteger i) = i.
Methods
quot :: a -> a -> a infixl 7 #
Integer division truncated toward zero.
WARNING: This function is partial (because it throws when 0 is passed as
the divisor) for all the integer types in base.
Integer remainder, satisfying
(x `quot` y)*y + (x `rem` y) == x
WARNING: This function is partial (because it throws when 0 is passed as
the divisor) for all the integer types in base.
Integer division truncated toward negative infinity.
WARNING: This function is partial (because it throws when 0 is passed as
the divisor) for all the integer types in base.
Integer modulus, satisfying
(x `div` y)*y + (x `mod` y) == x
WARNING: This function is partial (because it throws when 0 is passed as
the divisor) for all the integer types in base.
WARNING: This function is partial (because it throws when 0 is passed as
the divisor) for all the integer types in base.
WARNING: This function is partial (because it throws when 0 is passed as
the divisor) for all the integer types in base.
Conversion to Integer.
Instances
class (Num a, Ord a) => Real a where #
Real numbers.
The Haskell report defines no laws for Real, however Real instances
are customarily expected to adhere to the following law:
- Coherence with
fromRational - if the type also implements
Fractional, thenfromRationalis a left inverse fortoRational, i.e.fromRational (toRational i) = i
The law does not hold for Float, Double, CFloat,
CDouble, etc., because these types contain non-finite values,
which cannot be roundtripped through Rational.
Instances
The IsList class and its methods are intended to be used in
conjunction with the OverloadedLists extension.
Since: base-4.7.0.0
Methods
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
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 |
| IsList Version | Since: base-4.8.0.0 |
| IsList CallStack | Be aware that 'fromList . toList = id' only for unfrozen Since: base-4.9.0.0 |
| IsList (NonEmpty a) | Since: base-4.9.0.0 |
| IsList (ZipList a) | Since: base-4.15.0.0 |
| IsList [a] | Since: base-4.7.0.0 |
class Semigroup a => Monoid a where #
The class of monoids (types with an associative binary operation that has an identity). Instances should satisfy the following:
- Right identity
x<>mempty= x- Left identity
mempty<>x = x- Associativity
x(<>(y<>z) = (x<>y)<>zSemigrouplaw)- Concatenation
mconcat=foldr(<>)mempty
You can alternatively define mconcat instead of mempty, in which case the
laws are:
- Unit
mconcat(purex) = x- Multiplication
mconcat(joinxss) =mconcat(fmapmconcatxss)- Subclass
mconcat(toListxs) =sconcatxs
The method names refer to the monoid of lists under concatenation, but there are many other instances.
Some types can be viewed as a monoid in more than one way,
e.g. both addition and multiplication on numbers.
In such cases we often define newtypes and make those instances
of Monoid, e.g. Sum and Product.
NOTE: Semigroup is a superclass of Monoid since base-4.11.0.0.
Methods
Identity of mappend
Examples
>>>"Hello world" <> mempty"Hello world"
>>>mempty <> [1, 2, 3][1,2,3]
An associative operation
NOTE: This method is redundant and has the default
implementation since base-4.11.0.0.
Should it be implemented manually, since mappend = (<>)mappend is a synonym for
(<>), it is expected that the two functions are defined the same
way. In a future GHC release mappend will be removed from Monoid.
Fold a list using the monoid.
For most types, the default definition for mconcat will be
used, but the function is included in the class definition so
that an optimized version can be provided for specific types.
>>>mconcat ["Hello", " ", "Haskell", "!"]"Hello Haskell!"
Instances
| Monoid ByteArray | Since: base-4.17.0.0 |
| Monoid All | Since: base-2.1 |
| Monoid Any | Since: base-2.1 |
| Monoid Ordering | Since: base-2.1 |
| Monoid () | Since: base-2.1 |
| Monoid (Comparison a) |
mempty :: Comparison a mempty = Comparison _ _ -> EQ |
Defined in Data.Functor.Contravariant Methods mempty :: Comparison a # mappend :: Comparison a -> Comparison a -> Comparison a # mconcat :: [Comparison a] -> Comparison a # | |
| Monoid (Equivalence a) |
mempty :: Equivalence a mempty = Equivalence _ _ -> True |
Defined in Data.Functor.Contravariant Methods mempty :: Equivalence a # mappend :: Equivalence a -> Equivalence a -> Equivalence a # mconcat :: [Equivalence a] -> Equivalence a # | |
| Monoid (Predicate a) |
mempty :: Predicate a mempty = _ -> True |
| (Ord a, Bounded a) => Monoid (Max a) | Since: base-4.9.0.0 |
| (Ord a, Bounded a) => Monoid (Min a) | Since: base-4.9.0.0 |
| Monoid m => Monoid (WrappedMonoid m) | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods mempty :: WrappedMonoid m # mappend :: WrappedMonoid m -> WrappedMonoid m -> WrappedMonoid m # mconcat :: [WrappedMonoid m] -> WrappedMonoid m # | |
| Monoid a => Monoid (STM a) | Since: base-4.17.0.0 |
| FiniteBits a => Monoid (And a) | This constraint is arguably too strong. However,
as some types (such as Since: base-4.16 |
| FiniteBits a => Monoid (Iff a) | This constraint is arguably
too strong. However, as some types (such as Since: base-4.16 |
| Bits a => Monoid (Ior a) | Since: base-4.16 |
| Bits a => Monoid (Xor a) | Since: base-4.16 |
| Monoid a => Monoid (Identity a) | Since: base-4.9.0.0 |
| Monoid (First a) | Since: base-2.1 |
| Monoid (Last a) | Since: base-2.1 |
| Monoid a => Monoid (Down a) | Since: base-4.11.0.0 |
| Monoid a => Monoid (Dual a) | Since: base-2.1 |
| Monoid (Endo a) | Since: base-2.1 |
| Num a => Monoid (Product a) | Since: base-2.1 |
| Num a => Monoid (Sum a) | Since: base-2.1 |
| (Generic a, Monoid (Rep a ())) => Monoid (Generically a) | Since: base-4.17.0.0 |
Defined in GHC.Internal.Generics Methods mempty :: Generically a # mappend :: Generically a -> Generically a -> Generically a # mconcat :: [Generically a] -> Generically a # | |
| Monoid p => Monoid (Par1 p) | Since: base-4.12.0.0 |
| Monoid a => Monoid (IO a) | Since: base-4.9.0.0 |
| Semigroup a => Monoid (Maybe a) | Lift a semigroup into Since 4.11.0: constraint on inner Since: base-2.1 |
| Monoid a => Monoid (Solo a) | Since: base-4.15 |
| Monoid [a] | Since: base-2.1 |
| Monoid a => Monoid (Op a b) |
mempty :: Op a b mempty = Op _ -> mempty |
| Monoid (Proxy s) | Since: base-4.7.0.0 |
| Monoid (U1 p) | Since: base-4.12.0.0 |
| Monoid a => Monoid (ST s a) | Since: base-4.11.0.0 |
| (Monoid a, Monoid b) => Monoid (a, b) | Since: base-2.1 |
| Monoid b => Monoid (a -> b) | Since: base-2.1 |
| Monoid a => Monoid (Const a b) | Since: base-4.9.0.0 |
| (Applicative f, Monoid a) => Monoid (Ap f a) | Since: base-4.12.0.0 |
| Alternative f => Monoid (Alt f a) | Since: base-4.8.0.0 |
| Monoid (f p) => Monoid (Rec1 f p) | Since: base-4.12.0.0 |
| (Monoid a, Monoid b, Monoid c) => Monoid (a, b, c) | Since: base-2.1 |
| (Monoid (f a), Monoid (g a)) => Monoid (Product f g a) | Since: base-4.16.0.0 |
| (Monoid (f p), Monoid (g p)) => Monoid ((f :*: g) p) | Since: base-4.12.0.0 |
| Monoid c => Monoid (K1 i c p) | Since: base-4.12.0.0 |
| (Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d) | Since: base-2.1 |
| Monoid (f (g a)) => Monoid (Compose f g a) | Since: base-4.16.0.0 |
| Monoid (f (g p)) => Monoid ((f :.: g) p) | Since: base-4.12.0.0 |
| Monoid (f p) => Monoid (M1 i c f p) | Since: base-4.12.0.0 |
| (Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e) | Since: base-2.1 |
The Bounded class is used to name the upper and lower limits of a
type. Ord is not a superclass of Bounded since types that are not
totally ordered may also have upper and lower bounds.
The Bounded class may be derived for any enumeration type;
minBound is the first constructor listed in the data declaration
and maxBound is the last.
Bounded may also be derived for single-constructor datatypes whose
constituent types are in Bounded.
Instances
| Bounded All | Since: base-2.1 |
| Bounded Any | Since: base-2.1 |
| Bounded IntPtr | |
| Bounded WordPtr | |
| Bounded Associativity | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics | |
| Bounded DecidedStrictness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics | |
| Bounded SourceStrictness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics | |
| Bounded SourceUnpackedness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics | |
| Bounded Int16 | Since: base-2.1 |
| Bounded Int32 | Since: base-2.1 |
| Bounded Int64 | Since: base-2.1 |
| Bounded Int8 | Since: base-2.1 |
| Bounded CBlkCnt | |
| Bounded CBlkSize | |
| Bounded CClockId | |
| Bounded CDev | |
| Bounded CFsBlkCnt | |
| Bounded CFsFilCnt | |
| Bounded CGid | |
| Bounded CId | |
| Bounded CIno | |
| Bounded CKey | |
| Bounded CMode | |
| Bounded CNfds | |
| Bounded CNlink | |
| Bounded COff | |
| Bounded CPid | |
| Bounded CRLim | |
| Bounded CSocklen | |
| Bounded CSsize | |
| Bounded CTcflag | |
| Bounded CUid | |
| Bounded Fd | |
| Bounded GeneralCategory | Since: base-2.1 |
Defined in GHC.Internal.Unicode | |
| Bounded Word16 | Since: base-2.1 |
| Bounded Word32 | Since: base-2.1 |
| Bounded Word64 | Since: base-2.1 |
| Bounded Word8 | Since: base-2.1 |
| Bounded Ordering | Since: base-2.1 |
| Bounded () | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| Bounded Bool | Since: base-2.1 |
| Bounded Char | Since: base-2.1 |
| Bounded Int | Since: base-2.1 |
| Bounded Levity | Since: base-4.16.0.0 |
| Bounded VecCount | Since: base-4.10.0.0 |
| Bounded VecElem | Since: base-4.10.0.0 |
| Bounded Word | Since: base-2.1 |
| Bounded a => Bounded (First a) | Since: base-4.9.0.0 |
| Bounded a => Bounded (Last a) | Since: base-4.9.0.0 |
| Bounded a => Bounded (Max a) | Since: base-4.9.0.0 |
| Bounded a => Bounded (Min a) | Since: base-4.9.0.0 |
| Bounded m => Bounded (WrappedMonoid m) | Since: base-4.9.0.0 |
Defined in Data.Semigroup | |
| Bounded a => Bounded (And a) | Since: base-4.16 |
| Bounded a => Bounded (Iff a) | Since: base-4.16 |
| Bounded a => Bounded (Ior a) | Since: base-4.16 |
| Bounded a => Bounded (Xor a) | Since: base-4.16 |
| Bounded a => Bounded (Identity a) | Since: base-4.9.0.0 |
| Bounded a => Bounded (Down a) | Swaps Since: base-4.14.0.0 |
| Bounded a => Bounded (Dual a) | Since: base-2.1 |
| Bounded a => Bounded (Product a) | Since: base-2.1 |
| Bounded a => Bounded (Sum a) | Since: base-2.1 |
| Bounded a => Bounded (Solo a) | |
| Bounded (Proxy t) | Since: base-4.7.0.0 |
| (Bounded a, Bounded b) => Bounded (a, b) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| Bounded a => Bounded (Const a b) | Since: base-4.9.0.0 |
| (Applicative f, Bounded a) => Bounded (Ap f a) | Since: base-4.12.0.0 |
| a ~ b => Bounded (a :~: b) | Since: base-4.7.0.0 |
| (Bounded a, Bounded b, Bounded c) => Bounded (a, b, c) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| a ~~ b => Bounded (a :~~: b) | Since: base-4.10.0.0 |
| (Bounded a, Bounded b, Bounded c, Bounded d) => Bounded (a, b, c, d) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| Bounded (f (g a)) => Bounded (Compose f g a) | Since: base-4.19.0.0 |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e) => Bounded (a, b, c, d, e) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f) => Bounded (a, b, c, d, e, f) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g) => Bounded (a, b, c, d, e, f, g) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h) => Bounded (a, b, c, d, e, f, g, h) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i) => Bounded (a, b, c, d, e, f, g, h, i) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j) => Bounded (a, b, c, d, e, f, g, h, i, j) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k) => Bounded (a, b, c, d, e, f, g, h, i, j, k) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l, Bounded m) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l, m) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l, Bounded m, Bounded n) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l, m, n) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
| (Bounded a, Bounded b, Bounded c, Bounded d, Bounded e, Bounded f, Bounded g, Bounded h, Bounded i, Bounded j, Bounded k, Bounded l, Bounded m, Bounded n, Bounded o) => Bounded (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) | Since: base-2.1 |
Defined in GHC.Internal.Enum | |
Parsing of Strings, producing values.
Derived instances of Read make the following assumptions, which
derived instances of Show obey:
- If the constructor is defined to be an infix operator, then the
derived
Readinstance will parse only infix applications of the constructor (not the prefix form). - Associativity is not used to reduce the occurrence of parentheses, although precedence may be.
- If the constructor is defined using record syntax, the derived
Readwill parse only the record-syntax form, and furthermore, the fields must be given in the same order as the original declaration. - The derived
Readinstance allows arbitrary Haskell whitespace between tokens of the input string. Extra parentheses are also allowed.
For example, given the declarations
infixr 5 :^: data Tree a = Leaf a | Tree a :^: Tree a
the derived instance of Read in Haskell 2010 is equivalent to
instance (Read a) => Read (Tree a) where
readsPrec d r = readParen (d > app_prec)
(\r -> [(Leaf m,t) |
("Leaf",s) <- lex r,
(m,t) <- readsPrec (app_prec+1) s]) r
++ readParen (d > up_prec)
(\r -> [(u:^:v,w) |
(u,s) <- readsPrec (up_prec+1) r,
(":^:",t) <- lex s,
(v,w) <- readsPrec (up_prec+1) t]) r
where app_prec = 10
up_prec = 5Note that right-associativity of :^: is unused.
The derived instance in GHC is equivalent to
instance (Read a) => Read (Tree a) where
readPrec = parens $ (prec app_prec $ do
Ident "Leaf" <- lexP
m <- step readPrec
return (Leaf m))
+++ (prec up_prec $ do
u <- step readPrec
Symbol ":^:" <- lexP
v <- step readPrec
return (u :^: v))
where app_prec = 10
up_prec = 5
readListPrec = readListPrecDefaultWhy do both readsPrec and readPrec exist, and why does GHC opt to
implement readPrec in derived Read instances instead of readsPrec?
The reason is that readsPrec is based on the ReadS type, and although
ReadS is mentioned in the Haskell 2010 Report, it is not a very efficient
parser data structure.
readPrec, on the other hand, is based on a much more efficient ReadPrec
datatype (a.k.a "new-style parsers"), but its definition relies on the use
of the RankNTypes language extension. Therefore, readPrec (and its
cousin, readListPrec) are marked as GHC-only. Nevertheless, it is
recommended to use readPrec instead of readsPrec whenever possible
for the efficiency improvements it brings.
As mentioned above, derived Read instances in GHC will implement
readPrec instead of readsPrec. The default implementations of
readsPrec (and its cousin, readList) will simply use readPrec under
the hood. If you are writing a Read instance by hand, it is recommended
to write it like so:
instanceReadT wherereadPrec= ...readListPrec=readListPrecDefault
Methods
Arguments
| :: Int | the operator precedence of the enclosing
context (a number from |
| -> ReadS a |
attempts to parse a value from the front of the string, returning a list of (parsed value, remaining string) pairs. If there is no successful parse, the returned list is empty.
Derived instances of Read and Show satisfy the following:
That is, readsPrec parses the string produced by
showsPrec, and delivers the value that
showsPrec started with.
The method readList is provided to allow the programmer to
give a specialised way of parsing lists of values.
For example, this is used by the predefined Read instance of
the Char type, where values of type String are expected to
use double quotes, rather than square brackets.
Proposed replacement for readsPrec using new-style parsers (GHC only).
readListPrec :: ReadPrec [a] #
Proposed replacement for readList using new-style parsers (GHC only).
The default definition uses readList. Instances that define readPrec
should also define readListPrec as readListPrecDefault.
Instances
| Read Void | Reading a Since: base-4.8.0.0 |
| Read All | Since: base-2.1 |
| Read Any | Since: base-2.1 |
| Read Version | Since: base-2.1 |
| Read IntPtr | |
| Read WordPtr | |
| Read Associativity | Since: base-4.6.0.0 |
Defined in GHC.Internal.Generics Methods readsPrec :: Int -> ReadS Associativity # readList :: ReadS [Associativity] # | |
| Read DecidedStrictness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics Methods readsPrec :: Int -> ReadS DecidedStrictness # readList :: ReadS [DecidedStrictness] # | |
| Read Fixity | Since: base-4.6.0.0 |
| Read SourceStrictness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics Methods readsPrec :: Int -> ReadS SourceStrictness # readList :: ReadS [SourceStrictness] # | |
| Read SourceUnpackedness | Since: base-4.9.0.0 |
Defined in GHC.Internal.Generics Methods readsPrec :: Int -> ReadS SourceUnpackedness # readList :: ReadS [SourceUnpackedness] # | |
| Read SeekMode | Since: base-4.2.0.0 |
| Read ExitCode | |
| Read BufferMode | Since: base-4.2.0.0 |
Defined in GHC.Internal.IO.Handle.Types Methods readsPrec :: Int -> ReadS BufferMode # readList :: ReadS [BufferMode] # readPrec :: ReadPrec BufferMode # readListPrec :: ReadPrec [BufferMode] # | |
| Read Newline | Since: base-4.3.0.0 |
| Read NewlineMode | Since: base-4.3.0.0 |
Defined in GHC.Internal.IO.Handle.Types Methods readsPrec :: Int -> ReadS NewlineMode # readList :: ReadS [NewlineMode] # readPrec :: ReadPrec NewlineMode # readListPrec :: ReadPrec [NewlineMode] # | |
| Read IOMode | Since: base-4.2.0.0 |
| Read Int16 | Since: base-2.1 |
| Read Int32 | Since: base-2.1 |
| Read Int64 | Since: base-2.1 |
| Read Int8 | Since: base-2.1 |
| Read CBlkCnt | |
| Read CBlkSize | |
| Read CCc | |
| Read CClockId | |
| Read CDev | |
| Read CFsBlkCnt | |
| Read CFsFilCnt | |
| Read CGid | |
| Read CId | |
| Read CIno | |
| Read CKey | |
| Read CMode | |
| Read CNfds | |
| Read CNlink | |
| Read COff | |
| Read CPid | |
| Read CRLim | |
| Read CSocklen | |
| Read CSpeed | |
| Read CSsize | |
| Read CTcflag | |
| Read CUid | |
| Read Fd | |
| Read Lexeme | Since: base-2.1 |
| Read GeneralCategory | Since: base-2.1 |
Defined in GHC.Internal.Read Methods readsPrec :: Int -> ReadS GeneralCategory # readList :: ReadS [GeneralCategory] # | |
| Read Word16 | Since: base-2.1 |
| Read Word32 | Since: base-2.1 |
| Read Word64 | Since: base-2.1 |
| Read Word8 | Since: base-2.1 |
| Read Ordering | Since: base-2.1 |
| Read Integer | Since: base-2.1 |
| Read Natural | Since: base-4.8.0.0 |
| Read () | Since: base-2.1 |
| Read Bool | Since: base-2.1 |
| Read Char | Since: base-2.1 |
| Read Double | Since: base-2.1 |
| Read Float | Since: base-2.1 |
| Read Int | Since: base-2.1 |
| Read Word | Since: base-4.5.0.0 |
| Read a => Read (Complex a) | Since: base-2.1 |
| Read a => Read (First a) | Since: base-4.9.0.0 |
| Read a => Read (Last a) | Since: base-4.9.0.0 |
| Read a => Read (Max a) | Since: base-4.9.0.0 |
| Read a => Read (Min a) | Since: base-4.9.0.0 |
| Read m => Read (WrappedMonoid m) | Since: base-4.9.0.0 |
Defined in Data.Semigroup Methods readsPrec :: Int -> ReadS (WrappedMonoid m) # readList :: ReadS [WrappedMonoid m] # readPrec :: ReadPrec (WrappedMonoid m) # readListPrec :: ReadPrec [WrappedMonoid m] # | |
| Read a => Read (NonEmpty a) | Since: base-4.11.0.0 |
| Read a => Read (And a) | Since: base-4.16 |
| Read a => Read (Iff a) | Since: base-4.16 |
| Read a => Read (Ior a) | Since: base-4.16 |
| Read a => Read (Xor a) | Since: base-4.16 |
| Read a => Read (Identity a) | This instance would be equivalent to the derived instances of the
Since: base-4.8.0.0 |
| Read a => Read (First a) | Since: base-2.1 |
| Read a => Read (Last a) | Since: base-2.1 |
| Read a => Read (Down a) | This instance would be equivalent to the derived instances of the
Since: base-4.7.0.0 |
| Read a => Read (Dual a) | Since: base-2.1 |
| Read a => Read (Product a) | Since: base-2.1 |
| Read a => Read (Sum a) | Since: base-2.1 |
| Read a => Read (ZipList a) | Since: base-4.7.0.0 |
| Read p => Read (Par1 p) | Since: base-4.7.0.0 |
| (Integral a, Read a) => Read (Ratio a) | Since: base-2.1 |
| Read a => Read (Maybe a) | Since: base-2.1 |
| Read a => Read (Solo a) | Since: base-4.15 |
| Read a => Read [a] | Since: base-2.1 |
| HasResolution a => Read (Fixed a) | Since: base-4.3.0.0 |
| (Read a, Read b) => Read (Arg a b) | Since: base-4.9.0.0 |
| (Ix a, Read a, Read b) => Read (Array a b) | Since: base-2.1 |
| (Read a, Read b) => Read (Either a b) | Since: base-3.0 |
| Read (Proxy t) | Since: base-4.7.0.0 |
| Read (U1 p) | Since: base-4.9.0.0 |
| Read (V1 p) | Since: base-4.9.0.0 |
| (Read a, Read b) => Read (a, b) | Since: base-2.1 |
| Read a => Read (Const a b) | This instance would be equivalent to the derived instances of the
Since: base-4.8.0.0 |
| Read (f a) => Read (Ap f a) | Since: base-4.12.0.0 |
| Read (f a) => Read (Alt f a) | Since: base-4.8.0.0 |
| a ~ b => Read (a :~: b) | Since: base-4.7.0.0 |
| Read (f p) => Read (Rec1 f p) | Since: base-4.7.0.0 |
| (Read a, Read b, Read c) => Read (a, b, c) | Since: base-2.1 |
| (Read (f a), Read (g a)) => Read (Product f g a) | Since: base-4.18.0.0 |
| (Read (f a), Read (g a)) => Read (Sum f g a) | Since: base-4.18.0.0 |
| a ~~ b => Read (a :~~: b) | Since: base-4.10.0.0 |
| (Read (f p), Read (g p)) => Read ((f :*: g) p) | Since: base-4.7.0.0 |
| (Read (f p), Read (g p)) => Read ((f :+: g) p) | Since: base-4.7.0.0 |
| Read c => Read (K1 i c p) | Since: base-4.7.0.0 |
| (Read a, Read b, Read c, Read d) => Read (a, b, c, d) | Since: base-2.1 |
| Read (f (g a)) => Read (Compose f g a) | Since: base-4.18.0.0 |
| Read (f (g p)) => Read ((f :.: g) p) | Since: base-4.7.0.0 |
| Read (f p) => Read (M1 i c f p) | Since: base-4.7.0.0 |
| (Read a, Read b, Read c, Read d, Read e) => Read (a, b, c, d, e) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f) => Read (a, b, c, d, e, f) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g) => Read (a, b, c, d, e, f, g) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h) => Read (a, b, c, d, e, f, g, h) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i) => Read (a, b, c, d, e, f, g, h, i) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j) => Read (a, b, c, d, e, f, g, h, i, j) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k) => Read (a, b, c, d, e, f, g, h, i, j, k) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l) => Read (a, b, c, d, e, f, g, h, i, j, k, l) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m) | Since: base-2.1 |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m, Read n) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n) | Since: base-2.1 |
Defined in GHC.Internal.Read | |
| (Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m, Read n, Read o) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) | Since: base-2.1 |
Defined in GHC.Internal.Read | |
class (RealFrac a, Floating a) => RealFloat a where #
Efficient, machine-independent access to the components of a floating-point number.
Minimal complete definition
floatRadix, floatDigits, floatRange, decodeFloat, encodeFloat, isNaN, isInfinite, isDenormalized, isNegativeZero, isIEEE
Methods
floatRadix :: a -> Integer #
a constant function, returning the radix of the representation
(often 2)
floatDigits :: a -> Int #
a constant function, returning the number of digits of
floatRadix in the significand
floatRange :: a -> (Int, Int) #
a constant function, returning the lowest and highest values the exponent may assume
decodeFloat :: a -> (Integer, Int) #
The function decodeFloat applied to a real floating-point
number returns the significand expressed as an Integer and an
appropriately scaled exponent (an Int). If
yields decodeFloat x(m,n), then x is equal in value to m*b^^n, where b
is the floating-point radix, and furthermore, either m and n
are both zero or else b^(d-1) <= , where abs m < b^dd is
the value of .
In particular, floatDigits x. If the type
contains a negative zero, also decodeFloat 0 = (0,0).
The result of decodeFloat (-0.0) = (0,0) is unspecified if either of
decodeFloat x or isNaN x is isInfinite xTrue.
encodeFloat :: Integer -> Int -> a #
encodeFloat performs the inverse of decodeFloat in the
sense that for finite x with the exception of -0.0,
.
uncurry encodeFloat (decodeFloat x) = x is one of the two closest representable
floating-point numbers to encodeFloat m nm*b^^n (or ±Infinity if overflow
occurs); usually the closer, but if m contains too many bits,
the result may be rounded in the wrong direction.
exponent corresponds to the second component of decodeFloat.
and for finite nonzero exponent 0 = 0x,
.
If exponent x = snd (decodeFloat x) + floatDigits xx is a finite floating-point number, it is equal in value to
, where significand x * b ^^ exponent xb is the
floating-point radix.
The behaviour is unspecified on infinite or NaN values.
significand :: a -> a #
The first component of decodeFloat, scaled to lie in the open
interval (-1,1), either 0.0 or of absolute value >= 1/b,
where b is the floating-point radix.
The behaviour is unspecified on infinite or NaN values.
scaleFloat :: Int -> a -> a #
multiplies a floating-point number by an integer power of the radix
True if the argument is an IEEE "not-a-number" (NaN) value
isInfinite :: a -> Bool #
True if the argument is an IEEE infinity or negative infinity
isDenormalized :: a -> Bool #
True if the argument is too small to be represented in
normalized format
isNegativeZero :: a -> Bool #
True if the argument is an IEEE negative zero
True if the argument is an IEEE floating point number
a version of arctangent taking two real floating-point arguments.
For real floating x and y, computes the angle
(from the positive x-axis) of the vector from the origin to the
point atan2 y x(x,y). returns a value in the range [atan2 y x-pi,
pi]. It follows the Common Lisp semantics for the origin when
signed zeroes are supported. , with atan2 y 1y in a type
that is RealFloat, should return the same value as .
A default definition of atan yatan2 is provided, but implementors
can provide a more accurate implementation.
Instances
class (Real a, Fractional a) => RealFrac a where #
Extracting components of fractions.
Minimal complete definition
Methods
properFraction :: Integral b => a -> (b, a) #
The function properFraction takes a real fractional number x
and returns a pair (n,f) such that x = n+f, and:
nis an integral number with the same sign asx; andfis a fraction with the same type and sign asx, and with absolute value less than1.
The default definitions of the ceiling, floor, truncate
and round functions are in terms of properFraction.
truncate :: Integral b => a -> b #
returns the integer nearest truncate xx between zero and x
round :: Integral b => a -> b #
returns the nearest integer to round xx;
the even integer if x is equidistant between two integers
ceiling :: Integral b => a -> b #
returns the least integer not less than ceiling xx
floor :: Integral b => a -> b #
returns the greatest integer not greater than floor xx
Instances
| RealFrac Double | Beware that results for non-finite arguments are garbage:
and get even more non-sensical if you ask for Since: base-2.1 |
| RealFrac Float | Beware that results for non-finite arguments are garbage:
and get even more non-sensical if you ask for Since: base-2.1 |
| RealFrac a => RealFrac (Identity a) | Since: base-4.9.0.0 |
| RealFrac a => RealFrac (Down a) | Since: base-4.14.0.0 |
| Integral a => RealFrac (Ratio a) | Since: base-2.0.1 |
| HasResolution a => RealFrac (Fixed a) | Since: base-2.1 |
| RealFrac a => RealFrac (Const a b) | Since: base-4.9.0.0 |
| RealFrac (f (g a)) => RealFrac (Compose f g a) | Since: base-4.20.0.0 |
Conversion of values to readable Strings.
Derived instances of Show have the following properties, which
are compatible with derived instances of Read:
- The result of
showis a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used. - If the constructor is defined to be an infix operator, then
showsPrecwill produce infix applications of the constructor. - the representation will be enclosed in parentheses if the
precedence of the top-level constructor in
xis less thand(associativity is ignored). Thus, ifdis0then the result is never surrounded in parentheses; ifdis11it is always surrounded in parentheses, unless it is an atomic expression. - If the constructor is defined using record syntax, then
showwill produce the record-syntax form, with the fields given in the same order as the original declaration.
For example, given the declarations
infixr 5 :^: data Tree a = Leaf a | Tree a :^: Tree a
the derived instance of Show is equivalent to
instance (Show a) => Show (Tree a) where
showsPrec d (Leaf m) = showParen (d > app_prec) $
showString "Leaf " . showsPrec (app_prec+1) m
where app_prec = 10
showsPrec d (u :^: v) = showParen (d > up_prec) $
showsPrec (up_prec+1) u .
showString " :^: " .
showsPrec (up_prec+1) v
where up_prec = 5Note that right-associativity of :^: is ignored. For example,
produces the stringshow(Leaf 1 :^: Leaf 2 :^: Leaf 3)"Leaf 1 :^: (Leaf 2 :^: Leaf 3)".
Methods
Arguments
| :: Int | the operator precedence of the enclosing
context (a number from |
| -> a | the value to be converted to a |
| -> ShowS |
Convert a value to a readable String.
showsPrec should satisfy the law
showsPrec d x r ++ s == showsPrec d x (r ++ s)
Derived instances of Read and Show satisfy the following:
That is, readsPrec parses the string produced by
showsPrec, and delivers the value that showsPrec started with.
Instances
Representable types of kind *.
This class is derivable in GHC with the DeriveGeneric flag on.
A Generic instance must satisfy the following laws:
from.to≡idto.from≡id
Instances
class Generic1 (f :: k -> Type) #
Representable types of kind * -> * (or kind k -> *, when PolyKinds
is enabled).
This class is derivable in GHC with the DeriveGeneric flag on.
A Generic1 instance must satisfy the following laws:
from1.to1≡idto1.from1≡id
Instances
| Generic1 Complex | |||||
Defined in Data.Complex Associated Types
| |||||
| Generic1 First | |||||
Defined in Data.Semigroup Associated Types
| |||||
| Generic1 Last | |||||
Defined in Data.Semigroup Associated Types
| |||||
| Generic1 Max | |||||
Defined in Data.Semigroup Associated Types
| |||||
| Generic1 Min | |||||
Defined in Data.Semigroup Associated Types
| |||||
| Generic1 WrappedMonoid | |||||
Defined in Data.Semigroup Associated Types
Methods from1 :: WrappedMonoid a -> Rep1 WrappedMonoid a # to1 :: Rep1 WrappedMonoid a -> WrappedMonoid a # | |||||
| Generic1 NonEmpty | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 Identity | |||||
Defined in GHC.Internal.Data.Functor.Identity Associated Types
| |||||
| Generic1 First | |||||
Defined in GHC.Internal.Data.Monoid Associated Types
| |||||
| Generic1 Last | |||||
Defined in GHC.Internal.Data.Monoid Associated Types
| |||||
| Generic1 Down | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 Dual | |||||
Defined in GHC.Internal.Data.Semigroup.Internal Associated Types
| |||||
| Generic1 Product | |||||
Defined in GHC.Internal.Data.Semigroup.Internal Associated Types
| |||||
| Generic1 Sum | |||||
Defined in GHC.Internal.Data.Semigroup.Internal Associated Types
| |||||
| Generic1 ZipList | |||||
Defined in GHC.Internal.Functor.ZipList Associated Types
| |||||
| Generic1 Par1 | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 Maybe | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 Solo | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 [] | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (WrappedMonad m :: Type -> Type) | |||||
Defined in Control.Applicative Associated Types
Methods from1 :: WrappedMonad m a -> Rep1 (WrappedMonad m) a # to1 :: Rep1 (WrappedMonad m) a -> WrappedMonad m a # | |||||
| Generic1 (Arg a :: Type -> Type) | |||||
Defined in Data.Semigroup Associated Types
| |||||
| Generic1 (Either a :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,) a :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (Proxy :: k -> Type) | |||||
Defined in GHC.Internal.Generics | |||||
| Generic1 (U1 :: k -> Type) | |||||
Defined in GHC.Internal.Generics | |||||
| Generic1 (V1 :: k -> Type) | |||||
Defined in GHC.Internal.Generics | |||||
| Generic1 (WrappedArrow a b :: Type -> Type) | |||||
Defined in Control.Applicative Associated Types
Methods from1 :: WrappedArrow a b a0 -> Rep1 (WrappedArrow a b) a0 # to1 :: Rep1 (WrappedArrow a b) a0 -> WrappedArrow a b a0 # | |||||
| Generic1 (Kleisli m a :: Type -> Type) | |||||
Defined in GHC.Internal.Control.Arrow Associated Types
| |||||
| Generic1 ((,,) a b :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (Const a :: k -> Type) | |||||
Defined in GHC.Internal.Data.Functor.Const Associated Types
| |||||
| Generic1 (Ap f :: k -> Type) | |||||
Defined in GHC.Internal.Data.Monoid Associated Types
| |||||
| Generic1 (Alt f :: k -> Type) | |||||
Defined in GHC.Internal.Data.Semigroup.Internal Associated Types
| |||||
| Generic1 (Rec1 f :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (URec (Ptr ()) :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (URec Char :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (URec Double :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (URec Float :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (URec Int :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (URec Word :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,,,) a b c :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (Product f g :: k -> Type) | |||||
Defined in Data.Functor.Product Associated Types
| |||||
| Generic1 (Sum f g :: k -> Type) | |||||
Defined in Data.Functor.Sum Associated Types
| |||||
| Generic1 (f :*: g :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (f :+: g :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (K1 i c :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,,,,) a b c d :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Functor f => Generic1 (Compose f g :: k -> Type) | |||||
Defined in Data.Functor.Compose Associated Types
| |||||
| Functor f => Generic1 (f :.: g :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 (M1 i c f :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,,,,,) a b c d e :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,,,,,,) a b c d e f :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,,,,,,,) a b c d e f g :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Generic1 ((,,,,,,,,) a b c d e f g h :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, a0) -> Rep1 ((,,,,,,,,) a b c d e f g h) a0 # to1 :: Rep1 ((,,,,,,,,) a b c d e f g h) a0 -> (a, b, c, d, e, f, g, h, a0) # | |||||
| Generic1 ((,,,,,,,,,) a b c d e f g h i :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, i, a0) -> Rep1 ((,,,,,,,,,) a b c d e f g h i) a0 # to1 :: Rep1 ((,,,,,,,,,) a b c d e f g h i) a0 -> (a, b, c, d, e, f, g, h, i, a0) # | |||||
| Generic1 ((,,,,,,,,,,) a b c d e f g h i j :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, i, j, a0) -> Rep1 ((,,,,,,,,,,) a b c d e f g h i j) a0 # to1 :: Rep1 ((,,,,,,,,,,) a b c d e f g h i j) a0 -> (a, b, c, d, e, f, g, h, i, j, a0) # | |||||
| Generic1 ((,,,,,,,,,,,) a b c d e f g h i j k :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, i, j, k, a0) -> Rep1 ((,,,,,,,,,,,) a b c d e f g h i j k) a0 # to1 :: Rep1 ((,,,,,,,,,,,) a b c d e f g h i j k) a0 -> (a, b, c, d, e, f, g, h, i, j, k, a0) # | |||||
| Generic1 ((,,,,,,,,,,,,) a b c d e f g h i j k l :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, i, j, k, l, a0) -> Rep1 ((,,,,,,,,,,,,) a b c d e f g h i j k l) a0 # to1 :: Rep1 ((,,,,,,,,,,,,) a b c d e f g h i j k l) a0 -> (a, b, c, d, e, f, g, h, i, j, k, l, a0) # | |||||
| Generic1 ((,,,,,,,,,,,,,) a b c d e f g h i j k l m :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, i, j, k, l, m, a0) -> Rep1 ((,,,,,,,,,,,,,) a b c d e f g h i j k l m) a0 # to1 :: Rep1 ((,,,,,,,,,,,,,) a b c d e f g h i j k l m) a0 -> (a, b, c, d, e, f, g, h, i, j, k, l, m, a0) # | |||||
| Generic1 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m n :: Type -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
Methods from1 :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, a0) -> Rep1 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m n) a0 # to1 :: Rep1 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m n) a0 -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, a0) # | |||||
Double-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE double-precision type.
Instances
| PrintfArg Double | Since: base-2.1 | ||||
Defined in Text.Printf | |||||
| Data Double | Since: base-4.0.0.0 | ||||
Defined in GHC.Internal.Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Double -> c Double # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Double # toConstr :: Double -> Constr # dataTypeOf :: Double -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Double) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Double) # gmapT :: (forall b. Data b => b -> b) -> Double -> Double # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Double -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Double -> r # gmapQ :: (forall d. Data d => d -> u) -> Double -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Double -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Double -> m Double # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Double -> m Double # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Double -> m Double # | |||||
| Enum Double |
List generators have extremely peculiar behavior, mandated by Haskell Report 2010:
Since: base-2.1 | ||||
Defined in GHC.Internal.Float | |||||
| Floating Double | Since: base-2.1 | ||||
| RealFloat Double | Since: base-2.1 | ||||
Defined in GHC.Internal.Float Methods floatRadix :: Double -> Integer # floatDigits :: Double -> Int # floatRange :: Double -> (Int, Int) # decodeFloat :: Double -> (Integer, Int) # encodeFloat :: Integer -> Int -> Double # significand :: Double -> Double # scaleFloat :: Int -> Double -> Double # isInfinite :: Double -> Bool # isDenormalized :: Double -> Bool # isNegativeZero :: Double -> Bool # | |||||
| Storable Double | Since: base-2.1 | ||||
| Num Double | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:
Since: base-2.1 | ||||
| Read Double | Since: base-2.1 | ||||
| Fractional Double | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.
Since: base-2.1 | ||||
| Real Double | Beware that
Since: base-2.1 | ||||
Defined in GHC.Internal.Float Methods toRational :: Double -> Rational # | |||||
| RealFrac Double | Beware that results for non-finite arguments are garbage:
and get even more non-sensical if you ask for Since: base-2.1 | ||||
| Show Double | Since: base-2.1 | ||||
| Eq Double | Note that due to the presence of
Also note that
| ||||
| Ord Double | IEEE 754 IEEE 754-2008, section 5.11 requires that if at least one of arguments of
IEEE 754-2008, section 5.10 defines Thus, users must be extremely cautious when using Moving further, the behaviour of IEEE 754-2008 compliant | ||||
| Generic1 (URec Double :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Foldable (UDouble :: Type -> Type) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UDouble m -> m # foldMap :: Monoid m => (a -> m) -> UDouble a -> m # foldMap' :: Monoid m => (a -> m) -> UDouble a -> m # foldr :: (a -> b -> b) -> b -> UDouble a -> b # foldr' :: (a -> b -> b) -> b -> UDouble a -> b # foldl :: (b -> a -> b) -> b -> UDouble a -> b # foldl' :: (b -> a -> b) -> b -> UDouble a -> b # foldr1 :: (a -> a -> a) -> UDouble a -> a # foldl1 :: (a -> a -> a) -> UDouble a -> a # elem :: Eq a => a -> UDouble a -> Bool # maximum :: Ord a => UDouble a -> a # minimum :: Ord a => UDouble a -> a # | |||||
| Traversable (UDouble :: Type -> Type) | Since: base-4.9.0.0 | ||||
| Functor (URec Double :: Type -> Type) | Since: base-4.9.0.0 | ||||
| Generic (URec Double p) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Show (URec Double p) | Since: base-4.9.0.0 | ||||
| Eq (URec Double p) | Since: base-4.9.0.0 | ||||
| Ord (URec Double p) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Generics Methods compare :: URec Double p -> URec Double p -> Ordering # (<) :: URec Double p -> URec Double p -> Bool # (<=) :: URec Double p -> URec Double p -> Bool # (>) :: URec Double p -> URec Double p -> Bool # (>=) :: URec Double p -> URec Double p -> Bool # | |||||
| data URec Double (p :: k) | Used for marking occurrences of Since: base-4.9.0.0 | ||||
| type Rep1 (URec Double :: k -> Type) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Generics | |||||
| type Rep (URec Double p) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Generics | |||||
Single-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE single-precision type.
Instances
| PrintfArg Float | Since: base-2.1 | ||||
Defined in Text.Printf | |||||
| Data Float | Since: base-4.0.0.0 | ||||
Defined in GHC.Internal.Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Float -> c Float # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Float # dataTypeOf :: Float -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Float) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Float) # gmapT :: (forall b. Data b => b -> b) -> Float -> Float # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Float -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Float -> r # gmapQ :: (forall d. Data d => d -> u) -> Float -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Float -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Float -> m Float # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Float -> m Float # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Float -> m Float # | |||||
| Enum Float |
List generators have extremely peculiar behavior, mandated by Haskell Report 2010:
Since: base-2.1 | ||||
Defined in GHC.Internal.Float | |||||
| Floating Float | Since: base-2.1 | ||||
| RealFloat Float | Since: base-2.1 | ||||
Defined in GHC.Internal.Float Methods floatRadix :: Float -> Integer # floatDigits :: Float -> Int # floatRange :: Float -> (Int, Int) # decodeFloat :: Float -> (Integer, Int) # encodeFloat :: Integer -> Int -> Float # significand :: Float -> Float # scaleFloat :: Int -> Float -> Float # isInfinite :: Float -> Bool # isDenormalized :: Float -> Bool # isNegativeZero :: Float -> Bool # | |||||
| Storable Float | Since: base-2.1 | ||||
| Num Float | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:
Since: base-2.1 | ||||
| Read Float | Since: base-2.1 | ||||
| Fractional Float | This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.
Since: base-2.1 | ||||
| Real Float | Beware that
Since: base-2.1 | ||||
Defined in GHC.Internal.Float Methods toRational :: Float -> Rational # | |||||
| RealFrac Float | Beware that results for non-finite arguments are garbage:
and get even more non-sensical if you ask for Since: base-2.1 | ||||
| Show Float | Since: base-2.1 | ||||
| Eq Float | Note that due to the presence of
Also note that
| ||||
| Ord Float | See | ||||
| Generic1 (URec Float :: k -> Type) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Foldable (UFloat :: Type -> Type) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => UFloat m -> m # foldMap :: Monoid m => (a -> m) -> UFloat a -> m # foldMap' :: Monoid m => (a -> m) -> UFloat a -> m # foldr :: (a -> b -> b) -> b -> UFloat a -> b # foldr' :: (a -> b -> b) -> b -> UFloat a -> b # foldl :: (b -> a -> b) -> b -> UFloat a -> b # foldl' :: (b -> a -> b) -> b -> UFloat a -> b # foldr1 :: (a -> a -> a) -> UFloat a -> a # foldl1 :: (a -> a -> a) -> UFloat a -> a # elem :: Eq a => a -> UFloat a -> Bool # maximum :: Ord a => UFloat a -> a # minimum :: Ord a => UFloat a -> a # | |||||
| Traversable (UFloat :: Type -> Type) | Since: base-4.9.0.0 | ||||
| Functor (URec Float :: Type -> Type) | Since: base-4.9.0.0 | ||||
| Generic (URec Float p) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Show (URec Float p) | |||||
| Eq (URec Float p) | |||||
| Ord (URec Float p) | |||||
Defined in GHC.Internal.Generics | |||||
| data URec Float (p :: k) | Used for marking occurrences of Since: base-4.9.0.0 | ||||
| type Rep1 (URec Float :: k -> Type) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Generics | |||||
| type Rep (URec Float p) | |||||
Defined in GHC.Internal.Generics | |||||
Arbitrary precision integers. In contrast with fixed-size integral types
such as Int, the Integer type represents the entire infinite range of
integers.
Integers are stored in a kind of sign-magnitude form, hence do not expect two's complement form when using bit operations.
If the value is small (i.e., fits into an Int), the IS constructor is
used. Otherwise IP and IN constructors are used to store a BigNat
representing the positive or the negative value magnitude, respectively.
Invariant: IP and IN are used iff the value does not fit in IS.
Instances
| PrintfArg Integer | Since: base-2.1 |
Defined in Text.Printf | |
| Bits Integer | Since: base-2.1 |
Defined in GHC.Internal.Bits Methods (.&.) :: Integer -> Integer -> Integer # (.|.) :: Integer -> Integer -> Integer # xor :: Integer -> Integer -> Integer # complement :: Integer -> Integer # shift :: Integer -> Int -> Integer # rotate :: Integer -> Int -> Integer # setBit :: Integer -> Int -> Integer # clearBit :: Integer -> Int -> Integer # complementBit :: Integer -> Int -> Integer # testBit :: Integer -> Int -> Bool # bitSizeMaybe :: Integer -> Maybe Int # shiftL :: Integer -> Int -> Integer # unsafeShiftL :: Integer -> Int -> Integer # shiftR :: Integer -> Int -> Integer # unsafeShiftR :: Integer -> Int -> Integer # rotateL :: Integer -> Int -> Integer # | |
| Data Integer | Since: base-4.0.0.0 |
Defined in GHC.Internal.Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Integer -> c Integer # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Integer # toConstr :: Integer -> Constr # dataTypeOf :: Integer -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Integer) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Integer) # gmapT :: (forall b. Data b => b -> b) -> Integer -> Integer # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Integer -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Integer -> r # gmapQ :: (forall d. Data d => d -> u) -> Integer -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Integer -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Integer -> m Integer # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Integer -> m Integer # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Integer -> m Integer # | |
| Enum Integer | Since: base-2.1 |
| Ix Integer | Since: base-2.1 |
Defined in GHC.Internal.Ix | |
| Num Integer | Since: base-2.1 |
| Read Integer | Since: base-2.1 |
| Integral Integer | Since: base-2.0.1 |
Defined in GHC.Internal.Real | |
| Real Integer | Since: base-2.0.1 |
Defined in GHC.Internal.Real Methods toRational :: Integer -> Rational # | |
| Show Integer | Since: base-2.1 |
| Eq Integer | |
| Ord Integer | |
class a ~# b => (a :: k) ~ (b :: k) infix 4 #
Lifted, homogeneous equality. By lifted, we mean that it
can be bogus (deferred type error). By homogeneous, the two
types a and b must have the same kinds.
Non-empty (and non-strict) list type.
Since: base-4.9.0.0
Constructors
| a :| [a] infixr 5 |
Instances
| MonadZip NonEmpty | Since: base-4.9.0.0 | ||||
| Foldable1 NonEmpty | Since: base-4.18.0.0 | ||||
Defined in Data.Foldable1 Methods fold1 :: Semigroup m => NonEmpty m -> m # foldMap1 :: Semigroup m => (a -> m) -> NonEmpty a -> m # foldMap1' :: Semigroup m => (a -> m) -> NonEmpty a -> m # toNonEmpty :: NonEmpty a -> NonEmpty a # maximum :: Ord a => NonEmpty a -> a # minimum :: Ord a => NonEmpty a -> a # foldrMap1 :: (a -> b) -> (a -> b -> b) -> NonEmpty a -> b # foldlMap1' :: (a -> b) -> (b -> a -> b) -> NonEmpty a -> b # foldlMap1 :: (a -> b) -> (b -> a -> b) -> NonEmpty a -> b # foldrMap1' :: (a -> b) -> (a -> b -> b) -> NonEmpty a -> b # | |||||
| Eq1 NonEmpty | Since: base-4.10.0.0 | ||||
| Ord1 NonEmpty | Since: base-4.10.0.0 | ||||
Defined in Data.Functor.Classes | |||||
| Read1 NonEmpty | Since: base-4.10.0.0 | ||||
Defined in Data.Functor.Classes | |||||
| Show1 NonEmpty | Since: base-4.10.0.0 | ||||
| Applicative NonEmpty | Since: base-4.9.0.0 | ||||
| Functor NonEmpty | Since: base-4.9.0.0 | ||||
| Monad NonEmpty | Since: base-4.9.0.0 | ||||
| MonadFix NonEmpty | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Control.Monad.Fix | |||||
| Foldable NonEmpty | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.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 # elem :: Eq a => a -> NonEmpty a -> Bool # maximum :: Ord a => NonEmpty a -> a # minimum :: Ord a => NonEmpty a -> a # | |||||
| Traversable NonEmpty | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Data.Traversable | |||||
| Generic1 NonEmpty | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| Semigroup (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Data a => Data (NonEmpty a) | Since: base-4.9.0.0 | ||||
Defined in GHC.Internal.Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> NonEmpty a -> c (NonEmpty a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (NonEmpty a) # toConstr :: NonEmpty a -> Constr # dataTypeOf :: NonEmpty a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (NonEmpty a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (NonEmpty a)) # gmapT :: (forall b. Data b => b -> b) -> NonEmpty a -> NonEmpty a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> NonEmpty a -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> NonEmpty a -> r # gmapQ :: (forall d. Data d => d -> u) -> NonEmpty a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> NonEmpty a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> NonEmpty a -> m (NonEmpty a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> NonEmpty a -> m (NonEmpty a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> NonEmpty a -> m (NonEmpty a) # | |||||
| Generic (NonEmpty a) | |||||
Defined in GHC.Internal.Generics Associated Types
| |||||
| IsList (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Read a => Read (NonEmpty a) | Since: base-4.11.0.0 | ||||
| Show a => Show (NonEmpty a) | Since: base-4.11.0.0 | ||||
| Eq a => Eq (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Ord a => Ord (NonEmpty a) | Since: base-4.9.0.0 | ||||
| type Rep1 NonEmpty | Since: base-4.6.0.0 | ||||
Defined in GHC.Internal.Generics type Rep1 NonEmpty = D1 ('MetaData "NonEmpty" "GHC.Internal.Base" "ghc-internal" '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 []))) | |||||
| type Rep (NonEmpty a) | Since: base-4.6.0.0 | ||||
Defined in GHC.Internal.Generics type Rep (NonEmpty a) = D1 ('MetaData "NonEmpty" "GHC.Internal.Base" "ghc-internal" '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.Internal.IsList | |||||
error :: HasCallStack => [Char] -> a #
error stops execution and displays an error message.
errorWithoutStackTrace :: [Char] -> a #
A variant of error that does not produce a stack trace.
Since: base-4.9.0.0
undefined :: HasCallStack => a #
flip :: (a -> b -> c) -> b -> a -> c #
takes its (first) two arguments in the reverse order of flip ff.
flip f x y = f y x
flip . flip = id
Examples
>>>flip (++) "hello" "world""worldhello"
>>>let (.>) = flip (.) in (+1) .> show $ 5"6"
($!) :: (a -> b) -> a -> b infixr 0 #
Strict (call-by-value) application operator. It takes a function and an argument, evaluates the argument to weak head normal form (WHNF), then calls the function with that value.
until :: (a -> Bool) -> (a -> a) -> a -> a #
yields the result of applying until p ff until p holds.
utility function converting a Char to a show function that
simply prepends the character unchanged.
showString :: String -> ShowS #
utility function converting a String to a show function that
simply prepends the string unchanged.
(^^) :: (Fractional a, Integral b) => a -> b -> a infixr 8 #
raise a number to an integral power
gcd :: Integral a => a -> a -> a #
is the non-negative factor of both gcd x yx and y of which
every common factor of x and y is also a factor; for example
, gcd 4 2 = 2, gcd (-4) 6 = 2 = gcd 0 44. = gcd 0 00.
(That is, the common divisor that is "greatest" in the divisibility
preordering.)
Note: Since for signed fixed-width integer types, ,
the result may be negative if one of the arguments is abs minBound < 0 (and
necessarily is if the other is minBound0 or ) for such types.minBound
lcm :: Integral a => a -> a -> a #
is the smallest positive integer that both lcm x yx and y divide.
($>) :: Functor f => f a -> b -> f b infixl 4 #
Flipped version of <$.
Examples
Replace the contents of a with a constant
Maybe IntString:
>>>Nothing $> "foo"Nothing
>>>Just 90210 $> "foo"Just "foo"
Replace the contents of an
with a constant Either Int IntString, resulting in an :Either
Int String
>>>Left 8675309 $> "foo"Left 8675309
>>>Right 8675309 $> "foo"Right "foo"
Replace each element of a list with a constant String:
>>>[1,2,3] $> "foo"["foo","foo","foo"]
Replace the second element of a pair with a constant String:
>>>(1,2) $> "foo"(1,"foo")
Since: base-4.7.0.0
on :: (b -> b -> c) -> (a -> b) -> a -> a -> c infixl 0 #
runs the binary function on b u x yb on the results of applying
unary function u to two arguments x and y. From the opposite
perspective, it transforms two inputs and combines the outputs.
(op `on` f) x y = f x `op` f y
Examples
>>>sortBy (compare `on` length) [[0, 1, 2], [0, 1], [], [0]][[],[0],[0,1],[0,1,2]]
>>>((+) `on` length) [1, 2, 3] [-1]4
>>>((,) `on` (*2)) 2 3(4,6)
Algebraic properties
(&) :: a -> (a -> b) -> b infixl 1 #
& is a reverse application operator. This provides notational
convenience. Its precedence is one higher than that of the forward
application operator $, which allows & to be nested in $.
This is a version of , where flip idid is specialized from a -> a to (a -> b) -> (a -> b)
which by the associativity of (->) is (a -> b) -> a -> b.
flipping this yields a -> (a -> b) -> b which is the type signature of &
Examples
>>>5 & (+1) & show"6"
>>>sqrt $ [1 / n^2 | n <- [1..1000]] & sum & (*6)3.1406380562059946
Since: base-4.8.0.0
applyWhen :: Bool -> (a -> a) -> a -> a #
applyWhen applies a function to a value if a condition is true,
otherwise, it returns the value unchanged.
It is equivalent to .flip (bool id)
Examples
>>>map (\x -> applyWhen (odd x) (*2) x) [1..10][2,2,6,4,10,6,14,8,18,10]
>>>map (\x -> applyWhen (length x > 6) ((++ "...") . take 3) x) ["Hi!", "This is amazing", "Hope you're doing well today!", ":D"]["Hi!","Thi...","Hop...",":D"]
Algebraic properties
Since: base-4.18.0.0
Instances
| Alternative ReadP | Since: base-4.6.0.0 |
| Applicative ReadP | Since: base-4.6.0.0 |
| Functor ReadP | Since: base-2.1 |
| Monad ReadP | Since: base-2.1 |
| MonadPlus ReadP | Since: base-2.1 |
| MonadFail ReadP | Since: base-4.9.0.0 |
Defined in GHC.Internal.Text.ParserCombinators.ReadP | |
readP_to_S :: ReadP a -> ReadS a #
Converts a parser into a Haskell ReadS-style function.
This is the main way in which you can "run" a ReadP parser:
the expanded type is
readP_to_S :: ReadP a -> String -> [(a,String)]
readS_to_P :: ReadS a -> ReadP a #
Converts a Haskell ReadS-style function into a parser. Warning: This introduces local backtracking in the resulting parser, and therefore a possible inefficiency.
The lex function reads a single lexeme from the input, discarding
initial white space, and returning the characters that constitute the
lexeme. If the input string contains only white space, lex returns a
single successful `lexeme' consisting of the empty string. (Thus
.) If there is no legal lexeme at the
beginning of the input string, lex "" = [("","")]lex fails (i.e. returns []).
This lexer is not completely faithful to the Haskell lexical syntax in the following respects:
- Qualified names are not handled properly
- Octal and hexadecimal numerics are not recognized as a single token
- Comments are not treated properly
Instances
| Alternative ReadPrec | Since: base-4.6.0.0 |
| Applicative ReadPrec | Since: base-4.6.0.0 |
Defined in GHC.Internal.Text.ParserCombinators.ReadPrec | |
| Functor ReadPrec | Since: base-2.1 |
| Monad ReadPrec | Since: base-2.1 |
| MonadPlus ReadPrec | Since: base-2.1 |
| MonadFail ReadPrec | Since: base-4.9.0.0 |
Defined in GHC.Internal.Text.ParserCombinators.ReadPrec | |
readPrec_to_P :: ReadPrec a -> Int -> ReadP a #
readP_to_Prec :: (Int -> ReadP a) -> ReadPrec a #
readPrec_to_S :: ReadPrec a -> Int -> ReadS a #
readS_to_Prec :: (Int -> ReadS a) -> ReadPrec a #
data ThreadStatus #
The current status of a thread
Constructors
| ThreadRunning | the thread is currently runnable or running |
| ThreadFinished | the thread has finished |
| ThreadBlocked BlockReason | the thread is blocked on some resource |
| ThreadDied | the thread received an uncaught exception |
Instances
| Show ThreadStatus | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync Methods showsPrec :: Int -> ThreadStatus -> ShowS # show :: ThreadStatus -> String # showList :: [ThreadStatus] -> ShowS # | |
| Eq ThreadStatus | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync | |
| Ord ThreadStatus | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync Methods compare :: ThreadStatus -> ThreadStatus -> Ordering # (<) :: ThreadStatus -> ThreadStatus -> Bool # (<=) :: ThreadStatus -> ThreadStatus -> Bool # (>) :: ThreadStatus -> ThreadStatus -> Bool # (>=) :: ThreadStatus -> ThreadStatus -> Bool # max :: ThreadStatus -> ThreadStatus -> ThreadStatus # min :: ThreadStatus -> ThreadStatus -> ThreadStatus # | |
data BlockReason #
Constructors
| BlockedOnMVar | blocked on |
| BlockedOnBlackHole | blocked on a computation in progress by another thread |
| BlockedOnException | blocked in |
| BlockedOnSTM | blocked in |
| BlockedOnForeignCall | currently in a foreign call |
| BlockedOnOther | blocked on some other resource. Without |
Instances
| Show BlockReason | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync Methods showsPrec :: Int -> BlockReason -> ShowS # show :: BlockReason -> String # showList :: [BlockReason] -> ShowS # | |
| Eq BlockReason | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync | |
| Ord BlockReason | Since: base-4.3.0.0 |
Defined in GHC.Internal.Conc.Sync Methods compare :: BlockReason -> BlockReason -> Ordering # (<) :: BlockReason -> BlockReason -> Bool # (<=) :: BlockReason -> BlockReason -> Bool # (>) :: BlockReason -> BlockReason -> Bool # (>=) :: BlockReason -> BlockReason -> Bool # max :: BlockReason -> BlockReason -> BlockReason # min :: BlockReason -> BlockReason -> BlockReason # | |
Shared memory locations that support atomic memory transactions.
threadStatus :: ThreadId -> IO ThreadStatus #
Query the current execution status of a thread.
newStablePtrPrimMVar :: MVar a -> IO (StablePtr PrimMVar) #
Make a StablePtr that can be passed to the C function
hs_try_putmvar(). The RTS wants a StablePtr to the
underlying MVar#, but a StablePtr# can only refer to
lifted types, so we have to cheat by coercing.
readMaybe :: Read a => String -> Maybe a #
Parse a string using the Read instance.
Succeeds if there is exactly one valid result.
>>>readMaybe "123" :: Maybe IntJust 123
>>>readMaybe "hello" :: Maybe IntNothing
Since: base-4.6.0.0
read :: Read a => String -> a #
The read function reads input from a string, which must be
completely consumed by the input process. read fails with an error if the
parse is unsuccessful, and it is therefore discouraged from being used in
real applications. Use readMaybe or readEither for safe alternatives.
>>>read "123" :: Int123
>>>read "hello" :: Int*** Exception: Prelude.read: no parse
newtype Alt (f :: k -> Type) (a :: k) #
Monoid under <|>.
Alt l <> Alt r == Alt (l <|> r)
Examples
>>>Alt (Just 12) <> Alt (Just 24)Alt {getAlt = Just 12}
>>>Alt Nothing <> Alt (Just 24)Alt {getAlt = Just 24}
Since: base-4.8.0.0
Instances
| Generic1 (Alt f :: k -> Type) | |||||
Defined in GHC.Internal.Data.Semigroup.Internal Associated Types
| |||||
| MonadZip f => MonadZip (Alt f) | Since: base-4.8.0.0 | ||||
| Foldable1 f => Foldable1 (Alt f) | Since: base-4.18.0.0 | ||||
Defined in Data.Foldable1 Methods fold1 :: Semigroup m => Alt f m -> m # foldMap1 :: Semigroup m => (a -> m) -> Alt f a -> m # foldMap1' :: Semigroup m => (a -> m) -> Alt f a -> m # toNonEmpty :: Alt f a -> NonEmpty a # maximum :: Ord a => Alt f a -> a # minimum :: Ord a => Alt f a -> a # foldrMap1 :: (a -> b) -> (a -> b -> b) -> Alt f a -> b # foldlMap1' :: (a -> b) -> (b -> a -> b) -> Alt f a -> b # foldlMap1 :: (a -> b) -> (b -> a -> b) -> Alt f a -> b # foldrMap1' :: (a -> b) -> (a -> b -> b) -> Alt f a -> b # | |||||
| Contravariant f => Contravariant (Alt f) | |||||
| Alternative f => Alternative (Alt f) | Since: base-4.8.0.0 | ||||
| Applicative f => Applicative (Alt f) | Since: base-4.8.0.0 | ||||
| Functor f => Functor (Alt f) | Since: base-4.8.0.0 | ||||
| Monad f => Monad (Alt f) | Since: base-4.8.0.0 | ||||
| MonadPlus f => MonadPlus (Alt f) | Since: base-4.8.0.0 | ||||
| MonadFix f => MonadFix (Alt f) | Since: base-4.8.0.0 | ||||
Defined in GHC.Internal.Control.Monad.Fix | |||||
| Foldable f => Foldable (Alt f) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Alt f m -> m # foldMap :: Monoid m => (a -> m) -> Alt f a -> m # foldMap' :: Monoid m => (a -> m) -> Alt f a -> m # foldr :: (a -> b -> b) -> b -> Alt f a -> b # foldr' :: (a -> b -> b) -> b -> Alt f a -> b # foldl :: (b -> a -> b) -> b -> Alt f a -> b # foldl' :: (b -> a -> b) -> b -> Alt f a -> b # foldr1 :: (a -> a -> a) -> Alt f a -> a # foldl1 :: (a -> a -> a) -> Alt f a -> a # elem :: Eq a => a -> Alt f a -> Bool # maximum :: Ord a => Alt f a -> a # minimum :: Ord a => Alt f a -> a # | |||||
| Traversable f => Traversable (Alt f) | Since: base-4.12.0.0 | ||||
| Alternative f => Monoid (Alt f a) | Since: base-4.8.0.0 | ||||
| Alternative f => Semigroup (Alt f a) | Since: base-4.9.0.0 | ||||
| (Data (f a), Data a, Typeable f) => Data (Alt f a) | Since: base-4.8.0.0 | ||||
Defined in GHC.Internal.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 :: forall r r'. (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) # | |||||
| Enum (f a) => Enum (Alt f a) | Since: base-4.8.0.0 | ||||
| Generic (Alt f a) | |||||
Defined in GHC.Internal.Data.Semigroup.Internal Associated Types
| |||||
| Num (f a) => Num (Alt f a) | Since: base-4.8.0.0 | ||||
| Read (f a) => Read (Alt f a) | Since: base-4.8.0.0 | ||||
| Show (f a) => Show (Alt f a) | Since: base-4.8.0.0 | ||||
| Eq (f a) => Eq (Alt f a) | Since: base-4.8.0.0 | ||||
| Ord (f a) => Ord (Alt f a) | Since: base-4.8.0.0 | ||||
Defined in GHC.Internal.Data.Semigroup.Internal | |||||
| type Rep1 (Alt f :: k -> Type) | Since: base-4.8.0.0 | ||||
Defined in GHC.Internal.Data.Semigroup.Internal | |||||
| type Rep (Alt f a) | Since: base-4.8.0.0 | ||||
Defined in GHC.Internal.Data.Semigroup.Internal | |||||
newtype Ap (f :: k -> Type) (a :: k) #
This data type witnesses the lifting of a Monoid into an
Applicative pointwise.
Examples
>>>Ap (Just [1, 2, 3]) <> Ap NothingAp {getAp = Nothing}
>>>Ap [Sum 10, Sum 20] <> Ap [Sum 1, Sum 2]Ap {getAp = [Sum {getSum = 11},Sum {getSum = 12},Sum {getSum = 21},Sum {getSum = 22}]}
Since: base-4.12.0.0
Instances
| Generic1 (Ap f :: k -> Type) | |||||
Defined in GHC.Internal.Data.Monoid Associated Types
| |||||
| Foldable1 f => Foldable1 (Ap f) | Since: base-4.18.0.0 | ||||
Defined in Data.Foldable1 Methods fold1 :: Semigroup m => Ap f m -> m # foldMap1 :: Semigroup m => (a -> m) -> Ap f a -> m # foldMap1' :: Semigroup m => (a -> m) -> Ap f a -> m # toNonEmpty :: Ap f a -> NonEmpty a # maximum :: Ord a => Ap f a -> a # minimum :: Ord a => Ap f a -> a # foldrMap1 :: (a -> b) -> (a -> b -> b) -> Ap f a -> b # foldlMap1' :: (a -> b) -> (b -> a -> b) -> Ap f a -> b # foldlMap1 :: (a -> b) -> (b -> a -> b) -> Ap f a -> b # foldrMap1' :: (a -> b) -> (a -> b -> b) -> Ap f a -> b # | |||||
| Alternative f => Alternative (Ap f) | Since: base-4.12.0.0 | ||||
| Applicative f => Applicative (Ap f) | Since: base-4.12.0.0 | ||||
| Functor f => Functor (Ap f) | Since: base-4.12.0.0 | ||||
| Monad f => Monad (Ap f) | Since: base-4.12.0.0 | ||||
| MonadPlus f => MonadPlus (Ap f) | Since: base-4.12.0.0 | ||||
| MonadFail f => MonadFail (Ap f) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Monoid | |||||
| MonadFix f => MonadFix (Ap f) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Control.Monad.Fix | |||||
| Foldable f => Foldable (Ap f) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Foldable Methods fold :: Monoid m => Ap f m -> m # foldMap :: Monoid m => (a -> m) -> Ap f a -> m # foldMap' :: Monoid m => (a -> m) -> Ap f a -> m # foldr :: (a -> b -> b) -> b -> Ap f a -> b # foldr' :: (a -> b -> b) -> b -> Ap f a -> b # foldl :: (b -> a -> b) -> b -> Ap f a -> b # foldl' :: (b -> a -> b) -> b -> Ap f a -> b # foldr1 :: (a -> a -> a) -> Ap f a -> a # foldl1 :: (a -> a -> a) -> Ap f a -> a # elem :: Eq a => a -> Ap f a -> Bool # maximum :: Ord a => Ap f a -> a # | |||||
| Traversable f => Traversable (Ap f) | Since: base-4.12.0.0 | ||||
| (Applicative f, Monoid a) => Monoid (Ap f a) | Since: base-4.12.0.0 | ||||
| (Applicative f, Semigroup a) => Semigroup (Ap f a) | Since: base-4.12.0.0 | ||||
| (Data (f a), Data a, Typeable f) => Data (Ap f a) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Ap f a -> c (Ap f a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Ap f a) # toConstr :: Ap f a -> Constr # dataTypeOf :: Ap f a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Ap f a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Ap f a)) # gmapT :: (forall b. Data b => b -> b) -> Ap f a -> Ap f a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Ap f a -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Ap f a -> r # gmapQ :: (forall d. Data d => d -> u) -> Ap f a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Ap f a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Ap f a -> m (Ap f a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Ap f a -> m (Ap f a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Ap f a -> m (Ap f a) # | |||||
| (Applicative f, Bounded a) => Bounded (Ap f a) | Since: base-4.12.0.0 | ||||
| Enum (f a) => Enum (Ap f a) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Monoid | |||||
| Generic (Ap f a) | |||||
Defined in GHC.Internal.Data.Monoid Associated Types
| |||||
| (Applicative f, Num a) => Num (Ap f a) | Note that even if the underlying Commutativity:
Additive inverse:
Distributivity:
Since: base-4.12.0.0 | ||||
| Read (f a) => Read (Ap f a) | Since: base-4.12.0.0 | ||||
| Show (f a) => Show (Ap f a) | Since: base-4.12.0.0 | ||||
| Eq (f a) => Eq (Ap f a) | Since: base-4.12.0.0 | ||||
| Ord (f a) => Ord (Ap f a) | Since: base-4.12.0.0 | ||||
| type Rep1 (Ap f :: k -> Type) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Monoid | |||||
| type Rep (Ap f a) | Since: base-4.12.0.0 | ||||
Defined in GHC.Internal.Data.Monoid | |||||
foldrM :: (Foldable t, Monad m) => (a -> b -> m b) -> b -> t a -> m b #
Right-to-left monadic fold over the elements of a structure.
Given a structure t with elements (a, b, c, ..., x, y), the result of
a fold with an operator function f is equivalent to:
foldrM f z t = do
yy <- f y z
xx <- f x yy
...
bb <- f b cc
aa <- f a bb
return aa -- Just @return z@ when the structure is emptyFor a Monad m, given two functions f1 :: a -> m b and f2 :: b -> m c,
their Kleisli composition (f1 >=> f2) :: a -> m c is defined by:
(f1 >=> f2) a = f1 a >>= f2
Another way of thinking about foldrM is that it amounts to an application
to z of a Kleisli composition:
foldrM f z t = f y >=> f x >=> ... >=> f b >=> f a $ z
The monadic effects of foldrM are sequenced from right to left, and e.g.
folds of infinite lists will diverge.
If at some step the bind operator ( short-circuits (as with, e.g.,
>>=)mzero in a MonadPlus), the evaluated effects will be from a tail of the
element sequence. If you want to evaluate the monadic effects in
left-to-right order, or perhaps be able to short-circuit after an initial
sequence of elements, you'll need to use foldlM instead.
If the monadic effects don't short-circuit, the outermost application of
f is to the leftmost element a, so that, ignoring effects, the result
looks like a right fold:
a `f` (b `f` (c `f` (... (x `f` (y `f` z))))).
Examples
Basic usage:
>>>let f i acc = do { print i ; return $ i : acc }>>>foldrM f [] [0..3]3 2 1 0 [0,1,2,3]
foldlM :: (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b #
Left-to-right monadic fold over the elements of a structure.
Given a structure t with elements (a, b, ..., w, x, y), the result of
a fold with an operator function f is equivalent to:
foldlM f z t = do
aa <- f z a
bb <- f aa b
...
xx <- f ww x
yy <- f xx y
return yy -- Just @return z@ when the structure is emptyFor a Monad m, given two functions f1 :: a -> m b and f2 :: b -> m c,
their Kleisli composition (f1 >=> f2) :: a -> m c is defined by:
(f1 >=> f2) a = f1 a >>= f2
Another way of thinking about foldlM is that it amounts to an application
to z of a Kleisli composition:
foldlM f z t =
flip f a >=> flip f b >=> ... >=> flip f x >=> flip f y $ zThe monadic effects of foldlM are sequenced from left to right.
If at some step the bind operator ( short-circuits (as with, e.g.,
>>=)mzero in a MonadPlus), the evaluated effects will be from an initial
segment of the element sequence. If you want to evaluate the monadic
effects in right-to-left order, or perhaps be able to short-circuit after
processing a tail of the sequence of elements, you'll need to use foldrM
instead.
If the monadic effects don't short-circuit, the outermost application of
f is to the rightmost element y, so that, ignoring effects, the result
looks like a left fold:
((((z `f` a) `f` b) ... `f` w) `f` x) `f` y
Examples
Basic usage:
>>>let f a e = do { print e ; return $ e : a }>>>foldlM f [] [0..3]0 1 2 3 [3,2,1,0]
traverse_ :: (Foldable t, Applicative f) => (a -> f b) -> t a -> f () #
Map each element of a structure to an Applicative action, evaluate these
actions from left to right, and ignore the results. For a version that
doesn't ignore the results see traverse.
traverse_ is just like mapM_, but generalised to Applicative actions.
Examples
Basic usage:
>>>traverse_ print ["Hello", "world", "!"]"Hello" "world" "!"
for_ :: (Foldable t, Applicative f) => t a -> (a -> f b) -> f () #
for_ is traverse_ with its arguments flipped. For a version
that doesn't ignore the results see for. This
is forM_ generalised to Applicative actions.
for_ is just like forM_, but generalised to Applicative actions.
Examples
Basic usage:
>>>for_ [1..4] print1 2 3 4
sequenceA_ :: (Foldable t, Applicative f) => t (f a) -> f () #
Evaluate each action in the structure from left to right, and
ignore the results. For a version that doesn't ignore the results
see sequenceA.
sequenceA_ is just like sequence_, but generalised to Applicative
actions.
Examples
Basic usage:
>>>sequenceA_ [print "Hello", print "world", print "!"]"Hello" "world" "!"
A monad supporting atomic memory transactions.
Instances
| Alternative STM | Takes the first non- Since: base-4.8.0.0 |
| Applicative STM | Since: base-4.8.0.0 |
| Functor STM | Since: base-4.3.0.0 |
| Monad STM | Since: base-4.3.0.0 |
| MonadPlus STM | Takes the first non- Since: base-4.3.0.0 |
| Monoid a => Monoid (STM a) | Since: base-4.17.0.0 |
| Semigroup a => Semigroup (STM a) | Since: base-4.17.0.0 |
reportHeapOverflow :: IO () #
numCapabilities :: Int #
the value passed to the +RTS -N flag. This is the number of
Haskell threads that can run truly simultaneously at any given
time, and is typically set to the number of physical processor cores on
the machine.
Strictly speaking it is better to use getNumCapabilities, because
the number of capabilities might vary at runtime.
getNumProcessors :: IO Int #
Returns the number of CPUs that the machine has
Since: base-4.5.0.0
childHandler :: SomeException -> IO () #
labelThread :: ThreadId -> String -> IO () #
labelThread stores a string as identifier for this thread. This
identifier will be used in the debugging output to make distinction of
different threads easier (otherwise you only have the thread state object's
address in the heap). It also emits an event to the RTS eventlog.
listThreads :: IO [ThreadId] #
List the Haskell threads of the current process.
Since: base-4.18
unsafeIOToSTM :: IO a -> STM a #
Unsafely performs IO in the STM monad. Beware: this is a highly dangerous thing to do.
- The STM implementation will often run transactions multiple times, so you need to be prepared for this if your IO has any side effects.
- The STM implementation will abort transactions that are known to
be invalid and need to be restarted. This may happen in the middle
of
unsafeIOToSTM, so make sure you don't acquire any resources that need releasing (exception handlers are ignored when aborting the transaction). That includes doing any IO using Handles, for example. Getting this wrong will probably lead to random deadlocks. - The transaction may have seen an inconsistent view of memory when
the IO runs. Invariants that you expect to be true throughout
your program may not be true inside a transaction, due to the
way transactions are implemented. Normally this wouldn't be visible
to the programmer, but using
unsafeIOToSTMcan expose it.
atomically :: STM a -> IO a #
Perform a series of STM actions atomically.
Using atomically inside an unsafePerformIO or unsafeInterleaveIO
subverts some of guarantees that STM provides. It makes it possible to
run a transaction inside of another transaction, depending on when the
thunk is evaluated. If a nested transaction is attempted, an exception
is thrown by the runtime. It is possible to safely use atomically inside
unsafePerformIO or unsafeInterleaveIO, but the typechecker does not
rule out programs that may attempt nested transactions, meaning that
the programmer must take special care to prevent these.
However, there are functions for creating transactional variables that
can always be safely called in unsafePerformIO. See: newTVarIO,
newTChanIO,
newBroadcastTChanIO,
newTQueueIO,
newTBQueueIO, and
newTMVarIO.
Using unsafePerformIO inside of atomically is also dangerous but for
different reasons. See unsafeIOToSTM for more on this.
Retry execution of the current memory transaction because it has seen
values in TVars which mean that it should not continue (e.g. the TVars
represent a shared buffer that is now empty). The implementation may
block the thread until one of the TVars that it has read from has been
updated. (GHC only)
throwSTM :: Exception e => e -> STM a #
A variant of throw that can only be used within the STM monad.
Throwing an exception in STM aborts the transaction and propagates the
exception. If the exception is caught via catchSTM, only the changes
enclosed by the catch are rolled back; changes made outside of catchSTM
persist.
If the exception is not caught inside of the STM, it is re-thrown by
atomically, and the entire STM is rolled back.
Although throwSTM has a type that is an instance of the type of throw, the
two functions are subtly different:
throw e `seq` x ===> throw e throwSTM e `seq` x ===> x
The first example will cause the exception e to be raised,
whereas the second one won't. In fact, throwSTM will only cause
an exception to be raised when it is used within the STM monad.
The throwSTM variant should be used in preference to throw to
raise an exception within the STM monad because it guarantees
ordering with respect to other STM operations, whereas throw
does not.
newTVarIO :: a -> IO (TVar a) #
IO version of newTVar. This is useful for creating top-level
TVars using unsafePerformIO, because using
atomically inside unsafePerformIO isn't
possible.
readTVarIO :: TVar a -> IO a #
reportStackOverflow :: IO () #
reportError :: SomeException -> IO () #
setUncaughtExceptionHandler :: (SomeException -> IO ()) -> IO () #
getUncaughtExceptionHandler :: IO (SomeException -> IO ()) #
type HandlerFun = ForeignPtr Word8 -> IO () #
setHandler :: Signal -> Maybe (HandlerFun, Dynamic) -> IO (Maybe (HandlerFun, Dynamic)) #
runHandlers :: ForeignPtr Word8 -> Signal -> IO () #
ensureIOManagerIsRunning :: IO () #
ioManagerCapabilitiesChanged :: IO () #
registerDelay :: Int -> IO (TVar Bool) #
Switch the value of returned TVar from initial value False to True
after a given number of microseconds. The caveats associated with
threadDelay also apply.
Be careful not to exceed maxBound :: Int, which on 32-bit machines is only
2147483647 μs, less than 36 minutes.
The Item type function returns the type of items of the structure
l.
Instances
| type Item ByteArray | |
Defined in Data.Array.Byte | |
| type Item Version | |
Defined in GHC.Internal.IsList | |
| type Item CallStack | |
Defined in GHC.Internal.IsList | |
| type Item (NonEmpty a) | |
Defined in GHC.Internal.IsList | |
| type Item (ZipList a) | |
Defined in GHC.Internal.IsList | |
| type Item [a] | |
Defined in GHC.Internal.IsList type Item [a] = a | |
sortWith :: Ord b => (a -> b) -> [a] -> [a] #
The sortWith function sorts a list of elements using the
user supplied function to project something out of each element
In general if the user supplied function is expensive to compute then
you should probably be using sortOn, as it only needs
to compute it once for each element. sortWith, on the other hand
must compute the mapping function for every comparison that it performs.
groupWith :: Ord b => (a -> b) -> [a] -> [[a]] #
The groupWith function uses the user supplied function which
projects an element out of every list element in order to first sort the
input list and then to form groups by equality on these projected elements
newtype ArrowMonad (a :: Type -> Type -> Type) b #
The ArrowApply class is equivalent to Monad: any monad gives rise
to a Kleisli arrow, and any instance of ArrowApply defines a monad.
Constructors
| ArrowMonad (a () b) |
Instances
| ArrowPlus a => Alternative (ArrowMonad a) | Since: base-4.6.0.0 |
Defined in GHC.Internal.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] # | |
| Arrow a => Applicative (ArrowMonad a) | Since: base-4.6.0.0 |
Defined in GHC.Internal.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 # | |
| Arrow a => Functor (ArrowMonad a) | Since: base-4.6.0.0 |
Defined in GHC.Internal.Control.Arrow Methods fmap :: (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b # (<$) :: a0 -> ArrowMonad a b -> ArrowMonad a a0 # | |
| ArrowApply a => Monad (ArrowMonad a) | Since: base-2.1 |
Defined in GHC.Internal.Control.Arrow Methods (>>=) :: ArrowMonad a a0 -> (a0 -> ArrowMonad a b) -> ArrowMonad a b # (>>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b # return :: a0 -> ArrowMonad a a0 # | |
| (ArrowApply a, ArrowPlus a) => MonadPlus (ArrowMonad a) | Since: base-4.6.0.0 |
Defined in GHC.Internal.Control.Arrow | |
newtype Kleisli (m :: Type -> Type) a b #
Kleisli arrows of a monad.
Constructors
| Kleisli | |
Fields
| |
Instances
| Monad m => Category (Kleisli m :: Type -> Type -> Type) | Since: base-3.0 | ||||
| Generic1 (Kleisli m a :: Type -> Type) | |||||
Defined in GHC.Internal.Control.Arrow Associated Types
| |||||
| Monad m => Arrow (Kleisli m) | Since: base-2.1 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| Monad m => ArrowApply (Kleisli m) | Since: base-2.1 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| Monad m => ArrowChoice (Kleisli m) | Since: base-2.1 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| MonadFix m => ArrowLoop (Kleisli m) | Beware that for many monads (those for which the Since: base-2.1 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| MonadPlus m => ArrowPlus (Kleisli m) | Since: base-2.1 | ||||
| MonadPlus m => ArrowZero (Kleisli m) | Since: base-2.1 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| Alternative m => Alternative (Kleisli m a) | Since: base-4.14.0.0 | ||||
| Applicative m => Applicative (Kleisli m a) | Since: base-4.14.0.0 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| Functor m => Functor (Kleisli m a) | Since: base-4.14.0.0 | ||||
| Monad m => Monad (Kleisli m a) | Since: base-4.14.0.0 | ||||
| MonadPlus m => MonadPlus (Kleisli m a) | Since: base-4.14.0.0 | ||||
| Generic (Kleisli m a b) | |||||
Defined in GHC.Internal.Control.Arrow Associated Types
| |||||
| type Rep1 (Kleisli m a :: Type -> Type) | Since: base-4.14.0.0 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
| type Rep (Kleisli m a b) | Since: base-4.14.0.0 | ||||
Defined in GHC.Internal.Control.Arrow | |||||
(<<^) :: Arrow a => a c d -> (b -> c) -> a b d infixr 1 #
Precomposition with a pure function (right-to-left variant).
(^<<) :: Arrow a => (c -> d) -> a b c -> a b d infixr 1 #
Postcomposition with a pure function (right-to-left variant).
leftApp :: ArrowApply a => a b c -> a (Either b d) (Either c d) #
Any instance of ArrowApply can be made into an instance of
ArrowChoice by defining left = leftApp.
printf :: PrintfType r => String -> r #
Format a variable number of arguments with the C-style formatting string.
>>>printf "%s, %d, %.4f" "hello" 123 pihello, 123, 3.1416
The return value is either String or ( (which
should be IO a)(, but Haskell's type system
makes this hard).IO ())
The format string consists of ordinary characters and
conversion specifications, which specify how to format
one of the arguments to printf in the output string. A
format specification is introduced by the % character;
this character can be self-escaped into the format string
using %%. A format specification ends with a
format character that provides the primary information about
how to format the value. The rest of the conversion
specification is optional. In order, one may have flag
characters, a width specifier, a precision specifier, and
type-specific modifier characters.
Unlike C printf(3), the formatting of this printf
is driven by the argument type; formatting is type specific. The
types formatted by printf "out of the box" are:
printf is also extensible to support other types: see below.
A conversion specification begins with the
character %, followed by zero or more of the following flags:
- left adjust (default is right adjust) + always use a sign (+ or -) for signed conversions space leading space for positive numbers in signed conversions 0 pad with zeros rather than spaces # use an \"alternate form\": see below
When both flags are given, - overrides 0 and + overrides space.
A negative width specifier in a * conversion is treated as
positive but implies the left adjust flag.
The "alternate form" for unsigned radix conversions is
as in C printf(3):
%o prefix with a leading 0 if needed %x prefix with a leading 0x if nonzero %X prefix with a leading 0X if nonzero %b prefix with a leading 0b if nonzero %[eEfFgG] ensure that the number contains a decimal point
Any flags are followed optionally by a field width:
num field width * as num, but taken from argument list
The field width is a minimum, not a maximum: it will be expanded as needed to avoid mutilating a value.
Any field width is followed optionally by a precision:
.num precision . same as .0 .* as num, but taken from argument list
Negative precision is taken as 0. The meaning of the precision depends on the conversion type.
Integral minimum number of digits to show RealFloat number of digits after the decimal point String maximum number of characters
The precision for Integral types is accomplished by zero-padding. If both precision and zero-pad are given for an Integral field, the zero-pad is ignored.
Any precision is followed optionally for Integral types by a width modifier; the only use of this modifier being to set the implicit size of the operand for conversion of a negative operand to unsigned:
hh Int8 h Int16 l Int32 ll Int64 L Int64
The specification ends with a format character:
c character Integral d decimal Integral o octal Integral x hexadecimal Integral X hexadecimal Integral b binary Integral u unsigned decimal Integral f floating point RealFloat F floating point RealFloat g general format float RealFloat G general format float RealFloat e exponent format float RealFloat E exponent format float RealFloat s string String v default format any type
The "%v" specifier is provided for all built-in types, and should be provided for user-defined type formatters as well. It picks a "best" representation for the given type. For the built-in types the "%v" specifier is converted as follows:
c Char u other unsigned Integral d other signed Integral g RealFloat s String
Mismatch between the argument types and the format string, as well as any other syntactic or semantic errors in the format string, will cause an exception to be thrown at runtime.
Note that the formatting for RealFloat types is
currently a bit different from that of C printf(3),
conforming instead to showEFloat,
showFFloat and showGFloat (and their
alternate versions showFFloatAlt and
showGFloatAlt). This is hard to fix: the fixed
versions would format in a backward-incompatible way.
In any case the Haskell behavior is generally more
sensible than the C behavior. A brief summary of some
key differences:
- Haskell
printfnever uses the default "6-digit" precision used by C printf. - Haskell
printftreats the "precision" specifier as indicating the number of digits after the decimal point. - Haskell
printfprints the exponent of e-format numbers without a gratuitous plus sign, and with the minimum possible number of digits. - Haskell
printfwill place a zero after a decimal point when possible.