entwine-0.0.2: entwine - Concurrency tools

Safe HaskellNone
LanguageHaskell98

Entwine.P

Contents

Synopsis

Primitive types

Bool

data Bool #

Constructors

False 
True 
Instances
Bounded Bool

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Bool

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Bool -> Bool #

pred :: Bool -> Bool #

toEnum :: Int -> Bool #

fromEnum :: Bool -> Int #

enumFrom :: Bool -> [Bool] #

enumFromThen :: Bool -> Bool -> [Bool] #

enumFromTo :: Bool -> Bool -> [Bool] #

enumFromThenTo :: Bool -> Bool -> Bool -> [Bool] #

Eq Bool 
Instance details

Defined in GHC.Classes

Methods

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

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

Ord Bool 
Instance details

Defined in GHC.Classes

Methods

compare :: Bool -> Bool -> Ordering #

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

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

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

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

max :: Bool -> Bool -> Bool #

min :: Bool -> Bool -> Bool #

Read Bool

Since: base-2.1

Instance details

Defined in GHC.Read

Show Bool 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Bool -> ShowS #

show :: Bool -> String #

showList :: [Bool] -> ShowS #

Ix Bool

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

range :: (Bool, Bool) -> [Bool] #

index :: (Bool, Bool) -> Bool -> Int #

unsafeIndex :: (Bool, Bool) -> Bool -> Int

inRange :: (Bool, Bool) -> Bool -> Bool #

rangeSize :: (Bool, Bool) -> Int #

unsafeRangeSize :: (Bool, Bool) -> Int

Generic Bool 
Instance details

Defined in GHC.Generics

Associated Types

type Rep Bool :: * -> * #

Methods

from :: Bool -> Rep Bool x #

to :: Rep Bool x -> Bool #

Lift Bool 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Bool -> Q Exp #

SingKind Bool

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Associated Types

type DemoteRep Bool :: *

Methods

fromSing :: Sing a -> DemoteRep Bool

SingI False

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

sing :: Sing False

SingI True

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

sing :: Sing True

type Rep Bool 
Instance details

Defined in GHC.Generics

type Rep Bool = D1 (MetaData "Bool" "GHC.Types" "ghc-prim" False) (C1 (MetaCons "False" PrefixI False) (U1 :: * -> *) :+: C1 (MetaCons "True" PrefixI False) (U1 :: * -> *))
data Sing (a :: Bool) 
Instance details

Defined in GHC.Generics

data Sing (a :: Bool) where
type DemoteRep Bool 
Instance details

Defined in GHC.Generics

type DemoteRep Bool = Bool

bool :: a -> a -> Bool -> a #

Case analysis for the Bool type. bool x y p evaluates to x when p is False, and evaluates to y when p is True.

This is equivalent to if p then y else x; that is, one can think of it as an if-then-else construct with its arguments reordered.

Examples

Expand

Basic usage:

>>> bool "foo" "bar" True
"bar"
>>> bool "foo" "bar" False
"foo"

Confirm that bool x y p and if p then y else x are equivalent:

>>> let p = True; x = "bar"; y = "foo"
>>> bool x y p == if p then y else x
True
>>> let p = False
>>> bool x y p == if p then y else x
True

Since: base-4.7.0.0

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

Boolean "and"

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

Boolean "or"

not :: Bool -> Bool #

Boolean "not"

otherwise :: Bool #

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

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

Char

data Char #

The character type Char is an enumeration whose values represent Unicode (or equivalently ISO/IEC 10646) code points (i.e. characters, see http://www.unicode.org/ for details). This set extends the ISO 8859-1 (Latin-1) character set (the first 256 characters), which is itself an extension of the ASCII character set (the first 128 characters). A character literal in Haskell has type Char.

To convert a Char to or from the corresponding Int value defined by Unicode, use toEnum and fromEnum from the Enum class respectively (or equivalently ord and chr).

Instances
Bounded Char

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Char

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Char -> Char #

pred :: Char -> Char #

toEnum :: Int -> Char #

fromEnum :: Char -> Int #

enumFrom :: Char -> [Char] #

enumFromThen :: Char -> Char -> [Char] #

enumFromTo :: Char -> Char -> [Char] #

enumFromThenTo :: Char -> Char -> Char -> [Char] #

Eq Char 
Instance details

Defined in GHC.Classes

Methods

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

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

Ord Char 
Instance details

Defined in GHC.Classes

Methods

compare :: Char -> Char -> Ordering #

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

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

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

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

max :: Char -> Char -> Char #

min :: Char -> Char -> Char #

Read Char

Since: base-2.1

Instance details

Defined in GHC.Read

Show Char

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Char -> ShowS #

show :: Char -> String #

showList :: [Char] -> ShowS #

Ix Char

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

range :: (Char, Char) -> [Char] #

index :: (Char, Char) -> Char -> Int #

unsafeIndex :: (Char, Char) -> Char -> Int

inRange :: (Char, Char) -> Char -> Bool #

rangeSize :: (Char, Char) -> Int #

unsafeRangeSize :: (Char, Char) -> Int

Lift Char 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Char -> Q Exp #

ErrorList Char 
Instance details

Defined in Control.Monad.Trans.Error

Methods

listMsg :: String -> [Char] #

Generic1 (URec Char :: k -> *) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Char) :: k -> * #

Methods

from1 :: URec Char a -> Rep1 (URec Char) a #

to1 :: Rep1 (URec Char) a -> URec Char a #

Functor (URec Char :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

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

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

Foldable (URec Char :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Char m -> m #

foldMap :: Monoid m => (a -> m) -> URec Char a -> m #

foldr :: (a -> b -> b) -> b -> URec Char a -> b #

foldr' :: (a -> b -> b) -> b -> URec Char a -> b #

foldl :: (b -> a -> b) -> b -> URec Char a -> b #

foldl' :: (b -> a -> b) -> b -> URec Char a -> b #

foldr1 :: (a -> a -> a) -> URec Char a -> a #

foldl1 :: (a -> a -> a) -> URec Char a -> a #

toList :: URec Char a -> [a] #

null :: URec Char a -> Bool #

length :: URec Char a -> Int #

elem :: Eq a => a -> URec Char a -> Bool #

maximum :: Ord a => URec Char a -> a #

minimum :: Ord a => URec Char a -> a #

sum :: Num a => URec Char a -> a #

product :: Num a => URec Char a -> a #

Traversable (URec Char :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Char a -> f (URec Char b) #

sequenceA :: Applicative f => URec Char (f a) -> f (URec Char a) #

mapM :: Monad m => (a -> m b) -> URec Char a -> m (URec Char b) #

sequence :: Monad m => URec Char (m a) -> m (URec Char a) #

Eq (URec Char p) 
Instance details

Defined in GHC.Generics

Methods

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

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

Ord (URec Char p) 
Instance details

Defined in GHC.Generics

Methods

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

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

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

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

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

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

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

Show (URec Char p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Char p -> ShowS #

show :: URec Char p -> String #

showList :: [URec Char p] -> ShowS #

Generic (URec Char p) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Char p) :: * -> * #

Methods

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

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

data URec Char (p :: k)

Used for marking occurrences of Char#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Char (p :: k) = UChar {}
type Rep1 (URec Char :: k -> *) 
Instance details

Defined in GHC.Generics

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

Defined in GHC.Generics

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

Int

data Integer #

Invariant: Jn# and Jp# are used iff value doesn't fit in S#

Useful properties resulting from the invariants:

Instances
Enum Integer

Since: base-2.1

Instance details

Defined in GHC.Enum

Eq Integer 
Instance details

Defined in GHC.Integer.Type

Methods

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

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

Integral Integer

Since: base-2.0.1

Instance details

Defined in GHC.Real

Num Integer

Since: base-2.1

Instance details

Defined in GHC.Num

Ord Integer 
Instance details

Defined in GHC.Integer.Type

Read Integer

Since: base-2.1

Instance details

Defined in GHC.Read

Real Integer

Since: base-2.0.1

Instance details

Defined in GHC.Real

Show Integer

Since: base-2.1

Instance details

Defined in GHC.Show

Ix Integer

Since: base-2.1

Instance details

Defined in GHC.Arr

Lift Integer 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Integer -> Q Exp #

data Int #

A fixed-precision integer type with at least the range [-2^29 .. 2^29-1]. The exact range for a given implementation can be determined by using minBound and maxBound from the Bounded class.

Instances
Bounded Int

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

minBound :: Int #

maxBound :: Int #

Enum Int

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Int -> Int #

pred :: Int -> Int #

toEnum :: Int -> Int #

fromEnum :: Int -> Int #

enumFrom :: Int -> [Int] #

enumFromThen :: Int -> Int -> [Int] #

enumFromTo :: Int -> Int -> [Int] #

enumFromThenTo :: Int -> Int -> Int -> [Int] #

Eq Int 
Instance details

Defined in GHC.Classes

Methods

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

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

Integral Int

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

quot :: Int -> Int -> Int #

rem :: Int -> Int -> Int #

div :: Int -> Int -> Int #

mod :: Int -> Int -> Int #

quotRem :: Int -> Int -> (Int, Int) #

divMod :: Int -> Int -> (Int, Int) #

toInteger :: Int -> Integer #

Num Int

Since: base-2.1

Instance details

Defined in GHC.Num

Methods

(+) :: Int -> Int -> Int #

(-) :: Int -> Int -> Int #

(*) :: Int -> Int -> Int #

negate :: Int -> Int #

abs :: Int -> Int #

signum :: Int -> Int #

fromInteger :: Integer -> Int #

Ord Int 
Instance details

Defined in GHC.Classes

Methods

compare :: Int -> Int -> Ordering #

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

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

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

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

max :: Int -> Int -> Int #

min :: Int -> Int -> Int #

Read Int

Since: base-2.1

Instance details

Defined in GHC.Read

Real Int

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

toRational :: Int -> Rational #

Show Int

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Int -> ShowS #

show :: Int -> String #

showList :: [Int] -> ShowS #

Ix Int

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

range :: (Int, Int) -> [Int] #

index :: (Int, Int) -> Int -> Int #

unsafeIndex :: (Int, Int) -> Int -> Int

inRange :: (Int, Int) -> Int -> Bool #

rangeSize :: (Int, Int) -> Int #

unsafeRangeSize :: (Int, Int) -> Int

Lift Int 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Int -> Q Exp #

Generic1 (URec Int :: k -> *) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Int) :: k -> * #

Methods

from1 :: URec Int a -> Rep1 (URec Int) a #

to1 :: Rep1 (URec Int) a -> URec Int a #

Functor (URec Int :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Int a -> URec Int b #

(<$) :: a -> URec Int b -> URec Int a #

Foldable (URec Int :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Int m -> m #

foldMap :: Monoid m => (a -> m) -> URec Int a -> m #

foldr :: (a -> b -> b) -> b -> URec Int a -> b #

foldr' :: (a -> b -> b) -> b -> URec Int a -> b #

foldl :: (b -> a -> b) -> b -> URec Int a -> b #

foldl' :: (b -> a -> b) -> b -> URec Int a -> b #

foldr1 :: (a -> a -> a) -> URec Int a -> a #

foldl1 :: (a -> a -> a) -> URec Int a -> a #

toList :: URec Int a -> [a] #

null :: URec Int a -> Bool #

length :: URec Int a -> Int #

elem :: Eq a => a -> URec Int a -> Bool #

maximum :: Ord a => URec Int a -> a #

minimum :: Ord a => URec Int a -> a #

sum :: Num a => URec Int a -> a #

product :: Num a => URec Int a -> a #

Traversable (URec Int :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Int a -> f (URec Int b) #

sequenceA :: Applicative f => URec Int (f a) -> f (URec Int a) #

mapM :: Monad m => (a -> m b) -> URec Int a -> m (URec Int b) #

sequence :: Monad m => URec Int (m a) -> m (URec Int a) #

Eq (URec Int p) 
Instance details

Defined in GHC.Generics

Methods

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

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

Ord (URec Int p) 
Instance details

Defined in GHC.Generics

Methods

compare :: URec Int p -> URec Int p -> Ordering #

(<) :: URec Int p -> URec Int p -> Bool #

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

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

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

max :: URec Int p -> URec Int p -> URec Int p #

min :: URec Int p -> URec Int p -> URec Int p #

Show (URec Int p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Int p -> ShowS #

show :: URec Int p -> String #

showList :: [URec Int p] -> ShowS #

Generic (URec Int p) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Int p) :: * -> * #

Methods

from :: URec Int p -> Rep (URec Int p) x #

to :: Rep (URec Int p) x -> URec Int p #

data URec Int (p :: k)

Used for marking occurrences of Int#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Int (p :: k) = UInt {}
type Rep1 (URec Int :: k -> *) 
Instance details

Defined in GHC.Generics

type Rep1 (URec Int :: k -> *) = D1 (MetaData "URec" "GHC.Generics" "base" False) (C1 (MetaCons "UInt" PrefixI True) (S1 (MetaSel (Just "uInt#") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (UInt :: k -> *)))
type Rep (URec Int p) 
Instance details

Defined in GHC.Generics

type Rep (URec Int p) = D1 (MetaData "URec" "GHC.Generics" "base" False) (C1 (MetaCons "UInt" PrefixI True) (S1 (MetaSel (Just "uInt#") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (UInt :: * -> *)))

data Int8 #

8-bit signed integer type

Instances
Bounded Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

succ :: Int8 -> Int8 #

pred :: Int8 -> Int8 #

toEnum :: Int -> Int8 #

fromEnum :: Int8 -> Int #

enumFrom :: Int8 -> [Int8] #

enumFromThen :: Int8 -> Int8 -> [Int8] #

enumFromTo :: Int8 -> Int8 -> [Int8] #

enumFromThenTo :: Int8 -> Int8 -> Int8 -> [Int8] #

Eq Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Integral Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

quot :: Int8 -> Int8 -> Int8 #

rem :: Int8 -> Int8 -> Int8 #

div :: Int8 -> Int8 -> Int8 #

mod :: Int8 -> Int8 -> Int8 #

quotRem :: Int8 -> Int8 -> (Int8, Int8) #

divMod :: Int8 -> Int8 -> (Int8, Int8) #

toInteger :: Int8 -> Integer #

Num Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

(+) :: Int8 -> Int8 -> Int8 #

(-) :: Int8 -> Int8 -> Int8 #

(*) :: Int8 -> Int8 -> Int8 #

negate :: Int8 -> Int8 #

abs :: Int8 -> Int8 #

signum :: Int8 -> Int8 #

fromInteger :: Integer -> Int8 #

Ord Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int8 -> Int8 -> Ordering #

(<) :: Int8 -> Int8 -> Bool #

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

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

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

max :: Int8 -> Int8 -> Int8 #

min :: Int8 -> Int8 -> Int8 #

Read Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

toRational :: Int8 -> Rational #

Show Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int8 -> ShowS #

show :: Int8 -> String #

showList :: [Int8] -> ShowS #

Ix Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

range :: (Int8, Int8) -> [Int8] #

index :: (Int8, Int8) -> Int8 -> Int #

unsafeIndex :: (Int8, Int8) -> Int8 -> Int

inRange :: (Int8, Int8) -> Int8 -> Bool #

rangeSize :: (Int8, Int8) -> Int #

unsafeRangeSize :: (Int8, Int8) -> Int

Lift Int8 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Int8 -> Q Exp #

Bits Int8

Since: base-2.1

Instance details

Defined in GHC.Int

FiniteBits Int8

Since: base-4.6.0.0

Instance details

Defined in GHC.Int

data Int16 #

16-bit signed integer type

Instances
Bounded Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Eq Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Integral Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Ord Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int16 -> Int16 -> Ordering #

(<) :: Int16 -> Int16 -> Bool #

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

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

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

max :: Int16 -> Int16 -> Int16 #

min :: Int16 -> Int16 -> Int16 #

Read Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

toRational :: Int16 -> Rational #

Show Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int16 -> ShowS #

show :: Int16 -> String #

showList :: [Int16] -> ShowS #

Ix Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Lift Int16 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Int16 -> Q Exp #

Bits Int16

Since: base-2.1

Instance details

Defined in GHC.Int

FiniteBits Int16

Since: base-4.6.0.0

Instance details

Defined in GHC.Int

data Int32 #

32-bit signed integer type

Instances
Bounded Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Eq Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Integral Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Ord Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int32 -> Int32 -> Ordering #

(<) :: Int32 -> Int32 -> Bool #

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

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

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

max :: Int32 -> Int32 -> Int32 #

min :: Int32 -> Int32 -> Int32 #

Read Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

toRational :: Int32 -> Rational #

Show Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int32 -> ShowS #

show :: Int32 -> String #

showList :: [Int32] -> ShowS #

Ix Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Lift Int32 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Int32 -> Q Exp #

Bits Int32

Since: base-2.1

Instance details

Defined in GHC.Int

FiniteBits Int32

Since: base-4.6.0.0

Instance details

Defined in GHC.Int

data Int64 #

64-bit signed integer type

Instances
Bounded Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Eq Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Integral Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Ord Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int64 -> Int64 -> Ordering #

(<) :: Int64 -> Int64 -> Bool #

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

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

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

max :: Int64 -> Int64 -> Int64 #

min :: Int64 -> Int64 -> Int64 #

Read Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Real Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

toRational :: Int64 -> Rational #

Show Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int64 -> ShowS #

show :: Int64 -> String #

showList :: [Int64] -> ShowS #

Ix Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Lift Int64 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Int64 -> Q Exp #

Bits Int64

Since: base-2.1

Instance details

Defined in GHC.Int

FiniteBits Int64

Since: base-4.6.0.0

Instance details

Defined in GHC.Int

div :: Integral a => a -> a -> a infixl 7 #

integer division truncated toward negative infinity

toInteger :: Integral a => a -> Integer #

conversion to Integer

Word

data Word64 #

64-bit unsigned integer type

Instances
Bounded Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Eq Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

(==) :: Word64 -> Word64 -> Bool #

(/=) :: Word64 -> Word64 -> Bool #

Integral Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Ord Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Read Word64

Since: base-2.1

Instance details

Defined in GHC.Read

Real Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Show Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Ix Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Lift Word64 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Word64 -> Q Exp #

Bits Word64

Since: base-2.1

Instance details

Defined in GHC.Word

FiniteBits Word64

Since: base-4.6.0.0

Instance details

Defined in GHC.Word

Real

fromIntegral :: (Integral a, Num b) => a -> b #

general coercion from integral types

fromRational :: Fractional a => Rational -> a #

Conversion from a Rational (that is Ratio Integer). A floating literal stands for an application of fromRational to a value of type Rational, so such literals have type (Fractional a) => a.

data Double #

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
Eq Double 
Instance details

Defined in GHC.Classes

Methods

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

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

Floating Double

Since: base-2.1

Instance details

Defined in GHC.Float

Ord Double 
Instance details

Defined in GHC.Classes

Read Double

Since: base-2.1

Instance details

Defined in GHC.Read

RealFloat Double

Since: base-2.1

Instance details

Defined in GHC.Float

Lift Double 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Double -> Q Exp #

Generic1 (URec Double :: k -> *) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec Double) :: k -> * #

Methods

from1 :: URec Double a -> Rep1 (URec Double) a #

to1 :: Rep1 (URec Double) a -> URec Double a #

Functor (URec Double :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Double a -> URec Double b #

(<$) :: a -> URec Double b -> URec Double a #

Foldable (URec Double :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Double m -> m #

foldMap :: Monoid m => (a -> m) -> URec Double a -> m #

foldr :: (a -> b -> b) -> b -> URec Double a -> b #

foldr' :: (a -> b -> b) -> b -> URec Double a -> b #

foldl :: (b -> a -> b) -> b -> URec Double a -> b #

foldl' :: (b -> a -> b) -> b -> URec Double a -> b #

foldr1 :: (a -> a -> a) -> URec Double a -> a #

foldl1 :: (a -> a -> a) -> URec Double a -> a #

toList :: URec Double a -> [a] #

null :: URec Double a -> Bool #

length :: URec Double a -> Int #

elem :: Eq a => a -> URec Double a -> Bool #

maximum :: Ord a => URec Double a -> a #

minimum :: Ord a => URec Double a -> a #

sum :: Num a => URec Double a -> a #

product :: Num a => URec Double a -> a #

Traversable (URec Double :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Double a -> f (URec Double b) #

sequenceA :: Applicative f => URec Double (f a) -> f (URec Double a) #

mapM :: Monad m => (a -> m b) -> URec Double a -> m (URec Double b) #

sequence :: Monad m => URec Double (m a) -> m (URec Double a) #

Eq (URec Double p) 
Instance details

Defined in GHC.Generics

Methods

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

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

Ord (URec Double p) 
Instance details

Defined in GHC.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 #

max :: URec Double p -> URec Double p -> URec Double p #

min :: URec Double p -> URec Double p -> URec Double p #

Show (URec Double p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Double p -> ShowS #

show :: URec Double p -> String #

showList :: [URec Double p] -> ShowS #

Generic (URec Double p) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec Double p) :: * -> * #

Methods

from :: URec Double p -> Rep (URec Double p) x #

to :: Rep (URec Double p) x -> URec Double p #

data URec Double (p :: k)

Used for marking occurrences of Double#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec Double (p :: k) = UDouble {}
type Rep1 (URec Double :: k -> *) 
Instance details

Defined in GHC.Generics

type Rep1 (URec Double :: k -> *) = D1 (MetaData "URec" "GHC.Generics" "base" False) (C1 (MetaCons "UDouble" PrefixI True) (S1 (MetaSel (Just "uDouble#") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (UDouble :: k -> *)))
type Rep (URec Double p) 
Instance details

Defined in GHC.Generics

type Rep (URec Double p) = D1 (MetaData "URec" "GHC.Generics" "base" False) (C1 (MetaCons "UDouble" PrefixI True) (S1 (MetaSel (Just "uDouble#") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (UDouble :: * -> *)))

Algebraic structures

Semigroup

class Semigroup a where #

The class of semigroups (types with an associative binary operation).

Instances should satisfy the associativity law:

Since: base-4.9.0.0

Minimal complete definition

(<>)

Methods

(<>) :: a -> a -> a infixr 6 #

An associative operation.

sconcat :: NonEmpty a -> a #

Reduce a non-empty list with <>

The default definition should be sufficient, but this can be overridden for efficiency.

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

Repeat a value n times.

Given that this works on a Semigroup it is allowed to fail if you request 0 or fewer repetitions, and the default definition will do so.

By making this a member of the class, idempotent semigroups and monoids can upgrade this to execute in O(1) by picking stimes = stimesIdempotent or stimes = stimesIdempotentMonoid respectively.

Instances
Semigroup Ordering

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Semigroup ()

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: () -> () -> () #

sconcat :: NonEmpty () -> () #

stimes :: Integral b => b -> () -> () #

Semigroup Void

Since: base-4.9.0.0

Instance details

Defined in Data.Void

Methods

(<>) :: Void -> Void -> Void #

sconcat :: NonEmpty Void -> Void #

stimes :: Integral b => b -> Void -> Void #

Semigroup All

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

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

sconcat :: NonEmpty All -> All #

stimes :: Integral b => b -> All -> All #

Semigroup Any

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

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

sconcat :: NonEmpty Any -> Any #

stimes :: Integral b => b -> Any -> Any #

Semigroup IntSet

Since: containers-0.5.7

Instance details

Defined in Data.IntSet.Internal

Semigroup Finalizer # 
Instance details

Defined in Entwine.Data.Finalizer

Semigroup [a]

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

sconcat :: NonEmpty [a] -> [a] #

stimes :: Integral b => b -> [a] -> [a] #

Semigroup a => Semigroup (Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

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

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

Semigroup a => Semigroup (IO a)

Since: base-4.10.0.0

Instance details

Defined in GHC.Base

Methods

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

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

stimes :: Integral b => b -> IO a -> IO a #

Semigroup a => Semigroup (Concurrently a)

Only defined by async for base >= 4.9

Since: async-2.1.0

Instance details

Defined in Control.Concurrent.Async

Ord a => Semigroup (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

stimes :: Integral b => b -> Min a -> Min a #

Ord a => Semigroup (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

stimes :: Integral b => b -> Max a -> Max a #

Semigroup (First a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

stimes :: Integral b => b -> First a -> First a #

Semigroup (Last a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

stimes :: Integral b => b -> Last a -> Last a #

Monoid m => Semigroup (WrappedMonoid m)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Semigroup a => Semigroup (Option a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

stimes :: Integral b => b -> Option a -> Option a #

Semigroup (First a)

Since: base-4.9.0.0

Instance details

Defined in Data.Monoid

Methods

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

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

stimes :: Integral b => b -> First a -> First a #

Semigroup (Last a)

Since: base-4.9.0.0

Instance details

Defined in Data.Monoid

Methods

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

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

stimes :: Integral b => b -> Last a -> Last a #

Semigroup a => Semigroup (Dual a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

stimes :: Integral b => b -> Dual a -> Dual a #

Semigroup (Endo a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Endo a -> Endo a -> Endo a #

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

stimes :: Integral b => b -> Endo a -> Endo a #

Num a => Semigroup (Sum a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

stimes :: Integral b => b -> Sum a -> Sum a #

Num a => Semigroup (Product a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(<>) :: Product a -> Product a -> Product a #

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

stimes :: Integral b => b -> Product a -> Product a #

Semigroup a => Semigroup (Down a)

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

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

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

stimes :: Integral b => b -> Down a -> Down a #

Semigroup (NonEmpty a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

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

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

Semigroup (IntMap a)

Since: containers-0.5.7

Instance details

Defined in Data.IntMap.Internal

Methods

(<>) :: IntMap a -> IntMap a -> IntMap a #

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

stimes :: Integral b => b -> IntMap a -> IntMap a #

Semigroup (Seq a)

Since: containers-0.5.7

Instance details

Defined in Data.Sequence.Internal

Methods

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

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

stimes :: Integral b => b -> Seq a -> Seq a #

Ord a => Semigroup (Set a)

Since: containers-0.5.7

Instance details

Defined in Data.Set.Internal

Methods

(<>) :: Set a -> Set a -> Set a #

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

stimes :: Integral b => b -> Set a -> Set a #

Semigroup (MergeSet a) 
Instance details

Defined in Data.Set.Internal

Methods

(<>) :: MergeSet a -> MergeSet a -> MergeSet a #

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

stimes :: Integral b => b -> MergeSet a -> MergeSet a #

Semigroup b => Semigroup (a -> b)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

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

stimes :: Integral b0 => b0 -> (a -> b) -> a -> b #

Semigroup (Either a b)

Since: base-4.9.0.0

Instance details

Defined in Data.Either

Methods

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

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

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

(Semigroup a, Semigroup b) => Semigroup (a, b)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b) -> (a, b) -> (a, b) #

sconcat :: NonEmpty (a, b) -> (a, b) #

stimes :: Integral b0 => b0 -> (a, b) -> (a, b) #

Semigroup (Proxy s)

Since: base-4.9.0.0

Instance details

Defined in Data.Proxy

Methods

(<>) :: Proxy s -> Proxy s -> Proxy s #

sconcat :: NonEmpty (Proxy s) -> Proxy s #

stimes :: Integral b => b -> Proxy s -> Proxy s #

Ord k => Semigroup (Map k v) 
Instance details

Defined in Data.Map.Internal

Methods

(<>) :: Map k v -> Map k v -> Map k v #

sconcat :: NonEmpty (Map k v) -> Map k v #

stimes :: Integral b => b -> Map k v -> Map k v #

(Semigroup a, Semigroup b, Semigroup c) => Semigroup (a, b, c)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b, c) -> (a, b, c) -> (a, b, c) #

sconcat :: NonEmpty (a, b, c) -> (a, b, c) #

stimes :: Integral b0 => b0 -> (a, b, c) -> (a, b, c) #

Alternative f => Semigroup (Alt f a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

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

sconcat :: NonEmpty (Alt f a) -> Alt f a #

stimes :: Integral b => b -> Alt f a -> Alt f a #

(Semigroup a, Semigroup b, Semigroup c, Semigroup d) => Semigroup (a, b, c, d)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) #

sconcat :: NonEmpty (a, b, c, d) -> (a, b, c, d) #

stimes :: Integral b0 => b0 -> (a, b, c, d) -> (a, b, c, d) #

(Semigroup a, Semigroup b, Semigroup c, Semigroup d, Semigroup e) => Semigroup (a, b, c, d, e)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(<>) :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) #

sconcat :: NonEmpty (a, b, c, d, e) -> (a, b, c, d, e) #

stimes :: Integral b0 => b0 -> (a, b, c, d, e) -> (a, b, c, d, e) #

Monoid

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 laws:

The method names refer to the monoid of lists under concatenation, but there are many other instances.

Some types can be viewed as a monoid in more than one way, e.g. both addition and multiplication on numbers. In such cases we often define newtypes and make those instances of Monoid, e.g. Sum and Product.

NOTE: Semigroup is a superclass of Monoid since base-4.11.0.0.

Minimal complete definition

mempty

Methods

mempty :: a #

Identity of mappend

mappend :: a -> a -> a #

An associative operation

NOTE: This method is redundant and has the default implementation mappend = '(<>)' since base-4.11.0.0.

mconcat :: [a] -> a #

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.

Instances
Monoid Ordering

Since: base-2.1

Instance details

Defined in GHC.Base

Monoid ()

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: () #

mappend :: () -> () -> () #

mconcat :: [()] -> () #

Monoid All

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: All #

mappend :: All -> All -> All #

mconcat :: [All] -> All #

Monoid Any

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Any #

mappend :: Any -> Any -> Any #

mconcat :: [Any] -> Any #

Monoid IntSet 
Instance details

Defined in Data.IntSet.Internal

Monoid Finalizer # 
Instance details

Defined in Entwine.Data.Finalizer

Monoid [a]

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: [a] #

mappend :: [a] -> [a] -> [a] #

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

Semigroup a => Monoid (Maybe a)

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

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

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: Maybe a #

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

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

Monoid a => Monoid (IO a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

mempty :: IO a #

mappend :: IO a -> IO a -> IO a #

mconcat :: [IO a] -> IO a #

(Semigroup a, Monoid a) => Monoid (Concurrently a)

Since: async-2.1.0

Instance details

Defined in Control.Concurrent.Async

(Ord a, Bounded a) => Monoid (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

mempty :: Min a #

mappend :: Min a -> Min a -> Min a #

mconcat :: [Min a] -> Min a #

(Ord a, Bounded a) => Monoid (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

mempty :: Max a #

mappend :: Max a -> Max a -> Max a #

mconcat :: [Max a] -> Max a #

Monoid m => Monoid (WrappedMonoid m)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Semigroup a => Monoid (Option a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

mempty :: Option a #

mappend :: Option a -> Option a -> Option a #

mconcat :: [Option a] -> Option a #

Monoid (First a)

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

mempty :: First a #

mappend :: First a -> First a -> First a #

mconcat :: [First a] -> First a #

Monoid (Last a)

Since: base-2.1

Instance details

Defined in Data.Monoid

Methods

mempty :: Last a #

mappend :: Last a -> Last a -> Last a #

mconcat :: [Last a] -> Last a #

Monoid a => Monoid (Dual a)

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Dual a #

mappend :: Dual a -> Dual a -> Dual a #

mconcat :: [Dual a] -> Dual a #

Monoid (Endo a)

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Endo a #

mappend :: Endo a -> Endo a -> Endo a #

mconcat :: [Endo a] -> Endo a #

Num a => Monoid (Sum a)

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Sum a #

mappend :: Sum a -> Sum a -> Sum a #

mconcat :: [Sum a] -> Sum a #

Num a => Monoid (Product a)

Since: base-2.1

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Product a #

mappend :: Product a -> Product a -> Product a #

mconcat :: [Product a] -> Product a #

Monoid a => Monoid (Down a)

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

mempty :: Down a #

mappend :: Down a -> Down a -> Down a #

mconcat :: [Down a] -> Down a #

Monoid (IntMap a) 
Instance details

Defined in Data.IntMap.Internal

Methods

mempty :: IntMap a #

mappend :: IntMap a -> IntMap a -> IntMap a #

mconcat :: [IntMap a] -> IntMap a #

Monoid (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Methods

mempty :: Seq a #

mappend :: Seq a -> Seq a -> Seq a #

mconcat :: [Seq a] -> Seq a #

Ord a => Monoid (Set a) 
Instance details

Defined in Data.Set.Internal

Methods

mempty :: Set a #

mappend :: Set a -> Set a -> Set a #

mconcat :: [Set a] -> Set a #

Monoid (MergeSet a) 
Instance details

Defined in Data.Set.Internal

Methods

mempty :: MergeSet a #

mappend :: MergeSet a -> MergeSet a -> MergeSet a #

mconcat :: [MergeSet a] -> MergeSet a #

Monoid b => Monoid (a -> b)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: a -> b #

mappend :: (a -> b) -> (a -> b) -> a -> b #

mconcat :: [a -> b] -> a -> b #

(Monoid a, Monoid b) => Monoid (a, b)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b) #

mappend :: (a, b) -> (a, b) -> (a, b) #

mconcat :: [(a, b)] -> (a, b) #

Monoid (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

mempty :: Proxy s #

mappend :: Proxy s -> Proxy s -> Proxy s #

mconcat :: [Proxy s] -> Proxy s #

Ord k => Monoid (Map k v) 
Instance details

Defined in Data.Map.Internal

Methods

mempty :: Map k v #

mappend :: Map k v -> Map k v -> Map k v #

mconcat :: [Map k v] -> Map k v #

(Monoid a, Monoid b, Monoid c) => Monoid (a, b, c)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b, c) #

mappend :: (a, b, c) -> (a, b, c) -> (a, b, c) #

mconcat :: [(a, b, c)] -> (a, b, c) #

Alternative f => Monoid (Alt f a)

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

mempty :: Alt f a #

mappend :: Alt f a -> Alt f a -> Alt f a #

mconcat :: [Alt f a] -> Alt f a #

(Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b, c, d) #

mappend :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) #

mconcat :: [(a, b, c, d)] -> (a, b, c, d) #

(Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: (a, b, c, d, e) #

mappend :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) #

mconcat :: [(a, b, c, d, e)] -> (a, b, c, d, e) #

Functor

class Functor (f :: * -> *) where #

The Functor class is used for types that can be mapped over. Instances of Functor should satisfy the following laws:

fmap id  ==  id
fmap (f . g)  ==  fmap f . fmap g

The instances of Functor for lists, Maybe and IO satisfy these laws.

Minimal complete definition

fmap

Methods

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

(<$) :: a -> f b -> f a infixl 4 #

Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version.

Instances
Functor []

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> [a] -> [b] #

(<$) :: a -> [b] -> [a] #

Functor Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

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

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

Functor IO

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> IO a -> IO b #

(<$) :: a -> IO b -> IO a #

Functor Par1 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> Par1 a -> Par1 b #

(<$) :: a -> Par1 b -> Par1 a #

Functor Q 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

fmap :: (a -> b) -> Q a -> Q b #

(<$) :: a -> Q b -> Q a #

Functor Async 
Instance details

Defined in Control.Concurrent.Async

Methods

fmap :: (a -> b) -> Async a -> Async b #

(<$) :: a -> Async b -> Async a #

Functor Concurrently 
Instance details

Defined in Control.Concurrent.Async

Methods

fmap :: (a -> b) -> Concurrently a -> Concurrently b #

(<$) :: a -> Concurrently b -> Concurrently a #

Functor Complex 
Instance details

Defined in Data.Complex

Methods

fmap :: (a -> b) -> Complex a -> Complex b #

(<$) :: a -> Complex b -> Complex a #

Functor Min

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Min a -> Min b #

(<$) :: a -> Min b -> Min a #

Functor Max

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Max a -> Max b #

(<$) :: a -> Max b -> Max a #

Functor First

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> First a -> First b #

(<$) :: a -> First b -> First a #

Functor Last

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Last a -> Last b #

(<$) :: a -> Last b -> Last a #

Functor Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a -> b) -> Option a -> Option b #

(<$) :: a -> Option b -> Option a #

Functor ZipList 
Instance details

Defined in Control.Applicative

Methods

fmap :: (a -> b) -> ZipList a -> ZipList b #

(<$) :: a -> ZipList b -> ZipList a #

Functor STM

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

fmap :: (a -> b) -> STM a -> STM b #

(<$) :: a -> STM b -> STM a #

Functor First 
Instance details

Defined in Data.Monoid

Methods

fmap :: (a -> b) -> First a -> First b #

(<$) :: a -> First b -> First a #

Functor Last 
Instance details

Defined in Data.Monoid

Methods

fmap :: (a -> b) -> Last a -> Last b #

(<$) :: a -> Last b -> Last a #

Functor Dual

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Dual a -> Dual b #

(<$) :: a -> Dual b -> Dual a #

Functor Sum

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Sum a -> Sum b #

(<$) :: a -> Sum b -> Sum a #

Functor Product

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

fmap :: (a -> b) -> Product a -> Product b #

(<$) :: a -> Product b -> Product a #

Functor Down

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

fmap :: (a -> b) -> Down a -> Down b #

(<$) :: a -> Down b -> Down a #

Functor ReadP

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

fmap :: (a -> b) -> ReadP a -> ReadP b #

(<$) :: a -> ReadP b -> ReadP a #

Functor NonEmpty

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

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

Functor IntMap 
Instance details

Defined in Data.IntMap.Internal

Methods

fmap :: (a -> b) -> IntMap a -> IntMap b #

(<$) :: a -> IntMap b -> IntMap a #

Functor Tree 
Instance details

Defined in Data.Tree

Methods

fmap :: (a -> b) -> Tree a -> Tree b #

(<$) :: a -> Tree b -> Tree a #

Functor Seq 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> Seq a -> Seq b #

(<$) :: a -> Seq b -> Seq a #

Functor FingerTree 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> FingerTree a -> FingerTree b #

(<$) :: a -> FingerTree b -> FingerTree a #

Functor Digit 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> Digit a -> Digit b #

(<$) :: a -> Digit b -> Digit a #

Functor Node 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> Node a -> Node b #

(<$) :: a -> Node b -> Node a #

Functor Elem 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> Elem a -> Elem b #

(<$) :: a -> Elem b -> Elem a #

Functor ViewL 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> ViewL a -> ViewL b #

(<$) :: a -> ViewL b -> ViewL a #

Functor ViewR 
Instance details

Defined in Data.Sequence.Internal

Methods

fmap :: (a -> b) -> ViewR a -> ViewR b #

(<$) :: a -> ViewR b -> ViewR a #

Functor P 
Instance details

Defined in Text.ParserCombinators.ReadP

Methods

fmap :: (a -> b) -> P a -> P b #

(<$) :: a -> P b -> P a #

Functor (Either a)

Since: base-3.0

Instance details

Defined in Data.Either

Methods

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

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

Functor (V1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> V1 a -> V1 b #

(<$) :: a -> V1 b -> V1 a #

Functor (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> U1 a -> U1 b #

(<$) :: a -> U1 b -> U1 a #

Functor ((,) a)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a0 -> b) -> (a, a0) -> (a, b) #

(<$) :: a0 -> (a, b) -> (a, a0) #

Functor (Array i)

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

fmap :: (a -> b) -> Array i a -> Array i b #

(<$) :: a -> Array i b -> Array i a #

Functor (Arg a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fmap :: (a0 -> b) -> Arg a a0 -> Arg a b #

(<$) :: a0 -> Arg a b -> Arg a a0 #

Monad m => Functor (WrappedMonad m)

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

fmap :: (a -> b) -> WrappedMonad m a -> WrappedMonad m b #

(<$) :: a -> WrappedMonad m b -> WrappedMonad m a #

Arrow a => Functor (ArrowMonad a)

Since: base-4.6.0.0

Instance details

Defined in Control.Arrow

Methods

fmap :: (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b #

(<$) :: a0 -> ArrowMonad a b -> ArrowMonad a a0 #

Functor (Proxy :: * -> *)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

fmap :: (a -> b) -> Proxy a -> Proxy b #

(<$) :: a -> Proxy b -> Proxy a #

Functor (Map k) 
Instance details

Defined in Data.Map.Internal

Methods

fmap :: (a -> b) -> Map k a -> Map k b #

(<$) :: a -> Map k b -> Map k a #

Monad m => Functor (Handler m) 
Instance details

Defined in Control.Monad.Catch

Methods

fmap :: (a -> b) -> Handler m a -> Handler m b #

(<$) :: a -> Handler m b -> Handler m a #

Functor f => Functor (Rec1 f) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> Rec1 f a -> Rec1 f b #

(<$) :: a -> Rec1 f b -> Rec1 f a #

Functor (URec Char :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

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

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

Functor (URec Double :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Double a -> URec Double b #

(<$) :: a -> URec Double b -> URec Double a #

Functor (URec Float :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Float a -> URec Float b #

(<$) :: a -> URec Float b -> URec Float a #

Functor (URec Int :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Int a -> URec Int b #

(<$) :: a -> URec Int b -> URec Int a #

Functor (URec Word :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec Word a -> URec Word b #

(<$) :: a -> URec Word b -> URec Word a #

Functor (URec (Ptr ()) :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec (Ptr ()) a -> URec (Ptr ()) b #

(<$) :: a -> URec (Ptr ()) b -> URec (Ptr ()) a #

Arrow a => Functor (WrappedArrow a b)

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

fmap :: (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 #

(<$) :: a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 #

Functor f => Functor (Alt f) 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

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

Since: containers-0.5.9

Instance details

Defined in Data.IntMap.Internal

Methods

fmap :: (a -> b) -> WhenMissing f x a -> WhenMissing f x b #

(<$) :: a -> WhenMissing f x b -> WhenMissing f x a #

Functor m => Functor (ErrorT e m) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

fmap :: (a -> b) -> ErrorT e m a -> ErrorT e m b #

(<$) :: a -> ErrorT e m b -> ErrorT e m a #

Functor m => Functor (ExceptT e m) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

fmap :: (a -> b) -> ExceptT e m a -> ExceptT e m b #

(<$) :: a -> ExceptT e m b -> ExceptT e m a #

Functor ((->) r :: * -> *)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> (r -> a) -> r -> b #

(<$) :: a -> (r -> b) -> r -> a #

Functor (K1 i c :: * -> *) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> K1 i c a -> K1 i c b #

(<$) :: a -> K1 i c b -> K1 i c a #

(Functor f, Functor g) => Functor (f :+: g) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> (f :+: g) a -> (f :+: g) b #

(<$) :: a -> (f :+: g) b -> (f :+: g) a #

(Functor f, Functor g) => Functor (f :*: g) 
Instance details

Defined in GHC.Generics

Methods

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

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

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

fmap :: (a -> b) -> Product f g a -> Product f g b #

(<$) :: a -> Product f g b -> Product f g a #

(Functor f, Functor g) => Functor (Sum f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

fmap :: (a -> b) -> Sum f g a -> Sum f g b #

(<$) :: a -> Sum f g b -> Sum f g a #

Functor f => Functor (WhenMatched f x y)

Since: containers-0.5.9

Instance details

Defined in Data.IntMap.Internal

Methods

fmap :: (a -> b) -> WhenMatched f x y a -> WhenMatched f x y b #

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

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

Since: containers-0.5.9

Instance details

Defined in Data.Map.Internal

Methods

fmap :: (a -> b) -> WhenMissing f k x a -> WhenMissing f k x b #

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

Functor f => Functor (M1 i c f) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> M1 i c f a -> M1 i c f b #

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

(Functor f, Functor g) => Functor (f :.: g) 
Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> (f :.: g) a -> (f :.: g) b #

(<$) :: a -> (f :.: g) b -> (f :.: g) a #

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

fmap :: (a -> b) -> Compose f g a -> Compose f g b #

(<$) :: a -> Compose f g b -> Compose f g a #

Functor f => Functor (WhenMatched f k x y)

Since: containers-0.5.9

Instance details

Defined in Data.Map.Internal

Methods

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

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

(<$>) :: Functor f => (a -> b) -> f a -> f b infixl 4 #

An infix synonym for fmap.

The name of this operator is an allusion to $. Note the similarities between their types:

 ($)  ::              (a -> b) ->   a ->   b
(<$>) :: Functor f => (a -> b) -> f a -> f b

Whereas $ is function application, <$> is function application lifted over a Functor.

Examples

Expand

Convert from a Maybe Int to a Maybe String using show:

>>> show <$> Nothing
Nothing
>>> show <$> Just 3
Just "3"

Convert from an Either Int Int to an Either Int String using show:

>>> show <$> Left 17
Left 17
>>> show <$> Right 17
Right "17"

Double each element of a list:

>>> (*2) <$> [1,2,3]
[2,4,6]

Apply even to the second element of a pair:

>>> even <$> (2,2)
(2,True)

($>) :: Functor f => f a -> b -> f b infixl 4 #

Flipped version of <$.

Examples

Expand

Replace the contents of a Maybe Int with a constant String:

>>> Nothing $> "foo"
Nothing
>>> Just 90210 $> "foo"
Just "foo"

Replace the contents of an Either Int Int with a constant String, 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

void :: Functor f => f a -> f () #

void value discards or ignores the result of evaluation, such as the return value of an IO action.

Examples

Expand

Replace the contents of a Maybe Int with unit:

>>> void Nothing
Nothing
>>> void (Just 3)
Just ()

Replace the contents of an Either Int Int with unit, resulting in an Either Int '()':

>>> void (Left 8675309)
Left 8675309
>>> void (Right 8675309)
Right ()

Replace every element of a list with unit:

>>> void [1,2,3]
[(),(),()]

Replace the second element of a pair with unit:

>>> void (1,2)
(1,())

Discard the result of an IO action:

>>> mapM print [1,2]
1
2
[(),()]
>>> void $ mapM print [1,2]
1
2

with :: Functor f => f a -> (a -> b) -> f b Source #

Bifunctor

class Bifunctor (p :: * -> * -> *) where #

A bifunctor is a type constructor that takes two type arguments and is a functor in both arguments. That is, unlike with Functor, a type constructor such as Either does not need to be partially applied for a Bifunctor instance, and the methods in this class permit mapping functions over the Left value or the Right value, or both at the same time.

Formally, the class Bifunctor represents a bifunctor from Hask -> Hask.

Intuitively it is a bifunctor where both the first and second arguments are covariant.

You can define a Bifunctor by either defining bimap or by defining both first and second.

If you supply bimap, you should ensure that:

bimap id idid

If you supply first and second, ensure:

first idid
second idid

If you supply both, you should also ensure:

bimap f g ≡ first f . second g

These ensure by parametricity:

bimap  (f . g) (h . i) ≡ bimap f h . bimap g i
first  (f . g) ≡ first  f . first  g
second (f . g) ≡ second f . second g

Since: base-4.8.0.0

Minimal complete definition

bimap | first, second

Methods

bimap :: (a -> b) -> (c -> d) -> p a c -> p b d #

Map over both arguments at the same time.

bimap f g ≡ first f . second g

Examples

Expand
>>> bimap toUpper (+1) ('j', 3)
('J',4)
>>> bimap toUpper (+1) (Left 'j')
Left 'J'
>>> bimap toUpper (+1) (Right 3)
Right 4

first :: (a -> b) -> p a c -> p b c #

Map covariantly over the first argument.

first f ≡ bimap f id

Examples

Expand
>>> first toUpper ('j', 3)
('J',3)
>>> first toUpper (Left 'j')
Left 'J'

second :: (b -> c) -> p a b -> p a c #

Map covariantly over the second argument.

secondbimap id

Examples

Expand
>>> second (+1) ('j', 3)
('j',4)
>>> second (+1) (Right 3)
Right 4
Instances
Bifunctor Either

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

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

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

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

Bifunctor (,)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> (a, c) -> (b, d) #

first :: (a -> b) -> (a, c) -> (b, c) #

second :: (b -> c) -> (a, b) -> (a, c) #

Bifunctor Arg

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

bimap :: (a -> b) -> (c -> d) -> Arg a c -> Arg b d #

first :: (a -> b) -> Arg a c -> Arg b c #

second :: (b -> c) -> Arg a b -> Arg a c #

Bifunctor ((,,) x1)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> (x1, a, c) -> (x1, b, d) #

first :: (a -> b) -> (x1, a, c) -> (x1, b, c) #

second :: (b -> c) -> (x1, a, b) -> (x1, a, c) #

Bifunctor (Const :: * -> * -> *)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> Const a c -> Const b d #

first :: (a -> b) -> Const a c -> Const b c #

second :: (b -> c) -> Const a b -> Const a c #

Bifunctor (K1 i :: * -> * -> *)

Since: base-4.9.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> K1 i a c -> K1 i b d #

first :: (a -> b) -> K1 i a c -> K1 i b c #

second :: (b -> c) -> K1 i a b -> K1 i a c #

Bifunctor ((,,,) x1 x2)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> (x1, x2, a, c) -> (x1, x2, b, d) #

first :: (a -> b) -> (x1, x2, a, c) -> (x1, x2, b, c) #

second :: (b -> c) -> (x1, x2, a, b) -> (x1, x2, a, c) #

Bifunctor ((,,,,) x1 x2 x3)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> (x1, x2, x3, a, c) -> (x1, x2, x3, b, d) #

first :: (a -> b) -> (x1, x2, x3, a, c) -> (x1, x2, x3, b, c) #

second :: (b -> c) -> (x1, x2, x3, a, b) -> (x1, x2, x3, a, c) #

Bifunctor ((,,,,,) x1 x2 x3 x4)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> (x1, x2, x3, x4, a, c) -> (x1, x2, x3, x4, b, d) #

first :: (a -> b) -> (x1, x2, x3, x4, a, c) -> (x1, x2, x3, x4, b, c) #

second :: (b -> c) -> (x1, x2, x3, x4, a, b) -> (x1, x2, x3, x4, a, c) #

Bifunctor ((,,,,,,) x1 x2 x3 x4 x5)

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> (x1, x2, x3, x4, x5, a, c) -> (x1, x2, x3, x4, x5, b, d) #

first :: (a -> b) -> (x1, x2, x3, x4, x5, a, c) -> (x1, x2, x3, x4, x5, b, c) #

second :: (b -> c) -> (x1, x2, x3, x4, x5, a, b) -> (x1, x2, x3, x4, x5, a, c) #

Applicative

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

A functor with application, providing operations to

  • embed pure expressions (pure), and
  • sequence computations and combine their results (<*> and liftA2).

A minimal complete definition must include implementations of pure and of either <*> or liftA2. If it defines both, then they must behave the same as their default definitions:

(<*>) = liftA2 id
liftA2 f x y = f <$> x <*> y

Further, any definition must satisfy the following:

identity
pure id <*> v = v
composition
pure (.) <*> u <*> v <*> w = u <*> (v <*> w)
homomorphism
pure f <*> pure x = pure (f x)
interchange
u <*> pure y = pure ($ y) <*> u

The other methods have the following default definitions, which may be overridden with equivalent specialized implementations:

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

It may be useful to note that supposing

forall x y. p (q x y) = f x . g y

it follows from the above that

liftA2 p (liftA2 q u v) = liftA2 f u . liftA2 g v

If f is also a Monad, it should satisfy

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

Minimal complete definition

pure, ((<*>) | liftA2)

Methods

pure :: a -> f a #

Lift a value.

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

Sequential application.

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

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

Lift a binary function to actions.

Some functors support an implementation of liftA2 that is more efficient than the default one. In particular, if fmap is an expensive operation, it is likely better to use liftA2 than to fmap over the structure and then use <*>.

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

Sequence actions, discarding the value of the first argument.

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

Sequence actions, discarding the value of the second argument.

Instances
Applicative []

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> [a] #

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

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

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

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

Applicative Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> Maybe a #

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

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

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

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

Applicative IO

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> IO a #

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

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

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

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

Applicative Par1

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> Par1 a #

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

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

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

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

Applicative Q 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

pure :: a -> Q a #

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

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

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

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

Applicative Concurrently 
Instance details

Defined in Control.Concurrent.Async

Applicative Complex

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

pure :: a -> Complex a #

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

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

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

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

Applicative Min

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Min a #

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

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

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

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

Applicative Max

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Max a #

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

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

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

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

Applicative First

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> First a #

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

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

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

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

Applicative Last

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Last a #

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

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

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

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

Applicative Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

pure :: a -> Option a #

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

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

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

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

Applicative ZipList
f '<$>' 'ZipList' xs1 '<*>' ... '<*>' 'ZipList' xsN
    = 'ZipList' (zipWithN f xs1 ... xsN)

where zipWithN refers to the zipWith function of the appropriate arity (zipWith, zipWith3, zipWith4, ...). For example:

(\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..]
    = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..])
    = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> ZipList a #

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

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

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

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

Applicative STM

Since: base-4.8.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

pure :: a -> STM a #

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

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

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

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

Applicative First 
Instance details

Defined in Data.Monoid

Methods

pure :: a -> First a #

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

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

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

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

Applicative Last 
Instance details

Defined in Data.Monoid

Methods

pure :: a -> Last a #

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

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

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

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

Applicative Dual

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Dual a #

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

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

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

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

Applicative Sum

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Sum a #

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

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

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

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

Applicative Product

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Product a #

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

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

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

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

Applicative Down

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

pure :: a -> Down a #

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

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

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

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

Applicative ReadP

Since: base-4.6.0.0

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> ReadP a #

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

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

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

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

Applicative NonEmpty

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

pure :: a -> NonEmpty a #

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

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

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

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

Applicative Tree 
Instance details

Defined in Data.Tree

Methods

pure :: a -> Tree a #

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

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

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

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

Applicative Seq

Since: containers-0.5.4

Instance details

Defined in Data.Sequence.Internal

Methods

pure :: a -> Seq a #

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

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

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

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

Applicative P

Since: base-4.5.0.0

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> P a #

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

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

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

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

Applicative (Either e)

Since: base-3.0

Instance details

Defined in Data.Either

Methods

pure :: a -> Either e a #

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

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

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

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

Applicative (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> U1 a #

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

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

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

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

Monoid a => Applicative ((,) a)

For tuples, the Monoid constraint on a determines how the first values merge. For example, Strings concatenate:

("hello ", (+15)) <*> ("world!", 2002)
("hello world!",2017)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a0 -> (a, a0) #

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

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

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

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

Monad m => Applicative (WrappedMonad m)

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a #

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

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

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

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

Arrow a => Applicative (ArrowMonad a)

Since: base-4.6.0.0

Instance details

Defined in Control.Arrow

Methods

pure :: a0 -> ArrowMonad a a0 #

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

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

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

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

Applicative (Proxy :: * -> *)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

pure :: a -> Proxy a #

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

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

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

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

Applicative f => Applicative (Rec1 f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> Rec1 f a #

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

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

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

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

Arrow a => Applicative (WrappedArrow a b)

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a0 -> WrappedArrow a b a0 #

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

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

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

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

Applicative f => Applicative (Alt f) 
Instance details

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Alt f a #

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

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

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

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

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

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

Since: containers-0.5.9

Instance details

Defined in Data.IntMap.Internal

Methods

pure :: a -> WhenMissing f x a #

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

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

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

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

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

Defined in Control.Monad.Trans.Error

Methods

pure :: a -> ErrorT e m a #

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

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

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

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

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

Defined in Control.Monad.Trans.Except

Methods

pure :: a -> ExceptT e m a #

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

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

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

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

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

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a0 -> a -> a0 #

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

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

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

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

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

pure :: a -> Product f g a #

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

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

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

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

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

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

Since: containers-0.5.9

Instance details

Defined in Data.IntMap.Internal

Methods

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

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

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

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

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

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

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

Since: containers-0.5.9

Instance details

Defined in Data.Map.Internal

Methods

pure :: a -> WhenMissing f k x a #

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

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

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

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

Applicative f => Applicative (M1 i c f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> M1 i c f a #

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

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

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

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

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

pure :: a -> Compose f g a #

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

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

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

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

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

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

Since: containers-0.5.9

Instance details

Defined in Data.Map.Internal

Methods

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

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

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

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

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

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

A variant of <*> with the arguments reversed.

orA :: Applicative f => f Bool -> f Bool -> f Bool infixl 8 Source #

Logical disjunction.

andA :: Applicative f => f Bool -> f Bool -> f Bool infixl 8 Source #

Logical conjunction.

optional :: Alternative f => f a -> f (Maybe a) #

One or none.

Alternative

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

A monoid on applicative functors.

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

Minimal complete definition

empty, (<|>)

Methods

empty :: f a #

The identity of <|>

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

An associative binary operation

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

One or more.

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

Zero or more.

Instances
Alternative []

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

empty :: [a] #

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

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

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

Alternative Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

empty :: Maybe a #

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

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

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

Alternative IO

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

empty :: IO a #

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

some :: IO a -> IO [a] #

many :: IO a -> IO [a] #

Alternative Concurrently 
Instance details

Defined in Control.Concurrent.Async

Alternative Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

empty :: Option a #

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

some :: Option a -> Option [a] #

many :: Option a -> Option [a] #

Alternative ZipList

Since: base-4.11.0.0

Instance details

Defined in Control.Applicative

Methods

empty :: ZipList a #

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

some :: ZipList a -> ZipList [a] #

many :: ZipList a -> ZipList [a] #

Alternative STM

Since: base-4.8.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

empty :: STM a #

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

some :: STM a -> STM [a] #

many :: STM a -> STM [a] #

Alternative ReadP

Since: base-4.6.0.0

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

empty :: ReadP a #

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

some :: ReadP a -> ReadP [a] #

many :: ReadP a -> ReadP [a] #

Alternative Seq

Since: containers-0.5.4

Instance details

Defined in Data.Sequence.Internal

Methods

empty :: Seq a #

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

some :: Seq a -> Seq [a] #

many :: Seq a -> Seq [a] #

Alternative P

Since: base-4.5.0.0

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

empty :: P a #

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

some :: P a -> P [a] #

many :: P a -> P [a] #

Alternative (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

empty :: U1 a #

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

some :: U1 a -> U1 [a] #

many :: U1 a -> U1 [a] #

MonadPlus m => Alternative (WrappedMonad m)

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

empty :: WrappedMonad m a #

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

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

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

ArrowPlus a => Alternative (ArrowMonad a)

Since: base-4.6.0.0

Instance details

Defined in Control.Arrow

Methods

empty :: ArrowMonad a a0 #

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

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

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

Alternative (Proxy :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in Data.Proxy

Methods

empty :: Proxy a #

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

some :: Proxy a -> Proxy [a] #

many :: Proxy a -> Proxy [a] #

Alternative f => Alternative (Rec1 f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

empty :: Rec1 f a #

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

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

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

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

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

empty :: WrappedArrow a b a0 #

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

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

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

Alternative f => Alternative (Alt f) 
Instance details

Defined in Data.Semigroup.Internal

Methods

empty :: Alt f a #

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

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

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

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

Defined in Control.Monad.Trans.Error

Methods

empty :: ErrorT e m a #

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

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

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

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

Defined in Control.Monad.Trans.Except

Methods

empty :: ExceptT e m a #

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

empty :: (f :*: g) a #

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

empty :: Product f g a #

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

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

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

Alternative f => Alternative (M1 i c f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

empty :: M1 i c f a #

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

empty :: (f :.: g) a #

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

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

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

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

empty :: Compose f g a #

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

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

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

asum :: (Foldable t, Alternative f) => t (f a) -> f a #

The sum of a collection of actions, generalizing concat.

asum [Just Hello, Nothing, Just World] Just Hello

Monad

class Applicative m => Monad (m :: * -> *) where #

The Monad class defines the basic operations over a monad, a concept from a branch of mathematics known as category theory. From the perspective of a Haskell programmer, however, it is best to think of a monad as an abstract datatype of actions. Haskell's do expressions provide a convenient syntax for writing monadic expressions.

Instances of Monad should satisfy the following laws:

Furthermore, the Monad and Applicative operations should relate as follows:

The above laws imply:

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

The instances of Monad for lists, Maybe and IO defined in the Prelude satisfy these laws.

Minimal complete definition

(>>=)

Methods

(>>=) :: m a -> (a -> m b) -> m b infixl 1 #

Sequentially compose two actions, passing any value produced by the first as an argument to the second.

(>>) :: m a -> m b -> m b infixl 1 #

Sequentially compose two actions, discarding any value produced by the first, like sequencing operators (such as the semicolon) in imperative languages.

return :: a -> m a #

Inject a value into the monadic type.

fail :: String -> m a #

Fail with a message. This operation is not part of the mathematical definition of a monad, but is invoked on pattern-match failure in a do expression.

As part of the MonadFail proposal (MFP), this function is moved to its own class MonadFail (see Control.Monad.Fail for more details). The definition here will be removed in a future release.

Instances
Monad []

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: [a] -> (a -> [b]) -> [b] #

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

return :: a -> [a] #

fail :: String -> [a] #

Monad Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

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

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

return :: a -> Maybe a #

fail :: String -> Maybe a #

Monad IO

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: IO a -> (a -> IO b) -> IO b #

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

return :: a -> IO a #

fail :: String -> IO a #

Monad Par1

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: Par1 a -> (a -> Par1 b) -> Par1 b #

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

return :: a -> Par1 a #

fail :: String -> Par1 a #

Monad Q 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

(>>=) :: Q a -> (a -> Q b) -> Q b #

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

return :: a -> Q a #

fail :: String -> Q a #

Monad Complex

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

(>>=) :: Complex a -> (a -> Complex b) -> Complex b #

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

return :: a -> Complex a #

fail :: String -> Complex a #

Monad Min

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Min a -> (a -> Min b) -> Min b #

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

return :: a -> Min a #

fail :: String -> Min a #

Monad Max

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Max a -> (a -> Max b) -> Max b #

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

return :: a -> Max a #

fail :: String -> Max a #

Monad First

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: First a -> (a -> First b) -> First b #

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

return :: a -> First a #

fail :: String -> First a #

Monad Last

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Last a -> (a -> Last b) -> Last b #

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

return :: a -> Last a #

fail :: String -> Last a #

Monad Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(>>=) :: Option a -> (a -> Option b) -> Option b #

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

return :: a -> Option a #

fail :: String -> Option a #

Monad STM

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

(>>=) :: STM a -> (a -> STM b) -> STM b #

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

return :: a -> STM a #

fail :: String -> STM a #

Monad First 
Instance details

Defined in Data.Monoid

Methods

(>>=) :: First a -> (a -> First b) -> First b #

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

return :: a -> First a #

fail :: String -> First a #

Monad Last 
Instance details

Defined in Data.Monoid

Methods

(>>=) :: Last a -> (a -> Last b) -> Last b #

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

return :: a -> Last a #

fail :: String -> Last a #

Monad Dual

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Dual a -> (a -> Dual b) -> Dual b #

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

return :: a -> Dual a #

fail :: String -> Dual a #

Monad Sum

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Sum a -> (a -> Sum b) -> Sum b #

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

return :: a -> Sum a #

fail :: String -> Sum a #

Monad Product

Since: base-4.8.0.0

Instance details

Defined in Data.Semigroup.Internal

Methods

(>>=) :: Product a -> (a -> Product b) -> Product b #

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

return :: a -> Product a #

fail :: String -> Product a #

Monad Down

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

(>>=) :: Down a -> (a -> Down b) -> Down b #

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

return :: a -> Down a #

fail :: String -> Down a #

Monad ReadP

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

(>>=) :: ReadP a -> (a -> ReadP b) -> ReadP b #

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

return :: a -> ReadP a #

fail :: String -> ReadP a #

Monad NonEmpty

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

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

return :: a -> NonEmpty a #

fail :: String -> NonEmpty a #

Monad Tree 
Instance details

Defined in Data.Tree

Methods

(>>=) :: Tree a -> (a -> Tree b) -> Tree b #

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

return :: a -> Tree a #

fail :: String -> Tree a #

Monad Seq 
Instance details

Defined in Data.Sequence.Internal

Methods

(>>=) :: Seq a -> (a -> Seq b) -> Seq b #

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

return :: a -> Seq a #

fail :: String -> Seq a #

Monad P

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

(>>=) :: P a -> (a -> P b) -> P b #

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

return :: a -> P a #

fail :: String -> P a #

Monad (Either e)

Since: base-4.4.0.0

Instance details

Defined in Data.Either

Methods

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

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

return :: a -> Either e a #

fail :: String -> Either e a #

Monad (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: U1 a -> (a -> U1 b) -> U1 b #

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

return :: a -> U1 a #

fail :: String -> U1 a #

Monoid a => Monad ((,) a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

(>>=) :: (a, a0) -> (a0 -> (a, b)) -> (a, b) #

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

return :: a0 -> (a, a0) #

fail :: String -> (a, a0) #

Monad m => Monad (WrappedMonad m) 
Instance details

Defined in Control.Applicative

Methods

(>>=) :: WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b #

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

return :: a -> WrappedMonad m a #

fail :: String -> WrappedMonad m a #

ArrowApply a => Monad (ArrowMonad a)

Since: base-2.1

Instance details

Defined in 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 #

fail :: String -> ArrowMonad a a0 #

Monad (Proxy :: * -> *)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

(>>=) :: Proxy a -> (a -> Proxy b) -> Proxy b #

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

return :: a -> Proxy a #

fail :: String -> Proxy a #

Monad f => Monad (Rec1 f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: Rec1 f a -> (a -> Rec1 f b) -> Rec1 f b #

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

return :: a -> Rec1 f a #

fail :: String -> Rec1 f a #

Monad f => Monad (Alt f) 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

return :: a -> Alt f a #

fail :: String -> Alt f a #

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

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

Since: containers-0.5.9

Instance details

Defined in Data.IntMap.Internal

Methods

(>>=) :: WhenMissing f x a -> (a -> WhenMissing f x b) -> WhenMissing f x b #

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

return :: a -> WhenMissing f x a #

fail :: String -> WhenMissing f x a #

(Monad m, Error e) => Monad (ErrorT e m) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

(>>=) :: ErrorT e m a -> (a -> ErrorT e m b) -> ErrorT e m b #

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

return :: a -> ErrorT e m a #

fail :: String -> ErrorT e m a #

Monad m => Monad (ExceptT e m) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

(>>=) :: ExceptT e m a -> (a -> ExceptT e m b) -> ExceptT e m b #

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

return :: a -> ExceptT e m a #

fail :: String -> ExceptT e m a #

Monad ((->) r :: * -> *)

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

(>>=) :: (r -> a) -> (a -> r -> b) -> r -> b #

(>>) :: (r -> a) -> (r -> b) -> r -> b #

return :: a -> r -> a #

fail :: String -> r -> a #

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

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

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

return :: a -> (f :*: g) a #

fail :: String -> (f :*: g) a #

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

(>>=) :: Product f g a -> (a -> Product f g b) -> Product f g b #

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

return :: a -> Product f g a #

fail :: String -> Product f g a #

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

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

Since: containers-0.5.9

Instance details

Defined in Data.IntMap.Internal

Methods

(>>=) :: WhenMatched f x y a -> (a -> WhenMatched f x y b) -> WhenMatched f x y b #

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

return :: a -> WhenMatched f x y a #

fail :: String -> WhenMatched f x y a #

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

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

Since: containers-0.5.9

Instance details

Defined in Data.Map.Internal

Methods

(>>=) :: WhenMissing f k x a -> (a -> WhenMissing f k x b) -> WhenMissing f k x b #

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

return :: a -> WhenMissing f k x a #

fail :: String -> WhenMissing f k x a #

Monad f => Monad (M1 i c f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(>>=) :: M1 i c f a -> (a -> M1 i c f b) -> M1 i c f b #

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

return :: a -> M1 i c f a #

fail :: String -> M1 i c f a #

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

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

Since: containers-0.5.9

Instance details

Defined in Data.Map.Internal

Methods

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

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

return :: a -> WhenMatched f k x y a #

fail :: String -> WhenMatched f k x y a #

join :: Monad m => m (m a) -> m a #

The join function is the conventional monad join operator. It is used to remove one level of monadic structure, projecting its bound argument into the outer level.

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

Identifier version of =<<.

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

Conditional execution of Applicative expressions. For example,

when debug (putStrLn "Debugging")

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

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

The reverse of when.

mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m () #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM.

As of base 4.8.0.0, mapM_ is just traverse_, specialized to Monad.

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

forever act repeats the action infinitely.

unlessM :: Monad m => m Bool -> m () -> m () Source #

whenM :: Monad m => m Bool -> m () -> m () Source #

ifM :: Monad m => m Bool -> m a -> m a -> m a Source #

guardM :: MonadPlus m => m Bool -> m () Source #

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

This generalizes the list-based filter function.

(=<<) :: Monad m => (a -> m b) -> m a -> m b infixr 1 #

Same as >>=, but with the arguments interchanged.

liftM :: Monad m => (a1 -> r) -> m a1 -> m r #

Promote a function to a monad.

MonadPlus

class (Alternative m, Monad m) => MonadPlus (m :: * -> *) where #

Monads that also support choice and failure.

Methods

mzero :: m a #

The identity of mplus. It should also satisfy the equations

mzero >>= f  =  mzero
v >> mzero   =  mzero

The default definition is

mzero = empty

mplus :: m a -> m a -> m a #

An associative operation. The default definition is

mplus = (<|>)
Instances
MonadPlus []

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mzero :: [a] #

mplus :: [a] -> [a] -> [a] #

MonadPlus Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mzero :: Maybe a #

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

MonadPlus IO

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

mzero :: IO a #

mplus :: IO a -> IO a -> IO a #

MonadPlus Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

mzero :: Option a #

mplus :: Option a -> Option a -> Option a #

MonadPlus STM

Since: base-4.3.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

mzero :: STM a #

mplus :: STM a -> STM a -> STM a #

MonadPlus ReadP

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

mzero :: ReadP a #

mplus :: ReadP a -> ReadP a -> ReadP a #

MonadPlus Seq 
Instance details

Defined in Data.Sequence.Internal

Methods

mzero :: Seq a #

mplus :: Seq a -> Seq a -> Seq a #

MonadPlus P

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadP

Methods

mzero :: P a #

mplus :: P a -> P a -> P a #

MonadPlus (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

mzero :: U1 a #

mplus :: U1 a -> U1 a -> U1 a #

(ArrowApply a, ArrowPlus a) => MonadPlus (ArrowMonad a)

Since: base-4.6.0.0

Instance details

Defined in Control.Arrow

Methods

mzero :: ArrowMonad a a0 #

mplus :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 #

MonadPlus (Proxy :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in Data.Proxy

Methods

mzero :: Proxy a #

mplus :: Proxy a -> Proxy a -> Proxy a #

MonadPlus f => MonadPlus (Rec1 f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

mzero :: Rec1 f a #

mplus :: Rec1 f a -> Rec1 f a -> Rec1 f a #

MonadPlus f => MonadPlus (Alt f) 
Instance details

Defined in Data.Semigroup.Internal

Methods

mzero :: Alt f a #

mplus :: Alt f a -> Alt f a -> Alt f a #

(Monad m, Error e) => MonadPlus (ErrorT e m) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

mzero :: ErrorT e m a #

mplus :: ErrorT e m a -> ErrorT e m a -> ErrorT e m a #

(Monad m, Monoid e) => MonadPlus (ExceptT e m) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

mzero :: ExceptT e m a #

mplus :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a #

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

mzero :: (f :*: g) a #

mplus :: (f :*: g) a -> (f :*: g) a -> (f :*: g) a #

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

mzero :: Product f g a #

mplus :: Product f g a -> Product f g a -> Product f g a #

MonadPlus f => MonadPlus (M1 i c f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

mzero :: M1 i c f a #

mplus :: M1 i c f a -> M1 i c f a -> M1 i c f a #

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

Conditional failure of Alternative computations. Defined by

guard True  = pure ()
guard False = empty

Examples

Expand

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

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

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

A definition of safeDiv using guards, but not guard:

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

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

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

msum :: (Foldable t, MonadPlus m) => t (m a) -> m a #

The sum of a collection of actions, generalizing concat. As of base 4.8.0.0, msum is just asum, specialized to MonadPlus.

MonadIO

class Monad m => MonadIO (m :: * -> *) where #

Monads in which IO computations may be embedded. Any monad built by applying a sequence of monad transformers to the IO monad will be an instance of this class.

Instances should satisfy the following laws, which state that liftIO is a transformer of monads:

Minimal complete definition

liftIO

Methods

liftIO :: IO a -> m a #

Lift a computation from the IO monad.

Instances
MonadIO IO

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.IO.Class

Methods

liftIO :: IO a -> IO a #

MonadIO Q 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

liftIO :: IO a -> Q a #

(Error e, MonadIO m) => MonadIO (ErrorT e m) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

liftIO :: IO a -> ErrorT e m a #

MonadIO m => MonadIO (ExceptT e m) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

liftIO :: IO a -> ExceptT e m a #

Data structures

Either

data Either a b #

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

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

Examples

Expand

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

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

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

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

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

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

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

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

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

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

Constructors

Left a 
Right b 
Instances
Bifunctor Either

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

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

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

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

Eq2 Either

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

Ord2 Either

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

Read2 Either

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

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

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

Show2 Either

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Monad (Either e)

Since: base-4.4.0.0

Instance details

Defined in Data.Either

Methods

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

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

return :: a -> Either e a #

fail :: String -> Either e a #

Functor (Either a)

Since: base-3.0

Instance details

Defined in Data.Either

Methods

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

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

Applicative (Either e)

Since: base-3.0

Instance details

Defined in Data.Either

Methods

pure :: a -> Either e a #

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

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

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

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

Foldable (Either a)

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

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

null :: Either a a0 -> Bool #

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 #

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

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

Traversable (Either a)

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

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

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

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

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

Eq a => Eq1 (Either a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

Ord a => Ord1 (Either a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

Read a => Read1 (Either a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

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

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

Show a => Show1 (Either a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

e ~ SomeException => MonadThrow (Either e) 
Instance details

Defined in Control.Monad.Catch

Methods

throwM :: Exception e0 => e0 -> Either e a #

e ~ SomeException => MonadCatch (Either e)

Since: exceptions-0.8.3

Instance details

Defined in Control.Monad.Catch

Methods

catch :: Exception e0 => Either e a -> (e0 -> Either e a) -> Either e a #

e ~ SomeException => MonadMask (Either e)

Since: exceptions-0.8.3

Instance details

Defined in Control.Monad.Catch

Methods

mask :: ((forall a. Either e a -> Either e a) -> Either e b) -> Either e b #

uninterruptibleMask :: ((forall a. Either e a -> Either e a) -> Either e b) -> Either e b #

Generic1 (Either a :: * -> *) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (Either a) :: k -> * #

Methods

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

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

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

Defined in Data.Either

Methods

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

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

(Ord a, Ord b) => Ord (Either a b) 
Instance details

Defined in Data.Either

Methods

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

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

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

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

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

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

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

(Read a, Read b) => Read (Either a b) 
Instance details

Defined in Data.Either

(Show a, Show b) => Show (Either a b) 
Instance details

Defined in Data.Either

Methods

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

show :: Either a b -> String #

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

Generic (Either a b) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (Either a b) :: * -> * #

Methods

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

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

Semigroup (Either a b)

Since: base-4.9.0.0

Instance details

Defined in Data.Either

Methods

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

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

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

(Lift a, Lift b) => Lift (Either a b) 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Either a b -> Q Exp #

type Rep1 (Either a :: * -> *) 
Instance details

Defined in GHC.Generics

type Rep (Either a b) 
Instance details

Defined in GHC.Generics

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

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

Examples

Expand

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

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

isRight :: Either a b -> Bool #

Return True if the given value is a Right-value, False otherwise.

Examples

Expand

Basic usage:

>>> isRight (Left "foo")
False
>>> isRight (Right 3)
True

Assuming a Left value signifies some sort of error, we can use isRight to write a very simple reporting function that only outputs "SUCCESS" when a computation has succeeded.

This example shows how isRight might be used to avoid pattern matching when one does not care about the value contained in the constructor:

>>> import Control.Monad ( when )
>>> let report e = when (isRight e) $ putStrLn "SUCCESS"
>>> report (Left "parse error")
>>> report (Right 1)
SUCCESS

Since: base-4.7.0.0

Maybe

data Maybe a #

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

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

Constructors

Nothing 
Just a 
Instances
Monad Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

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

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

return :: a -> Maybe a #

fail :: String -> Maybe a #

Functor Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

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

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

Applicative Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

pure :: a -> Maybe a #

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

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

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

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

Foldable Maybe

Since: base-2.1

Instance details

Defined in Data.Foldable

Methods

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

toList :: Maybe a -> [a] #

null :: Maybe a -> Bool #

length :: Maybe a -> Int #

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

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

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

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

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

Traversable Maybe

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

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

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

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

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

Eq1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

Ord1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

Read1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Maybe a) #

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Maybe a] #

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Maybe a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Maybe a] #

Show1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Alternative Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

empty :: Maybe a #

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

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

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

MonadPlus Maybe

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mzero :: Maybe a #

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

MonadThrow Maybe 
Instance details

Defined in Control.Monad.Catch

Methods

throwM :: Exception e => e -> Maybe a #

Eq a => Eq (Maybe a) 
Instance details

Defined in GHC.Base

Methods

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

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

Ord a => Ord (Maybe a) 
Instance details

Defined in GHC.Base

Methods

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

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

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

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

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

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

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

Read a => Read (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Read

Show a => Show (Maybe a) 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Maybe a -> ShowS #

show :: Maybe a -> String #

showList :: [Maybe a] -> ShowS #

Generic (Maybe a) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (Maybe a) :: * -> * #

Methods

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

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

Semigroup a => Semigroup (Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Methods

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

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

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

Semigroup a => Monoid (Maybe a)

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

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

Since: base-2.1

Instance details

Defined in GHC.Base

Methods

mempty :: Maybe a #

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

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

Lift a => Lift (Maybe a) 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Maybe a -> Q Exp #

SingKind a => SingKind (Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Associated Types

type DemoteRep (Maybe a) :: *

Methods

fromSing :: Sing a0 -> DemoteRep (Maybe a)

Generic1 Maybe 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 Maybe :: k -> * #

Methods

from1 :: Maybe a -> Rep1 Maybe a #

to1 :: Rep1 Maybe a -> Maybe a #

SingI (Nothing :: Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

sing :: Sing Nothing

SingI a2 => SingI (Just a2 :: Maybe a1)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

sing :: Sing (Just a2)

type Rep (Maybe a) 
Instance details

Defined in GHC.Generics

type Rep (Maybe a) = D1 (MetaData "Maybe" "GHC.Base" "base" False) (C1 (MetaCons "Nothing" PrefixI False) (U1 :: * -> *) :+: C1 (MetaCons "Just" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a)))
data Sing (b :: Maybe a) 
Instance details

Defined in GHC.Generics

data Sing (b :: Maybe a) where
type DemoteRep (Maybe a) 
Instance details

Defined in GHC.Generics

type DemoteRep (Maybe a) = Maybe (DemoteRep a)
type Rep1 Maybe 
Instance details

Defined in GHC.Generics

fromMaybe :: a -> Maybe a -> a #

The fromMaybe function takes a default value and and Maybe value. If the Maybe is Nothing, it returns the default values; otherwise, it returns the value contained in the Maybe.

Examples

Expand

Basic usage:

>>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"
>>> fromMaybe "" Nothing
""

Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default:

>>> import Text.Read ( readMaybe )
>>> fromMaybe 0 (readMaybe "5")
5
>>> fromMaybe 0 (readMaybe "")
0

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

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

Examples

Expand

Basic usage:

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

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

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

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

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

isJust :: Maybe a -> Bool #

The isJust function returns True iff its argument is of the form Just _.

Examples

Expand

Basic usage:

>>> isJust (Just 3)
True
>>> isJust (Just ())
True
>>> isJust Nothing
False

Only the outer constructor is taken into consideration:

>>> isJust (Just Nothing)
True

isNothing :: Maybe a -> Bool #

The isNothing function returns True iff its argument is Nothing.

Examples

Expand

Basic usage:

>>> isNothing (Just 3)
False
>>> isNothing (Just ())
False
>>> isNothing Nothing
True

Only the outer constructor is taken into consideration:

>>> isNothing (Just Nothing)
False

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

The mapMaybe function is a version of map which can throw out elements. In particular, the functional argument returns something of type Maybe b. If this is Nothing, no element is added on to the result list. If it is Just b, then b is included in the result list.

Examples

Expand

Using mapMaybe f x is a shortcut for catMaybes $ map f x in most cases:

>>> import Text.Read ( readMaybe )
>>> let readMaybeInt = readMaybe :: String -> Maybe Int
>>> mapMaybe readMaybeInt ["1", "Foo", "3"]
[1,3]
>>> catMaybes $ map readMaybeInt ["1", "Foo", "3"]
[1,3]

If we map the Just constructor, the entire list should be returned:

>>> mapMaybe Just [1,2,3]
[1,2,3]

maybeToRight :: l -> Maybe r -> Either l r Source #

catMaybes :: [Maybe a] -> [a] #

The catMaybes function takes a list of Maybes and returns a list of all the Just values.

Examples

Expand

Basic usage:

>>> catMaybes [Just 1, Nothing, Just 3]
[1,3]

When constructing a list of Maybe values, catMaybes can be used to return all of the "success" results (if the list is the result of a map, then mapMaybe would be more appropriate):

>>> import Text.Read ( readMaybe )
>>> [readMaybe x :: Maybe Int | x <- ["1", "Foo", "3"] ]
[Just 1,Nothing,Just 3]
>>> catMaybes $ [readMaybe x :: Maybe Int | x <- ["1", "Foo", "3"] ]
[1,3]

listToMaybe :: [a] -> Maybe a #

The listToMaybe function returns Nothing on an empty list or Just a where a is the first element of the list.

Examples

Expand

Basic usage:

>>> listToMaybe []
Nothing
>>> listToMaybe [9]
Just 9
>>> listToMaybe [1,2,3]
Just 1

Composing maybeToList with listToMaybe should be the identity on singleton/empty lists:

>>> maybeToList $ listToMaybe [5]
[5]
>>> maybeToList $ listToMaybe []
[]

But not on lists with more than one element:

>>> maybeToList $ listToMaybe [1,2,3]
[1]

Tuple

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

Extract the first component of a pair.

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

Extract the second component of a pair.

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

curry converts an uncurried function to a curried function.

Examples

Expand
>>> curry fst 1 2
1

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

uncurry converts a curried function to a function on pairs.

Examples

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

List

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

filter, applied to a predicate and a list, returns the list of those elements that satisfy the predicate; i.e.,

filter p xs = [ x | x <- xs, p x]

notElem :: (Foldable t, Eq a) => a -> t a -> Bool infix 4 #

notElem is the negation of elem.

any :: Foldable t => (a -> Bool) -> t a -> Bool #

Determines whether any element of the structure satisfies the predicate.

and :: Foldable t => t Bool -> Bool #

and returns the conjunction of a container of Bools. For the result to be True, the container must be finite; False, however, results from a False value finitely far from the left end.

intercalate :: [a] -> [[a]] -> [a] #

intercalate xs xss is equivalent to (concat (intersperse xs xss)). It inserts the list xs in between the lists in xss and concatenates the result.

>>> intercalate ", " ["Lorem", "ipsum", "dolor"]
"Lorem, ipsum, dolor"

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

The isPrefixOf function takes two lists and returns True iff the first list is a prefix of the second.

>>> "Hello" `isPrefixOf` "Hello World!"
True
>>> "Hello" `isPrefixOf` "Wello Horld!"
False

reverse :: [a] -> [a] #

reverse xs returns the elements of xs in reverse order. xs must be finite.

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

break, applied to a predicate p and a list xs, returns a tuple where first element is longest prefix (possibly empty) of xs of elements that do not satisfy p and second element is the remainder of the list:

break (> 3) [1,2,3,4,1,2,3,4] == ([1,2,3],[4,1,2,3,4])
break (< 9) [1,2,3] == ([],[1,2,3])
break (> 9) [1,2,3] == ([1,2,3],[])

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

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

splitAt n xs returns a tuple where first element is xs prefix of length n and second element is the remainder of the list:

splitAt 6 "Hello World!" == ("Hello ","World!")
splitAt 3 [1,2,3,4,5] == ([1,2,3],[4,5])
splitAt 1 [1,2,3] == ([1],[2,3])
splitAt 3 [1,2,3] == ([1,2,3],[])
splitAt 4 [1,2,3] == ([1,2,3],[])
splitAt 0 [1,2,3] == ([],[1,2,3])
splitAt (-1) [1,2,3] == ([],[1,2,3])

It is equivalent to (take n xs, drop n xs) when n is not _|_ (splitAt _|_ xs = _|_). splitAt is an instance of the more general genericSplitAt, in which n may be of any integral type.

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

drop n xs returns the suffix of xs after the first n elements, or [] if n > length xs:

drop 6 "Hello World!" == "World!"
drop 3 [1,2,3,4,5] == [4,5]
drop 3 [1,2] == []
drop 3 [] == []
drop (-1) [1,2] == [1,2]
drop 0 [1,2] == [1,2]

It is an instance of the more general genericDrop, in which n may be of any integral type.

ordNub :: Ord a => [a] -> [a] Source #

O(n log n) Remove duplicate elements from a list.

Unlike nub, this version requires Ord and runs in O(n log n) instead of O(n²). Like nub the output order is identical to the input order. See sortNub for nub behaviour with sorted output.

ordNub "foo bar baz" == "fo barz"
ordNub [3,2,1,2,1] == [3,2,1]
List.take 3 (ordNub [4,5,6,undefined]) == [4,5,6]
ordNub xs == List.nub xs

ordNubBy :: (a -> a -> Ordering) -> [a] -> [a] Source #

O(n log n) Behaves exactly like ordNub except it uses a user-supplied comparison function.

ordNubBy (comparing length) ["foo","bar","quux"] == ["foo","quux"]
ordNubBy (comparing fst) [("foo", 10),("foo", 20),("bar", 30)] == [("foo", 10),("bar", 30)]

Typeclasses

Enum

class Enum a #

Class Enum defines operations on sequentially ordered types.

The enumFrom... methods are used in Haskell's translation of arithmetic sequences.

Instances of Enum may be derived for any enumeration type (types whose constructors have no fields). The nullary constructors are assumed to be numbered left-to-right by fromEnum from 0 through n-1. See Chapter 10 of the Haskell Report for more details.

For any type that is an instance of class Bounded as well as Enum, the following should hold:

   enumFrom     x   = enumFromTo     x maxBound
   enumFromThen x y = enumFromThenTo x y bound
     where
       bound | fromEnum y >= fromEnum x = maxBound
             | otherwise                = minBound

Minimal complete definition

toEnum, fromEnum

Instances
Enum Bool

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Bool -> Bool #

pred :: Bool -> Bool #

toEnum :: Int -> Bool #

fromEnum :: Bool -> Int #

enumFrom :: Bool -> [Bool] #

enumFromThen :: Bool -> Bool -> [Bool] #

enumFromTo :: Bool -> Bool -> [Bool] #

enumFromThenTo :: Bool -> Bool -> Bool -> [Bool] #

Enum Char

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Char -> Char #

pred :: Char -> Char #

toEnum :: Int -> Char #

fromEnum :: Char -> Int #

enumFrom :: Char -> [Char] #

enumFromThen :: Char -> Char -> [Char] #

enumFromTo :: Char -> Char -> [Char] #

enumFromThenTo :: Char -> Char -> Char -> [Char] #

Enum Int

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Int -> Int #

pred :: Int -> Int #

toEnum :: Int -> Int #

fromEnum :: Int -> Int #

enumFrom :: Int -> [Int] #

enumFromThen :: Int -> Int -> [Int] #

enumFromTo :: Int -> Int -> [Int] #

enumFromThenTo :: Int -> Int -> Int -> [Int] #

Enum Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

succ :: Int8 -> Int8 #

pred :: Int8 -> Int8 #

toEnum :: Int -> Int8 #

fromEnum :: Int8 -> Int #

enumFrom :: Int8 -> [Int8] #

enumFromThen :: Int8 -> Int8 -> [Int8] #

enumFromTo :: Int8 -> Int8 -> [Int8] #

enumFromThenTo :: Int8 -> Int8 -> Int8 -> [Int8] #

Enum Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Enum Integer

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Ordering

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Word

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: Word -> Word #

pred :: Word -> Word #

toEnum :: Int -> Word #

fromEnum :: Word -> Int #

enumFrom :: Word -> [Word] #

enumFromThen :: Word -> Word -> [Word] #

enumFromTo :: Word -> Word -> [Word] #

enumFromThenTo :: Word -> Word -> Word -> [Word] #

Enum Word8

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word16

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word32

Since: base-2.1

Instance details

Defined in GHC.Word

Enum Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Enum VecCount

Since: base-4.10.0.0

Instance details

Defined in GHC.Enum

Enum VecElem

Since: base-4.10.0.0

Instance details

Defined in GHC.Enum

Enum ()

Since: base-2.1

Instance details

Defined in GHC.Enum

Methods

succ :: () -> () #

pred :: () -> () #

toEnum :: Int -> () #

fromEnum :: () -> Int #

enumFrom :: () -> [()] #

enumFromThen :: () -> () -> [()] #

enumFromTo :: () -> () -> [()] #

enumFromThenTo :: () -> () -> () -> [()] #

Enum SeekMode 
Instance details

Defined in GHC.IO.Device

Enum Associativity 
Instance details

Defined in GHC.Generics

Enum SourceUnpackedness 
Instance details

Defined in GHC.Generics

Enum SourceStrictness 
Instance details

Defined in GHC.Generics

Enum DecidedStrictness 
Instance details

Defined in GHC.Generics

Enum IOMode 
Instance details

Defined in GHC.IO.IOMode

Enum Extension 
Instance details

Defined in GHC.LanguageExtensions.Type

Integral a => Enum (Ratio a)

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

succ :: Ratio a -> Ratio a #

pred :: Ratio a -> Ratio a #

toEnum :: Int -> Ratio a #

fromEnum :: Ratio a -> Int #

enumFrom :: Ratio a -> [Ratio a] #

enumFromThen :: Ratio a -> Ratio a -> [Ratio a] #

enumFromTo :: Ratio a -> Ratio a -> [Ratio a] #

enumFromThenTo :: Ratio a -> Ratio a -> Ratio a -> [Ratio a] #

Enum a => Enum (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Min a -> Min a #

pred :: Min a -> Min a #

toEnum :: Int -> Min a #

fromEnum :: Min a -> Int #

enumFrom :: Min a -> [Min a] #

enumFromThen :: Min a -> Min a -> [Min a] #

enumFromTo :: Min a -> Min a -> [Min a] #

enumFromThenTo :: Min a -> Min a -> Min a -> [Min a] #

Enum a => Enum (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Max a -> Max a #

pred :: Max a -> Max a #

toEnum :: Int -> Max a #

fromEnum :: Max a -> Int #

enumFrom :: Max a -> [Max a] #

enumFromThen :: Max a -> Max a -> [Max a] #

enumFromTo :: Max a -> Max a -> [Max a] #

enumFromThenTo :: Max a -> Max a -> Max a -> [Max a] #

Enum a => Enum (First a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: First a -> First a #

pred :: First a -> First a #

toEnum :: Int -> First a #

fromEnum :: First a -> Int #

enumFrom :: First a -> [First a] #

enumFromThen :: First a -> First a -> [First a] #

enumFromTo :: First a -> First a -> [First a] #

enumFromThenTo :: First a -> First a -> First a -> [First a] #

Enum a => Enum (Last a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Last a -> Last a #

pred :: Last a -> Last a #

toEnum :: Int -> Last a #

fromEnum :: Last a -> Int #

enumFrom :: Last a -> [Last a] #

enumFromThen :: Last a -> Last a -> [Last a] #

enumFromTo :: Last a -> Last a -> [Last a] #

enumFromThenTo :: Last a -> Last a -> Last a -> [Last a] #

Enum a => Enum (WrappedMonoid a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Enum (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

succ :: Proxy s -> Proxy s #

pred :: Proxy s -> Proxy s #

toEnum :: Int -> Proxy s #

fromEnum :: Proxy s -> Int #

enumFrom :: Proxy s -> [Proxy s] #

enumFromThen :: Proxy s -> Proxy s -> [Proxy s] #

enumFromTo :: Proxy s -> Proxy s -> [Proxy s] #

enumFromThenTo :: Proxy s -> Proxy s -> Proxy s -> [Proxy s] #

Enum (f a) => Enum (Alt f a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

succ :: Alt f a -> Alt f a #

pred :: Alt f a -> Alt f a #

toEnum :: Int -> Alt f a #

fromEnum :: Alt f a -> Int #

enumFrom :: Alt f a -> [Alt f a] #

enumFromThen :: Alt f a -> Alt f a -> [Alt f a] #

enumFromTo :: Alt f a -> Alt f a -> [Alt f a] #

enumFromThenTo :: Alt f a -> Alt f a -> Alt f a -> [Alt f a] #

a ~ b => Enum (a :~: b)

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

succ :: (a :~: b) -> a :~: b #

pred :: (a :~: b) -> a :~: b #

toEnum :: Int -> a :~: b #

fromEnum :: (a :~: b) -> Int #

enumFrom :: (a :~: b) -> [a :~: b] #

enumFromThen :: (a :~: b) -> (a :~: b) -> [a :~: b] #

enumFromTo :: (a :~: b) -> (a :~: b) -> [a :~: b] #

enumFromThenTo :: (a :~: b) -> (a :~: b) -> (a :~: b) -> [a :~: b] #

a ~~ b => Enum (a :~~: b)

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

succ :: (a :~~: b) -> a :~~: b #

pred :: (a :~~: b) -> a :~~: b #

toEnum :: Int -> a :~~: b #

fromEnum :: (a :~~: b) -> Int #

enumFrom :: (a :~~: b) -> [a :~~: b] #

enumFromThen :: (a :~~: b) -> (a :~~: b) -> [a :~~: b] #

enumFromTo :: (a :~~: b) -> (a :~~: b) -> [a :~~: b] #

enumFromThenTo :: (a :~~: b) -> (a :~~: b) -> (a :~~: b) -> [a :~~: b] #

Num

class Num a where #

Basic numeric class.

Minimal complete definition

(+), (*), abs, signum, fromInteger, (negate | (-))

Methods

(+) :: a -> a -> a infixl 6 #

(-) :: a -> a -> a infixl 6 #

(*) :: a -> a -> a infixl 7 #

negate :: a -> a #

Unary negation.

abs :: a -> a #

Absolute value.

signum :: a -> a #

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 Int

Since: base-2.1

Instance details

Defined in GHC.Num

Methods

(+) :: Int -> Int -> Int #

(-) :: Int -> Int -> Int #

(*) :: Int -> Int -> Int #

negate :: Int -> Int #

abs :: Int -> Int #

signum :: Int -> Int #

fromInteger :: Integer -> Int #

Num Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

(+) :: Int8 -> Int8 -> Int8 #

(-) :: Int8 -> Int8 -> Int8 #

(*) :: Int8 -> Int8 -> Int8 #

negate :: Int8 -> Int8 #

abs :: Int8 -> Int8 #

signum :: Int8 -> Int8 #

fromInteger :: Integer -> Int8 #

Num Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Num Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Num Integer

Since: base-2.1

Instance details

Defined in GHC.Num

Num Word

Since: base-2.1

Instance details

Defined in GHC.Num

Methods

(+) :: Word -> Word -> Word #

(-) :: Word -> Word -> Word #

(*) :: Word -> Word -> Word #

negate :: Word -> Word #

abs :: Word -> Word #

signum :: Word -> Word #

fromInteger :: Integer -> Word #

Num Word8

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word16

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word32

Since: base-2.1

Instance details

Defined in GHC.Word

Num Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Integral a => Num (Ratio a)

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

(+) :: Ratio a -> Ratio a -> Ratio a #

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

(*) :: Ratio a -> Ratio a -> Ratio a #

negate :: Ratio a -> Ratio a #

abs :: Ratio a -> Ratio a #

signum :: Ratio a -> Ratio a #

fromInteger :: Integer -> Ratio a #

RealFloat a => Num (Complex a)

Since: base-2.1

Instance details

Defined in Data.Complex

Methods

(+) :: Complex a -> Complex a -> Complex a #

(-) :: Complex a -> Complex a -> Complex a #

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

negate :: Complex a -> Complex a #

abs :: Complex a -> Complex a #

signum :: Complex a -> Complex a #

fromInteger :: Integer -> Complex a #

Num a => Num (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(+) :: Min a -> Min a -> Min a #

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

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

negate :: Min a -> Min a #

abs :: Min a -> Min a #

signum :: Min a -> Min a #

fromInteger :: Integer -> Min a #

Num a => Num (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(+) :: Max a -> Max a -> Max a #

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

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

negate :: Max a -> Max a #

abs :: Max a -> Max a #

signum :: Max a -> Max a #

fromInteger :: Integer -> Max a #

Num a => Num (Sum a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

(+) :: Sum a -> Sum a -> Sum a #

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

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

negate :: Sum a -> Sum a #

abs :: Sum a -> Sum a #

signum :: Sum a -> Sum a #

fromInteger :: Integer -> Sum a #

Num a => Num (Product a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

(+) :: Product a -> Product a -> Product a #

(-) :: Product a -> Product a -> Product a #

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

negate :: Product a -> Product a #

abs :: Product a -> Product a #

signum :: Product a -> Product a #

fromInteger :: Integer -> Product a #

Num a => Num (Down a)

Since: base-4.11.0.0

Instance details

Defined in Data.Ord

Methods

(+) :: Down a -> Down a -> Down a #

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

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

negate :: Down a -> Down a #

abs :: Down a -> Down a #

signum :: Down a -> Down a #

fromInteger :: Integer -> Down a #

Num (f a) => Num (Alt f a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

(+) :: Alt f a -> Alt f a -> Alt f a #

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

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

negate :: Alt f a -> Alt f a #

abs :: Alt f a -> Alt f a #

signum :: Alt f a -> Alt f a #

fromInteger :: Integer -> Alt f a #

Eq

class Eq a where #

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.

Minimal complete definition: either == or /=.

Minimal complete definition

(==) | (/=)

Methods

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

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

Instances
Eq Bool 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Char 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Double 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Float 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Int 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Eq Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Eq Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Eq Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

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

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

Eq Integer 
Instance details

Defined in GHC.Integer.Type

Methods

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

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

Eq Ordering 
Instance details

Defined in GHC.Classes

Eq Word 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Word8

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

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

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

Eq Word16

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

(==) :: Word16 -> Word16 -> Bool #

(/=) :: Word16 -> Word16 -> Bool #

Eq Word32

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

(==) :: Word32 -> Word32 -> Bool #

(/=) :: Word32 -> Word32 -> Bool #

Eq Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

(==) :: Word64 -> Word64 -> Bool #

(/=) :: Word64 -> Word64 -> Bool #

Eq SomeTypeRep 
Instance details

Defined in Data.Typeable.Internal

Eq Exp 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Match 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Clause 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Pat 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Type 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Dec 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Name 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq FunDep 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq InjectivityAnn 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Overlap 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq DerivStrategy 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq () 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq TyCon 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Module 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq TrName 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Handle

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle.Types

Methods

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

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

Eq ThreadId

Since: base-4.2.0.0

Instance details

Defined in GHC.Conc.Sync

Eq AsyncCancelled 
Instance details

Defined in Control.Concurrent.Async

Eq BigNat 
Instance details

Defined in GHC.Integer.Type

Methods

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

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

Eq Void

Since: base-4.8.0.0

Instance details

Defined in Data.Void

Methods

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

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

Eq SpecConstrAnnotation 
Instance details

Defined in GHC.Exts

Eq HandlePosn

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle

Eq BlockReason 
Instance details

Defined in GHC.Conc.Sync

Eq ThreadStatus 
Instance details

Defined in GHC.Conc.Sync

Eq AsyncException 
Instance details

Defined in GHC.IO.Exception

Eq ArrayException 
Instance details

Defined in GHC.IO.Exception

Eq ExitCode 
Instance details

Defined in GHC.IO.Exception

Eq IOErrorType

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Eq BufferMode 
Instance details

Defined in GHC.IO.Handle.Types

Eq Newline 
Instance details

Defined in GHC.IO.Handle.Types

Methods

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

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

Eq NewlineMode 
Instance details

Defined in GHC.IO.Handle.Types

Eq IODeviceType 
Instance details

Defined in GHC.IO.Device

Eq SeekMode 
Instance details

Defined in GHC.IO.Device

Eq CodingProgress 
Instance details

Defined in GHC.IO.Encoding.Types

Eq MaskingState 
Instance details

Defined in GHC.IO

Eq IOException

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Eq ErrorCall 
Instance details

Defined in GHC.Exception

Eq ArithException 
Instance details

Defined in GHC.Exception

Eq All 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

Eq Any 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

Eq Fixity 
Instance details

Defined in GHC.Generics

Methods

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

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

Eq Associativity 
Instance details

Defined in GHC.Generics

Eq SourceUnpackedness 
Instance details

Defined in GHC.Generics

Eq SourceStrictness 
Instance details

Defined in GHC.Generics

Eq DecidedStrictness 
Instance details

Defined in GHC.Generics

Eq IOMode 
Instance details

Defined in GHC.IO.IOMode

Methods

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

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

Eq SrcLoc 
Instance details

Defined in GHC.Stack.Types

Methods

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

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

Eq IntSet 
Instance details

Defined in Data.IntSet.Internal

Methods

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

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

Eq Extension 
Instance details

Defined in GHC.LanguageExtensions.Type

Eq ForeignSrcLang 
Instance details

Defined in GHC.ForeignSrcLang.Type

Eq ModName 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq PkgName 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Module 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq OccName 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq NameFlavour 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq NameSpace 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Loc 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Info 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq ModuleInfo 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Fixity 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq FixityDirection 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Lit 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Body 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Guard 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Stmt 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Range 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq DerivClause 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq TypeFamilyHead 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq TySynEqn 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Foreign 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Callconv 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Safety 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Pragma 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Inline 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq RuleMatch 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Phases 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq RuleBndr 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq AnnTarget 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq SourceUnpackedness 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq SourceStrictness 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq DecidedStrictness 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Con 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Bang 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq PatSynDir 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq PatSynArgs 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq TyVarBndr 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq FamilyResultSig 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq TyLit 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq Role 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

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

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

Eq AnnLookup 
Instance details

Defined in Language.Haskell.TH.Syntax

Eq Duration # 
Instance details

Defined in Entwine.Data.Duration

Eq TerminationAction # 
Instance details

Defined in Entwine.Guard

Eq AsyncTimeout # 
Instance details

Defined in Entwine.Async

Eq a => Eq [a] 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq a => Eq (Maybe a) 
Instance details

Defined in GHC.Base

Methods

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

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

Eq a => Eq (Ratio a) 
Instance details

Defined in GHC.Real

Methods

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

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

Eq (Ptr a) 
Instance details

Defined in GHC.Ptr

Methods

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

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

Eq (FunPtr a) 
Instance details

Defined in GHC.Ptr

Methods

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

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

Eq p => Eq (Par1 p) 
Instance details

Defined in GHC.Generics

Methods

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

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

Eq (MVar a)

Since: base-4.1.0.0

Instance details

Defined in GHC.MVar

Methods

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

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

Eq (MSem i) 
Instance details

Defined in Control.Concurrent.MSem

Methods

(==) :: MSem i -> MSem i -> Bool #

(/=) :: MSem i -> MSem i -> Bool #

Eq (Async a) 
Instance details

Defined in Control.Concurrent.Async

Methods

(==) :: Async a -> Async a -> Bool #

(/=) :: Async a -> Async a -> Bool #

Eq a => Eq (Complex a) 
Instance details

Defined in Data.Complex

Methods

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

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

Eq a => Eq (Min a) 
Instance details

Defined in Data.Semigroup

Methods

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

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

Eq a => Eq (Max a) 
Instance details

Defined in Data.Semigroup

Methods

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

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

Eq a => Eq (First a) 
Instance details

Defined in Data.Semigroup

Methods

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

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

Eq a => Eq (Last a) 
Instance details

Defined in Data.Semigroup

Methods

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

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

Eq m => Eq (WrappedMonoid m) 
Instance details

Defined in Data.Semigroup

Eq a => Eq (Option a) 
Instance details

Defined in Data.Semigroup

Methods

(==) :: Option a -> Option a -> Bool #

(/=) :: Option a -> Option a -> Bool #

Eq (Chan a) 
Instance details

Defined in Control.Concurrent.Chan

Methods

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

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

Eq a => Eq (ZipList a) 
Instance details

Defined in Control.Applicative

Methods

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

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

Eq (TVar a)

Since: base-4.8.0.0

Instance details

Defined in GHC.Conc.Sync

Methods

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

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

Eq (IORef a)

Pointer equality.

Since: base-4.1.0.0

Instance details

Defined in GHC.IORef

Methods

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

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

Eq a => Eq (First a) 
Instance details

Defined in Data.Monoid

Methods

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

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

Eq a => Eq (Last a) 
Instance details

Defined in Data.Monoid

Methods

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

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

Eq a => Eq (Dual a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

Eq a => Eq (Sum a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

Eq a => Eq (Product a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

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

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

Eq a => Eq (Down a) 
Instance details

Defined in Data.Ord

Methods

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

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

Eq a => Eq (NonEmpty a) 
Instance details

Defined in GHC.Base

Methods

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

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

Eq a => Eq (IntMap a) 
Instance details

Defined in Data.IntMap.Internal

Methods

(==) :: IntMap a -> IntMap a -> Bool #

(/=) :: IntMap a -> IntMap a -> Bool #

Eq a => Eq (Tree a) 
Instance details

Defined in Data.Tree

Methods

(==) :: Tree a -> Tree a -> Bool #

(/=) :: Tree a -> Tree a -> Bool #

Eq a => Eq (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Methods

(==) :: Seq a -> Seq a -> Bool #

(/=) :: Seq a -> Seq a -> Bool #

Eq a => Eq (ViewL a) 
Instance details

Defined in Data.Sequence.Internal

Methods

(==) :: ViewL a -> ViewL a -> Bool #

(/=) :: ViewL a -> ViewL a -> Bool #

Eq a => Eq (ViewR a) 
Instance details

Defined in Data.Sequence.Internal

Methods

(==) :: ViewR a -> ViewR a -> Bool #

(/=) :: ViewR a -> ViewR a -> Bool #

Eq a => Eq (Set a) 
Instance details

Defined in Data.Set.Internal

Methods

(==) :: Set a -> Set a -> Bool #

(/=) :: Set a -> Set a -> Bool #

Eq (TBQueue a) 
Instance details

Defined in Control.Concurrent.STM.TBQueue

Methods

(==) :: TBQueue a -> TBQueue a -> Bool #

(/=) :: TBQueue a -> TBQueue a -> Bool #

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

Defined in Data.Either

Methods

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

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

Eq (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

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

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

Eq (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

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

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

Eq (TypeRep a)

Since: base-2.1

Instance details

Defined in Data.Typeable.Internal

Methods

(==) :: TypeRep a -> TypeRep a -> Bool #

(/=) :: TypeRep a -> TypeRep a -> Bool #

(Eq a, Eq b) => Eq (a, b) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b) -> (a, b) -> Bool #

(/=) :: (a, b) -> (a, b) -> Bool #

(Ix i, Eq e) => Eq (Array i e)

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

(==) :: Array i e -> Array i e -> Bool #

(/=) :: Array i e -> Array i e -> Bool #

Eq a => Eq (Arg a b)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

(==) :: Arg a b -> Arg a b -> Bool #

(/=) :: Arg a b -> Arg a b -> Bool #

Eq (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

(==) :: Proxy s -> Proxy s -> Bool #

(/=) :: Proxy s -> Proxy s -> Bool #

(Eq k, Eq a) => Eq (Map k a) 
Instance details

Defined in Data.Map.Internal

Methods

(==) :: Map k a -> Map k a -> Bool #

(/=) :: Map k a -> Map k a -> Bool #

Eq (f p) => Eq (Rec1 f p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: Rec1 f p -> Rec1 f p -> Bool #

(/=) :: Rec1 f p -> Rec1 f p -> Bool #

Eq (URec (Ptr ()) p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool #

(/=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool #

Eq (URec Char p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Char p -> URec Char p -> Bool #

(/=) :: URec Char p -> URec Char p -> Bool #

Eq (URec Double p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Double p -> URec Double p -> Bool #

(/=) :: URec Double p -> URec Double p -> Bool #

Eq (URec Float p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Float p -> URec Float p -> Bool #

(/=) :: URec Float p -> URec Float p -> Bool #

Eq (URec Int p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Int p -> URec Int p -> Bool #

(/=) :: URec Int p -> URec Int p -> Bool #

Eq (URec Word p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: URec Word p -> URec Word p -> Bool #

(/=) :: URec Word p -> URec Word p -> Bool #

(Eq a, Eq b, Eq c) => Eq (a, b, c) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c) -> (a, b, c) -> Bool #

(/=) :: (a, b, c) -> (a, b, c) -> Bool #

Eq (STArray s i e)

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

(==) :: STArray s i e -> STArray s i e -> Bool #

(/=) :: STArray s i e -> STArray s i e -> Bool #

Eq (f a) => Eq (Alt f a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

(==) :: Alt f a -> Alt f a -> Bool #

(/=) :: Alt f a -> Alt f a -> Bool #

Eq (a :~: b) 
Instance details

Defined in Data.Type.Equality

Methods

(==) :: (a :~: b) -> (a :~: b) -> Bool #

(/=) :: (a :~: b) -> (a :~: b) -> Bool #

(Eq e, Eq1 m, Eq a) => Eq (ErrorT e m a) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

(==) :: ErrorT e m a -> ErrorT e m a -> Bool #

(/=) :: ErrorT e m a -> ErrorT e m a -> Bool #

(Eq e, Eq1 m, Eq a) => Eq (ExceptT e m a) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

(==) :: ExceptT e m a -> ExceptT e m a -> Bool #

(/=) :: ExceptT e m a -> ExceptT e m a -> Bool #

Eq c => Eq (K1 i c p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: K1 i c p -> K1 i c p -> Bool #

(/=) :: K1 i c p -> K1 i c p -> Bool #

(Eq (f p), Eq (g p)) => Eq ((f :+: g) p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: (f :+: g) p -> (f :+: g) p -> Bool #

(/=) :: (f :+: g) p -> (f :+: g) p -> Bool #

(Eq (f p), Eq (g p)) => Eq ((f :*: g) p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: (f :*: g) p -> (f :*: g) p -> Bool #

(/=) :: (f :*: g) p -> (f :*: g) p -> Bool #

(Eq a, Eq b, Eq c, Eq d) => Eq (a, b, c, d) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d) -> (a, b, c, d) -> Bool #

(/=) :: (a, b, c, d) -> (a, b, c, d) -> Bool #

(Eq1 f, Eq1 g, Eq a) => Eq (Product f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

(==) :: Product f g a -> Product f g a -> Bool #

(/=) :: Product f g a -> Product f g a -> Bool #

(Eq1 f, Eq1 g, Eq a) => Eq (Sum f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

(==) :: Sum f g a -> Sum f g a -> Bool #

(/=) :: Sum f g a -> Sum f g a -> Bool #

Eq (a :~~: b)

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

(==) :: (a :~~: b) -> (a :~~: b) -> Bool #

(/=) :: (a :~~: b) -> (a :~~: b) -> Bool #

Eq (f p) => Eq (M1 i c f p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: M1 i c f p -> M1 i c f p -> Bool #

(/=) :: M1 i c f p -> M1 i c f p -> Bool #

Eq (f (g p)) => Eq ((f :.: g) p) 
Instance details

Defined in GHC.Generics

Methods

(==) :: (f :.: g) p -> (f :.: g) p -> Bool #

(/=) :: (f :.: g) p -> (f :.: g) p -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e) => Eq (a, b, c, d, e) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool #

(/=) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool #

(Eq1 f, Eq1 g, Eq a) => Eq (Compose f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

(==) :: Compose f g a -> Compose f g a -> Bool #

(/=) :: Compose f g a -> Compose f g a -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f) => Eq (a, b, c, d, e, f) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool #

(/=) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g) => Eq (a, b, c, d, e, f, g) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool #

(/=) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h) => Eq (a, b, c, d, e, f, g, h) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i) => Eq (a, b, c, d, e, f, g, h, i) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j) => Eq (a, b, c, d, e, f, g, h, i, j) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k) => Eq (a, b, c, d, e, f, g, h, i, j, k) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l) => Eq (a, b, c, d, e, f, g, h, i, j, k, l) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m, Eq n) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #

(Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, Eq j, Eq k, Eq l, Eq m, Eq n, Eq o) => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) 
Instance details

Defined in GHC.Classes

Methods

(==) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

(/=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

Read

class Read a where #

Parsing of Strings, producing values.

Derived instances of Read make the following assumptions, which derived instances of Show obey:

  • If the constructor is defined to be an infix operator, then the derived Read instance will parse only infix applications of the constructor (not the prefix form).
  • Associativity is not used to reduce the occurrence of parentheses, although precedence may be.
  • If the constructor is defined using record syntax, the derived Read will parse only the record-syntax form, and furthermore, the fields must be given in the same order as the original declaration.
  • The derived Read instance allows arbitrary Haskell whitespace between tokens of the input string. Extra parentheses are also allowed.

For example, given the declarations

infixr 5 :^:
data Tree a =  Leaf a  |  Tree a :^: Tree a

the derived instance of Read in Haskell 2010 is equivalent to

instance (Read a) => Read (Tree a) where

        readsPrec d r =  readParen (d > app_prec)
                         (\r -> [(Leaf m,t) |
                                 ("Leaf",s) <- lex r,
                                 (m,t) <- readsPrec (app_prec+1) s]) r

                      ++ readParen (d > up_prec)
                         (\r -> [(u:^:v,w) |
                                 (u,s) <- readsPrec (up_prec+1) r,
                                 (":^:",t) <- lex s,
                                 (v,w) <- readsPrec (up_prec+1) t]) r

          where app_prec = 10
                up_prec = 5

Note that right-associativity of :^: is unused.

The derived instance in GHC is equivalent to

instance (Read a) => Read (Tree a) where

        readPrec = parens $ (prec app_prec $ do
                                 Ident "Leaf" <- lexP
                                 m <- step readPrec
                                 return (Leaf m))

                     +++ (prec up_prec $ do
                                 u <- step readPrec
                                 Symbol ":^:" <- lexP
                                 v <- step readPrec
                                 return (u :^: v))

          where app_prec = 10
                up_prec = 5

        readListPrec = readListPrecDefault

Why do both readsPrec and readPrec exist, and why does GHC opt to implement readPrec in derived Read instances instead of readsPrec? The reason is that readsPrec is based on the ReadS type, and although ReadS is mentioned in the Haskell 2010 Report, it is not a very efficient parser data structure.

readPrec, on the other hand, is based on a much more efficient ReadPrec datatype (a.k.a "new-style parsers"), but its definition relies on the use of the RankNTypes language extension. Therefore, readPrec (and its cousin, readListPrec) are marked as GHC-only. Nevertheless, it is recommended to use readPrec instead of readsPrec whenever possible for the efficiency improvements it brings.

As mentioned above, derived Read instances in GHC will implement readPrec instead of readsPrec. The default implementations of readsPrec (and its cousin, readList) will simply use readPrec under the hood. If you are writing a Read instance by hand, it is recommended to write it like so:

instance Read T where
  readPrec     = ...
  readListPrec = readListPrecDefault

Minimal complete definition

readsPrec | readPrec

Methods

readsPrec #

Arguments

:: Int

the operator precedence of the enclosing context (a number from 0 to 11). Function application has precedence 10.

-> ReadS a 

attempts to parse a value from the front of the string, returning a list of (parsed value, remaining string) pairs. If there is no successful parse, the returned list is empty.

Derived instances of Read and Show satisfy the following:

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

readList :: ReadS [a] #

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 should be are expected to use double quotes, rather than square brackets.

readPrec :: ReadPrec a #

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 Bool

Since: base-2.1

Instance details

Defined in GHC.Read

Read Char

Since: base-2.1

Instance details

Defined in GHC.Read

Read Double

Since: base-2.1

Instance details

Defined in GHC.Read

Read Float

Since: base-2.1

Instance details

Defined in GHC.Read

Read Int

Since: base-2.1

Instance details

Defined in GHC.Read

Read Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Read Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Read Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Read Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Read Integer

Since: base-2.1

Instance details

Defined in GHC.Read

Read Ordering

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word

Since: base-4.5.0.0

Instance details

Defined in GHC.Read

Read Word8

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word16

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word32

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word64

Since: base-2.1

Instance details

Defined in GHC.Read

Read ()

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS () #

readList :: ReadS [()] #

readPrec :: ReadPrec () #

readListPrec :: ReadPrec [()] #

Read Void

Reading a Void value is always a parse error, considering Void as a data type with no constructors.

Since: base-4.8.0.0

Instance details

Defined in Data.Void

Read ExitCode 
Instance details

Defined in GHC.IO.Exception

Read BufferMode 
Instance details

Defined in GHC.IO.Handle.Types

Read Newline 
Instance details

Defined in GHC.IO.Handle.Types

Read NewlineMode 
Instance details

Defined in GHC.IO.Handle.Types

Read SeekMode 
Instance details

Defined in GHC.IO.Device

Read All 
Instance details

Defined in Data.Semigroup.Internal

Read Any 
Instance details

Defined in Data.Semigroup.Internal

Read Fixity 
Instance details

Defined in GHC.Generics

Read Associativity 
Instance details

Defined in GHC.Generics

Read SourceUnpackedness 
Instance details

Defined in GHC.Generics

Read SourceStrictness 
Instance details

Defined in GHC.Generics

Read DecidedStrictness 
Instance details

Defined in GHC.Generics

Read IOMode 
Instance details

Defined in GHC.IO.IOMode

Read Lexeme

Since: base-2.1

Instance details

Defined in GHC.Read

Read GeneralCategory 
Instance details

Defined in GHC.Read

Read IntSet 
Instance details

Defined in Data.IntSet.Internal

Read a => Read [a]

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS [a] #

readList :: ReadS [[a]] #

readPrec :: ReadPrec [a] #

readListPrec :: ReadPrec [[a]] #

Read a => Read (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Read

(Integral a, Read a) => Read (Ratio a)

Since: base-2.1

Instance details

Defined in GHC.Read

Read p => Read (Par1 p) 
Instance details

Defined in GHC.Generics

Read a => Read (Complex a) 
Instance details

Defined in Data.Complex

Read a => Read (Min a) 
Instance details

Defined in Data.Semigroup

Read a => Read (Max a) 
Instance details

Defined in Data.Semigroup

Read a => Read (First a) 
Instance details

Defined in Data.Semigroup

Read a => Read (Last a) 
Instance details

Defined in Data.Semigroup

Read m => Read (WrappedMonoid m) 
Instance details

Defined in Data.Semigroup

Read a => Read (Option a) 
Instance details

Defined in Data.Semigroup

Read a => Read (ZipList a) 
Instance details

Defined in Control.Applicative

Read a => Read (First a) 
Instance details

Defined in Data.Monoid

Read a => Read (Last a) 
Instance details

Defined in Data.Monoid

Read a => Read (Dual a) 
Instance details

Defined in Data.Semigroup.Internal

Read a => Read (Sum a) 
Instance details

Defined in Data.Semigroup.Internal

Read a => Read (Product a) 
Instance details

Defined in Data.Semigroup.Internal

Read a => Read (Down a)

Since: base-4.7.0.0

Instance details

Defined in Data.Ord

Read a => Read (NonEmpty a) 
Instance details

Defined in GHC.Read

Read e => Read (IntMap e) 
Instance details

Defined in Data.IntMap.Internal

Read a => Read (Tree a) 
Instance details

Defined in Data.Tree

Read a => Read (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Read a => Read (ViewL a) 
Instance details

Defined in Data.Sequence.Internal

Read a => Read (ViewR a) 
Instance details

Defined in Data.Sequence.Internal

(Read a, Ord a) => Read (Set a) 
Instance details

Defined in Data.Set.Internal

(Read a, Read b) => Read (Either a b) 
Instance details

Defined in Data.Either

Read (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

(Read a, Read b) => Read (a, b)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b) #

readList :: ReadS [(a, b)] #

readPrec :: ReadPrec (a, b) #

readListPrec :: ReadPrec [(a, b)] #

(Ix a, Read a, Read b) => Read (Array a b)

Since: base-2.1

Instance details

Defined in GHC.Read

(Read a, Read b) => Read (Arg a b) 
Instance details

Defined in Data.Semigroup

Methods

readsPrec :: Int -> ReadS (Arg a b) #

readList :: ReadS [Arg a b] #

readPrec :: ReadPrec (Arg a b) #

readListPrec :: ReadPrec [Arg a b] #

Read (Proxy t)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

(Ord k, Read k, Read e) => Read (Map k e) 
Instance details

Defined in Data.Map.Internal

Methods

readsPrec :: Int -> ReadS (Map k e) #

readList :: ReadS [Map k e] #

readPrec :: ReadPrec (Map k e) #

readListPrec :: ReadPrec [Map k e] #

Read (f p) => Read (Rec1 f p) 
Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (Rec1 f p) #

readList :: ReadS [Rec1 f p] #

readPrec :: ReadPrec (Rec1 f p) #

readListPrec :: ReadPrec [Rec1 f p] #

(Read a, Read b, Read c) => Read (a, b, c)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c) #

readList :: ReadS [(a, b, c)] #

readPrec :: ReadPrec (a, b, c) #

readListPrec :: ReadPrec [(a, b, c)] #

Read (f a) => Read (Alt f a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

readsPrec :: Int -> ReadS (Alt f a) #

readList :: ReadS [Alt f a] #

readPrec :: ReadPrec (Alt f a) #

readListPrec :: ReadPrec [Alt f a] #

a ~ b => Read (a :~: b)

Since: base-4.7.0.0

Instance details

Defined in Data.Type.Equality

Methods

readsPrec :: Int -> ReadS (a :~: b) #

readList :: ReadS [a :~: b] #

readPrec :: ReadPrec (a :~: b) #

readListPrec :: ReadPrec [a :~: b] #

(Read e, Read1 m, Read a) => Read (ErrorT e m a) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

readsPrec :: Int -> ReadS (ErrorT e m a) #

readList :: ReadS [ErrorT e m a] #

readPrec :: ReadPrec (ErrorT e m a) #

readListPrec :: ReadPrec [ErrorT e m a] #

(Read e, Read1 m, Read a) => Read (ExceptT e m a) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

readsPrec :: Int -> ReadS (ExceptT e m a) #

readList :: ReadS [ExceptT e m a] #

readPrec :: ReadPrec (ExceptT e m a) #

readListPrec :: ReadPrec [ExceptT e m a] #

Read c => Read (K1 i c p) 
Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (K1 i c p) #

readList :: ReadS [K1 i c p] #

readPrec :: ReadPrec (K1 i c p) #

readListPrec :: ReadPrec [K1 i c p] #

(Read (f p), Read (g p)) => Read ((f :+: g) p) 
Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :+: g) p) #

readList :: ReadS [(f :+: g) p] #

readPrec :: ReadPrec ((f :+: g) p) #

readListPrec :: ReadPrec [(f :+: g) p] #

(Read (f p), Read (g p)) => Read ((f :*: g) p) 
Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :*: g) p) #

readList :: ReadS [(f :*: g) p] #

readPrec :: ReadPrec ((f :*: g) p) #

readListPrec :: ReadPrec [(f :*: g) p] #

(Read a, Read b, Read c, Read d) => Read (a, b, c, d)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d) #

readList :: ReadS [(a, b, c, d)] #

readPrec :: ReadPrec (a, b, c, d) #

readListPrec :: ReadPrec [(a, b, c, d)] #

(Read1 f, Read1 g, Read a) => Read (Product f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

readsPrec :: Int -> ReadS (Product f g a) #

readList :: ReadS [Product f g a] #

readPrec :: ReadPrec (Product f g a) #

readListPrec :: ReadPrec [Product f g a] #

(Read1 f, Read1 g, Read a) => Read (Sum f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

readsPrec :: Int -> ReadS (Sum f g a) #

readList :: ReadS [Sum f g a] #

readPrec :: ReadPrec (Sum f g a) #

readListPrec :: ReadPrec [Sum f g a] #

a ~~ b => Read (a :~~: b)

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

readsPrec :: Int -> ReadS (a :~~: b) #

readList :: ReadS [a :~~: b] #

readPrec :: ReadPrec (a :~~: b) #

readListPrec :: ReadPrec [a :~~: b] #

Read (f p) => Read (M1 i c f p) 
Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (M1 i c f p) #

readList :: ReadS [M1 i c f p] #

readPrec :: ReadPrec (M1 i c f p) #

readListPrec :: ReadPrec [M1 i c f p] #

Read (f (g p)) => Read ((f :.: g) p) 
Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :.: g) p) #

readList :: ReadS [(f :.: g) p] #

readPrec :: ReadPrec ((f :.: g) p) #

readListPrec :: ReadPrec [(f :.: g) p] #

(Read a, Read b, Read c, Read d, Read e) => Read (a, b, c, d, e)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e) #

readList :: ReadS [(a, b, c, d, e)] #

readPrec :: ReadPrec (a, b, c, d, e) #

readListPrec :: ReadPrec [(a, b, c, d, e)] #

(Read1 f, Read1 g, Read a) => Read (Compose f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

readsPrec :: Int -> ReadS (Compose f g a) #

readList :: ReadS [Compose f g a] #

readPrec :: ReadPrec (Compose f g a) #

readListPrec :: ReadPrec [Compose f g a] #

(Read a, Read b, Read c, Read d, Read e, Read f) => Read (a, b, c, d, e, f)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f) #

readList :: ReadS [(a, b, c, d, e, f)] #

readPrec :: ReadPrec (a, b, c, d, e, f) #

readListPrec :: ReadPrec [(a, b, c, d, e, f)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g) #

readList :: ReadS [(a, b, c, d, e, f, g)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h) #

readList :: ReadS [(a, b, c, d, e, f, g, h)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] #

(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

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] #

readEither :: Read a => String -> Either String a #

Parse a string using the Read instance. Succeeds if there is exactly one valid result. A Left value indicates a parse error.

>>> readEither "123" :: Either String Int
Right 123
>>> readEither "hello" :: Either String Int
Left "Prelude.read: no parse"

Since: base-4.6.0.0

readMaybe :: Read a => String -> Maybe a #

Parse a string using the Read instance. Succeeds if there is exactly one valid result.

>>> readMaybe "123" :: Maybe Int
Just 123
>>> readMaybe "hello" :: Maybe Int
Nothing

Since: base-4.6.0.0

Show

class Show a where #

Conversion of values to readable Strings.

Derived instances of Show have the following properties, which are compatible with derived instances of Read:

  • The result of show is a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used.
  • If the constructor is defined to be an infix operator, then showsPrec will produce infix applications of the constructor.
  • the representation will be enclosed in parentheses if the precedence of the top-level constructor in x is less than d (associativity is ignored). Thus, if d is 0 then the result is never surrounded in parentheses; if d is 11 it is always surrounded in parentheses, unless it is an atomic expression.
  • If the constructor is defined using record syntax, then show will produce the record-syntax form, with the fields given in the same order as the original declaration.

For example, given the declarations

infixr 5 :^:
data Tree a =  Leaf a  |  Tree a :^: Tree a

the derived instance of Show is equivalent to

instance (Show a) => Show (Tree a) where

       showsPrec d (Leaf m) = showParen (d > app_prec) $
            showString "Leaf " . showsPrec (app_prec+1) m
         where app_prec = 10

       showsPrec d (u :^: v) = showParen (d > up_prec) $
            showsPrec (up_prec+1) u .
            showString " :^: "      .
            showsPrec (up_prec+1) v
         where up_prec = 5

Note that right-associativity of :^: is ignored. For example,

  • show (Leaf 1 :^: Leaf 2 :^: Leaf 3) produces the string "Leaf 1 :^: (Leaf 2 :^: Leaf 3)".

Minimal complete definition

showsPrec | show

Methods

showsPrec #

Arguments

:: Int

the operator precedence of the enclosing context (a number from 0 to 11). Function application has precedence 10.

-> a

the value to be converted to a String

-> ShowS 

Convert a value to a readable String.

showsPrec should satisfy the law

showsPrec d x r ++ s  ==  showsPrec d x (r ++ s)

Derived instances of Read and Show satisfy the following:

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

show :: a -> String #

A specialised variant of showsPrec, using precedence context zero, and returning an ordinary String.

showList :: [a] -> ShowS #

The method showList is provided to allow the programmer to give a specialised way of showing lists of values. For example, this is used by the predefined Show instance of the Char type, where values of type String should be shown in double quotes, rather than between square brackets.

Instances
Show Bool 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Bool -> ShowS #

show :: Bool -> String #

showList :: [Bool] -> ShowS #

Show Char

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Char -> ShowS #

show :: Char -> String #

showList :: [Char] -> ShowS #

Show Int

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Int -> ShowS #

show :: Int -> String #

showList :: [Int] -> ShowS #

Show Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int8 -> ShowS #

show :: Int8 -> String #

showList :: [Int8] -> ShowS #

Show Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int16 -> ShowS #

show :: Int16 -> String #

showList :: [Int16] -> ShowS #

Show Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int32 -> ShowS #

show :: Int32 -> String #

showList :: [Int32] -> ShowS #

Show Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

showsPrec :: Int -> Int64 -> ShowS #

show :: Int64 -> String #

showList :: [Int64] -> ShowS #

Show Integer

Since: base-2.1

Instance details

Defined in GHC.Show

Show Ordering 
Instance details

Defined in GHC.Show

Show Word

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Word -> ShowS #

show :: Word -> String #

showList :: [Word] -> ShowS #

Show Word8

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

showsPrec :: Int -> Word8 -> ShowS #

show :: Word8 -> String #

showList :: [Word8] -> ShowS #

Show Word16

Since: base-2.1

Instance details

Defined in GHC.Word

Show Word32

Since: base-2.1

Instance details

Defined in GHC.Word

Show Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Show RuntimeRep 
Instance details

Defined in GHC.Show

Show VecCount 
Instance details

Defined in GHC.Show

Show VecElem 
Instance details

Defined in GHC.Show

Show CallStack

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show SomeTypeRep

Since: base-4.10.0.0

Instance details

Defined in Data.Typeable.Internal

Show Exp 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Exp -> ShowS #

show :: Exp -> String #

showList :: [Exp] -> ShowS #

Show Match 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Match -> ShowS #

show :: Match -> String #

showList :: [Match] -> ShowS #

Show Clause 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Pat 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Pat -> ShowS #

show :: Pat -> String #

showList :: [Pat] -> ShowS #

Show Type 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Type -> ShowS #

show :: Type -> String #

showList :: [Type] -> ShowS #

Show Dec 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Dec -> ShowS #

show :: Dec -> String #

showList :: [Dec] -> ShowS #

Show Name 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Name -> ShowS #

show :: Name -> String #

showList :: [Name] -> ShowS #

Show FunDep 
Instance details

Defined in Language.Haskell.TH.Syntax

Show InjectivityAnn 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Overlap 
Instance details

Defined in Language.Haskell.TH.Syntax

Show DerivStrategy 
Instance details

Defined in Language.Haskell.TH.Syntax

Show () 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> () -> ShowS #

show :: () -> String #

showList :: [()] -> ShowS #

Show TyCon

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> TyCon -> ShowS #

show :: TyCon -> String #

showList :: [TyCon] -> ShowS #

Show Module

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show TrName

Since: base-4.9.0.0

Instance details

Defined in GHC.Show

Show KindRep 
Instance details

Defined in GHC.Show

Show TypeLitSort 
Instance details

Defined in GHC.Show

Show Handle

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle.Types

Show ThreadId

Since: base-4.2.0.0

Instance details

Defined in GHC.Conc.Sync

Show AsyncCancelled 
Instance details

Defined in Control.Concurrent.Async

Show ExceptionInLinkedThread 
Instance details

Defined in Control.Concurrent.Async

Show HandleType

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle.Types

Methods

showsPrec :: Int -> HandleType -> ShowS #

show :: HandleType -> String #

showList :: [HandleType] -> ShowS #

Show Void

Since: base-4.8.0.0

Instance details

Defined in Data.Void

Methods

showsPrec :: Int -> Void -> ShowS #

show :: Void -> String #

showList :: [Void] -> ShowS #

Show HandlePosn

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Handle

Show BlockReason 
Instance details

Defined in GHC.Conc.Sync

Show ThreadStatus 
Instance details

Defined in GHC.Conc.Sync

Show BlockedIndefinitelyOnMVar

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show BlockedIndefinitelyOnSTM

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show Deadlock

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show AllocationLimitExceeded

Since: base-4.7.1.0

Instance details

Defined in GHC.IO.Exception

Show CompactionFailed

Since: base-4.10.0.0

Instance details

Defined in GHC.IO.Exception

Show AssertionFailed

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show SomeAsyncException

Since: base-4.7.0.0

Instance details

Defined in GHC.IO.Exception

Show AsyncException

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show ArrayException

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show FixIOException

Since: base-4.11.0.0

Instance details

Defined in GHC.IO.Exception

Show ExitCode 
Instance details

Defined in GHC.IO.Exception

Show IOErrorType

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show BufferMode 
Instance details

Defined in GHC.IO.Handle.Types

Show Newline 
Instance details

Defined in GHC.IO.Handle.Types

Show NewlineMode 
Instance details

Defined in GHC.IO.Handle.Types

Show SeekMode 
Instance details

Defined in GHC.IO.Device

Show TextEncoding

Since: base-4.3.0.0

Instance details

Defined in GHC.IO.Encoding.Types

Show CodingProgress 
Instance details

Defined in GHC.IO.Encoding.Types

Show MaskingState 
Instance details

Defined in GHC.IO

Show IOException

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Show ErrorCall

Since: base-4.0.0.0

Instance details

Defined in GHC.Exception

Show ArithException

Since: base-4.0.0.0

Instance details

Defined in GHC.Exception

Show All 
Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> All -> ShowS #

show :: All -> String #

showList :: [All] -> ShowS #

Show Any 
Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Any -> ShowS #

show :: Any -> String #

showList :: [Any] -> ShowS #

Show Fixity 
Instance details

Defined in GHC.Generics

Show Associativity 
Instance details

Defined in GHC.Generics

Show SourceUnpackedness 
Instance details

Defined in GHC.Generics

Show SourceStrictness 
Instance details

Defined in GHC.Generics

Show DecidedStrictness 
Instance details

Defined in GHC.Generics

Show IOMode 
Instance details

Defined in GHC.IO.IOMode

Show SomeException

Since: base-3.0

Instance details

Defined in GHC.Exception

Show SrcLoc 
Instance details

Defined in GHC.Show

Show IntSet 
Instance details

Defined in Data.IntSet.Internal

Show Extension 
Instance details

Defined in GHC.LanguageExtensions.Type

Show ForeignSrcLang 
Instance details

Defined in GHC.ForeignSrcLang.Type

Show ModName 
Instance details

Defined in Language.Haskell.TH.Syntax

Show PkgName 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Module 
Instance details

Defined in Language.Haskell.TH.Syntax

Show OccName 
Instance details

Defined in Language.Haskell.TH.Syntax

Show NameFlavour 
Instance details

Defined in Language.Haskell.TH.Syntax

Show NameSpace 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Loc 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Loc -> ShowS #

show :: Loc -> String #

showList :: [Loc] -> ShowS #

Show Info 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Info -> ShowS #

show :: Info -> String #

showList :: [Info] -> ShowS #

Show ModuleInfo 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Fixity 
Instance details

Defined in Language.Haskell.TH.Syntax

Show FixityDirection 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Lit 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Lit -> ShowS #

show :: Lit -> String #

showList :: [Lit] -> ShowS #

Show Body 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Body -> ShowS #

show :: Body -> String #

showList :: [Body] -> ShowS #

Show Guard 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Guard -> ShowS #

show :: Guard -> String #

showList :: [Guard] -> ShowS #

Show Stmt 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Stmt -> ShowS #

show :: Stmt -> String #

showList :: [Stmt] -> ShowS #

Show Range 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Range -> ShowS #

show :: Range -> String #

showList :: [Range] -> ShowS #

Show DerivClause 
Instance details

Defined in Language.Haskell.TH.Syntax

Show TypeFamilyHead 
Instance details

Defined in Language.Haskell.TH.Syntax

Show TySynEqn 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Foreign 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Callconv 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Safety 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Pragma 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Inline 
Instance details

Defined in Language.Haskell.TH.Syntax

Show RuleMatch 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Phases 
Instance details

Defined in Language.Haskell.TH.Syntax

Show RuleBndr 
Instance details

Defined in Language.Haskell.TH.Syntax

Show AnnTarget 
Instance details

Defined in Language.Haskell.TH.Syntax

Show SourceUnpackedness 
Instance details

Defined in Language.Haskell.TH.Syntax

Show SourceStrictness 
Instance details

Defined in Language.Haskell.TH.Syntax

Show DecidedStrictness 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Con 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Con -> ShowS #

show :: Con -> String #

showList :: [Con] -> ShowS #

Show Bang 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Bang -> ShowS #

show :: Bang -> String #

showList :: [Bang] -> ShowS #

Show PatSynDir 
Instance details

Defined in Language.Haskell.TH.Syntax

Show PatSynArgs 
Instance details

Defined in Language.Haskell.TH.Syntax

Show TyVarBndr 
Instance details

Defined in Language.Haskell.TH.Syntax

Show FamilyResultSig 
Instance details

Defined in Language.Haskell.TH.Syntax

Show TyLit 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> TyLit -> ShowS #

show :: TyLit -> String #

showList :: [TyLit] -> ShowS #

Show Role 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

showsPrec :: Int -> Role -> ShowS #

show :: Role -> String #

showList :: [Role] -> ShowS #

Show AnnLookup 
Instance details

Defined in Language.Haskell.TH.Syntax

Show Duration # 
Instance details

Defined in Entwine.Data.Duration

Show TerminationAction # 
Instance details

Defined in Entwine.Guard

Show AsyncTimeout # 
Instance details

Defined in Entwine.Async

Show a => Show [a]

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> [a] -> ShowS #

show :: [a] -> String #

showList :: [[a]] -> ShowS #

Show a => Show (Maybe a) 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Maybe a -> ShowS #

show :: Maybe a -> String #

showList :: [Maybe a] -> ShowS #

Show a => Show (Ratio a)

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

showsPrec :: Int -> Ratio a -> ShowS #

show :: Ratio a -> String #

showList :: [Ratio a] -> ShowS #

Show (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

showsPrec :: Int -> Ptr a -> ShowS #

show :: Ptr a -> String #

showList :: [Ptr a] -> ShowS #

Show (FunPtr a)

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

showsPrec :: Int -> FunPtr a -> ShowS #

show :: FunPtr a -> String #

showList :: [FunPtr a] -> ShowS #

Show p => Show (Par1 p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> Par1 p -> ShowS #

show :: Par1 p -> String #

showList :: [Par1 p] -> ShowS #

Show a => Show (Complex a) 
Instance details

Defined in Data.Complex

Methods

showsPrec :: Int -> Complex a -> ShowS #

show :: Complex a -> String #

showList :: [Complex a] -> ShowS #

Show a => Show (Min a) 
Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Min a -> ShowS #

show :: Min a -> String #

showList :: [Min a] -> ShowS #

Show a => Show (Max a) 
Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Max a -> ShowS #

show :: Max a -> String #

showList :: [Max a] -> ShowS #

Show a => Show (First a) 
Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> First a -> ShowS #

show :: First a -> String #

showList :: [First a] -> ShowS #

Show a => Show (Last a) 
Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Last a -> ShowS #

show :: Last a -> String #

showList :: [Last a] -> ShowS #

Show m => Show (WrappedMonoid m) 
Instance details

Defined in Data.Semigroup

Show a => Show (Option a) 
Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Option a -> ShowS #

show :: Option a -> String #

showList :: [Option a] -> ShowS #

Show a => Show (ZipList a) 
Instance details

Defined in Control.Applicative

Methods

showsPrec :: Int -> ZipList a -> ShowS #

show :: ZipList a -> String #

showList :: [ZipList a] -> ShowS #

Show a => Show (First a) 
Instance details

Defined in Data.Monoid

Methods

showsPrec :: Int -> First a -> ShowS #

show :: First a -> String #

showList :: [First a] -> ShowS #

Show a => Show (Last a) 
Instance details

Defined in Data.Monoid

Methods

showsPrec :: Int -> Last a -> ShowS #

show :: Last a -> String #

showList :: [Last a] -> ShowS #

Show a => Show (Dual a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Dual a -> ShowS #

show :: Dual a -> String #

showList :: [Dual a] -> ShowS #

Show a => Show (Sum a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Sum a -> ShowS #

show :: Sum a -> String #

showList :: [Sum a] -> ShowS #

Show a => Show (Product a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Product a -> ShowS #

show :: Product a -> String #

showList :: [Product a] -> ShowS #

Show a => Show (Down a)

Since: base-4.7.0.0

Instance details

Defined in Data.Ord

Methods

showsPrec :: Int -> Down a -> ShowS #

show :: Down a -> String #

showList :: [Down a] -> ShowS #

Show a => Show (NonEmpty a) 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> NonEmpty a -> ShowS #

show :: NonEmpty a -> String #

showList :: [NonEmpty a] -> ShowS #

Show a => Show (IntMap a) 
Instance details

Defined in Data.IntMap.Internal

Methods

showsPrec :: Int -> IntMap a -> ShowS #

show :: IntMap a -> String #

showList :: [IntMap a] -> ShowS #

Show a => Show (Tree a) 
Instance details

Defined in Data.Tree

Methods

showsPrec :: Int -> Tree a -> ShowS #

show :: Tree a -> String #

showList :: [Tree a] -> ShowS #

Show a => Show (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Methods

showsPrec :: Int -> Seq a -> ShowS #

show :: Seq a -> String #

showList :: [Seq a] -> ShowS #

Show a => Show (ViewL a) 
Instance details

Defined in Data.Sequence.Internal

Methods

showsPrec :: Int -> ViewL a -> ShowS #

show :: ViewL a -> String #

showList :: [ViewL a] -> ShowS #

Show a => Show (ViewR a) 
Instance details

Defined in Data.Sequence.Internal

Methods

showsPrec :: Int -> ViewR a -> ShowS #

show :: ViewR a -> String #

showList :: [ViewR a] -> ShowS #

Show a => Show (Set a) 
Instance details

Defined in Data.Set.Internal

Methods

showsPrec :: Int -> Set a -> ShowS #

show :: Set a -> String #

showList :: [Set a] -> ShowS #

Show a => Show (RunError a) # 
Instance details

Defined in Entwine.Parallel

Methods

showsPrec :: Int -> RunError a -> ShowS #

show :: RunError a -> String #

showList :: [RunError a] -> ShowS #

(Show a, Show b) => Show (Either a b) 
Instance details

Defined in Data.Either

Methods

showsPrec :: Int -> Either a b -> ShowS #

show :: Either a b -> String #

showList :: [Either a b] -> ShowS #

Show (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> V1 p -> ShowS #

show :: V1 p -> String #

showList :: [V1 p] -> ShowS #

Show (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> U1 p -> ShowS #

show :: U1 p -> String #

showList :: [U1 p] -> ShowS #

Show (TypeRep a) 
Instance details

Defined in Data.Typeable.Internal

Methods

showsPrec :: Int -> TypeRep a -> ShowS #

show :: TypeRep a -> String #

showList :: [TypeRep a] -> ShowS #

(Show a, Show b) => Show (a, b)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b) -> ShowS #

show :: (a, b) -> String #

showList :: [(a, b)] -> ShowS #

(Ix a, Show a, Show b) => Show (Array a b)

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

showsPrec :: Int -> Array a b -> ShowS #

show :: Array a b -> String #

showList :: [Array a b] -> ShowS #

(Show a, Show b) => Show (Arg a b) 
Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Arg a b -> ShowS #

show :: Arg a b -> String #

showList :: [Arg a b] -> ShowS #

Show (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

showsPrec :: Int -> Proxy s -> ShowS #

show :: Proxy s -> String #

showList :: [Proxy s] -> ShowS #

(Show k, Show a) => Show (Map k a) 
Instance details

Defined in Data.Map.Internal

Methods

showsPrec :: Int -> Map k a -> ShowS #

show :: Map k a -> String #

showList :: [Map k a] -> ShowS #

Show (f p) => Show (Rec1 f p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> Rec1 f p -> ShowS #

show :: Rec1 f p -> String #

showList :: [Rec1 f p] -> ShowS #

Show (URec Char p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Char p -> ShowS #

show :: URec Char p -> String #

showList :: [URec Char p] -> ShowS #

Show (URec Double p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Double p -> ShowS #

show :: URec Double p -> String #

showList :: [URec Double p] -> ShowS #

Show (URec Float p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Float p -> ShowS #

show :: URec Float p -> String #

showList :: [URec Float p] -> ShowS #

Show (URec Int p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Int p -> ShowS #

show :: URec Int p -> String #

showList :: [URec Int p] -> ShowS #

Show (URec Word p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> URec Word p -> ShowS #

show :: URec Word p -> String #

showList :: [URec Word p] -> ShowS #

(Show a, Show b, Show c) => Show (a, b, c)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c) -> ShowS #

show :: (a, b, c) -> String #

showList :: [(a, b, c)] -> ShowS #

Show (f a) => Show (Alt f a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

showsPrec :: Int -> Alt f a -> ShowS #

show :: Alt f a -> String #

showList :: [Alt f a] -> ShowS #

Show (a :~: b) 
Instance details

Defined in Data.Type.Equality

Methods

showsPrec :: Int -> (a :~: b) -> ShowS #

show :: (a :~: b) -> String #

showList :: [a :~: b] -> ShowS #

(Show e, Show1 m, Show a) => Show (ErrorT e m a) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

showsPrec :: Int -> ErrorT e m a -> ShowS #

show :: ErrorT e m a -> String #

showList :: [ErrorT e m a] -> ShowS #

(Show e, Show1 m, Show a) => Show (ExceptT e m a) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

showsPrec :: Int -> ExceptT e m a -> ShowS #

show :: ExceptT e m a -> String #

showList :: [ExceptT e m a] -> ShowS #

Show c => Show (K1 i c p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> K1 i c p -> ShowS #

show :: K1 i c p -> String #

showList :: [K1 i c p] -> ShowS #

(Show (f p), Show (g p)) => Show ((f :+: g) p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> (f :+: g) p -> ShowS #

show :: (f :+: g) p -> String #

showList :: [(f :+: g) p] -> ShowS #

(Show (f p), Show (g p)) => Show ((f :*: g) p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> (f :*: g) p -> ShowS #

show :: (f :*: g) p -> String #

showList :: [(f :*: g) p] -> ShowS #

(Show a, Show b, Show c, Show d) => Show (a, b, c, d)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d) -> ShowS #

show :: (a, b, c, d) -> String #

showList :: [(a, b, c, d)] -> ShowS #

(Show1 f, Show1 g, Show a) => Show (Product f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

showsPrec :: Int -> Product f g a -> ShowS #

show :: Product f g a -> String #

showList :: [Product f g a] -> ShowS #

(Show1 f, Show1 g, Show a) => Show (Sum f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

showsPrec :: Int -> Sum f g a -> ShowS #

show :: Sum f g a -> String #

showList :: [Sum f g a] -> ShowS #

Show (a :~~: b)

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

showsPrec :: Int -> (a :~~: b) -> ShowS #

show :: (a :~~: b) -> String #

showList :: [a :~~: b] -> ShowS #

Show (f p) => Show (M1 i c f p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> M1 i c f p -> ShowS #

show :: M1 i c f p -> String #

showList :: [M1 i c f p] -> ShowS #

Show (f (g p)) => Show ((f :.: g) p) 
Instance details

Defined in GHC.Generics

Methods

showsPrec :: Int -> (f :.: g) p -> ShowS #

show :: (f :.: g) p -> String #

showList :: [(f :.: g) p] -> ShowS #

(Show a, Show b, Show c, Show d, Show e) => Show (a, b, c, d, e)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e) -> ShowS #

show :: (a, b, c, d, e) -> String #

showList :: [(a, b, c, d, e)] -> ShowS #

(Show1 f, Show1 g, Show a) => Show (Compose f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

showsPrec :: Int -> Compose f g a -> ShowS #

show :: Compose f g a -> String #

showList :: [Compose f g a] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f) => Show (a, b, c, d, e, f)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f) -> ShowS #

show :: (a, b, c, d, e, f) -> String #

showList :: [(a, b, c, d, e, f)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g) => Show (a, b, c, d, e, f, g)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g) -> ShowS #

show :: (a, b, c, d, e, f, g) -> String #

showList :: [(a, b, c, d, e, f, g)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h) => Show (a, b, c, d, e, f, g, h)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h) -> ShowS #

show :: (a, b, c, d, e, f, g, h) -> String #

showList :: [(a, b, c, d, e, f, g, h)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i) => Show (a, b, c, d, e, f, g, h, i)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i) -> String #

showList :: [(a, b, c, d, e, f, g, h, i)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j) => Show (a, b, c, d, e, f, g, h, i, j)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i, j) -> String #

showList :: [(a, b, c, d, e, f, g, h, i, j)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k) => Show (a, b, c, d, e, f, g, h, i, j, k)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i, j, k) -> String #

showList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l) => Show (a, b, c, d, e, f, g, h, i, j, k, l)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i, j, k, l) -> String #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> String #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m, Show n) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> String #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> ShowS #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m, Show n, Show o) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)

Since: base-2.1

Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> ShowS #

show :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> String #

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> ShowS #

ShowS

type ShowS = String -> String #

The shows functions return a function that prepends the output String to an existing String. This allows constant-time concatenation of results using function composition.

showString :: String -> ShowS #

utility function converting a String to a show function that simply prepends the string unchanged.

Foldable

class Foldable (t :: * -> *) where #

Data structures that can be folded.

For example, given a data type

data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)

a suitable instance would be

instance Foldable Tree where
   foldMap f Empty = mempty
   foldMap f (Leaf x) = f x
   foldMap f (Node l k r) = foldMap f l `mappend` f k `mappend` foldMap f r

This is suitable even for abstract types, as the monoid is assumed to satisfy the monoid laws. Alternatively, one could define foldr:

instance Foldable Tree where
   foldr f z Empty = z
   foldr f z (Leaf x) = f x z
   foldr f z (Node l k r) = foldr f (f k (foldr f z r)) l

Foldable instances are expected to satisfy the following laws:

foldr f z t = appEndo (foldMap (Endo . f) t ) z
foldl f z t = appEndo (getDual (foldMap (Dual . Endo . flip f) t)) z
fold = foldMap id
length = getSum . foldMap (Sum . const  1)

sum, product, maximum, and minimum should all be essentially equivalent to foldMap forms, such as

sum = getSum . foldMap Sum

but may be less defined.

If the type is also a Functor instance, it should satisfy

foldMap f = fold . fmap f

which implies that

foldMap f . fmap g = foldMap (f . g)

Minimal complete definition

foldMap | foldr

Methods

fold :: Monoid m => t m -> m #

Combine the elements of a structure using a monoid.

foldMap :: Monoid m => (a -> m) -> t a -> m #

Map each element of the structure to a monoid, and combine the results.

foldr :: (a -> b -> b) -> b -> t a -> b #

Right-associative fold of a structure.

In the case of lists, foldr, when applied to a binary operator, a starting value (typically the right-identity of the operator), and a list, reduces the list using the binary operator, from right to left:

foldr f z [x1, x2, ..., xn] == x1 `f` (x2 `f` ... (xn `f` z)...)

Note that, since the head of the resulting expression is produced by an application of the operator to the first element of the list, foldr can produce a terminating expression from an infinite list.

For a general Foldable structure this should be semantically identical to,

foldr f z = foldr f z . toList

foldr' :: (a -> b -> b) -> b -> t a -> b #

Right-associative fold of a structure, but with strict application of the operator.

foldl :: (b -> a -> b) -> b -> t a -> b #

Left-associative fold of a structure.

In the case of lists, foldl, when applied to a binary operator, a starting value (typically the left-identity of the operator), and a list, reduces the list using the binary operator, from left to right:

foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn

Note that to produce the outermost application of the operator the entire input list must be traversed. This means that foldl' will diverge if given an infinite list.

Also note that if you want an efficient left-fold, you probably want to use foldl' instead of foldl. The reason for this is that latter does not force the "inner" results (e.g. z f x1 in the above example) before applying them to the operator (e.g. to (f x2)). This results in a thunk chain O(n) elements long, which then must be evaluated from the outside-in.

For a general Foldable structure this should be semantically identical to,

foldl f z = foldl f z . toList

foldl' :: (b -> a -> b) -> b -> t a -> b #

Left-associative fold of a structure but with strict application of the operator.

This ensures that each step of the fold is forced to weak head normal form before being applied, avoiding the collection of thunks that would otherwise occur. This is often what you want to strictly reduce a finite list to a single, monolithic result (e.g. length).

For a general Foldable structure this should be semantically identical to,

foldl f z = foldl' f z . toList

foldr1 :: (a -> a -> a) -> t a -> a #

A variant of foldr that has no base case, and thus may only be applied to non-empty structures.

foldr1 f = foldr1 f . toList

foldl1 :: (a -> a -> a) -> t a -> a #

A variant of foldl that has no base case, and thus may only be applied to non-empty structures.

foldl1 f = foldl1 f . toList

toList :: t a -> [a] #

List of elements of a structure, from left to right.

null :: t a -> Bool #

Test whether the structure is empty. The default implementation is optimized for structures that are similar to cons-lists, because there is no general way to do better.

length :: t a -> Int #

Returns the size/length of a finite structure as an Int. The default implementation is optimized for structures that are similar to cons-lists, because there is no general way to do better.

elem :: Eq a => a -> t a -> Bool infix 4 #

Does the element occur in the structure?

maximum :: Ord a => t a -> a #

The largest element of a non-empty structure.

minimum :: Ord a => t a -> a #

The least element of a non-empty structure.

sum :: Num a => t a -> a #

The sum function computes the sum of the numbers of a structure.

product :: Num a => t a -> a #

The product function computes the product of the numbers of a structure.

Instances
Foldable []

Since: base-2.1

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => [m] -> 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 #

toList :: [a] -> [a] #

null :: [a] -> Bool #

length :: [a] -> Int #

elem :: Eq a => a -> [a] -> Bool #

maximum :: Ord a => [a] -> a #

minimum :: Ord a => [a] -> a #

sum :: Num a => [a] -> a #

product :: Num a => [a] -> a #

Foldable Maybe

Since: base-2.1

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Maybe m -> 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 #

toList :: Maybe a -> [a] #

null :: Maybe a -> Bool #

length :: Maybe a -> Int #

elem :: Eq a => a -> Maybe a -> Bool #

maximum :: Ord a => Maybe a -> a #

minimum :: Ord a => Maybe a -> a #

sum :: Num a => Maybe a -> a #

product :: Num a => Maybe a -> a #

Foldable Par1 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Par1 m -> 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 #

toList :: Par1 a -> [a] #

null :: Par1 a -> Bool #

length :: Par1 a -> Int #

elem :: Eq a => a -> Par1 a -> Bool #

maximum :: Ord a => Par1 a -> a #

minimum :: Ord a => Par1 a -> a #

sum :: Num a => Par1 a -> a #

product :: Num a => Par1 a -> a #

Foldable Complex 
Instance details

Defined in Data.Complex

Methods

fold :: Monoid m => Complex m -> 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 #

toList :: Complex a -> [a] #

null :: Complex a -> Bool #

length :: Complex a -> Int #

elem :: Eq a => a -> Complex a -> Bool #

maximum :: Ord a => Complex a -> a #

minimum :: Ord a => Complex a -> a #

sum :: Num a => Complex a -> a #

product :: Num a => Complex a -> a #

Foldable Min

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Min m -> 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 #

toList :: Min a -> [a] #

null :: Min a -> Bool #

length :: Min a -> Int #

elem :: Eq a => a -> Min a -> Bool #

maximum :: Ord a => Min a -> a #

minimum :: Ord a => Min a -> a #

sum :: Num a => Min a -> a #

product :: Num a => Min a -> a #

Foldable Max

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Max m -> 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 #

toList :: Max a -> [a] #

null :: Max a -> Bool #

length :: Max a -> Int #

elem :: Eq a => a -> Max a -> Bool #

maximum :: Ord a => Max a -> a #

minimum :: Ord a => Max a -> a #

sum :: Num a => Max a -> a #

product :: Num a => Max a -> a #

Foldable First

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => First m -> 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 #

toList :: First a -> [a] #

null :: First a -> Bool #

length :: First a -> Int #

elem :: Eq a => a -> First a -> Bool #

maximum :: Ord a => First a -> a #

minimum :: Ord a => First a -> a #

sum :: Num a => First a -> a #

product :: Num a => First a -> a #

Foldable Last

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Last m -> 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 #

toList :: Last a -> [a] #

null :: Last a -> Bool #

length :: Last a -> Int #

elem :: Eq a => a -> Last a -> Bool #

maximum :: Ord a => Last a -> a #

minimum :: Ord a => Last a -> a #

sum :: Num a => Last a -> a #

product :: Num a => Last a -> a #

Foldable Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Option m -> m #

foldMap :: Monoid m => (a -> m) -> Option a -> m #

foldr :: (a -> b -> b) -> b -> Option a -> b #

foldr' :: (a -> b -> b) -> b -> Option a -> b #

foldl :: (b -> a -> b) -> b -> Option a -> b #

foldl' :: (b -> a -> b) -> b -> Option a -> b #

foldr1 :: (a -> a -> a) -> Option a -> a #

foldl1 :: (a -> a -> a) -> Option a -> a #

toList :: Option a -> [a] #

null :: Option a -> Bool #

length :: Option a -> Int #

elem :: Eq a => a -> Option a -> Bool #

maximum :: Ord a => Option a -> a #

minimum :: Ord a => Option a -> a #

sum :: Num a => Option a -> a #

product :: Num a => Option a -> a #

Foldable ZipList 
Instance details

Defined in Control.Applicative

Methods

fold :: Monoid m => ZipList m -> 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 #

toList :: ZipList a -> [a] #

null :: ZipList a -> Bool #

length :: ZipList a -> Int #

elem :: Eq a => a -> ZipList a -> Bool #

maximum :: Ord a => ZipList a -> a #

minimum :: Ord a => ZipList a -> a #

sum :: Num a => ZipList a -> a #

product :: Num a => ZipList a -> a #

Foldable First

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => First m -> 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 #

toList :: First a -> [a] #

null :: First a -> Bool #

length :: First a -> Int #

elem :: Eq a => a -> First a -> Bool #

maximum :: Ord a => First a -> a #

minimum :: Ord a => First a -> a #

sum :: Num a => First a -> a #

product :: Num a => First a -> a #

Foldable Last

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Last m -> 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 #

toList :: Last a -> [a] #

null :: Last a -> Bool #

length :: Last a -> Int #

elem :: Eq a => a -> Last a -> Bool #

maximum :: Ord a => Last a -> a #

minimum :: Ord a => Last a -> a #

sum :: Num a => Last a -> a #

product :: Num a => Last a -> a #

Foldable Dual

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Dual m -> 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 #

toList :: Dual a -> [a] #

null :: Dual a -> Bool #

length :: Dual a -> Int #

elem :: Eq a => a -> Dual a -> Bool #

maximum :: Ord a => Dual a -> a #

minimum :: Ord a => Dual a -> a #

sum :: Num a => Dual a -> a #

product :: Num a => Dual a -> a #

Foldable Sum

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Sum m -> 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 #

toList :: Sum a -> [a] #

null :: Sum a -> Bool #

length :: Sum a -> Int #

elem :: Eq a => a -> Sum a -> Bool #

maximum :: Ord a => Sum a -> a #

minimum :: Ord a => Sum a -> a #

sum :: Num a => Sum a -> a #

product :: Num a => Sum a -> a #

Foldable Product

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Product m -> 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 #

toList :: Product a -> [a] #

null :: Product a -> Bool #

length :: Product a -> Int #

elem :: Eq a => a -> Product a -> Bool #

maximum :: Ord a => Product a -> a #

minimum :: Ord a => Product a -> a #

sum :: Num a => Product a -> a #

product :: Num a => Product a -> a #

Foldable NonEmpty

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => NonEmpty m -> m #

foldMap :: Monoid m => (a -> m) -> NonEmpty a -> m #

foldr :: (a -> b -> b) -> b -> NonEmpty a -> b #

foldr' :: (a -> b -> b) -> b -> NonEmpty a -> b #

foldl :: (b -> a -> b) -> b -> NonEmpty a -> b #

foldl' :: (b -> a -> b) -> b -> NonEmpty a -> b #

foldr1 :: (a -> a -> a) -> NonEmpty a -> a #

foldl1 :: (a -> a -> a) -> NonEmpty a -> a #

toList :: NonEmpty a -> [a] #

null :: NonEmpty a -> Bool #

length :: NonEmpty a -> Int #

elem :: Eq a => a -> NonEmpty a -> Bool #

maximum :: Ord a => NonEmpty a -> a #

minimum :: Ord a => NonEmpty a -> a #

sum :: Num a => NonEmpty a -> a #

product :: Num a => NonEmpty a -> a #

Foldable IntMap 
Instance details

Defined in Data.IntMap.Internal

Methods

fold :: Monoid m => IntMap m -> m #

foldMap :: Monoid m => (a -> m) -> IntMap a -> m #

foldr :: (a -> b -> b) -> b -> IntMap a -> b #

foldr' :: (a -> b -> b) -> b -> IntMap a -> b #

foldl :: (b -> a -> b) -> b -> IntMap a -> b #

foldl' :: (b -> a -> b) -> b -> IntMap a -> b #

foldr1 :: (a -> a -> a) -> IntMap a -> a #

foldl1 :: (a -> a -> a) -> IntMap a -> a #

toList :: IntMap a -> [a] #

null :: IntMap a -> Bool #

length :: IntMap a -> Int #

elem :: Eq a => a -> IntMap a -> Bool #

maximum :: Ord a => IntMap a -> a #

minimum :: Ord a => IntMap a -> a #

sum :: Num a => IntMap a -> a #

product :: Num a => IntMap a -> a #

Foldable Tree 
Instance details

Defined in Data.Tree

Methods

fold :: Monoid m => Tree m -> m #

foldMap :: Monoid m => (a -> m) -> Tree a -> m #

foldr :: (a -> b -> b) -> b -> Tree a -> b #

foldr' :: (a -> b -> b) -> b -> Tree a -> b #

foldl :: (b -> a -> b) -> b -> Tree a -> b #

foldl' :: (b -> a -> b) -> b -> Tree a -> b #

foldr1 :: (a -> a -> a) -> Tree a -> a #

foldl1 :: (a -> a -> a) -> Tree a -> a #

toList :: Tree a -> [a] #

null :: Tree a -> Bool #

length :: Tree a -> Int #

elem :: Eq a => a -> Tree a -> Bool #

maximum :: Ord a => Tree a -> a #

minimum :: Ord a => Tree a -> a #

sum :: Num a => Tree a -> a #

product :: Num a => Tree a -> a #

Foldable Seq 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => Seq m -> m #

foldMap :: Monoid m => (a -> m) -> Seq a -> m #

foldr :: (a -> b -> b) -> b -> Seq a -> b #

foldr' :: (a -> b -> b) -> b -> Seq a -> b #

foldl :: (b -> a -> b) -> b -> Seq a -> b #

foldl' :: (b -> a -> b) -> b -> Seq a -> b #

foldr1 :: (a -> a -> a) -> Seq a -> a #

foldl1 :: (a -> a -> a) -> Seq a -> a #

toList :: Seq a -> [a] #

null :: Seq a -> Bool #

length :: Seq a -> Int #

elem :: Eq a => a -> Seq a -> Bool #

maximum :: Ord a => Seq a -> a #

minimum :: Ord a => Seq a -> a #

sum :: Num a => Seq a -> a #

product :: Num a => Seq a -> a #

Foldable FingerTree 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => FingerTree m -> m #

foldMap :: Monoid m => (a -> m) -> FingerTree a -> m #

foldr :: (a -> b -> b) -> b -> FingerTree a -> b #

foldr' :: (a -> b -> b) -> b -> FingerTree a -> b #

foldl :: (b -> a -> b) -> b -> FingerTree a -> b #

foldl' :: (b -> a -> b) -> b -> FingerTree a -> b #

foldr1 :: (a -> a -> a) -> FingerTree a -> a #

foldl1 :: (a -> a -> a) -> FingerTree a -> a #

toList :: FingerTree a -> [a] #

null :: FingerTree a -> Bool #

length :: FingerTree a -> Int #

elem :: Eq a => a -> FingerTree a -> Bool #

maximum :: Ord a => FingerTree a -> a #

minimum :: Ord a => FingerTree a -> a #

sum :: Num a => FingerTree a -> a #

product :: Num a => FingerTree a -> a #

Foldable Digit 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => Digit m -> m #

foldMap :: Monoid m => (a -> m) -> Digit a -> m #

foldr :: (a -> b -> b) -> b -> Digit a -> b #

foldr' :: (a -> b -> b) -> b -> Digit a -> b #

foldl :: (b -> a -> b) -> b -> Digit a -> b #

foldl' :: (b -> a -> b) -> b -> Digit a -> b #

foldr1 :: (a -> a -> a) -> Digit a -> a #

foldl1 :: (a -> a -> a) -> Digit a -> a #

toList :: Digit a -> [a] #

null :: Digit a -> Bool #

length :: Digit a -> Int #

elem :: Eq a => a -> Digit a -> Bool #

maximum :: Ord a => Digit a -> a #

minimum :: Ord a => Digit a -> a #

sum :: Num a => Digit a -> a #

product :: Num a => Digit a -> a #

Foldable Node 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => Node m -> m #

foldMap :: Monoid m => (a -> m) -> Node a -> m #

foldr :: (a -> b -> b) -> b -> Node a -> b #

foldr' :: (a -> b -> b) -> b -> Node a -> b #

foldl :: (b -> a -> b) -> b -> Node a -> b #

foldl' :: (b -> a -> b) -> b -> Node a -> b #

foldr1 :: (a -> a -> a) -> Node a -> a #

foldl1 :: (a -> a -> a) -> Node a -> a #

toList :: Node a -> [a] #

null :: Node a -> Bool #

length :: Node a -> Int #

elem :: Eq a => a -> Node a -> Bool #

maximum :: Ord a => Node a -> a #

minimum :: Ord a => Node a -> a #

sum :: Num a => Node a -> a #

product :: Num a => Node a -> a #

Foldable Elem 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => Elem m -> m #

foldMap :: Monoid m => (a -> m) -> Elem a -> m #

foldr :: (a -> b -> b) -> b -> Elem a -> b #

foldr' :: (a -> b -> b) -> b -> Elem a -> b #

foldl :: (b -> a -> b) -> b -> Elem a -> b #

foldl' :: (b -> a -> b) -> b -> Elem a -> b #

foldr1 :: (a -> a -> a) -> Elem a -> a #

foldl1 :: (a -> a -> a) -> Elem a -> a #

toList :: Elem a -> [a] #

null :: Elem a -> Bool #

length :: Elem a -> Int #

elem :: Eq a => a -> Elem a -> Bool #

maximum :: Ord a => Elem a -> a #

minimum :: Ord a => Elem a -> a #

sum :: Num a => Elem a -> a #

product :: Num a => Elem a -> a #

Foldable ViewL 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => ViewL m -> m #

foldMap :: Monoid m => (a -> m) -> ViewL a -> m #

foldr :: (a -> b -> b) -> b -> ViewL a -> b #

foldr' :: (a -> b -> b) -> b -> ViewL a -> b #

foldl :: (b -> a -> b) -> b -> ViewL a -> b #

foldl' :: (b -> a -> b) -> b -> ViewL a -> b #

foldr1 :: (a -> a -> a) -> ViewL a -> a #

foldl1 :: (a -> a -> a) -> ViewL a -> a #

toList :: ViewL a -> [a] #

null :: ViewL a -> Bool #

length :: ViewL a -> Int #

elem :: Eq a => a -> ViewL a -> Bool #

maximum :: Ord a => ViewL a -> a #

minimum :: Ord a => ViewL a -> a #

sum :: Num a => ViewL a -> a #

product :: Num a => ViewL a -> a #

Foldable ViewR 
Instance details

Defined in Data.Sequence.Internal

Methods

fold :: Monoid m => ViewR m -> m #

foldMap :: Monoid m => (a -> m) -> ViewR a -> m #

foldr :: (a -> b -> b) -> b -> ViewR a -> b #

foldr' :: (a -> b -> b) -> b -> ViewR a -> b #

foldl :: (b -> a -> b) -> b -> ViewR a -> b #

foldl' :: (b -> a -> b) -> b -> ViewR a -> b #

foldr1 :: (a -> a -> a) -> ViewR a -> a #

foldl1 :: (a -> a -> a) -> ViewR a -> a #

toList :: ViewR a -> [a] #

null :: ViewR a -> Bool #

length :: ViewR a -> Int #

elem :: Eq a => a -> ViewR a -> Bool #

maximum :: Ord a => ViewR a -> a #

minimum :: Ord a => ViewR a -> a #

sum :: Num a => ViewR a -> a #

product :: Num a => ViewR a -> a #

Foldable Set 
Instance details

Defined in Data.Set.Internal

Methods

fold :: Monoid m => Set m -> m #

foldMap :: Monoid m => (a -> m) -> Set a -> m #

foldr :: (a -> b -> b) -> b -> Set a -> b #

foldr' :: (a -> b -> b) -> b -> Set a -> b #

foldl :: (b -> a -> b) -> b -> Set a -> b #

foldl' :: (b -> a -> b) -> b -> Set a -> b #

foldr1 :: (a -> a -> a) -> Set a -> a #

foldl1 :: (a -> a -> a) -> Set a -> a #

toList :: Set a -> [a] #

null :: Set a -> Bool #

length :: Set a -> Int #

elem :: Eq a => a -> Set a -> Bool #

maximum :: Ord a => Set a -> a #

minimum :: Ord a => Set a -> a #

sum :: Num a => Set a -> a #

product :: Num a => Set a -> a #

Foldable (Either a)

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Either a m -> 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] #

null :: Either a a0 -> Bool #

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 #

sum :: Num a0 => Either a a0 -> a0 #

product :: Num a0 => Either a a0 -> a0 #

Foldable (V1 :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => V1 m -> 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 #

toList :: V1 a -> [a] #

null :: V1 a -> Bool #

length :: V1 a -> Int #

elem :: Eq a => a -> V1 a -> Bool #

maximum :: Ord a => V1 a -> a #

minimum :: Ord a => V1 a -> a #

sum :: Num a => V1 a -> a #

product :: Num a => V1 a -> a #

Foldable (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => U1 m -> 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 #

toList :: U1 a -> [a] #

null :: U1 a -> Bool #

length :: U1 a -> Int #

elem :: Eq a => a -> U1 a -> Bool #

maximum :: Ord a => U1 a -> a #

minimum :: Ord a => U1 a -> a #

sum :: Num a => U1 a -> a #

product :: Num a => U1 a -> a #

Foldable ((,) a)

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (a, m) -> 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 #

toList :: (a, a0) -> [a0] #

null :: (a, a0) -> Bool #

length :: (a, a0) -> Int #

elem :: Eq a0 => a0 -> (a, a0) -> Bool #

maximum :: Ord a0 => (a, a0) -> a0 #

minimum :: Ord a0 => (a, a0) -> a0 #

sum :: Num a0 => (a, a0) -> a0 #

product :: Num a0 => (a, a0) -> a0 #

Foldable (Array i)

Since: base-4.8.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Array i m -> 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 #

toList :: Array i a -> [a] #

null :: Array i a -> Bool #

length :: Array i a -> Int #

elem :: Eq a => a -> Array i a -> Bool #

maximum :: Ord a => Array i a -> a #

minimum :: Ord a => Array i a -> a #

sum :: Num a => Array i a -> a #

product :: Num a => Array i a -> a #

Foldable (Arg a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

fold :: Monoid m => Arg a m -> 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 #

toList :: Arg a a0 -> [a0] #

null :: Arg a a0 -> Bool #

length :: Arg a a0 -> Int #

elem :: Eq a0 => a0 -> Arg a a0 -> Bool #

maximum :: Ord a0 => Arg a a0 -> a0 #

minimum :: Ord a0 => Arg a a0 -> a0 #

sum :: Num a0 => Arg a a0 -> a0 #

product :: Num a0 => Arg a a0 -> a0 #

Foldable (Proxy :: * -> *)

Since: base-4.7.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Proxy m -> 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 #

toList :: Proxy a -> [a] #

null :: Proxy a -> Bool #

length :: Proxy a -> Int #

elem :: Eq a => a -> Proxy a -> Bool #

maximum :: Ord a => Proxy a -> a #

minimum :: Ord a => Proxy a -> a #

sum :: Num a => Proxy a -> a #

product :: Num a => Proxy a -> a #

Foldable (Map k) 
Instance details

Defined in Data.Map.Internal

Methods

fold :: Monoid m => Map k m -> m #

foldMap :: Monoid m => (a -> m) -> Map k a -> m #

foldr :: (a -> b -> b) -> b -> Map k a -> b #

foldr' :: (a -> b -> b) -> b -> Map k a -> b #

foldl :: (b -> a -> b) -> b -> Map k a -> b #

foldl' :: (b -> a -> b) -> b -> Map k a -> b #

foldr1 :: (a -> a -> a) -> Map k a -> a #

foldl1 :: (a -> a -> a) -> Map k a -> a #

toList :: Map k a -> [a] #

null :: Map k a -> Bool #

length :: Map k a -> Int #

elem :: Eq a => a -> Map k a -> Bool #

maximum :: Ord a => Map k a -> a #

minimum :: Ord a => Map k a -> a #

sum :: Num a => Map k a -> a #

product :: Num a => Map k a -> a #

Foldable f => Foldable (Rec1 f) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Rec1 f m -> 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 #

toList :: Rec1 f a -> [a] #

null :: Rec1 f a -> Bool #

length :: Rec1 f a -> Int #

elem :: Eq a => a -> Rec1 f a -> Bool #

maximum :: Ord a => Rec1 f a -> a #

minimum :: Ord a => Rec1 f a -> a #

sum :: Num a => Rec1 f a -> a #

product :: Num a => Rec1 f a -> a #

Foldable (URec Char :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Char m -> m #

foldMap :: Monoid m => (a -> m) -> URec Char a -> m #

foldr :: (a -> b -> b) -> b -> URec Char a -> b #

foldr' :: (a -> b -> b) -> b -> URec Char a -> b #

foldl :: (b -> a -> b) -> b -> URec Char a -> b #

foldl' :: (b -> a -> b) -> b -> URec Char a -> b #

foldr1 :: (a -> a -> a) -> URec Char a -> a #

foldl1 :: (a -> a -> a) -> URec Char a -> a #

toList :: URec Char a -> [a] #

null :: URec Char a -> Bool #

length :: URec Char a -> Int #

elem :: Eq a => a -> URec Char a -> Bool #

maximum :: Ord a => URec Char a -> a #

minimum :: Ord a => URec Char a -> a #

sum :: Num a => URec Char a -> a #

product :: Num a => URec Char a -> a #

Foldable (URec Double :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Double m -> m #

foldMap :: Monoid m => (a -> m) -> URec Double a -> m #

foldr :: (a -> b -> b) -> b -> URec Double a -> b #

foldr' :: (a -> b -> b) -> b -> URec Double a -> b #

foldl :: (b -> a -> b) -> b -> URec Double a -> b #

foldl' :: (b -> a -> b) -> b -> URec Double a -> b #

foldr1 :: (a -> a -> a) -> URec Double a -> a #

foldl1 :: (a -> a -> a) -> URec Double a -> a #

toList :: URec Double a -> [a] #

null :: URec Double a -> Bool #

length :: URec Double a -> Int #

elem :: Eq a => a -> URec Double a -> Bool #

maximum :: Ord a => URec Double a -> a #

minimum :: Ord a => URec Double a -> a #

sum :: Num a => URec Double a -> a #

product :: Num a => URec Double a -> a #

Foldable (URec Float :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Float m -> m #

foldMap :: Monoid m => (a -> m) -> URec Float a -> m #

foldr :: (a -> b -> b) -> b -> URec Float a -> b #

foldr' :: (a -> b -> b) -> b -> URec Float a -> b #

foldl :: (b -> a -> b) -> b -> URec Float a -> b #

foldl' :: (b -> a -> b) -> b -> URec Float a -> b #

foldr1 :: (a -> a -> a) -> URec Float a -> a #

foldl1 :: (a -> a -> a) -> URec Float a -> a #

toList :: URec Float a -> [a] #

null :: URec Float a -> Bool #

length :: URec Float a -> Int #

elem :: Eq a => a -> URec Float a -> Bool #

maximum :: Ord a => URec Float a -> a #

minimum :: Ord a => URec Float a -> a #

sum :: Num a => URec Float a -> a #

product :: Num a => URec Float a -> a #

Foldable (URec Int :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Int m -> m #

foldMap :: Monoid m => (a -> m) -> URec Int a -> m #

foldr :: (a -> b -> b) -> b -> URec Int a -> b #

foldr' :: (a -> b -> b) -> b -> URec Int a -> b #

foldl :: (b -> a -> b) -> b -> URec Int a -> b #

foldl' :: (b -> a -> b) -> b -> URec Int a -> b #

foldr1 :: (a -> a -> a) -> URec Int a -> a #

foldl1 :: (a -> a -> a) -> URec Int a -> a #

toList :: URec Int a -> [a] #

null :: URec Int a -> Bool #

length :: URec Int a -> Int #

elem :: Eq a => a -> URec Int a -> Bool #

maximum :: Ord a => URec Int a -> a #

minimum :: Ord a => URec Int a -> a #

sum :: Num a => URec Int a -> a #

product :: Num a => URec Int a -> a #

Foldable (URec Word :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec Word m -> m #

foldMap :: Monoid m => (a -> m) -> URec Word a -> m #

foldr :: (a -> b -> b) -> b -> URec Word a -> b #

foldr' :: (a -> b -> b) -> b -> URec Word a -> b #

foldl :: (b -> a -> b) -> b -> URec Word a -> b #

foldl' :: (b -> a -> b) -> b -> URec Word a -> b #

foldr1 :: (a -> a -> a) -> URec Word a -> a #

foldl1 :: (a -> a -> a) -> URec Word a -> a #

toList :: URec Word a -> [a] #

null :: URec Word a -> Bool #

length :: URec Word a -> Int #

elem :: Eq a => a -> URec Word a -> Bool #

maximum :: Ord a => URec Word a -> a #

minimum :: Ord a => URec Word a -> a #

sum :: Num a => URec Word a -> a #

product :: Num a => URec Word a -> a #

Foldable (URec (Ptr ()) :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => URec (Ptr ()) m -> m #

foldMap :: Monoid m => (a -> m) -> URec (Ptr ()) a -> m #

foldr :: (a -> b -> b) -> b -> URec (Ptr ()) a -> b #

foldr' :: (a -> b -> b) -> b -> URec (Ptr ()) a -> b #

foldl :: (b -> a -> b) -> b -> URec (Ptr ()) a -> b #

foldl' :: (b -> a -> b) -> b -> URec (Ptr ()) a -> b #

foldr1 :: (a -> a -> a) -> URec (Ptr ()) a -> a #

foldl1 :: (a -> a -> a) -> URec (Ptr ()) a -> a #

toList :: URec (Ptr ()) a -> [a] #

null :: URec (Ptr ()) a -> Bool #

length :: URec (Ptr ()) a -> Int #

elem :: Eq a => a -> URec (Ptr ()) a -> Bool #

maximum :: Ord a => URec (Ptr ()) a -> a #

minimum :: Ord a => URec (Ptr ()) a -> a #

sum :: Num a => URec (Ptr ()) a -> a #

product :: Num a => URec (Ptr ()) a -> a #

Foldable f => Foldable (ErrorT e f) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

fold :: Monoid m => ErrorT e f m -> m #

foldMap :: Monoid m => (a -> m) -> ErrorT e f a -> m #

foldr :: (a -> b -> b) -> b -> ErrorT e f a -> b #

foldr' :: (a -> b -> b) -> b -> ErrorT e f a -> b #

foldl :: (b -> a -> b) -> b -> ErrorT e f a -> b #

foldl' :: (b -> a -> b) -> b -> ErrorT e f a -> b #

foldr1 :: (a -> a -> a) -> ErrorT e f a -> a #

foldl1 :: (a -> a -> a) -> ErrorT e f a -> a #

toList :: ErrorT e f a -> [a] #

null :: ErrorT e f a -> Bool #

length :: ErrorT e f a -> Int #

elem :: Eq a => a -> ErrorT e f a -> Bool #

maximum :: Ord a => ErrorT e f a -> a #

minimum :: Ord a => ErrorT e f a -> a #

sum :: Num a => ErrorT e f a -> a #

product :: Num a => ErrorT e f a -> a #

Foldable f => Foldable (ExceptT e f) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

fold :: Monoid m => ExceptT e f m -> m #

foldMap :: Monoid m => (a -> m) -> ExceptT e f a -> m #

foldr :: (a -> b -> b) -> b -> ExceptT e f a -> b #

foldr' :: (a -> b -> b) -> b -> ExceptT e f a -> b #

foldl :: (b -> a -> b) -> b -> ExceptT e f a -> b #

foldl' :: (b -> a -> b) -> b -> ExceptT e f a -> b #

foldr1 :: (a -> a -> a) -> ExceptT e f a -> a #

foldl1 :: (a -> a -> a) -> ExceptT e f a -> a #

toList :: ExceptT e f a -> [a] #

null :: ExceptT e f a -> Bool #

length :: ExceptT e f a -> Int #

elem :: Eq a => a -> ExceptT e f a -> Bool #

maximum :: Ord a => ExceptT e f a -> a #

minimum :: Ord a => ExceptT e f a -> a #

sum :: Num a => ExceptT e f a -> a #

product :: Num a => ExceptT e f a -> a #

Foldable (K1 i c :: * -> *) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => K1 i c m -> 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 #

toList :: K1 i c a -> [a] #

null :: K1 i c a -> Bool #

length :: K1 i c a -> Int #

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 #

sum :: Num a => K1 i c a -> a #

product :: Num a => K1 i c a -> a #

(Foldable f, Foldable g) => Foldable (f :+: g) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (f :+: g) m -> 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] #

null :: (f :+: g) a -> Bool #

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 #

sum :: Num a => (f :+: g) a -> a #

product :: Num a => (f :+: g) a -> a #

(Foldable f, Foldable g) => Foldable (f :*: g) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (f :*: g) m -> 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] #

null :: (f :*: g) a -> Bool #

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 #

sum :: Num a => (f :*: g) a -> a #

product :: Num a => (f :*: g) a -> a #

(Foldable f, Foldable g) => Foldable (Product f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

fold :: Monoid m => Product f g m -> 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 #

sum :: Num a => Product f g a -> a #

product :: Num a => Product f g a -> a #

(Foldable f, Foldable g) => Foldable (Sum f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

fold :: Monoid m => Sum f g m -> 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 #

toList :: Sum f g a -> [a] #

null :: Sum f g a -> Bool #

length :: Sum f g a -> Int #

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 #

sum :: Num a => Sum f g a -> a #

product :: Num a => Sum f g a -> a #

Foldable f => Foldable (M1 i c f) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => M1 i c f m -> 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 #

toList :: M1 i c f a -> [a] #

null :: M1 i c f a -> Bool #

length :: M1 i c f a -> Int #

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 #

sum :: Num a => M1 i c f a -> a #

product :: Num a => M1 i c f a -> a #

(Foldable f, Foldable g) => Foldable (f :.: g) 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => (f :.: g) m -> 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] #

null :: (f :.: g) a -> Bool #

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 #

sum :: Num a => (f :.: g) a -> a #

product :: Num a => (f :.: g) a -> a #

(Foldable f, Foldable g) => Foldable (Compose f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

fold :: Monoid m => Compose f g m -> 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 #

sum :: Num a => Compose f g a -> a #

product :: Num a => Compose f g a -> a #

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.

>>> for_ [1..4] print
1
2
3
4

forM_ :: (Foldable t, Monad m) => t a -> (a -> m b) -> m () #

forM_ is mapM_ with its arguments flipped. For a version that doesn't ignore the results see forM.

As of base 4.8.0.0, forM_ is just for_, specialized to Monad.

all :: Foldable t => (a -> Bool) -> t a -> Bool #

Determines whether all elements of the structure satisfy the predicate.

head :: Foldable f => f a -> Maybe a Source #

concat :: Foldable t => t [a] -> [a] #

The concatenation of all the elements of a container of lists.

concatMap :: Foldable t => (a -> [b]) -> t a -> [b] #

Map a function over all the elements of a container and concatenate the resulting lists.

Ord

class Eq a => Ord a where #

The Ord class is used for totally ordered datatypes.

Instances of Ord can be derived for any user-defined datatype whose constituent types are in Ord. The declared order of the constructors in the data declaration determines the ordering in derived Ord instances. The Ordering datatype allows a single comparison to determine the precise ordering of two objects.

Minimal complete definition: either compare or <=. Using compare can be more efficient for complex types.

Minimal complete definition

compare | (<=)

Methods

compare :: a -> a -> Ordering #

(<) :: a -> a -> Bool infix 4 #

(<=) :: a -> a -> Bool infix 4 #

(>) :: a -> a -> Bool infix 4 #

(>=) :: a -> a -> Bool infix 4 #

max :: a -> a -> a #

min :: a -> a -> a #

Instances
Ord Bool 
Instance details

Defined in GHC.Classes

Methods

compare :: Bool -> Bool -> Ordering #

(<) :: Bool -> Bool -> Bool #

(<=) :: Bool -> Bool -> Bool #

(>) :: Bool -> Bool -> Bool #

(>=) :: Bool -> Bool -> Bool #

max :: Bool -> Bool -> Bool #

min :: Bool -> Bool -> Bool #

Ord Char 
Instance details

Defined in GHC.Classes

Methods

compare :: Char -> Char -> Ordering #

(<) :: Char -> Char -> Bool #

(<=) :: Char -> Char -> Bool #

(>) :: Char -> Char -> Bool #

(>=) :: Char -> Char -> Bool #

max :: Char -> Char -> Char #

min :: Char -> Char -> Char #

Ord Double 
Instance details

Defined in GHC.Classes

Ord Float 
Instance details

Defined in GHC.Classes

Methods

compare :: Float -> Float -> Ordering #

(<) :: Float -> Float -> Bool #

(<=) :: Float -> Float -> Bool #

(>) :: Float -> Float -> Bool #

(>=) :: Float -> Float -> Bool #

max :: Float -> Float -> Float #

min :: Float -> Float -> Float #

Ord Int 
Instance details

Defined in GHC.Classes

Methods

compare :: Int -> Int -> Ordering #

(<) :: Int -> Int -> Bool #

(<=) :: Int -> Int -> Bool #

(>) :: Int -> Int -> Bool #

(>=) :: Int -> Int -> Bool #

max :: Int -> Int -> Int #

min :: Int -> Int -> Int #

Ord Int8

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int8 -> Int8 -> Ordering #

(<) :: Int8 -> Int8 -> Bool #

(<=) :: Int8 -> Int8 -> Bool #

(>) :: Int8 -> Int8 -> Bool #

(>=) :: Int8 -> Int8 -> Bool #

max :: Int8 -> Int8 -> Int8 #

min :: Int8 -> Int8 -> Int8 #

Ord Int16

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int16 -> Int16 -> Ordering #

(<) :: Int16 -> Int16 -> Bool #

(<=) :: Int16 -> Int16 -> Bool #

(>) :: Int16 -> Int16 -> Bool #

(>=) :: Int16 -> Int16 -> Bool #

max :: Int16 -> Int16 -> Int16 #

min :: Int16 -> Int16 -> Int16 #

Ord Int32

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int32 -> Int32 -> Ordering #

(<) :: Int32 -> Int32 -> Bool #

(<=) :: Int32 -> Int32 -> Bool #

(>) :: Int32 -> Int32 -> Bool #

(>=) :: Int32 -> Int32 -> Bool #

max :: Int32 -> Int32 -> Int32 #

min :: Int32 -> Int32 -> Int32 #

Ord Int64

Since: base-2.1

Instance details

Defined in GHC.Int

Methods

compare :: Int64 -> Int64 -> Ordering #

(<) :: Int64 -> Int64 -> Bool #

(<=) :: Int64 -> Int64 -> Bool #

(>) :: Int64 -> Int64 -> Bool #

(>=) :: Int64 -> Int64 -> Bool #

max :: Int64 -> Int64 -> Int64 #

min :: Int64 -> Int64 -> Int64 #

Ord Integer 
Instance details

Defined in GHC.Integer.Type

Ord Ordering 
Instance details

Defined in GHC.Classes

Ord Word 
Instance details

Defined in GHC.Classes

Methods

compare :: Word -> Word -> Ordering #

(<) :: Word -> Word -> Bool #

(<=) :: Word -> Word -> Bool #

(>) :: Word -> Word -> Bool #

(>=) :: Word -> Word -> Bool #

max :: Word -> Word -> Word #

min :: Word -> Word -> Word #

Ord Word8

Since: base-2.1

Instance details

Defined in GHC.Word

Methods

compare :: Word8 -> Word8 -> Ordering #

(<) :: Word8 -> Word8 -> Bool #

(<=) :: Word8 -> Word8 -> Bool #

(>) :: Word8 -> Word8 -> Bool #

(>=) :: Word8 -> Word8 -> Bool #

max :: Word8 -> Word8 -> Word8 #

min :: Word8 -> Word8 -> Word8 #

Ord Word16

Since: base-2.1

Instance details

Defined in GHC.Word

Ord Word32

Since: base-2.1

Instance details

Defined in GHC.Word

Ord Word64

Since: base-2.1

Instance details

Defined in GHC.Word

Ord SomeTypeRep 
Instance details

Defined in Data.Typeable.Internal

Ord Exp 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Exp -> Exp -> Ordering #

(<) :: Exp -> Exp -> Bool #

(<=) :: Exp -> Exp -> Bool #

(>) :: Exp -> Exp -> Bool #

(>=) :: Exp -> Exp -> Bool #

max :: Exp -> Exp -> Exp #

min :: Exp -> Exp -> Exp #

Ord Match 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Match -> Match -> Ordering #

(<) :: Match -> Match -> Bool #

(<=) :: Match -> Match -> Bool #

(>) :: Match -> Match -> Bool #

(>=) :: Match -> Match -> Bool #

max :: Match -> Match -> Match #

min :: Match -> Match -> Match #

Ord Clause 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Pat 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Pat -> Pat -> Ordering #

(<) :: Pat -> Pat -> Bool #

(<=) :: Pat -> Pat -> Bool #

(>) :: Pat -> Pat -> Bool #

(>=) :: Pat -> Pat -> Bool #

max :: Pat -> Pat -> Pat #

min :: Pat -> Pat -> Pat #

Ord Type 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Type -> Type -> Ordering #

(<) :: Type -> Type -> Bool #

(<=) :: Type -> Type -> Bool #

(>) :: Type -> Type -> Bool #

(>=) :: Type -> Type -> Bool #

max :: Type -> Type -> Type #

min :: Type -> Type -> Type #

Ord Dec 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Dec -> Dec -> Ordering #

(<) :: Dec -> Dec -> Bool #

(<=) :: Dec -> Dec -> Bool #

(>) :: Dec -> Dec -> Bool #

(>=) :: Dec -> Dec -> Bool #

max :: Dec -> Dec -> Dec #

min :: Dec -> Dec -> Dec #

Ord Name 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Name -> Name -> Ordering #

(<) :: Name -> Name -> Bool #

(<=) :: Name -> Name -> Bool #

(>) :: Name -> Name -> Bool #

(>=) :: Name -> Name -> Bool #

max :: Name -> Name -> Name #

min :: Name -> Name -> Name #

Ord FunDep 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord InjectivityAnn 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Overlap 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord DerivStrategy 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord () 
Instance details

Defined in GHC.Classes

Methods

compare :: () -> () -> Ordering #

(<) :: () -> () -> Bool #

(<=) :: () -> () -> Bool #

(>) :: () -> () -> Bool #

(>=) :: () -> () -> Bool #

max :: () -> () -> () #

min :: () -> () -> () #

Ord TyCon 
Instance details

Defined in GHC.Classes

Methods

compare :: TyCon -> TyCon -> Ordering #

(<) :: TyCon -> TyCon -> Bool #

(<=) :: TyCon -> TyCon -> Bool #

(>) :: TyCon -> TyCon -> Bool #

(>=) :: TyCon -> TyCon -> Bool #

max :: TyCon -> TyCon -> TyCon #

min :: TyCon -> TyCon -> TyCon #

Ord ThreadId

Since: base-4.2.0.0

Instance details

Defined in GHC.Conc.Sync

Ord BigNat 
Instance details

Defined in GHC.Integer.Type

Ord Void

Since: base-4.8.0.0

Instance details

Defined in Data.Void

Methods

compare :: Void -> Void -> Ordering #

(<) :: Void -> Void -> Bool #

(<=) :: Void -> Void -> Bool #

(>) :: Void -> Void -> Bool #

(>=) :: Void -> Void -> Bool #

max :: Void -> Void -> Void #

min :: Void -> Void -> Void #

Ord BlockReason 
Instance details

Defined in GHC.Conc.Sync

Ord ThreadStatus 
Instance details

Defined in GHC.Conc.Sync

Ord AsyncException 
Instance details

Defined in GHC.IO.Exception

Ord ArrayException 
Instance details

Defined in GHC.IO.Exception

Ord ExitCode 
Instance details

Defined in GHC.IO.Exception

Ord BufferMode 
Instance details

Defined in GHC.IO.Handle.Types

Ord Newline 
Instance details

Defined in GHC.IO.Handle.Types

Ord NewlineMode 
Instance details

Defined in GHC.IO.Handle.Types

Ord SeekMode 
Instance details

Defined in GHC.IO.Device

Ord ErrorCall 
Instance details

Defined in GHC.Exception

Ord ArithException 
Instance details

Defined in GHC.Exception

Ord All 
Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: All -> All -> Ordering #

(<) :: All -> All -> Bool #

(<=) :: All -> All -> Bool #

(>) :: All -> All -> Bool #

(>=) :: All -> All -> Bool #

max :: All -> All -> All #

min :: All -> All -> All #

Ord Any 
Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Any -> Any -> Ordering #

(<) :: Any -> Any -> Bool #

(<=) :: Any -> Any -> Bool #

(>) :: Any -> Any -> Bool #

(>=) :: Any -> Any -> Bool #

max :: Any -> Any -> Any #

min :: Any -> Any -> Any #

Ord Fixity 
Instance details

Defined in GHC.Generics

Ord Associativity 
Instance details

Defined in GHC.Generics

Ord SourceUnpackedness 
Instance details

Defined in GHC.Generics

Ord SourceStrictness 
Instance details

Defined in GHC.Generics

Ord DecidedStrictness 
Instance details

Defined in GHC.Generics

Ord IOMode 
Instance details

Defined in GHC.IO.IOMode

Ord IntSet 
Instance details

Defined in Data.IntSet.Internal

Ord ModName 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord PkgName 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Module 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord OccName 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord NameFlavour 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord NameSpace 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Loc 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Loc -> Loc -> Ordering #

(<) :: Loc -> Loc -> Bool #

(<=) :: Loc -> Loc -> Bool #

(>) :: Loc -> Loc -> Bool #

(>=) :: Loc -> Loc -> Bool #

max :: Loc -> Loc -> Loc #

min :: Loc -> Loc -> Loc #

Ord Info 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Info -> Info -> Ordering #

(<) :: Info -> Info -> Bool #

(<=) :: Info -> Info -> Bool #

(>) :: Info -> Info -> Bool #

(>=) :: Info -> Info -> Bool #

max :: Info -> Info -> Info #

min :: Info -> Info -> Info #

Ord ModuleInfo 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Fixity 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord FixityDirection 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Lit 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Lit -> Lit -> Ordering #

(<) :: Lit -> Lit -> Bool #

(<=) :: Lit -> Lit -> Bool #

(>) :: Lit -> Lit -> Bool #

(>=) :: Lit -> Lit -> Bool #

max :: Lit -> Lit -> Lit #

min :: Lit -> Lit -> Lit #

Ord Body 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Body -> Body -> Ordering #

(<) :: Body -> Body -> Bool #

(<=) :: Body -> Body -> Bool #

(>) :: Body -> Body -> Bool #

(>=) :: Body -> Body -> Bool #

max :: Body -> Body -> Body #

min :: Body -> Body -> Body #

Ord Guard 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Guard -> Guard -> Ordering #

(<) :: Guard -> Guard -> Bool #

(<=) :: Guard -> Guard -> Bool #

(>) :: Guard -> Guard -> Bool #

(>=) :: Guard -> Guard -> Bool #

max :: Guard -> Guard -> Guard #

min :: Guard -> Guard -> Guard #

Ord Stmt 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Stmt -> Stmt -> Ordering #

(<) :: Stmt -> Stmt -> Bool #

(<=) :: Stmt -> Stmt -> Bool #

(>) :: Stmt -> Stmt -> Bool #

(>=) :: Stmt -> Stmt -> Bool #

max :: Stmt -> Stmt -> Stmt #

min :: Stmt -> Stmt -> Stmt #

Ord Range 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Range -> Range -> Ordering #

(<) :: Range -> Range -> Bool #

(<=) :: Range -> Range -> Bool #

(>) :: Range -> Range -> Bool #

(>=) :: Range -> Range -> Bool #

max :: Range -> Range -> Range #

min :: Range -> Range -> Range #

Ord DerivClause 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord TypeFamilyHead 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord TySynEqn 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Foreign 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Callconv 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Safety 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Pragma 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Inline 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord RuleMatch 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Phases 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord RuleBndr 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord AnnTarget 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord SourceUnpackedness 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord SourceStrictness 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord DecidedStrictness 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord Con 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Con -> Con -> Ordering #

(<) :: Con -> Con -> Bool #

(<=) :: Con -> Con -> Bool #

(>) :: Con -> Con -> Bool #

(>=) :: Con -> Con -> Bool #

max :: Con -> Con -> Con #

min :: Con -> Con -> Con #

Ord Bang 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Bang -> Bang -> Ordering #

(<) :: Bang -> Bang -> Bool #

(<=) :: Bang -> Bang -> Bool #

(>) :: Bang -> Bang -> Bool #

(>=) :: Bang -> Bang -> Bool #

max :: Bang -> Bang -> Bang #

min :: Bang -> Bang -> Bang #

Ord PatSynDir 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord PatSynArgs 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord TyVarBndr 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord FamilyResultSig 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord TyLit 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: TyLit -> TyLit -> Ordering #

(<) :: TyLit -> TyLit -> Bool #

(<=) :: TyLit -> TyLit -> Bool #

(>) :: TyLit -> TyLit -> Bool #

(>=) :: TyLit -> TyLit -> Bool #

max :: TyLit -> TyLit -> TyLit #

min :: TyLit -> TyLit -> TyLit #

Ord Role 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

compare :: Role -> Role -> Ordering #

(<) :: Role -> Role -> Bool #

(<=) :: Role -> Role -> Bool #

(>) :: Role -> Role -> Bool #

(>=) :: Role -> Role -> Bool #

max :: Role -> Role -> Role #

min :: Role -> Role -> Role #

Ord AnnLookup 
Instance details

Defined in Language.Haskell.TH.Syntax

Ord a => Ord [a] 
Instance details

Defined in GHC.Classes

Methods

compare :: [a] -> [a] -> Ordering #

(<) :: [a] -> [a] -> Bool #

(<=) :: [a] -> [a] -> Bool #

(>) :: [a] -> [a] -> Bool #

(>=) :: [a] -> [a] -> Bool #

max :: [a] -> [a] -> [a] #

min :: [a] -> [a] -> [a] #

Ord a => Ord (Maybe a) 
Instance details

Defined in GHC.Base

Methods

compare :: Maybe a -> Maybe a -> Ordering #

(<) :: Maybe a -> Maybe a -> Bool #

(<=) :: Maybe a -> Maybe a -> Bool #

(>) :: Maybe a -> Maybe a -> Bool #

(>=) :: Maybe a -> Maybe a -> Bool #

max :: Maybe a -> Maybe a -> Maybe a #

min :: Maybe a -> Maybe a -> Maybe a #

Integral a => Ord (Ratio a)

Since: base-2.0.1

Instance details

Defined in GHC.Real

Methods

compare :: Ratio a -> Ratio a -> Ordering #

(<) :: Ratio a -> Ratio a -> Bool #

(<=) :: Ratio a -> Ratio a -> Bool #

(>) :: Ratio a -> Ratio a -> Bool #

(>=) :: Ratio a -> Ratio a -> Bool #

max :: Ratio a -> Ratio a -> Ratio a #

min :: Ratio a -> Ratio a -> Ratio a #

Ord (Ptr a) 
Instance details

Defined in GHC.Ptr

Methods

compare :: Ptr a -> Ptr a -> Ordering #

(<) :: Ptr a -> Ptr a -> Bool #

(<=) :: Ptr a -> Ptr a -> Bool #

(>) :: Ptr a -> Ptr a -> Bool #

(>=) :: Ptr a -> Ptr a -> Bool #

max :: Ptr a -> Ptr a -> Ptr a #

min :: Ptr a -> Ptr a -> Ptr a #

Ord (FunPtr a) 
Instance details

Defined in GHC.Ptr

Methods

compare :: FunPtr a -> FunPtr a -> Ordering #

(<) :: FunPtr a -> FunPtr a -> Bool #

(<=) :: FunPtr a -> FunPtr a -> Bool #

(>) :: FunPtr a -> FunPtr a -> Bool #

(>=) :: FunPtr a -> FunPtr a -> Bool #

max :: FunPtr a -> FunPtr a -> FunPtr a #

min :: FunPtr a -> FunPtr a -> FunPtr a #

Ord p => Ord (Par1 p) 
Instance details

Defined in GHC.Generics

Methods

compare :: Par1 p -> Par1 p -> Ordering #

(<) :: Par1 p -> Par1 p -> Bool #

(<=) :: Par1 p -> Par1 p -> Bool #

(>) :: Par1 p -> Par1 p -> Bool #

(>=) :: Par1 p -> Par1 p -> Bool #

max :: Par1 p -> Par1 p -> Par1 p #

min :: Par1 p -> Par1 p -> Par1 p #

Ord (Async a) 
Instance details

Defined in Control.Concurrent.Async

Methods

compare :: Async a -> Async a -> Ordering #

(<) :: Async a -> Async a -> Bool #

(<=) :: Async a -> Async a -> Bool #

(>) :: Async a -> Async a -> Bool #

(>=) :: Async a -> Async a -> Bool #

max :: Async a -> Async a -> Async a #

min :: Async a -> Async a -> Async a #

Ord a => Ord (Min a) 
Instance details

Defined in Data.Semigroup

Methods

compare :: Min a -> Min a -> Ordering #

(<) :: Min a -> Min a -> Bool #

(<=) :: Min a -> Min a -> Bool #

(>) :: Min a -> Min a -> Bool #

(>=) :: Min a -> Min a -> Bool #

max :: Min a -> Min a -> Min a #

min :: Min a -> Min a -> Min a #

Ord a => Ord (Max a) 
Instance details

Defined in Data.Semigroup

Methods

compare :: Max a -> Max a -> Ordering #

(<) :: Max a -> Max a -> Bool #

(<=) :: Max a -> Max a -> Bool #

(>) :: Max a -> Max a -> Bool #

(>=) :: Max a -> Max a -> Bool #

max :: Max a -> Max a -> Max a #

min :: Max a -> Max a -> Max a #

Ord a => Ord (First a) 
Instance details

Defined in Data.Semigroup

Methods

compare :: First a -> First a -> Ordering #

(<) :: First a -> First a -> Bool #

(<=) :: First a -> First a -> Bool #

(>) :: First a -> First a -> Bool #

(>=) :: First a -> First a -> Bool #

max :: First a -> First a -> First a #

min :: First a -> First a -> First a #

Ord a => Ord (Last a) 
Instance details

Defined in Data.Semigroup

Methods

compare :: Last a -> Last a -> Ordering #

(<) :: Last a -> Last a -> Bool #

(<=) :: Last a -> Last a -> Bool #

(>) :: Last a -> Last a -> Bool #

(>=) :: Last a -> Last a -> Bool #

max :: Last a -> Last a -> Last a #

min :: Last a -> Last a -> Last a #

Ord m => Ord (WrappedMonoid m) 
Instance details

Defined in Data.Semigroup

Ord a => Ord (Option a) 
Instance details

Defined in Data.Semigroup

Methods

compare :: Option a -> Option a -> Ordering #

(<) :: Option a -> Option a -> Bool #

(<=) :: Option a -> Option a -> Bool #

(>) :: Option a -> Option a -> Bool #

(>=) :: Option a -> Option a -> Bool #

max :: Option a -> Option a -> Option a #

min :: Option a -> Option a -> Option a #

Ord a => Ord (ZipList a) 
Instance details

Defined in Control.Applicative

Methods

compare :: ZipList a -> ZipList a -> Ordering #

(<) :: ZipList a -> ZipList a -> Bool #

(<=) :: ZipList a -> ZipList a -> Bool #

(>) :: ZipList a -> ZipList a -> Bool #

(>=) :: ZipList a -> ZipList a -> Bool #

max :: ZipList a -> ZipList a -> ZipList a #

min :: ZipList a -> ZipList a -> ZipList a #

Ord a => Ord (First a) 
Instance details

Defined in Data.Monoid

Methods

compare :: First a -> First a -> Ordering #

(<) :: First a -> First a -> Bool #

(<=) :: First a -> First a -> Bool #

(>) :: First a -> First a -> Bool #

(>=) :: First a -> First a -> Bool #

max :: First a -> First a -> First a #

min :: First a -> First a -> First a #

Ord a => Ord (Last a) 
Instance details

Defined in Data.Monoid

Methods

compare :: Last a -> Last a -> Ordering #

(<) :: Last a -> Last a -> Bool #

(<=) :: Last a -> Last a -> Bool #

(>) :: Last a -> Last a -> Bool #

(>=) :: Last a -> Last a -> Bool #

max :: Last a -> Last a -> Last a #

min :: Last a -> Last a -> Last a #

Ord a => Ord (Dual a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Dual a -> Dual a -> Ordering #

(<) :: Dual a -> Dual a -> Bool #

(<=) :: Dual a -> Dual a -> Bool #

(>) :: Dual a -> Dual a -> Bool #

(>=) :: Dual a -> Dual a -> Bool #

max :: Dual a -> Dual a -> Dual a #

min :: Dual a -> Dual a -> Dual a #

Ord a => Ord (Sum a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Sum a -> Sum a -> Ordering #

(<) :: Sum a -> Sum a -> Bool #

(<=) :: Sum a -> Sum a -> Bool #

(>) :: Sum a -> Sum a -> Bool #

(>=) :: Sum a -> Sum a -> Bool #

max :: Sum a -> Sum a -> Sum a #

min :: Sum a -> Sum a -> Sum a #

Ord a => Ord (Product a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Product a -> Product a -> Ordering #

(<) :: Product a -> Product a -> Bool #

(<=) :: Product a -> Product a -> Bool #

(>) :: Product a -> Product a -> Bool #

(>=) :: Product a -> Product a -> Bool #

max :: Product a -> Product a -> Product a #

min :: Product a -> Product a -> Product a #

Ord a => Ord (Down a)

Since: base-4.6.0.0

Instance details

Defined in Data.Ord

Methods

compare :: Down a -> Down a -> Ordering #

(<) :: Down a -> Down a -> Bool #

(<=) :: Down a -> Down a -> Bool #

(>) :: Down a -> Down a -> Bool #

(>=) :: Down a -> Down a -> Bool #

max :: Down a -> Down a -> Down a #

min :: Down a -> Down a -> Down a #

Ord a => Ord (NonEmpty a) 
Instance details

Defined in GHC.Base

Methods

compare :: NonEmpty a -> NonEmpty a -> Ordering #

(<) :: NonEmpty a -> NonEmpty a -> Bool #

(<=) :: NonEmpty a -> NonEmpty a -> Bool #

(>) :: NonEmpty a -> NonEmpty a -> Bool #

(>=) :: NonEmpty a -> NonEmpty a -> Bool #

max :: NonEmpty a -> NonEmpty a -> NonEmpty a #

min :: NonEmpty a -> NonEmpty a -> NonEmpty a #

Ord a => Ord (IntMap a) 
Instance details

Defined in Data.IntMap.Internal

Methods

compare :: IntMap a -> IntMap a -> Ordering #

(<) :: IntMap a -> IntMap a -> Bool #

(<=) :: IntMap a -> IntMap a -> Bool #

(>) :: IntMap a -> IntMap a -> Bool #

(>=) :: IntMap a -> IntMap a -> Bool #

max :: IntMap a -> IntMap a -> IntMap a #

min :: IntMap a -> IntMap a -> IntMap a #

Ord a => Ord (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Methods

compare :: Seq a -> Seq a -> Ordering #

(<) :: Seq a -> Seq a -> Bool #

(<=) :: Seq a -> Seq a -> Bool #

(>) :: Seq a -> Seq a -> Bool #

(>=) :: Seq a -> Seq a -> Bool #

max :: Seq a -> Seq a -> Seq a #

min :: Seq a -> Seq a -> Seq a #

Ord a => Ord (ViewL a) 
Instance details

Defined in Data.Sequence.Internal

Methods

compare :: ViewL a -> ViewL a -> Ordering #

(<) :: ViewL a -> ViewL a -> Bool #

(<=) :: ViewL a -> ViewL a -> Bool #

(>) :: ViewL a -> ViewL a -> Bool #

(>=) :: ViewL a -> ViewL a -> Bool #

max :: ViewL a -> ViewL a -> ViewL a #

min :: ViewL a -> ViewL a -> ViewL a #

Ord a => Ord (ViewR a) 
Instance details

Defined in Data.Sequence.Internal

Methods

compare :: ViewR a -> ViewR a -> Ordering #

(<) :: ViewR a -> ViewR a -> Bool #

(<=) :: ViewR a -> ViewR a -> Bool #

(>) :: ViewR a -> ViewR a -> Bool #

(>=) :: ViewR a -> ViewR a -> Bool #

max :: ViewR a -> ViewR a -> ViewR a #

min :: ViewR a -> ViewR a -> ViewR a #

Ord a => Ord (Set a) 
Instance details

Defined in Data.Set.Internal

Methods

compare :: Set a -> Set a -> Ordering #

(<) :: Set a -> Set a -> Bool #

(<=) :: Set a -> Set a -> Bool #

(>) :: Set a -> Set a -> Bool #

(>=) :: Set a -> Set a -> Bool #

max :: Set a -> Set a -> Set a #

min :: Set a -> Set a -> Set a #

(Ord a, Ord b) => Ord (Either a b) 
Instance details

Defined in Data.Either

Methods

compare :: Either a b -> Either a b -> Ordering #

(<) :: Either a b -> Either a b -> Bool #

(<=) :: Either a b -> Either a b -> Bool #

(>) :: Either a b -> Either a b -> Bool #

(>=) :: Either a b -> Either a b -> Bool #

max :: Either a b -> Either a b -> Either a b #

min :: Either a b -> Either a b -> Either a b #

Ord (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: V1 p -> V1 p -> Ordering #

(<) :: V1 p -> V1 p -> Bool #

(<=) :: V1 p -> V1 p -> Bool #

(>) :: V1 p -> V1 p -> Bool #

(>=) :: V1 p -> V1 p -> Bool #

max :: V1 p -> V1 p -> V1 p #

min :: V1 p -> V1 p -> V1 p #

Ord (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: U1 p -> U1 p -> Ordering #

(<) :: U1 p -> U1 p -> Bool #

(<=) :: U1 p -> U1 p -> Bool #

(>) :: U1 p -> U1 p -> Bool #

(>=) :: U1 p -> U1 p -> Bool #

max :: U1 p -> U1 p -> U1 p #

min :: U1 p -> U1 p -> U1 p #

Ord (TypeRep a)

Since: base-4.4.0.0

Instance details

Defined in Data.Typeable.Internal

Methods

compare :: TypeRep a -> TypeRep a -> Ordering #

(<) :: TypeRep a -> TypeRep a -> Bool #

(<=) :: TypeRep a -> TypeRep a -> Bool #

(>) :: TypeRep a -> TypeRep a -> Bool #

(>=) :: TypeRep a -> TypeRep a -> Bool #

max :: TypeRep a -> TypeRep a -> TypeRep a #

min :: TypeRep a -> TypeRep a -> TypeRep a #

(Ord a, Ord b) => Ord (a, b) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b) -> (a, b) -> Ordering #

(<) :: (a, b) -> (a, b) -> Bool #

(<=) :: (a, b) -> (a, b) -> Bool #

(>) :: (a, b) -> (a, b) -> Bool #

(>=) :: (a, b) -> (a, b) -> Bool #

max :: (a, b) -> (a, b) -> (a, b) #

min :: (a, b) -> (a, b) -> (a, b) #

(Ix i, Ord e) => Ord (Array i e)

Since: base-2.1

Instance details

Defined in GHC.Arr

Methods

compare :: Array i e -> Array i e -> Ordering #

(<) :: Array i e -> Array i e -> Bool #

(<=) :: Array i e -> Array i e -> Bool #

(>) :: Array i e -> Array i e -> Bool #

(>=) :: Array i e -> Array i e -> Bool #

max :: Array i e -> Array i e -> Array i e #

min :: Array i e -> Array i e -> Array i e #

Ord a => Ord (Arg a b)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

compare :: Arg a b -> Arg a b -> Ordering #

(<) :: Arg a b -> Arg a b -> Bool #

(<=) :: Arg a b -> Arg a b -> Bool #

(>) :: Arg a b -> Arg a b -> Bool #

(>=) :: Arg a b -> Arg a b -> Bool #

max :: Arg a b -> Arg a b -> Arg a b #

min :: Arg a b -> Arg a b -> Arg a b #

Ord (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

Methods

compare :: Proxy s -> Proxy s -> Ordering #

(<) :: Proxy s -> Proxy s -> Bool #

(<=) :: Proxy s -> Proxy s -> Bool #

(>) :: Proxy s -> Proxy s -> Bool #

(>=) :: Proxy s -> Proxy s -> Bool #

max :: Proxy s -> Proxy s -> Proxy s #

min :: Proxy s -> Proxy s -> Proxy s #

(Ord k, Ord v) => Ord (Map k v) 
Instance details

Defined in Data.Map.Internal

Methods

compare :: Map k v -> Map k v -> Ordering #

(<) :: Map k v -> Map k v -> Bool #

(<=) :: Map k v -> Map k v -> Bool #

(>) :: Map k v -> Map k v -> Bool #

(>=) :: Map k v -> Map k v -> Bool #

max :: Map k v -> Map k v -> Map k v #

min :: Map k v -> Map k v -> Map k v #

Ord (f p) => Ord (Rec1 f p) 
Instance details

Defined in GHC.Generics

Methods

compare :: Rec1 f p -> Rec1 f p -> Ordering #

(<) :: Rec1 f p -> Rec1 f p -> Bool #

(<=) :: Rec1 f p -> Rec1 f p -> Bool #

(>) :: Rec1 f p -> Rec1 f p -> Bool #

(>=) :: Rec1 f p -> Rec1 f p -> Bool #

max :: Rec1 f p -> Rec1 f p -> Rec1 f p #

min :: Rec1 f p -> Rec1 f p -> Rec1 f p #

Ord (URec (Ptr ()) p) 
Instance details

Defined in GHC.Generics

Methods

compare :: URec (Ptr ()) p -> URec (Ptr ()) p -> Ordering #

(<) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool #

(<=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool #

(>) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool #

(>=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool #

max :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p #

min :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p #

Ord (URec Char p) 
Instance details

Defined in GHC.Generics

Methods

compare :: URec Char p -> URec Char p -> Ordering #

(<) :: URec Char p -> URec Char p -> Bool #

(<=) :: URec Char p -> URec Char p -> Bool #

(>) :: URec Char p -> URec Char p -> Bool #

(>=) :: URec Char p -> URec Char p -> Bool #

max :: URec Char p -> URec Char p -> URec Char p #

min :: URec Char p -> URec Char p -> URec Char p #

Ord (URec Double p) 
Instance details

Defined in GHC.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 #

max :: URec Double p -> URec Double p -> URec Double p #

min :: URec Double p -> URec Double p -> URec Double p #

Ord (URec Float p) 
Instance details

Defined in GHC.Generics

Methods

compare :: URec Float p -> URec Float p -> Ordering #

(<) :: URec Float p -> URec Float p -> Bool #

(<=) :: URec Float p -> URec Float p -> Bool #

(>) :: URec Float p -> URec Float p -> Bool #

(>=) :: URec Float p -> URec Float p -> Bool #

max :: URec Float p -> URec Float p -> URec Float p #

min :: URec Float p -> URec Float p -> URec Float p #

Ord (URec Int p) 
Instance details

Defined in GHC.Generics

Methods

compare :: URec Int p -> URec Int p -> Ordering #

(<) :: URec Int p -> URec Int p -> Bool #

(<=) :: URec Int p -> URec Int p -> Bool #

(>) :: URec Int p -> URec Int p -> Bool #

(>=) :: URec Int p -> URec Int p -> Bool #

max :: URec Int p -> URec Int p -> URec Int p #

min :: URec Int p -> URec Int p -> URec Int p #

Ord (URec Word p) 
Instance details

Defined in GHC.Generics

Methods

compare :: URec Word p -> URec Word p -> Ordering #

(<) :: URec Word p -> URec Word p -> Bool #

(<=) :: URec Word p -> URec Word p -> Bool #

(>) :: URec Word p -> URec Word p -> Bool #

(>=) :: URec Word p -> URec Word p -> Bool #

max :: URec Word p -> URec Word p -> URec Word p #

min :: URec Word p -> URec Word p -> URec Word p #

(Ord a, Ord b, Ord c) => Ord (a, b, c) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c) -> (a, b, c) -> Ordering #

(<) :: (a, b, c) -> (a, b, c) -> Bool #

(<=) :: (a, b, c) -> (a, b, c) -> Bool #

(>) :: (a, b, c) -> (a, b, c) -> Bool #

(>=) :: (a, b, c) -> (a, b, c) -> Bool #

max :: (a, b, c) -> (a, b, c) -> (a, b, c) #

min :: (a, b, c) -> (a, b, c) -> (a, b, c) #

Ord (f a) => Ord (Alt f a) 
Instance details

Defined in Data.Semigroup.Internal

Methods

compare :: Alt f a -> Alt f a -> Ordering #

(<) :: Alt f a -> Alt f a -> Bool #

(<=) :: Alt f a -> Alt f a -> Bool #

(>) :: Alt f a -> Alt f a -> Bool #

(>=) :: Alt f a -> Alt f a -> Bool #

max :: Alt f a -> Alt f a -> Alt f a #

min :: Alt f a -> Alt f a -> Alt f a #

Ord (a :~: b) 
Instance details

Defined in Data.Type.Equality

Methods

compare :: (a :~: b) -> (a :~: b) -> Ordering #

(<) :: (a :~: b) -> (a :~: b) -> Bool #

(<=) :: (a :~: b) -> (a :~: b) -> Bool #

(>) :: (a :~: b) -> (a :~: b) -> Bool #

(>=) :: (a :~: b) -> (a :~: b) -> Bool #

max :: (a :~: b) -> (a :~: b) -> a :~: b #

min :: (a :~: b) -> (a :~: b) -> a :~: b #

(Ord e, Ord1 m, Ord a) => Ord (ErrorT e m a) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

compare :: ErrorT e m a -> ErrorT e m a -> Ordering #

(<) :: ErrorT e m a -> ErrorT e m a -> Bool #

(<=) :: ErrorT e m a -> ErrorT e m a -> Bool #

(>) :: ErrorT e m a -> ErrorT e m a -> Bool #

(>=) :: ErrorT e m a -> ErrorT e m a -> Bool #

max :: ErrorT e m a -> ErrorT e m a -> ErrorT e m a #

min :: ErrorT e m a -> ErrorT e m a -> ErrorT e m a #

(Ord e, Ord1 m, Ord a) => Ord (ExceptT e m a) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

compare :: ExceptT e m a -> ExceptT e m a -> Ordering #

(<) :: ExceptT e m a -> ExceptT e m a -> Bool #

(<=) :: ExceptT e m a -> ExceptT e m a -> Bool #

(>) :: ExceptT e m a -> ExceptT e m a -> Bool #

(>=) :: ExceptT e m a -> ExceptT e m a -> Bool #

max :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a #

min :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a #

Ord c => Ord (K1 i c p) 
Instance details

Defined in GHC.Generics

Methods

compare :: K1 i c p -> K1 i c p -> Ordering #

(<) :: K1 i c p -> K1 i c p -> Bool #

(<=) :: K1 i c p -> K1 i c p -> Bool #

(>) :: K1 i c p -> K1 i c p -> Bool #

(>=) :: K1 i c p -> K1 i c p -> Bool #

max :: K1 i c p -> K1 i c p -> K1 i c p #

min :: K1 i c p -> K1 i c p -> K1 i c p #

(Ord (f p), Ord (g p)) => Ord ((f :+: g) p) 
Instance details

Defined in GHC.Generics

Methods

compare :: (f :+: g) p -> (f :+: g) p -> Ordering #

(<) :: (f :+: g) p -> (f :+: g) p -> Bool #

(<=) :: (f :+: g) p -> (f :+: g) p -> Bool #

(>) :: (f :+: g) p -> (f :+: g) p -> Bool #

(>=) :: (f :+: g) p -> (f :+: g) p -> Bool #

max :: (f :+: g) p -> (f :+: g) p -> (f :+: g) p #

min :: (f :+: g) p -> (f :+: g) p -> (f :+: g) p #

(Ord (f p), Ord (g p)) => Ord ((f :*: g) p) 
Instance details

Defined in GHC.Generics

Methods

compare :: (f :*: g) p -> (f :*: g) p -> Ordering #

(<) :: (f :*: g) p -> (f :*: g) p -> Bool #

(<=) :: (f :*: g) p -> (f :*: g) p -> Bool #

(>) :: (f :*: g) p -> (f :*: g) p -> Bool #

(>=) :: (f :*: g) p -> (f :*: g) p -> Bool #

max :: (f :*: g) p -> (f :*: g) p -> (f :*: g) p #

min :: (f :*: g) p -> (f :*: g) p -> (f :*: g) p #

(Ord a, Ord b, Ord c, Ord d) => Ord (a, b, c, d) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d) -> (a, b, c, d) -> Ordering #

(<) :: (a, b, c, d) -> (a, b, c, d) -> Bool #

(<=) :: (a, b, c, d) -> (a, b, c, d) -> Bool #

(>) :: (a, b, c, d) -> (a, b, c, d) -> Bool #

(>=) :: (a, b, c, d) -> (a, b, c, d) -> Bool #

max :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) #

min :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d) #

(Ord1 f, Ord1 g, Ord a) => Ord (Product f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

compare :: Product f g a -> Product f g a -> Ordering #

(<) :: Product f g a -> Product f g a -> Bool #

(<=) :: Product f g a -> Product f g a -> Bool #

(>) :: Product f g a -> Product f g a -> Bool #

(>=) :: Product f g a -> Product f g a -> Bool #

max :: Product f g a -> Product f g a -> Product f g a #

min :: Product f g a -> Product f g a -> Product f g a #

(Ord1 f, Ord1 g, Ord a) => Ord (Sum f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

compare :: Sum f g a -> Sum f g a -> Ordering #

(<) :: Sum f g a -> Sum f g a -> Bool #

(<=) :: Sum f g a -> Sum f g a -> Bool #

(>) :: Sum f g a -> Sum f g a -> Bool #

(>=) :: Sum f g a -> Sum f g a -> Bool #

max :: Sum f g a -> Sum f g a -> Sum f g a #

min :: Sum f g a -> Sum f g a -> Sum f g a #

Ord (a :~~: b)

Since: base-4.10.0.0

Instance details

Defined in Data.Type.Equality

Methods

compare :: (a :~~: b) -> (a :~~: b) -> Ordering #

(<) :: (a :~~: b) -> (a :~~: b) -> Bool #

(<=) :: (a :~~: b) -> (a :~~: b) -> Bool #

(>) :: (a :~~: b) -> (a :~~: b) -> Bool #

(>=) :: (a :~~: b) -> (a :~~: b) -> Bool #

max :: (a :~~: b) -> (a :~~: b) -> a :~~: b #

min :: (a :~~: b) -> (a :~~: b) -> a :~~: b #

Ord (f p) => Ord (M1 i c f p) 
Instance details

Defined in GHC.Generics

Methods

compare :: M1 i c f p -> M1 i c f p -> Ordering #

(<) :: M1 i c f p -> M1 i c f p -> Bool #

(<=) :: M1 i c f p -> M1 i c f p -> Bool #

(>) :: M1 i c f p -> M1 i c f p -> Bool #

(>=) :: M1 i c f p -> M1 i c f p -> Bool #

max :: M1 i c f p -> M1 i c f p -> M1 i c f p #

min :: M1 i c f p -> M1 i c f p -> M1 i c f p #

Ord (f (g p)) => Ord ((f :.: g) p) 
Instance details

Defined in GHC.Generics

Methods

compare :: (f :.: g) p -> (f :.: g) p -> Ordering #

(<) :: (f :.: g) p -> (f :.: g) p -> Bool #

(<=) :: (f :.: g) p -> (f :.: g) p -> Bool #

(>) :: (f :.: g) p -> (f :.: g) p -> Bool #

(>=) :: (f :.: g) p -> (f :.: g) p -> Bool #

max :: (f :.: g) p -> (f :.: g) p -> (f :.: g) p #

min :: (f :.: g) p -> (f :.: g) p -> (f :.: g) p #

(Ord a, Ord b, Ord c, Ord d, Ord e) => Ord (a, b, c, d, e) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e) -> (a, b, c, d, e) -> Ordering #

(<) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool #

(<=) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool #

(>) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool #

(>=) :: (a, b, c, d, e) -> (a, b, c, d, e) -> Bool #

max :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) #

min :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e) #

(Ord1 f, Ord1 g, Ord a) => Ord (Compose f g a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

compare :: Compose f g a -> Compose f g a -> Ordering #

(<) :: Compose f g a -> Compose f g a -> Bool #

(<=) :: Compose f g a -> Compose f g a -> Bool #

(>) :: Compose f g a -> Compose f g a -> Bool #

(>=) :: Compose f g a -> Compose f g a -> Bool #

max :: Compose f g a -> Compose f g a -> Compose f g a #

min :: Compose f g a -> Compose f g a -> Compose f g a #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f) => Ord (a, b, c, d, e, f) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Ordering #

(<) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool #

(<=) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool #

(>) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool #

(>=) :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> Bool #

max :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> (a, b, c, d, e, f) #

min :: (a, b, c, d, e, f) -> (a, b, c, d, e, f) -> (a, b, c, d, e, f) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g) => Ord (a, b, c, d, e, f, g) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Ordering #

(<) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool #

(<=) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool #

(>) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool #

(>=) :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> Bool #

max :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) #

min :: (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) -> (a, b, c, d, e, f, g) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h) => Ord (a, b, c, d, e, f, g, h) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool #

(>) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> Bool #

max :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) #

min :: (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) -> (a, b, c, d, e, f, g, h) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i) => Ord (a, b, c, d, e, f, g, h, i) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> Bool #

max :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) #

min :: (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) -> (a, b, c, d, e, f, g, h, i) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j) => Ord (a, b, c, d, e, f, g, h, i, j) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> Bool #

max :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) #

min :: (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) -> (a, b, c, d, e, f, g, h, i, j) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k) => Ord (a, b, c, d, e, f, g, h, i, j, k) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> Bool #

max :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) #

min :: (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) -> (a, b, c, d, e, f, g, h, i, j, k) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l) => Ord (a, b, c, d, e, f, g, h, i, j, k, l) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #

max :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) #

min :: (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) -> (a, b, c, d, e, f, g, h, i, j, k, l) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #

max :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) #

min :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) -> (a, b, c, d, e, f, g, h, i, j, k, l, m) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m, Ord n) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m, n) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #

max :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #

min :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #

(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m, Ord n, Ord o) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) 
Instance details

Defined in GHC.Classes

Methods

compare :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Ordering #

(<) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

(<=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

(>) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

(>=) :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

max :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

min :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

data Ordering #

Constructors

LT 
EQ 
GT 
Instances
Bounded Ordering

Since: base-2.1

Instance details

Defined in GHC.Enum

Enum Ordering

Since: base-2.1

Instance details

Defined in GHC.Enum

Eq Ordering 
Instance details

Defined in GHC.Classes

Ord Ordering 
Instance details

Defined in GHC.Classes

Read Ordering

Since: base-2.1

Instance details

Defined in GHC.Read

Show Ordering 
Instance details

Defined in GHC.Show

Ix Ordering

Since: base-2.1

Instance details

Defined in GHC.Arr

Generic Ordering 
Instance details

Defined in GHC.Generics

Associated Types

type Rep Ordering :: * -> * #

Methods

from :: Ordering -> Rep Ordering x #

to :: Rep Ordering x -> Ordering #

Semigroup Ordering

Since: base-4.9.0.0

Instance details

Defined in GHC.Base

Monoid Ordering

Since: base-2.1

Instance details

Defined in GHC.Base

type Rep Ordering 
Instance details

Defined in GHC.Generics

type Rep Ordering = D1 (MetaData "Ordering" "GHC.Types" "ghc-prim" False) (C1 (MetaCons "LT" PrefixI False) (U1 :: * -> *) :+: (C1 (MetaCons "EQ" PrefixI False) (U1 :: * -> *) :+: C1 (MetaCons "GT" PrefixI False) (U1 :: * -> *)))

comparing :: Ord a => (b -> a) -> b -> b -> Ordering #

comparing p x y = compare (p x) (p y)

Useful combinator for use in conjunction with the xxxBy family of functions from Data.List, for example:

  ... sortBy (comparing fst) ...

Traversable

class (Functor t, Foldable t) => Traversable (t :: * -> *) where #

Functors representing data structures that can be traversed from left to right.

A definition of traverse must satisfy the following laws:

naturality
t . traverse f = traverse (t . f) for every applicative transformation t
identity
traverse Identity = Identity
composition
traverse (Compose . fmap g . f) = Compose . fmap (traverse g) . traverse f

A definition of sequenceA must satisfy the following laws:

naturality
t . sequenceA = sequenceA . fmap t for every applicative transformation t
identity
sequenceA . fmap Identity = Identity
composition
sequenceA . fmap Compose = Compose . fmap sequenceA . sequenceA

where an applicative transformation is a function

t :: (Applicative f, Applicative g) => f a -> g a

preserving the Applicative operations, i.e.

and the identity functor Identity and composition of functors Compose are defined as

  newtype Identity a = Identity a

  instance Functor Identity where
    fmap f (Identity x) = Identity (f x)

  instance Applicative Identity where
    pure x = Identity x
    Identity f <*> Identity x = Identity (f x)

  newtype Compose f g a = Compose (f (g a))

  instance (Functor f, Functor g) => Functor (Compose f g) where
    fmap f (Compose x) = Compose (fmap (fmap f) x)

  instance (Applicative f, Applicative g) => Applicative (Compose f g) where
    pure x = Compose (pure (pure x))
    Compose f <*> Compose x = Compose ((<*>) <$> f <*> x)

(The naturality law is implied by parametricity.)

Instances are similar to Functor, e.g. given a data type

data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)

a suitable instance would be

instance Traversable Tree where
   traverse f Empty = pure Empty
   traverse f (Leaf x) = Leaf <$> f x
   traverse f (Node l k r) = Node <$> traverse f l <*> f k <*> traverse f r

This is suitable even for abstract types, as the laws for <*> imply a form of associativity.

The superclass instances should satisfy the following:

Minimal complete definition

traverse | sequenceA

Methods

traverse :: Applicative f => (a -> f b) -> t a -> f (t b) #

Map each element of a structure to an action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see traverse_.

sequenceA :: Applicative f => t (f a) -> f (t a) #

Evaluate each action in the structure from left to right, and and collect the results. For a version that ignores the results see sequenceA_.

mapM :: Monad m => (a -> m b) -> t a -> m (t b) #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see mapM_.

sequence :: Monad m => t (m a) -> m (t a) #

Evaluate each monadic action in the structure from left to right, and collect the results. For a version that ignores the results see sequence_.

Instances
Traversable []

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> [a] -> f [b] #

sequenceA :: Applicative f => [f a] -> f [a] #

mapM :: Monad m => (a -> m b) -> [a] -> m [b] #

sequence :: Monad m => [m a] -> m [a] #

Traversable Maybe

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Maybe a -> f (Maybe b) #

sequenceA :: Applicative f => Maybe (f a) -> f (Maybe a) #

mapM :: Monad m => (a -> m b) -> Maybe a -> m (Maybe b) #

sequence :: Monad m => Maybe (m a) -> m (Maybe a) #

Traversable Par1 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Par1 a -> f (Par1 b) #

sequenceA :: Applicative f => Par1 (f a) -> f (Par1 a) #

mapM :: Monad m => (a -> m b) -> Par1 a -> m (Par1 b) #

sequence :: Monad m => Par1 (m a) -> m (Par1 a) #

Traversable Complex 
Instance details

Defined in Data.Complex

Methods

traverse :: Applicative f => (a -> f b) -> Complex a -> f (Complex b) #

sequenceA :: Applicative f => Complex (f a) -> f (Complex a) #

mapM :: Monad m => (a -> m b) -> Complex a -> m (Complex b) #

sequence :: Monad m => Complex (m a) -> m (Complex a) #

Traversable Min

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Min a -> f (Min b) #

sequenceA :: Applicative f => Min (f a) -> f (Min a) #

mapM :: Monad m => (a -> m b) -> Min a -> m (Min b) #

sequence :: Monad m => Min (m a) -> m (Min a) #

Traversable Max

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Max a -> f (Max b) #

sequenceA :: Applicative f => Max (f a) -> f (Max a) #

mapM :: Monad m => (a -> m b) -> Max a -> m (Max b) #

sequence :: Monad m => Max (m a) -> m (Max a) #

Traversable First

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> First a -> f (First b) #

sequenceA :: Applicative f => First (f a) -> f (First a) #

mapM :: Monad m => (a -> m b) -> First a -> m (First b) #

sequence :: Monad m => First (m a) -> m (First a) #

Traversable Last

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Last a -> f (Last b) #

sequenceA :: Applicative f => Last (f a) -> f (Last a) #

mapM :: Monad m => (a -> m b) -> Last a -> m (Last b) #

sequence :: Monad m => Last (m a) -> m (Last a) #

Traversable Option

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a -> f b) -> Option a -> f (Option b) #

sequenceA :: Applicative f => Option (f a) -> f (Option a) #

mapM :: Monad m => (a -> m b) -> Option a -> m (Option b) #

sequence :: Monad m => Option (m a) -> m (Option a) #

Traversable ZipList

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> ZipList a -> f (ZipList b) #

sequenceA :: Applicative f => ZipList (f a) -> f (ZipList a) #

mapM :: Monad m => (a -> m b) -> ZipList a -> m (ZipList b) #

sequence :: Monad m => ZipList (m a) -> m (ZipList a) #

Traversable Identity 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Identity a -> f (Identity b) #

sequenceA :: Applicative f => Identity (f a) -> f (Identity a) #

mapM :: Monad m => (a -> m b) -> Identity a -> m (Identity b) #

sequence :: Monad m => Identity (m a) -> m (Identity a) #

Traversable First

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> First a -> f (First b) #

sequenceA :: Applicative f => First (f a) -> f (First a) #

mapM :: Monad m => (a -> m b) -> First a -> m (First b) #

sequence :: Monad m => First (m a) -> m (First a) #

Traversable Last

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Last a -> f (Last b) #

sequenceA :: Applicative f => Last (f a) -> f (Last a) #

mapM :: Monad m => (a -> m b) -> Last a -> m (Last b) #

sequence :: Monad m => Last (m a) -> m (Last a) #

Traversable Dual

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Dual a -> f (Dual b) #

sequenceA :: Applicative f => Dual (f a) -> f (Dual a) #

mapM :: Monad m => (a -> m b) -> Dual a -> m (Dual b) #

sequence :: Monad m => Dual (m a) -> m (Dual a) #

Traversable Sum

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Sum a -> f (Sum b) #

sequenceA :: Applicative f => Sum (f a) -> f (Sum a) #

mapM :: Monad m => (a -> m b) -> Sum a -> m (Sum b) #

sequence :: Monad m => Sum (m a) -> m (Sum a) #

Traversable Product

Since: base-4.8.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Product a -> f (Product b) #

sequenceA :: Applicative f => Product (f a) -> f (Product a) #

mapM :: Monad m => (a -> m b) -> Product a -> m (Product b) #

sequence :: Monad m => Product (m a) -> m (Product a) #

Traversable NonEmpty

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> NonEmpty a -> f (NonEmpty b) #

sequenceA :: Applicative f => NonEmpty (f a) -> f (NonEmpty a) #

mapM :: Monad m => (a -> m b) -> NonEmpty a -> m (NonEmpty b) #

sequence :: Monad m => NonEmpty (m a) -> m (NonEmpty a) #

Traversable IntMap 
Instance details

Defined in Data.IntMap.Internal

Methods

traverse :: Applicative f => (a -> f b) -> IntMap a -> f (IntMap b) #

sequenceA :: Applicative f => IntMap (f a) -> f (IntMap a) #

mapM :: Monad m => (a -> m b) -> IntMap a -> m (IntMap b) #

sequence :: Monad m => IntMap (m a) -> m (IntMap a) #

Traversable Tree 
Instance details

Defined in Data.Tree

Methods

traverse :: Applicative f => (a -> f b) -> Tree a -> f (Tree b) #

sequenceA :: Applicative f => Tree (f a) -> f (Tree a) #

mapM :: Monad m => (a -> m b) -> Tree a -> m (Tree b) #

sequence :: Monad m => Tree (m a) -> m (Tree a) #

Traversable Seq 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> Seq a -> f (Seq b) #

sequenceA :: Applicative f => Seq (f a) -> f (Seq a) #

mapM :: Monad m => (a -> m b) -> Seq a -> m (Seq b) #

sequence :: Monad m => Seq (m a) -> m (Seq a) #

Traversable FingerTree 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> FingerTree a -> f (FingerTree b) #

sequenceA :: Applicative f => FingerTree (f a) -> f (FingerTree a) #

mapM :: Monad m => (a -> m b) -> FingerTree a -> m (FingerTree b) #

sequence :: Monad m => FingerTree (m a) -> m (FingerTree a) #

Traversable Digit 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> Digit a -> f (Digit b) #

sequenceA :: Applicative f => Digit (f a) -> f (Digit a) #

mapM :: Monad m => (a -> m b) -> Digit a -> m (Digit b) #

sequence :: Monad m => Digit (m a) -> m (Digit a) #

Traversable Node 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> Node a -> f (Node b) #

sequenceA :: Applicative f => Node (f a) -> f (Node a) #

mapM :: Monad m => (a -> m b) -> Node a -> m (Node b) #

sequence :: Monad m => Node (m a) -> m (Node a) #

Traversable Elem 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> Elem a -> f (Elem b) #

sequenceA :: Applicative f => Elem (f a) -> f (Elem a) #

mapM :: Monad m => (a -> m b) -> Elem a -> m (Elem b) #

sequence :: Monad m => Elem (m a) -> m (Elem a) #

Traversable ViewL 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> ViewL a -> f (ViewL b) #

sequenceA :: Applicative f => ViewL (f a) -> f (ViewL a) #

mapM :: Monad m => (a -> m b) -> ViewL a -> m (ViewL b) #

sequence :: Monad m => ViewL (m a) -> m (ViewL a) #

Traversable ViewR 
Instance details

Defined in Data.Sequence.Internal

Methods

traverse :: Applicative f => (a -> f b) -> ViewR a -> f (ViewR b) #

sequenceA :: Applicative f => ViewR (f a) -> f (ViewR a) #

mapM :: Monad m => (a -> m b) -> ViewR a -> m (ViewR b) #

sequence :: Monad m => ViewR (m a) -> m (ViewR a) #

Traversable (Either a)

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a0 -> f b) -> Either a a0 -> f (Either a b) #

sequenceA :: Applicative f => Either a (f a0) -> f (Either a a0) #

mapM :: Monad m => (a0 -> m b) -> Either a a0 -> m (Either a b) #

sequence :: Monad m => Either a (m a0) -> m (Either a a0) #

Traversable (V1 :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> V1 a -> f (V1 b) #

sequenceA :: Applicative f => V1 (f a) -> f (V1 a) #

mapM :: Monad m => (a -> m b) -> V1 a -> m (V1 b) #

sequence :: Monad m => V1 (m a) -> m (V1 a) #

Traversable (U1 :: * -> *)

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> U1 a -> f (U1 b) #

sequenceA :: Applicative f => U1 (f a) -> f (U1 a) #

mapM :: Monad m => (a -> m b) -> U1 a -> m (U1 b) #

sequence :: Monad m => U1 (m a) -> m (U1 a) #

Traversable ((,) a)

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a0 -> f b) -> (a, a0) -> f (a, b) #

sequenceA :: Applicative f => (a, f a0) -> f (a, a0) #

mapM :: Monad m => (a0 -> m b) -> (a, a0) -> m (a, b) #

sequence :: Monad m => (a, m a0) -> m (a, a0) #

Ix i => Traversable (Array i)

Since: base-2.1

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Array i a -> f (Array i b) #

sequenceA :: Applicative f => Array i (f a) -> f (Array i a) #

mapM :: Monad m => (a -> m b) -> Array i a -> m (Array i b) #

sequence :: Monad m => Array i (m a) -> m (Array i a) #

Traversable (Arg a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

traverse :: Applicative f => (a0 -> f b) -> Arg a a0 -> f (Arg a b) #

sequenceA :: Applicative f => Arg a (f a0) -> f (Arg a a0) #

mapM :: Monad m => (a0 -> m b) -> Arg a a0 -> m (Arg a b) #

sequence :: Monad m => Arg a (m a0) -> m (Arg a a0) #

Traversable (Proxy :: * -> *)

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Proxy a -> f (Proxy b) #

sequenceA :: Applicative f => Proxy (f a) -> f (Proxy a) #

mapM :: Monad m => (a -> m b) -> Proxy a -> m (Proxy b) #

sequence :: Monad m => Proxy (m a) -> m (Proxy a) #

Traversable (Map k) 
Instance details

Defined in Data.Map.Internal

Methods

traverse :: Applicative f => (a -> f b) -> Map k a -> f (Map k b) #

sequenceA :: Applicative f => Map k (f a) -> f (Map k a) #

mapM :: Monad m => (a -> m b) -> Map k a -> m (Map k b) #

sequence :: Monad m => Map k (m a) -> m (Map k a) #

Traversable f => Traversable (Rec1 f) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Rec1 f a -> f0 (Rec1 f b) #

sequenceA :: Applicative f0 => Rec1 f (f0 a) -> f0 (Rec1 f a) #

mapM :: Monad m => (a -> m b) -> Rec1 f a -> m (Rec1 f b) #

sequence :: Monad m => Rec1 f (m a) -> m (Rec1 f a) #

Traversable (URec Char :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Char a -> f (URec Char b) #

sequenceA :: Applicative f => URec Char (f a) -> f (URec Char a) #

mapM :: Monad m => (a -> m b) -> URec Char a -> m (URec Char b) #

sequence :: Monad m => URec Char (m a) -> m (URec Char a) #

Traversable (URec Double :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Double a -> f (URec Double b) #

sequenceA :: Applicative f => URec Double (f a) -> f (URec Double a) #

mapM :: Monad m => (a -> m b) -> URec Double a -> m (URec Double b) #

sequence :: Monad m => URec Double (m a) -> m (URec Double a) #

Traversable (URec Float :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Float a -> f (URec Float b) #

sequenceA :: Applicative f => URec Float (f a) -> f (URec Float a) #

mapM :: Monad m => (a -> m b) -> URec Float a -> m (URec Float b) #

sequence :: Monad m => URec Float (m a) -> m (URec Float a) #

Traversable (URec Int :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Int a -> f (URec Int b) #

sequenceA :: Applicative f => URec Int (f a) -> f (URec Int a) #

mapM :: Monad m => (a -> m b) -> URec Int a -> m (URec Int b) #

sequence :: Monad m => URec Int (m a) -> m (URec Int a) #

Traversable (URec Word :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec Word a -> f (URec Word b) #

sequenceA :: Applicative f => URec Word (f a) -> f (URec Word a) #

mapM :: Monad m => (a -> m b) -> URec Word a -> m (URec Word b) #

sequence :: Monad m => URec Word (m a) -> m (URec Word a) #

Traversable (URec (Ptr ()) :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> URec (Ptr ()) a -> f (URec (Ptr ()) b) #

sequenceA :: Applicative f => URec (Ptr ()) (f a) -> f (URec (Ptr ()) a) #

mapM :: Monad m => (a -> m b) -> URec (Ptr ()) a -> m (URec (Ptr ()) b) #

sequence :: Monad m => URec (Ptr ()) (m a) -> m (URec (Ptr ()) a) #

Traversable (Const m :: * -> *)

Since: base-4.7.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Const m a -> f (Const m b) #

sequenceA :: Applicative f => Const m (f a) -> f (Const m a) #

mapM :: Monad m0 => (a -> m0 b) -> Const m a -> m0 (Const m b) #

sequence :: Monad m0 => Const m (m0 a) -> m0 (Const m a) #

Traversable f => Traversable (ErrorT e f) 
Instance details

Defined in Control.Monad.Trans.Error

Methods

traverse :: Applicative f0 => (a -> f0 b) -> ErrorT e f a -> f0 (ErrorT e f b) #

sequenceA :: Applicative f0 => ErrorT e f (f0 a) -> f0 (ErrorT e f a) #

mapM :: Monad m => (a -> m b) -> ErrorT e f a -> m (ErrorT e f b) #

sequence :: Monad m => ErrorT e f (m a) -> m (ErrorT e f a) #

Traversable f => Traversable (ExceptT e f) 
Instance details

Defined in Control.Monad.Trans.Except

Methods

traverse :: Applicative f0 => (a -> f0 b) -> ExceptT e f a -> f0 (ExceptT e f b) #

sequenceA :: Applicative f0 => ExceptT e f (f0 a) -> f0 (ExceptT e f a) #

mapM :: Monad m => (a -> m b) -> ExceptT e f a -> m (ExceptT e f b) #

sequence :: Monad m => ExceptT e f (m a) -> m (ExceptT e f a) #

Traversable (K1 i c :: * -> *) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> K1 i c a -> f (K1 i c b) #

sequenceA :: Applicative f => K1 i c (f a) -> f (K1 i c a) #

mapM :: Monad m => (a -> m b) -> K1 i c a -> m (K1 i c b) #

sequence :: Monad m => K1 i c (m a) -> m (K1 i c a) #

(Traversable f, Traversable g) => Traversable (f :+: g) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :+: g) a -> f0 ((f :+: g) b) #

sequenceA :: Applicative f0 => (f :+: g) (f0 a) -> f0 ((f :+: g) a) #

mapM :: Monad m => (a -> m b) -> (f :+: g) a -> m ((f :+: g) b) #

sequence :: Monad m => (f :+: g) (m a) -> m ((f :+: g) a) #

(Traversable f, Traversable g) => Traversable (f :*: g) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :*: g) a -> f0 ((f :*: g) b) #

sequenceA :: Applicative f0 => (f :*: g) (f0 a) -> f0 ((f :*: g) a) #

mapM :: Monad m => (a -> m b) -> (f :*: g) a -> m ((f :*: g) b) #

sequence :: Monad m => (f :*: g) (m a) -> m ((f :*: g) a) #

(Traversable f, Traversable g) => Traversable (Product f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Product f g a -> f0 (Product f g b) #

sequenceA :: Applicative f0 => Product f g (f0 a) -> f0 (Product f g a) #

mapM :: Monad m => (a -> m b) -> Product f g a -> m (Product f g b) #

sequence :: Monad m => Product f g (m a) -> m (Product f g a) #

(Traversable f, Traversable g) => Traversable (Sum f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Sum

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Sum f g a -> f0 (Sum f g b) #

sequenceA :: Applicative f0 => Sum f g (f0 a) -> f0 (Sum f g a) #

mapM :: Monad m => (a -> m b) -> Sum f g a -> m (Sum f g b) #

sequence :: Monad m => Sum f g (m a) -> m (Sum f g a) #

Traversable f => Traversable (M1 i c f) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> M1 i c f a -> f0 (M1 i c f b) #

sequenceA :: Applicative f0 => M1 i c f (f0 a) -> f0 (M1 i c f a) #

mapM :: Monad m => (a -> m b) -> M1 i c f a -> m (M1 i c f b) #

sequence :: Monad m => M1 i c f (m a) -> m (M1 i c f a) #

(Traversable f, Traversable g) => Traversable (f :.: g) 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f0 => (a -> f0 b) -> (f :.: g) a -> f0 ((f :.: g) b) #

sequenceA :: Applicative f0 => (f :.: g) (f0 a) -> f0 ((f :.: g) a) #

mapM :: Monad m => (a -> m b) -> (f :.: g) a -> m ((f :.: g) b) #

sequence :: Monad m => (f :.: g) (m a) -> m ((f :.: g) a) #

(Traversable f, Traversable g) => Traversable (Compose f g)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Compose

Methods

traverse :: Applicative f0 => (a -> f0 b) -> Compose f g a -> f0 (Compose f g b) #

sequenceA :: Applicative f0 => Compose f g (f0 a) -> f0 (Compose f g a) #

mapM :: Monad m => (a -> m b) -> Compose f g a -> m (Compose f g b) #

sequence :: Monad m => Compose f g (m a) -> m (Compose f g a) #

for :: (Traversable t, Applicative f) => t a -> (a -> f b) -> f (t b) #

for is traverse with its arguments flipped. For a version that ignores the results see for_.

forM :: (Traversable t, Monad m) => t a -> (a -> m b) -> m (t b) #

forM is mapM with its arguments flipped. For a version that ignores the results see forM_.

traverse_ :: (Foldable t, Applicative f) => (a -> f b) -> t a -> f () #

Map each element of a structure to an action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see traverse.

Combinators

id :: a -> a #

Identity function.

id x = x

(.) :: (b -> c) -> (a -> b) -> a -> c infixr 9 #

Function composition.

($) :: (a -> b) -> a -> b infixr 0 #

Application operator. This operator is redundant, since ordinary application (f x) means the same as (f $ x). However, $ has low, right-associative binding precedence, so it sometimes allows parentheses to be omitted; for example:

f $ g $ h x  =  f (g (h x))

It is also useful in higher-order situations, such as map ($ 0) xs, or zipWith ($) fs xs.

($!) :: (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.

(&) :: 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 $.

>>> 5 & (+1) & show
"6"

Since: base-4.8.0.0

const :: a -> b -> a #

const x is a unary function which evaluates to x for all inputs.

>>> const 42 "hello"
42
>>> map (const 42) [0..3]
[42,42,42,42]

flip :: (a -> b -> c) -> b -> a -> c #

flip f takes its (first) two arguments in the reverse order of f.

>>> flip (++) "hello" "world"
"worldhello"

fix :: (a -> a) -> a #

fix f is the least fixed point of the function f, i.e. the least defined x such that f x = x.

For example, we can write the factorial function using direct recursion as

>>> let fac n = if n <= 1 then 1 else n * fac (n-1) in fac 5
120

This uses the fact that Haskell’s let introduces recursive bindings. We can rewrite this definition using fix,

>>> fix (\rec n -> if n <= 1 then 1 else n * rec (n-1)) 5
120

Instead of making a recursive call, we introduce a dummy parameter rec; when used within fix, this parameter then refers to fix' argument, hence the recursion is reintroduced.

on :: (b -> b -> c) -> (a -> b) -> a -> a -> c infixl 0 #

seq :: a -> b -> b #

The value of seq a b is bottom if a is bottom, and otherwise equal to b. In other words, it evaluates the first argument a to weak head normal form (WHNF). seq is usually introduced to improve performance by avoiding unneeded laziness.

A note on evaluation order: the expression seq a b does not guarantee that a will be evaluated before b. The only guarantee given by seq is that the both a and b will be evaluated before seq returns a value. In particular, this means that b may be evaluated before a. If you need to guarantee a specific order of evaluation, you must use the function pseq from the "parallel" package.

Text functions

data Text #

A space efficient, packed, unboxed Unicode text type.

Instances
type Item Text 
Instance details

Defined in Data.Text

type Item Text = Char

Partial functions

undefined :: HasCallStack => a Source #

Warning: undefined is unsafe

error :: HasCallStack => [Char] -> a Source #

Warning: error is unsafe

Debugging facilities

trace :: [Char] -> a -> a Source #

Warning: trace should only be used while debugging

traceM :: Applicative f => [Char] -> f () Source #

Warning: traceM should only be used while debugging

traceIO :: [Char] -> IO () Source #

Warning: traceIO should only be used while debugging