haskell-gi-base-0.26.9: Foundation for libraries generated by haskell-gi
Safe HaskellNone
LanguageHaskell2010

Data.GI.Base.ShortPrelude

Description

The Haskell Prelude exports a number of symbols that can easily collide with functions appearing in bindings. The generated code requires just a small subset of the functions in the Prelude, together with some of the functionality in Data.GI.Base, we reexport this explicitly here.

Synopsis

Documentation

data Char Source #

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

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

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

There is a special escape syntax for ASCII control characters:

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

Data.Char provides utilities to work with Char.

Instances

Instances details
IsChar Char

Since: base-2.1

Instance details

Defined in Text.Printf

PrintfArg Char

Since: base-2.1

Instance details

Defined in Text.Printf

Bounded Char

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum Char

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Storable Char

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Show Char

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Eq Char 
Instance details

Defined in GHC.Classes

Methods

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

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

Ord Char 
Instance details

Defined in GHC.Classes

TestCoercion SChar

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.TypeLits

Methods

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

TestEquality SChar

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.TypeLits

Methods

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

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

Defined in GHC.Internal.Generics

Associated Types

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

Methods

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

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

Foldable (UChar :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Foldable

Methods

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

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

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

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

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

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

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

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

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

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

null :: UChar a -> Bool Source #

length :: UChar a -> Int Source #

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

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

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

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

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

Traversable (UChar :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Traversable

Methods

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

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

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

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

IsGValue (Maybe String) Source # 
Instance details

Defined in Data.GI.Base.GValue

Functor (URec Char :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Generic (URec Char p) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

Methods

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

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

Show (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Eq (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Ord (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

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

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

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

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

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

data URec Char (p :: k)

Used for marking occurrences of Char#

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

ord :: Char -> Int Source #

The fromEnum method restricted to the type Char.

chr :: Int -> Char Source #

The toEnum method restricted to the type Char.

module Data.Int

data Word8 Source #

8-bit unsigned integer type

Instances

Instances details
PrintfArg Word8

Since: base-2.1

Instance details

Defined in Text.Printf

Bits Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

FiniteBits Word8

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Word

Bounded Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Storable Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Ix Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Num Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Integral Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Real Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Methods

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

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

Ord Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

IsGVariant Word8 Source # 
Instance details

Defined in Data.GI.Base.GVariant

IsGVariantBasicType Word8 Source # 
Instance details

Defined in Data.GI.Base.GVariant

data Word64 Source #

64-bit unsigned integer type

Instances

Instances details
PrintfArg Word64

Since: base-2.1

Instance details

Defined in Text.Printf

Bits Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

FiniteBits Word64

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Word

Bounded Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Storable Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Ix Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Num Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Integral Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Real Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Ord Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

IsGValue Word64 Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGVariant Word64 Source # 
Instance details

Defined in Data.GI.Base.GVariant

IsGVariantBasicType Word64 Source # 
Instance details

Defined in Data.GI.Base.GVariant

data Word32 Source #

32-bit unsigned integer type

Instances

Instances details
PrintfArg Word32

Since: base-2.1

Instance details

Defined in Text.Printf

Bits Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

FiniteBits Word32

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Word

Bounded Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Storable Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Ix Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Num Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Integral Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Real Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Ord Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

IsGValue Word32 Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGVariant Word32 Source # 
Instance details

Defined in Data.GI.Base.GVariant

IsGVariantBasicType Word32 Source # 
Instance details

Defined in Data.GI.Base.GVariant

data Word16 Source #

16-bit unsigned integer type

Instances

Instances details
PrintfArg Word16

Since: base-2.1

Instance details

Defined in Text.Printf

Bits Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

FiniteBits Word16

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Word

Bounded Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Storable Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Ix Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Num Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Integral Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Real Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Ord Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

IsGVariant Word16 Source # 
Instance details

Defined in Data.GI.Base.GVariant

IsGVariantBasicType Word16 Source # 
Instance details

Defined in Data.GI.Base.GVariant

data ByteString Source #

A space-efficient representation of a Word8 vector, supporting many efficient operations.

A ByteString contains 8-bit bytes, or by using the operations from Data.ByteString.Char8 it can be interpreted as containing 8-bit characters.

Instances

Instances details
NFData ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Methods

rnf :: ByteString -> () Source #

Monoid ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Semigroup ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Data ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Methods

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

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

toConstr :: ByteString -> Constr Source #

dataTypeOf :: ByteString -> DataType Source #

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

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

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

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

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

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

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

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

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

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

IsString ByteString

Beware: fromString truncates multi-byte characters to octets. e.g. "枯朶に烏のとまりけり秋の暮" becomes �6k�nh~�Q��n�

Instance details

Defined in Data.ByteString.Internal.Type

IsList ByteString

Since: bytestring-0.10.12.0

Instance details

Defined in Data.ByteString.Internal.Type

Associated Types

type Item ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Read ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Show ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Eq ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Ord ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

IsGVariant ByteString Source # 
Instance details

Defined in Data.GI.Base.GVariant

Lift ByteString

Since: bytestring-0.11.2.0

Instance details

Defined in Data.ByteString.Internal.Type

Methods

lift :: Quote m => ByteString -> m Exp Source #

liftTyped :: forall (m :: Type -> Type). Quote m => ByteString -> Code m ByteString Source #

type Item ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

newtype CUIntPtr Source #

Constructors

CUIntPtr Word64 

Instances

Instances details
Bits CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

FiniteBits CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Bounded CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ix CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Integral CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ord CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

newtype CIntPtr Source #

Constructors

CIntPtr Int64 

Instances

Instances details
Bits CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

FiniteBits CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Bounded CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ix CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Integral CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ord CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

newtype CDouble Source #

Haskell type representing the C double type. (The concrete types of Foreign.C.Types are platform-specific.)

Constructors

CDouble Double 

Instances

Instances details
Enum CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Floating CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

RealFloat CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Fractional CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

RealFrac CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ord CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

newtype CFloat Source #

Haskell type representing the C float type. (The concrete types of Foreign.C.Types are platform-specific.)

Constructors

CFloat Float 

Instances

Instances details
Enum CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Floating CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

RealFloat CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Fractional CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

RealFrac CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ord CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

newtype CULong Source #

Haskell type representing the C unsigned long type. (The concrete types of Foreign.C.Types are platform-specific.)

Constructors

CULong Word64 

Instances

Instances details
Bits CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

FiniteBits CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Bounded CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ix CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Integral CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ord CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

IsGValue CULong Source # 
Instance details

Defined in Data.GI.Base.GValue

newtype CLong Source #

Haskell type representing the C long type. (The concrete types of Foreign.C.Types are platform-specific.)

Constructors

CLong Int64 

Instances

Instances details
Bits CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

FiniteBits CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Bounded CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ix CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Integral CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Ord CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

IsGValue CLong Source # 
Instance details

Defined in Data.GI.Base.GValue

newtype CUInt Source #

Haskell type representing the C unsigned int type. (The concrete types of Foreign.C.Types are platform-specific.)

Constructors

CUInt Word32 

Instances

Instances details
Bits CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

FiniteBits CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Bounded CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ix CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Integral CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Ord CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

IsGValue CUInt Source # 
Instance details

Defined in Data.GI.Base.GValue

newtype CInt Source #

Haskell type representing the C int type. (The concrete types of Foreign.C.Types are platform-specific.)

Constructors

CInt Int32 

Instances

Instances details
Bits CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

FiniteBits CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Bounded CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Storable CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Ix CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Num CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Read CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Integral CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Real CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Ord CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

IsGValue CInt Source # 
Instance details

Defined in Data.GI.Base.GValue

type CString = Ptr CChar Source #

A C string is a reference to an array of C characters terminated by NUL.

data Ptr a Source #

A value of type Ptr a represents a pointer to an object, or an array of objects, which may be marshalled to or from Haskell values of type a.

The type a will often be an instance of class Storable which provides the marshalling operations. However this is not essential, and you can provide your own operations to access the pointer. For example you might write small foreign functions to get or set the fields of a C struct.

Instances

Instances details
Generic1 (URec (Ptr ()) :: k -> Type) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 (URec (Ptr ()) :: k -> Type) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UAddr" 'PrefixI 'True) (S1 ('MetaSel ('Just "uAddr#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UAddr :: k -> Type)))

Methods

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

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

Foldable (UAddr :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Foldable

Methods

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

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

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

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

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

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

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

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

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

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

null :: UAddr a -> Bool Source #

length :: UAddr a -> Int Source #

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

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

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

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

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

Traversable (UAddr :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Traversable

Methods

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

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

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

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

Storable (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Methods

sizeOf :: Ptr a -> Int Source #

alignment :: Ptr a -> Int Source #

peekElemOff :: Ptr (Ptr a) -> Int -> IO (Ptr a) Source #

pokeElemOff :: Ptr (Ptr a) -> Int -> Ptr a -> IO () Source #

peekByteOff :: Ptr b -> Int -> IO (Ptr a) Source #

pokeByteOff :: Ptr b -> Int -> Ptr a -> IO () Source #

peek :: Ptr (Ptr a) -> IO (Ptr a) Source #

poke :: Ptr (Ptr a) -> Ptr a -> IO () Source #

Show (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Methods

showsPrec :: Int -> Ptr a -> ShowS Source #

show :: Ptr a -> String Source #

showList :: [Ptr a] -> ShowS Source #

Eq (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Methods

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

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

Ord (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Methods

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

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

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

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

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

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

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

IsGValue (Ptr a) Source # 
Instance details

Defined in Data.GI.Base.GValue

Functor (URec (Ptr ()) :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Generic (URec (Ptr ()) p) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep (URec (Ptr ()) p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep (URec (Ptr ()) p) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UAddr" 'PrefixI 'True) (S1 ('MetaSel ('Just "uAddr#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UAddr :: Type -> Type)))

Methods

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

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

Eq (URec (Ptr ()) p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Ord (URec (Ptr ()) p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

compare :: URec (Ptr ()) p -> URec (Ptr ()) p -> Ordering Source #

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

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

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

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

max :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p Source #

min :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p Source #

data URec (Ptr ()) (p :: k)

Used for marking occurrences of Addr#

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

data URec (Ptr ()) (p :: k) = UAddr {}
type Rep1 (URec (Ptr ()) :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 (URec (Ptr ()) :: k -> Type) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UAddr" 'PrefixI 'True) (S1 ('MetaSel ('Just "uAddr#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UAddr :: k -> Type)))
type Rep (URec (Ptr ()) p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep (URec (Ptr ()) p) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UAddr" 'PrefixI 'True) (S1 ('MetaSel ('Just "uAddr#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UAddr :: Type -> Type)))

data FunPtr a Source #

A value of type FunPtr a is a pointer to a function callable from foreign code. The type a will normally be a foreign type, a function type with zero or more arguments where

A value of type FunPtr a may be a pointer to a foreign function, either returned by another foreign function or imported with a a static address import like

foreign import ccall "stdlib.h &free"
  p_free :: FunPtr (Ptr a -> IO ())

or a pointer to a Haskell function created using a wrapper stub declared to produce a FunPtr of the correct type. For example:

type Compare = Int -> Int -> Bool
foreign import ccall "wrapper"
  mkCompare :: Compare -> IO (FunPtr Compare)

Calls to wrapper stubs like mkCompare allocate storage, which should be released with freeHaskellFunPtr when no longer required.

To convert FunPtr values to corresponding Haskell functions, one can define a dynamic stub for the specific foreign type, e.g.

type IntFunction = CInt -> IO ()
foreign import ccall "dynamic"
  mkFun :: FunPtr IntFunction -> IntFunction

Instances

Instances details
Storable (FunPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Methods

sizeOf :: FunPtr a -> Int Source #

alignment :: FunPtr a -> Int Source #

peekElemOff :: Ptr (FunPtr a) -> Int -> IO (FunPtr a) Source #

pokeElemOff :: Ptr (FunPtr a) -> Int -> FunPtr a -> IO () Source #

peekByteOff :: Ptr b -> Int -> IO (FunPtr a) Source #

pokeByteOff :: Ptr b -> Int -> FunPtr a -> IO () Source #

peek :: Ptr (FunPtr a) -> IO (FunPtr a) Source #

poke :: Ptr (FunPtr a) -> FunPtr a -> IO () Source #

Show (FunPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Eq (FunPtr a) 
Instance details

Defined in GHC.Internal.Ptr

Methods

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

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

Ord (FunPtr a) 
Instance details

Defined in GHC.Internal.Ptr

Methods

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

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

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

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

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

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

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

nullPtr :: Ptr a Source #

The constant nullPtr contains a distinguished value of Ptr that is not associated with a valid memory location.

plusPtr :: Ptr a -> Int -> Ptr b Source #

Advances the given address by the given offset in bytes.

castFunPtrToPtr :: FunPtr a -> Ptr b Source #

Casts a FunPtr to a Ptr.

Note: this is valid only on architectures where data and function pointers range over the same set of addresses, and should only be used for bindings to external libraries whose interface already relies on this assumption.

castPtrToFunPtr :: Ptr a -> FunPtr b Source #

Casts a Ptr to a FunPtr.

Note: this is valid only on architectures where data and function pointers range over the same set of addresses, and should only be used for bindings to external libraries whose interface already relies on this assumption.

data ForeignPtr a Source #

The type ForeignPtr represents references to objects that are maintained in a foreign language, i.e., that are not part of the data structures usually managed by the Haskell storage manager. The essential difference between ForeignPtrs and vanilla memory references of type Ptr a is that the former may be associated with finalizers. A finalizer is a routine that is invoked when the Haskell storage manager detects that - within the Haskell heap and stack - there are no more references left that are pointing to the ForeignPtr. Typically, the finalizer will, then, invoke routines in the foreign language that free the resources bound by the foreign object.

The ForeignPtr is parameterised in the same way as Ptr. The type argument of ForeignPtr should normally be an instance of class Storable.

Instances

Instances details
Show (ForeignPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.ForeignPtr

Eq (ForeignPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.ForeignPtr

Ord (ForeignPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.ForeignPtr

sizeOf :: Storable a => a -> Int Source #

Computes the storage requirements (in bytes) of the argument. The value of the argument is not used.

peek :: Storable a => Ptr a -> IO a Source #

Read a value from the given memory location.

Note that the peek and poke functions might require properly aligned addresses to function correctly. This is architecture dependent; thus, portable code should ensure that when peeking or poking values of some type a, the alignment constraint for a, as given by the function alignment is fulfilled.

poke :: Storable a => Ptr a -> a -> IO () Source #

Write the given value to the given memory location. Alignment restrictions might apply; see peek.

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

An infix synonym for fmap.

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

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

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

Examples

Expand

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

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

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

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

Double each element of a list:

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

Apply even to the second element of a pair:

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

onException :: IO a -> IO b -> IO a Source #

Like finally, but only performs the final action if there was an exception raised by the computation.

clear :: forall info (attr :: Symbol) obj m. (AttrClearC info obj attr, MonadIO m) => obj -> AttrLabelProxy attr -> m () Source #

Set a nullable attribute to NULL.

data AttrOp obj (tag :: AttrOpTag) where Source #

Constructors for the different operations allowed on an attribute.

Constructors

(:=) :: forall obj info (attr :: Symbol) (tag :: AttrOpTag) b. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed tag info obj, AttrSetTypeConstraint info b) => AttrLabelProxy attr -> b -> AttrOp obj tag infixr 0

Assign a value to an attribute

(:=>) :: forall obj info (attr :: Symbol) (tag :: AttrOpTag) b. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed tag info obj, AttrSetTypeConstraint info b) => AttrLabelProxy attr -> IO b -> AttrOp obj tag infixr 0

Assign the result of an IO action to an attribute

(:~) :: forall obj info (attr :: Symbol) (tag :: AttrOpTag) b a. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, tag ~ 'AttrSet, AttrOpAllowed 'AttrSet info obj, AttrOpAllowed 'AttrGet info obj, AttrSetTypeConstraint info b, a ~ AttrGetType info) => AttrLabelProxy attr -> (a -> b) -> AttrOp obj tag infixr 0

Apply an update function to an attribute

(:~>) :: forall obj info (attr :: Symbol) (tag :: AttrOpTag) b a. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, tag ~ 'AttrSet, AttrOpAllowed 'AttrSet info obj, AttrOpAllowed 'AttrGet info obj, AttrSetTypeConstraint info b, a ~ AttrGetType info) => AttrLabelProxy attr -> (a -> IO b) -> AttrOp obj tag infixr 0

Apply an IO update function to an attribute

(:&=) :: forall obj info (attr :: Symbol) (tag :: AttrOpTag) b. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed tag info obj, AttrTransferTypeConstraint info b, AttrSetTypeConstraint info (AttrTransferType info)) => AttrLabelProxy attr -> b -> AttrOp obj tag

Assign a value to an attribute, allocating any necessary memory for representing the Haskell value as a C value. Note that it is the responsibility of the caller to make sure that the memory is freed when no longer used, otherwise there will be a memory leak. In the majority of cases you probably want to use := instead, which has no potential memory leaks (at the cost of sometimes requiring some explicit Haskell -> C marshalling).

(:!<~) :: forall obj info (attr :: Symbol) (tag1 :: AttrOpTag) b model (tag :: AttrOpTag). (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed tag1 info obj, AttrSetTypeConstraint info b, ?_haskell_gi_modelProxy :: ModelProxy model) => AttrLabelProxy attr -> DynVal model b -> AttrOp obj tag infixr 0

Bind a property to the given DynVal, so that the property is changed whenever the DynVal is. This requires the implicit param ?_haskell_gi_modelProxy, of type ModelProxy model to be set.

(:<~) :: forall obj info (attr :: Symbol) (tag :: AttrOpTag) b model. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed tag info obj, AttrSetTypeConstraint info b, AttrOpAllowed 'AttrGet info obj, EqMaybe b (AttrGetType info), ?_haskell_gi_modelProxy :: ModelProxy model) => AttrLabelProxy attr -> DynVal model b -> AttrOp obj tag infixr 0

Bind a property to the given DynVal, so that the property is changed whenever the DynVal is. This requires the implicit param ?_haskell_gi_modelProxy, of type ModelProxy model to be set. This will only actually set the property whenever the DynVal changes if the new value of the DynVal is different from the actual value of the property. If you want to set the property without checking equality you can use :!<~ instead.

Bind :: forall obj info (propName :: Symbol) (tag :: AttrOpTag) model outType (components :: [Symbol]) (fieldName :: Symbol). (HasAttributeList obj, GObject obj, info ~ ResolveAttribute propName obj, AttrInfo info, KnownSymbol (AttrLabel info), AttrBaseTypeConstraint info obj, AttrOpAllowed tag info obj, AttrOpAllowed 'AttrPut info obj, ?_haskell_gi_modelProxy :: ModelProxy model, outType ~ AttrGetType info, AttrSetTypeConstraint info outType, components ~ Components fieldName, PathFieldAccess components model outType, KnownSymbol fieldName, Eq outType) => AttrLabelProxy propName -> AttrLabelProxy fieldName -> AttrOp obj tag

Given an AttrLabelProxy, bind the given attribute to the corresponding field in the model proxy (if there's one), so that changes in the attribute are reflected back into changes of the model.

On :: forall obj info (tag :: AttrOpTag). (GObject obj, SignalInfo info) => SignalProxy obj info -> ((?self :: obj) => HaskellCallbackType info) -> AttrOp obj tag

Connect the given signal to a signal handler.

After :: forall obj info (tag :: AttrOpTag). (GObject obj, SignalInfo info) => SignalProxy obj info -> ((?self :: obj) => HaskellCallbackType info) -> AttrOp obj tag

Like On, but connect after the default signal.

class AttrInfo info where Source #

Info describing an attribute.

Minimal complete definition

Nothing

Associated Types

type AttrAllowedOps info :: [AttrOpTag] Source #

The operations that are allowed on the attribute.

type AttrBaseTypeConstraint info :: Type -> Constraint Source #

Constraint on the type for which we are allowed to create/set/get the attribute.

type AttrGetType info Source #

Type returned by attrGet.

type AttrSetTypeConstraint info :: Type -> Constraint Source #

Constraint on the value being set.

type AttrTransferTypeConstraint info :: Type -> Constraint Source #

Constraint on the value being set, with allocation allowed (see :&= below).

type AttrTransferType info Source #

Type resulting from the allocation.

type AttrTransferType info = AttrGetType info

type AttrLabel info :: Symbol Source #

Name of the attribute.

type AttrOrigin info Source #

Type which introduces the attribute.

Methods

attrGet :: AttrBaseTypeConstraint info o => o -> IO (AttrGetType info) Source #

Get the value of the given attribute.

default attrGet :: CheckNotElem 'AttrGet (AttrAllowedOps info) (GetNotProvidedError info) => o -> IO (AttrGetType info) Source #

attrSet :: (AttrBaseTypeConstraint info o, AttrSetTypeConstraint info b) => o -> b -> IO () Source #

Set the value of the given attribute, after the object having the attribute has already been created.

default attrSet :: CheckNotElem 'AttrSet (AttrAllowedOps info) (SetNotProvidedError info) => o -> b -> IO () Source #

attrClear :: AttrBaseTypeConstraint info o => o -> IO () Source #

Set the value of the given attribute to NULL (for nullable attributes).

default attrClear :: CheckNotElem 'AttrClear (AttrAllowedOps info) (ClearNotProvidedError info) => o -> IO () Source #

attrConstruct :: (AttrBaseTypeConstraint info o, AttrSetTypeConstraint info b) => b -> IO (GValueConstruct o) Source #

Build a GValue representing the attribute.

default attrConstruct :: CheckNotElem 'AttrConstruct (AttrAllowedOps info) (ConstructNotProvidedError info) => b -> IO (GValueConstruct o) Source #

attrTransfer :: (AttrBaseTypeConstraint info o, AttrTransferTypeConstraint info b) => Proxy o -> b -> IO (AttrTransferType info) Source #

Allocate memory as necessary to generate a settable type from the transfer type. This is useful for types which needs allocations for marshalling from Haskell to C, this makes the allocation explicit.

attrPut :: AttrBaseTypeConstraint info o => o -> AttrGetType info -> IO () Source #

Like attrSet, but it uses the same type as the getter. This is useful for some nullable types, for which the getter returns Maybe a, while the setter takes an a. attrPut will instead accept an Maybe a.

default attrPut :: CheckNotElem 'AttrPut (AttrAllowedOps info) (PutNotProvidedError info) => o -> AttrGetType info -> IO () Source #

dbgAttrInfo :: Maybe ResolvedSymbolInfo Source #

Return some information about the overloaded attribute, useful for debugging. See resolveAttr for how to access this conveniently.

data AttrOpTag Source #

Possible operations on an attribute.

Constructors

AttrGet

It is possible to read the value of the attribute with get.

AttrSet

It is possible to write the value of the attribute with set.

AttrConstruct

It is possible to set the value of the attribute in new.

AttrClear

It is possible to clear the value of the (nullable) attribute with clear.

AttrPut

It is possible to set a value of the same type as the one returned by get.

type family AttrOpAllowed (tag :: AttrOpTag) info useType where ... Source #

Whether a given AttrOpTag is allowed on an attribute, given the info type.

Equations

AttrOpAllowed tag info useType = AttrOpIsAllowed tag (AttrAllowedOps info) (AttrLabel info) (AttrOrigin info) useType 

type AttrGetC info obj (attr :: Symbol) result = (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed 'AttrGet info obj, result ~ AttrGetType info) Source #

Constraints on a obj/attr pair so get is possible, producing a value of type result.

type AttrSetC info obj (attr :: Symbol) value = (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed 'AttrSet info obj, AttrSetTypeConstraint info value) Source #

Constraint on a obj/attr pair so that set works on values of type value.

type AttrConstructC info obj (attr :: Symbol) value = (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed 'AttrConstruct info obj, AttrSetTypeConstraint info value) Source #

Constraint on a obj/value pair so that new works on values of type value.

type AttrClearC info obj (attr :: Symbol) = (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info, AttrBaseTypeConstraint info obj, AttrOpAllowed 'AttrClear info obj) Source #

Constraint on a obj/attr pair so that clear is allowed.

data AttrLabelProxy (a :: Symbol) Source #

A proxy for attribute labels.

Constructors

AttrLabelProxy 

Instances

Instances details
a ~ x => IsLabel x (AttrLabelProxy a) Source # 
Instance details

Defined in Data.GI.Base.Attributes

resolveAttr :: forall info (attr :: Symbol) obj. (HasAttributeList obj, info ~ ResolveAttribute attr obj, AttrInfo info) => obj -> AttrLabelProxy attr -> Maybe ResolvedSymbolInfo Source #

Return the fully qualified attribute name that a given overloaded attribute resolves to (mostly useful for debugging).

resolveAttr #sensitive button

bindPropToField :: forall o info (prop :: Symbol) (field :: Symbol) model outType (tag :: AttrOpTag) (components :: [Symbol]). (HasAttributeList o, GObject o, info ~ ResolveAttribute prop o, AttrInfo info, KnownSymbol (AttrLabel info), AttrBaseTypeConstraint info o, AttrOpAllowed tag info o, AttrOpAllowed 'AttrPut info o, ?_haskell_gi_modelProxy :: ModelProxy model, outType ~ AttrGetType info, AttrSetTypeConstraint info outType, components ~ Components field, PathFieldAccess components model outType, KnownSymbol field, Eq outType) => Proxy tag -> o -> AttrLabelProxy prop -> AttrLabelProxy field -> IO () Source #

Create a binding between the given property of an object and a field in the model.

class EqMaybe a b where Source #

Methods

eqMaybe :: a -> b -> Bool Source #

Instances

Instances details
Eq a => EqMaybe a a Source # 
Instance details

Defined in Data.GI.Base.Attributes

Methods

eqMaybe :: a -> a -> Bool Source #

Eq a => EqMaybe a (Maybe a) Source # 
Instance details

Defined in Data.GI.Base.Attributes

Methods

eqMaybe :: a -> Maybe a -> Bool Source #

type family AttrLabel info :: Symbol Source #

Name of the attribute.

type family AttrGetType info Source #

Type returned by attrGet.

type family AttrBaseTypeConstraint info :: Type -> Constraint Source #

Constraint on the type for which we are allowed to create/set/get the attribute.

type family AttrAllowedOps info :: [AttrOpTag] Source #

The operations that are allowed on the attribute.

type family AttrSetTypeConstraint info :: Type -> Constraint Source #

Constraint on the value being set.

type family AttrTransferTypeConstraint info :: Type -> Constraint Source #

Constraint on the value being set, with allocation allowed (see :&= below).

type family AttrTransferType info Source #

Type resulting from the allocation.

type family AttrOrigin info Source #

Type which introduces the attribute.

data GClosure a Source #

The basic type. This corresponds to a wrapped GClosure on the C side, which is a boxed object.

Instances

Instances details
GBoxed (GClosure a) Source #

GClosures are registered as boxed in the GLib type system.

Instance details

Defined in Data.GI.Base.GClosure

TypedObject (GClosure a) Source #

Find the associated GType for the given closure.

Instance details

Defined in Data.GI.Base.GClosure

HasParentTypes (GClosure a) Source # 
Instance details

Defined in Data.GI.Base.GClosure

type ParentTypes (GClosure a) Source #

There are no types in the bindings that a closure can be safely cast to.

Instance details

Defined in Data.GI.Base.GClosure

type ParentTypes (GClosure a) = '[] :: [Type]

class SignalInfo info where Source #

Information about an overloaded signal.

Minimal complete definition

connectSignal

Associated Types

type HaskellCallbackType info Source #

The type for the signal handler.

Methods

connectSignal :: GObject o => o -> (o -> HaskellCallbackType info) -> SignalConnectMode -> Maybe Text -> IO SignalHandlerId Source #

Connect a Haskell function to a signal of the given GObject, specifying whether the handler will be called before or after the default handler. Note that the callback being passed here admits an extra initial parameter with respect to the usual Haskell callback type. This will be passed as an implicit ?self argument to the Haskell callback.

dbgSignalInfo :: Maybe ResolvedSymbolInfo Source #

Optional extra debug information, for resolveSignal below.

data SignalConnectMode Source #

Whether to connect a handler to a signal with connectSignal so that it runs before/after the default handler for the given signal.

Constructors

SignalConnectBefore

Run before the default handler.

SignalConnectAfter

Run after the default handler.

connectSignalFunPtr :: GObject o => o -> Text -> FunPtr a -> SignalConnectMode -> Maybe Text -> IO SignalHandlerId Source #

Connect a signal to a handler, given as a FunPtr.

type SignalHandlerId = CULong Source #

Type of a GObject signal handler id.

data GObjectNotifySignalInfo Source #

Connection information for a "notify" signal indicating that a specific property changed (see PropertyNotify for the relevant constructor).

type family HaskellCallbackType info Source #

The type for the signal handler.

data Symbol Source #

(Kind) This is the kind of type-level symbols.

Instances

Instances details
SingKind Symbol

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Associated Types

type DemoteRep Symbol 
Instance details

Defined in GHC.Internal.Generics

type DemoteRep Symbol = String

Methods

fromSing :: forall (a :: Symbol). Sing a -> DemoteRep Symbol

TestCoercion SSymbol

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.TypeLits

Methods

testCoercion :: forall (a :: Symbol) (b :: Symbol). SSymbol a -> SSymbol b -> Maybe (Coercion a b) Source #

TestEquality SSymbol

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.TypeLits

Methods

testEquality :: forall (a :: Symbol) (b :: Symbol). SSymbol a -> SSymbol b -> Maybe (a :~: b) Source #

KnownSymbol a => SingI (a :: Symbol)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

sing :: Sing a

(GConstructorImpl repDefined name s t a b, _name ~ AppendSymbol "_" name) => GenericOptic repDefined (_name :: Symbol) A_Prism s t a b 
Instance details

Defined in Optics.Label

Methods

genericOptic :: Optic A_Prism NoIx s t a b

GFieldImpl name s t a b => GenericOptic repDefined (name :: Symbol) A_Lens s t a b 
Instance details

Defined in Optics.Label

Methods

genericOptic :: Optic A_Lens NoIx s t a b

(HasField fieldName field a, KnownSymbol fieldName) => HasField (fieldName :: Symbol) (DynVal model field) (DynVal model a) Source # 
Instance details

Defined in Data.GI.Base.DynVal

Methods

getField :: DynVal model field -> DynVal model a Source #

(path ~ GSetFieldPath con epath, When (IsLeft epath) (HideReps g h), GSetFieldProd path g h b) => GSetFieldSum ('PathLeaf epath) (M1 C ('MetaCons con fix hs) g) (M1 C ('MetaCons con fix hs) h) b 
Instance details

Defined in Optics.Internal.Generic

Methods

gsetFieldSum :: M1 C ('MetaCons con fix hs) g x -> b -> M1 C ('MetaCons con fix hs) h x Source #

GAffineFieldMaybe epath g h a b => GAffineFieldSum ('PathLeaf epath) (M1 C m g) (M1 C m h) a b 
Instance details

Defined in Optics.Internal.Generic

Methods

gafieldSum :: AffineTraversalVL (M1 C m g x) (M1 C m h x) a b Source #

(GFieldImpl fieldName model model val val, NonEmpty fieldName ('Text "Field names cannot be empty"), KnownSymbol fieldName) => PathFieldAccess '[fieldName] model val Source # 
Instance details

Defined in Data.GI.Base.Internal.PathFieldAccess

Methods

pathFieldAccess :: Proxy '[fieldName] -> Proxy model -> (Lens' model val, [Text]) Source #

(GFieldImpl fieldName model model val val, KnownSymbol fieldName, PathFieldAccess rest val inner) => PathFieldAccess (fieldName ': rest) model inner Source # 
Instance details

Defined in Data.GI.Base.Internal.PathFieldAccess

Methods

pathFieldAccess :: Proxy (fieldName ': rest) -> Proxy model -> (Lens' model inner, [Text]) Source #

g ~ h => GAffineFieldMaybe ('Left name :: Either Symbol [Path]) g h a b 
Instance details

Defined in Optics.Internal.Generic

Methods

gafieldMaybe :: AffineTraversalVL (g x) (h x) a b

GFieldProd prodPath g h a b => GAffineFieldMaybe ('Right prodPath :: Either Symbol [Path]) g h a b 
Instance details

Defined in Optics.Internal.Generic

Methods

gafieldMaybe :: AffineTraversalVL (g x) (h x) a b

(GSetFieldSum path1 g1 h1 b, GSetFieldSum path2 g2 h2 b) => GSetFieldSum ('PathTree path1 path2) (g1 :+: g2) (h1 :+: h2) b 
Instance details

Defined in Optics.Internal.Generic

Methods

gsetFieldSum :: (g1 :+: g2) x -> b -> (h1 :+: h2) x Source #

(GAffineFieldSum path1 g1 h1 a b, GAffineFieldSum path2 g2 h2 a b) => GAffineFieldSum ('PathTree path1 path2) (g1 :+: g2) (h1 :+: h2) a b 
Instance details

Defined in Optics.Internal.Generic

Methods

gafieldSum :: AffineTraversalVL ((g1 :+: g2) x) ((h1 :+: h2) x) a b Source #

type DemoteRep Symbol 
Instance details

Defined in GHC.Internal.Generics

type DemoteRep Symbol = String
data Sing (s :: Symbol) 
Instance details

Defined in GHC.Internal.Generics

data Sing (s :: Symbol) where

class Enum a where Source #

Class Enum defines operations on sequentially ordered types.

The enumFrom... methods are used in Haskell's translation of arithmetic sequences.

Instances of Enum may be derived for any enumeration type (types whose constructors have no fields). The nullary constructors are assumed to be numbered left-to-right by fromEnum from 0 through n-1. See Chapter 10 of the Haskell Report for more details.

For any type that is an instance of class Bounded as well as Enum, the following should hold:

   enumFrom     x   = enumFromTo     x maxBound
   enumFromThen x y = enumFromThenTo x y bound
     where
       bound | fromEnum y >= fromEnum x = maxBound
             | otherwise                = minBound

Methods

toEnum :: Int -> a Source #

Convert from an Int.

fromEnum :: a -> Int Source #

Convert to an Int. It is implementation-dependent what fromEnum returns when applied to a value that is too large to fit in an Int.

Instances

Instances details
Enum ByteOrder

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.ByteOrder

Enum CBool 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CClock 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CIntMax 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CLLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CPtrdiff 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CSChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CSUSeconds 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CShort 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CSigAtomic 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CSize 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CTime 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUIntMax 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CULLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUSeconds 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CUShort 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum CWchar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Enum IntPtr 
Instance details

Defined in GHC.Internal.Foreign.Ptr

Enum WordPtr 
Instance details

Defined in GHC.Internal.Foreign.Ptr

Enum Associativity

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Enum DecidedStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Enum SourceStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Enum SourceUnpackedness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Enum Int16

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Enum Int32

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Enum Int64

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Enum Int8

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Enum Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Enum Ordering

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum AttrOpTag Source # 
Instance details

Defined in Data.GI.Base.Attributes

Enum GParamFlag Source # 
Instance details

Defined in Data.GI.Base.GParamSpec

Enum I8 
Instance details

Defined in Data.Text.Foreign

Methods

succ :: I8 -> I8 Source #

pred :: I8 -> I8 Source #

toEnum :: Int -> I8 Source #

fromEnum :: I8 -> Int Source #

enumFrom :: I8 -> [I8] Source #

enumFromThen :: I8 -> I8 -> [I8] Source #

enumFromTo :: I8 -> I8 -> [I8] Source #

enumFromThenTo :: I8 -> I8 -> I8 -> [I8] Source #

Enum FPFormat 
Instance details

Defined in Data.Text.Lazy.Builder.RealFloat

Enum Integer

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum Natural

Since: base-4.8.0.0

Instance details

Defined in GHC.Internal.Enum

Enum ()

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Methods

succ :: () -> () Source #

pred :: () -> () Source #

toEnum :: Int -> () Source #

fromEnum :: () -> Int Source #

enumFrom :: () -> [()] Source #

enumFromThen :: () -> () -> [()] Source #

enumFromTo :: () -> () -> [()] Source #

enumFromThenTo :: () -> () -> () -> [()] Source #

Enum Bool

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum Char

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum Double

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Enum Float

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5 :: Float]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Enum Int

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum Levity

Since: base-4.16.0.0

Instance details

Defined in GHC.Internal.Enum

Enum VecCount

Since: base-4.10.0.0

Instance details

Defined in GHC.Internal.Enum

Enum VecElem

Since: base-4.10.0.0

Instance details

Defined in GHC.Internal.Enum

Enum Word

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum a => Enum (First a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: First a -> First a Source #

pred :: First a -> First a Source #

toEnum :: Int -> First a Source #

fromEnum :: First a -> Int Source #

enumFrom :: First a -> [First a] Source #

enumFromThen :: First a -> First a -> [First a] Source #

enumFromTo :: First a -> First a -> [First a] Source #

enumFromThenTo :: First a -> First a -> First a -> [First a] Source #

Enum a => Enum (Last a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Last a -> Last a Source #

pred :: Last a -> Last a Source #

toEnum :: Int -> Last a Source #

fromEnum :: Last a -> Int Source #

enumFrom :: Last a -> [Last a] Source #

enumFromThen :: Last a -> Last a -> [Last a] Source #

enumFromTo :: Last a -> Last a -> [Last a] Source #

enumFromThenTo :: Last a -> Last a -> Last a -> [Last a] Source #

Enum a => Enum (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Max a -> Max a Source #

pred :: Max a -> Max a Source #

toEnum :: Int -> Max a Source #

fromEnum :: Max a -> Int Source #

enumFrom :: Max a -> [Max a] Source #

enumFromThen :: Max a -> Max a -> [Max a] Source #

enumFromTo :: Max a -> Max a -> [Max a] Source #

enumFromThenTo :: Max a -> Max a -> Max a -> [Max a] Source #

Enum a => Enum (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

succ :: Min a -> Min a Source #

pred :: Min a -> Min a Source #

toEnum :: Int -> Min a Source #

fromEnum :: Min a -> Int Source #

enumFrom :: Min a -> [Min a] Source #

enumFromThen :: Min a -> Min a -> [Min a] Source #

enumFromTo :: Min a -> Min a -> [Min a] Source #

enumFromThenTo :: Min a -> Min a -> Min a -> [Min a] Source #

Enum a => Enum (WrappedMonoid a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Integral a => Enum (Ratio a)

Since: base-2.0.1

Instance details

Defined in GHC.Internal.Real

Methods

succ :: Ratio a -> Ratio a Source #

pred :: Ratio a -> Ratio a Source #

toEnum :: Int -> Ratio a Source #

fromEnum :: Ratio a -> Int Source #

enumFrom :: Ratio a -> [Ratio a] Source #

enumFromThen :: Ratio a -> Ratio a -> [Ratio a] Source #

enumFromTo :: Ratio a -> Ratio a -> [Ratio a] Source #

enumFromThenTo :: Ratio a -> Ratio a -> Ratio a -> [Ratio a] Source #

Enum a => Enum (Solo a) 
Instance details

Defined in GHC.Internal.Enum

Methods

succ :: Solo a -> Solo a Source #

pred :: Solo a -> Solo a Source #

toEnum :: Int -> Solo a Source #

fromEnum :: Solo a -> Int Source #

enumFrom :: Solo a -> [Solo a] Source #

enumFromThen :: Solo a -> Solo a -> [Solo a] Source #

enumFromTo :: Solo a -> Solo a -> [Solo a] Source #

enumFromThenTo :: Solo a -> Solo a -> Solo a -> [Solo a] Source #

Enum (Fixed a)

Recall that, for numeric types, succ and pred typically add and subtract 1, respectively. This is not true in the case of Fixed, whose successor and predecessor functions intuitively return the "next" and "previous" values in the enumeration. The results of these functions thus depend on the resolution of the Fixed value. For example, when enumerating values of resolution 10^-3 of type Milli = Fixed E3,

>>> succ (0.000 :: Milli)
0.001

and likewise

>>> pred (0.000 :: Milli)
-0.001

In other words, succ and pred increment and decrement a fixed-precision value by the least amount such that the value's resolution is unchanged. For example, 10^-12 is the smallest (positive) amount that can be added to a value of type Pico = Fixed E12 without changing its resolution, and so

>>> succ (0.000000000000 :: Pico)
0.000000000001

and similarly

>>> pred (0.000000000000 :: Pico)
-0.000000000001

This is worth bearing in mind when defining Fixed arithmetic sequences. In particular, you may be forgiven for thinking the sequence

  [1..10] :: [Pico]

evaluates to [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] :: [Pico].

However, this is not true. On the contrary, similarly to the above implementations of succ and pred, enumFromTo :: Pico -> Pico -> [Pico] has a "step size" of 10^-12. Hence, the list [1..10] :: [Pico] has the form

  [1.000000000000, 1.00000000001, 1.00000000002, ..., 10.000000000000]

and contains 9 * 10^12 + 1 values.

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

succ :: Fixed a -> Fixed a Source #

pred :: Fixed a -> Fixed a Source #

toEnum :: Int -> Fixed a Source #

fromEnum :: Fixed a -> Int Source #

enumFrom :: Fixed a -> [Fixed a] Source #

enumFromThen :: Fixed a -> Fixed a -> [Fixed a] Source #

enumFromTo :: Fixed a -> Fixed a -> [Fixed a] Source #

enumFromThenTo :: Fixed a -> Fixed a -> Fixed a -> [Fixed a] Source #

Enum (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Data.Proxy

Methods

succ :: Proxy s -> Proxy s Source #

pred :: Proxy s -> Proxy s Source #

toEnum :: Int -> Proxy s Source #

fromEnum :: Proxy s -> Int Source #

enumFrom :: Proxy s -> [Proxy s] Source #

enumFromThen :: Proxy s -> Proxy s -> [Proxy s] Source #

enumFromTo :: Proxy s -> Proxy s -> [Proxy s] Source #

enumFromThenTo :: Proxy s -> Proxy s -> Proxy s -> [Proxy s] Source #

Enum (f (g a)) => Enum (Compose f g a)

Since: base-4.19.0.0

Instance details

Defined in Data.Functor.Compose

Methods

succ :: Compose f g a -> Compose f g a Source #

pred :: Compose f g a -> Compose f g a Source #

toEnum :: Int -> Compose f g a Source #

fromEnum :: Compose f g a -> Int Source #

enumFrom :: Compose f g a -> [Compose f g a] Source #

enumFromThen :: Compose f g a -> Compose f g a -> [Compose f g a] Source #

enumFromTo :: Compose f g a -> Compose f g a -> [Compose f g a] Source #

enumFromThenTo :: Compose f g a -> Compose f g a -> Compose f g a -> [Compose f g a] Source #

class Show a where Source #

Conversion of values to readable Strings.

Derived instances of Show have the following properties, which are compatible with derived instances of Read:

  • The result of show is a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used.
  • If the constructor is defined to be an infix operator, then showsPrec will produce infix applications of the constructor.
  • the representation will be enclosed in parentheses if the precedence of the top-level constructor in x is less than d (associativity is ignored). Thus, if d is 0 then the result is never surrounded in parentheses; if d is 11 it is always surrounded in parentheses, unless it is an atomic expression.
  • If the constructor is defined using record syntax, then show will produce the record-syntax form, with the fields given in the same order as the original declaration.

For example, given the declarations

infixr 5 :^:
data Tree a =  Leaf a  |  Tree a :^: Tree a

the derived instance of Show is equivalent to

instance (Show a) => Show (Tree a) where

       showsPrec d (Leaf m) = showParen (d > app_prec) $
            showString "Leaf " . showsPrec (app_prec+1) m
         where app_prec = 10

       showsPrec d (u :^: v) = showParen (d > up_prec) $
            showsPrec (up_prec+1) u .
            showString " :^: "      .
            showsPrec (up_prec+1) v
         where up_prec = 5

Note that right-associativity of :^: is ignored. For example,

  • show (Leaf 1 :^: Leaf 2 :^: Leaf 3) produces the string "Leaf 1 :^: (Leaf 2 :^: Leaf 3)".

Minimal complete definition

showsPrec | show

Methods

showsPrec Source #

Arguments

:: Int

the operator precedence of the enclosing context (a number from 0 to 11). Function application has precedence 10.

-> a

the value to be converted to a String

-> ShowS 

Convert a value to a readable String.

showsPrec should satisfy the law

showsPrec d x r ++ s  ==  showsPrec d x (r ++ s)

Derived instances of Read and Show satisfy the following:

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

show :: a -> String Source #

A specialised variant of showsPrec, using precedence context zero, and returning an ordinary String.

showList :: [a] -> ShowS Source #

The method showList is provided to allow the programmer to give a specialised way of showing lists of values. For example, this is used by the predefined Show instance of the Char type, where values of type String should be shown in double quotes, rather than between square brackets.

Instances

Instances details
Show ByteArray

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Show Timeout

Since: base-4.0

Instance details

Defined in System.Timeout

Show Builder

Since: bytestring-0.11.1.0

Instance details

Defined in Data.ByteString.Builder

Show FormatMode 
Instance details

Defined in Data.ByteString.Builder.RealFloat

Methods

showsPrec :: Int -> FormatMode -> ShowS Source #

show :: FormatMode -> String Source #

showList :: [FormatMode] -> ShowS Source #

Show ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Show SizeOverflowException 
Instance details

Defined in Data.ByteString.Internal.Type

Show ByteString 
Instance details

Defined in Data.ByteString.Lazy.Internal

Show ShortByteString 
Instance details

Defined in Data.ByteString.Short.Internal

Show IntSet 
Instance details

Defined in Data.IntSet.Internal

Show BitQueue 
Instance details

Defined in Utils.Containers.Internal.BitQueue

Show BitQueueB 
Instance details

Defined in Utils.Containers.Internal.BitQueue

Show Void

Since: base-4.8.0.0

Instance details

Defined in GHC.Internal.Show

Show ByteOrder

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.ByteOrder

Show NestedAtomically

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show NoMatchingContinuationPrompt

Since: base-4.18

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show NoMethodError

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show NonTermination

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show PatternMatchFail

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show RecConError

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show RecSelError

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show RecUpdError

Since: base-4.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show TypeError

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Control.Exception.Base

Show Dynamic

Since: base-2.1

Instance details

Defined in GHC.Internal.Data.Dynamic

Show SomeTypeRep

Since: base-4.10.0.0

Instance details

Defined in GHC.Internal.Data.Typeable.Internal

Show ErrorCall

Since: base-4.0.0.0

Instance details

Defined in GHC.Internal.Exception

Show ArithException

Since: base-4.0.0.0

Instance details

Defined in GHC.Internal.Exception.Type

Show SomeException

Since: ghc-internal-3.0

Instance details

Defined in GHC.Internal.Exception.Type

Show CBool 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CClock 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CIntMax 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CLLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CPtrdiff 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CSChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CSUSeconds 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CShort 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CSigAtomic 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CSize 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CTime 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUIntMax 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CULLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUSeconds 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CUShort 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show CWchar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Show IntPtr 
Instance details

Defined in GHC.Internal.Foreign.Ptr

Show WordPtr 
Instance details

Defined in GHC.Internal.Foreign.Ptr

Show Associativity

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

Show DecidedStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Show Fixity

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

Show SourceStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Show SourceUnpackedness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Show MaskingState

Since: base-4.3.0.0

Instance details

Defined in GHC.Internal.IO

Show BufferMode

Since: base-4.2.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Show Handle

Since: base-4.1.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Show HandleType

Since: base-4.1.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Show Newline

Since: base-4.3.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Show NewlineMode

Since: base-4.3.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Show Int16

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Show Int32

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Show Int64

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Show Int8

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Show FractionalExponentBase 
Instance details

Defined in GHC.Internal.Real

Show CallStack

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Show

Show SrcLoc

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Show

Show SomeChar 
Instance details

Defined in GHC.Internal.TypeLits

Show SomeSymbol

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.TypeLits

Show Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Show KindRep 
Instance details

Defined in GHC.Internal.Show

Show Module

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Show

Show Ordering

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show TrName

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Show

Show TyCon

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show TypeLitSort

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.Show

Show AttrOpTag Source # 
Instance details

Defined in Data.GI.Base.Attributes

Show GType Source # 
Instance details

Defined in Data.GI.Base.BasicTypes

Show UnexpectedNullPointerReturn Source # 
Instance details

Defined in Data.GI.Base.BasicTypes

Show DVKey Source # 
Instance details

Defined in Data.GI.Base.DynVal

Show GError Source # 
Instance details

Defined in Data.GI.Base.GError

Show GParamFlag Source # 
Instance details

Defined in Data.GI.Base.GParamSpec

Show GVariantHandle Source # 
Instance details

Defined in Data.GI.Base.GVariant

Show GVariantObjectPath Source # 
Instance details

Defined in Data.GI.Base.GVariant

Show GVariantSignature Source # 
Instance details

Defined in Data.GI.Base.GVariant

Show ResolvedSymbolInfo Source # 
Instance details

Defined in Data.GI.Base.Overloading

Show Decoding 
Instance details

Defined in Data.Text.Encoding

Show UnicodeException 
Instance details

Defined in Data.Text.Encoding.Error

Show I8 
Instance details

Defined in Data.Text.Foreign

Show Text 
Instance details

Defined in Data.Text.Show

Show Builder 
Instance details

Defined in Data.Text.Internal.Builder

Show PartialUtf8CodePoint 
Instance details

Defined in Data.Text.Internal.Encoding

Methods

showsPrec :: Int -> PartialUtf8CodePoint -> ShowS Source #

show :: PartialUtf8CodePoint -> String Source #

showList :: [PartialUtf8CodePoint] -> ShowS Source #

Show Utf8State 
Instance details

Defined in Data.Text.Internal.Encoding

Show DecoderState 
Instance details

Defined in Data.Text.Internal.Encoding.Utf8

Show Size 
Instance details

Defined in Data.Text.Internal.Fusion.Size

Show FPFormat 
Instance details

Defined in Data.Text.Lazy.Builder.RealFloat

Show Iter 
Instance details

Defined in Data.Text.Unsafe

Show Integer

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show Natural

Since: base-4.8.0.0

Instance details

Defined in GHC.Internal.Show

Show ()

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> () -> ShowS Source #

show :: () -> String Source #

showList :: [()] -> ShowS Source #

Show Bool

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show Char

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show Double

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Show Float

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Show Int

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show Levity

Since: base-4.15.0.0

Instance details

Defined in GHC.Internal.Show

Show RuntimeRep

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.Show

Show VecCount

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.Show

Show VecElem

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.Show

Show Word

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show a => Show (Complex a)

Since: base-2.1

Instance details

Defined in Data.Complex

Show a => Show (First a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Show a => Show (Last a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Last a -> ShowS Source #

show :: Last a -> String Source #

showList :: [Last a] -> ShowS Source #

Show a => Show (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Max a -> ShowS Source #

show :: Max a -> String Source #

showList :: [Max a] -> ShowS Source #

Show a => Show (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

showsPrec :: Int -> Min a -> ShowS Source #

show :: Min a -> String Source #

showList :: [Min a] -> ShowS Source #

Show m => Show (WrappedMonoid m)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Show vertex => Show (SCC vertex)

Since: containers-0.5.9

Instance details

Defined in Data.Graph

Methods

showsPrec :: Int -> SCC vertex -> ShowS Source #

show :: SCC vertex -> String Source #

showList :: [SCC vertex] -> ShowS Source #

Show a => Show (IntMap a) 
Instance details

Defined in Data.IntMap.Internal

Show a => Show (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Methods

showsPrec :: Int -> Seq a -> ShowS Source #

show :: Seq a -> String Source #

showList :: [Seq a] -> ShowS Source #

Show a => Show (ViewL a) 
Instance details

Defined in Data.Sequence.Internal

Show a => Show (ViewR a) 
Instance details

Defined in Data.Sequence.Internal

Show a => Show (Intersection a) 
Instance details

Defined in Data.Set.Internal

Show a => Show (Set a) 
Instance details

Defined in Data.Set.Internal

Methods

showsPrec :: Int -> Set a -> ShowS Source #

show :: Set a -> String Source #

showList :: [Set a] -> ShowS Source #

Show a => Show (Tree a) 
Instance details

Defined in Data.Tree

Methods

showsPrec :: Int -> Tree a -> ShowS Source #

show :: Tree a -> String Source #

showList :: [Tree a] -> ShowS Source #

Show a => Show (NonEmpty a)

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.Show

Show a => Show (ExceptionWithContext a) 
Instance details

Defined in GHC.Internal.Exception.Type

Show e => Show (NoBacktrace e) 
Instance details

Defined in GHC.Internal.Exception.Type

Show (ForeignPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.ForeignPtr

Show p => Show (Par1 p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> Par1 p -> ShowS Source #

show :: Par1 p -> String Source #

showList :: [Par1 p] -> ShowS Source #

Show (FunPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Show (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Methods

showsPrec :: Int -> Ptr a -> ShowS Source #

show :: Ptr a -> String Source #

showList :: [Ptr a] -> ShowS Source #

Show a => Show (Ratio a)

Since: base-2.0.1

Instance details

Defined in GHC.Internal.Real

Show (SChar c)

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.TypeLits

Show (SSymbol s)

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.TypeLits

Show a => Show (HValue a) Source # 
Instance details

Defined in Data.GI.Base.GValue

Show a => Show (GVariantSinglet a) Source # 
Instance details

Defined in Data.GI.Base.GVariant

Show a => Show (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Show a => Show (Solo a)

Since: base-4.15

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> Solo a -> ShowS Source #

show :: Solo a -> String Source #

showList :: [Solo a] -> ShowS Source #

Show a => Show [a]

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> [a] -> ShowS Source #

show :: [a] -> String Source #

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

HasResolution a => Show (Fixed a)

Since: base-2.1

Instance details

Defined in Data.Fixed

(Show a, Show b) => Show (Arg a b)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

show :: Arg a b -> String Source #

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

(Show k, Show a) => Show (Map k a) 
Instance details

Defined in Data.Map.Internal

Methods

showsPrec :: Int -> Map k a -> ShowS Source #

show :: Map k a -> String Source #

showList :: [Map k a] -> ShowS Source #

Show (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Data.Proxy

Show (TypeRep a) 
Instance details

Defined in GHC.Internal.Data.Typeable.Internal

Show (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> U1 p -> ShowS Source #

show :: U1 p -> String Source #

showList :: [U1 p] -> ShowS Source #

Show (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> V1 p -> ShowS Source #

show :: V1 p -> String Source #

showList :: [V1 p] -> ShowS Source #

(Show key, Show value) => Show (GVariantDictEntry key value) Source # 
Instance details

Defined in Data.GI.Base.GVariant

(Show a, Show b) => Show (a, b)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b) -> ShowS Source #

show :: (a, b) -> String Source #

showList :: [(a, b)] -> ShowS Source #

Show (f p) => Show (Rec1 f p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> Rec1 f p -> ShowS Source #

show :: Rec1 f p -> String Source #

showList :: [Rec1 f p] -> ShowS Source #

Show (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Show (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Show (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

Show (URec Int p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Show (URec Word p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

(Show1 f, Show a) => Show (Backwards f a) 
Instance details

Defined in Control.Applicative.Backwards

(Show1 f, Show a) => Show (IdentityT f a) 
Instance details

Defined in Control.Monad.Trans.Identity

Show a => Show (Constant a b) 
Instance details

Defined in Data.Functor.Constant

(Show1 f, Show a) => Show (Reverse f a) 
Instance details

Defined in Data.Functor.Reverse

Methods

showsPrec :: Int -> Reverse f a -> ShowS Source #

show :: Reverse f a -> String Source #

showList :: [Reverse f a] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c) -> ShowS Source #

show :: (a, b, c) -> String Source #

showList :: [(a, b, c)] -> ShowS Source #

(Show (f a), Show (g a)) => Show (Product f g a)

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Product

Methods

showsPrec :: Int -> Product f g a -> ShowS Source #

show :: Product f g a -> String Source #

showList :: [Product f g a] -> ShowS Source #

(Show (f a), Show (g a)) => Show (Sum f g a)

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Sum

Methods

showsPrec :: Int -> Sum f g a -> ShowS Source #

show :: Sum f g a -> String Source #

showList :: [Sum f g a] -> ShowS Source #

(Show (f p), Show (g p)) => Show ((f :*: g) p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> (f :*: g) p -> ShowS Source #

show :: (f :*: g) p -> String Source #

showList :: [(f :*: g) p] -> ShowS Source #

(Show (f p), Show (g p)) => Show ((f :+: g) p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> (f :+: g) p -> ShowS Source #

show :: (f :+: g) p -> String Source #

showList :: [(f :+: g) p] -> ShowS Source #

Show c => Show (K1 i c p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> K1 i c p -> ShowS Source #

show :: K1 i c p -> String Source #

showList :: [K1 i c p] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d) -> ShowS Source #

show :: (a, b, c, d) -> String Source #

showList :: [(a, b, c, d)] -> ShowS Source #

Show (f (g a)) => Show (Compose f g a)

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Compose

Methods

showsPrec :: Int -> Compose f g a -> ShowS Source #

show :: Compose f g a -> String Source #

showList :: [Compose f g a] -> ShowS Source #

Show (f (g p)) => Show ((f :.: g) p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> (f :.: g) p -> ShowS Source #

show :: (f :.: g) p -> String Source #

showList :: [(f :.: g) p] -> ShowS Source #

Show (f p) => Show (M1 i c f p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

showsPrec :: Int -> M1 i c f p -> ShowS Source #

show :: M1 i c f p -> String Source #

showList :: [M1 i c f p] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e) -> ShowS Source #

show :: (a, b, c, d, e) -> String Source #

showList :: [(a, b, c, d, e)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f) => Show (a, b, c, d, e, f)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f) -> ShowS Source #

show :: (a, b, c, d, e, f) -> String Source #

showList :: [(a, b, c, d, e, f)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g) => Show (a, b, c, d, e, f, g)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g) -> ShowS Source #

show :: (a, b, c, d, e, f, g) -> String Source #

showList :: [(a, b, c, d, e, f, g)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h) => Show (a, b, c, d, e, f, g, h)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h) -> ShowS Source #

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

showList :: [(a, b, c, d, e, f, g, h)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i) => Show (a, b, c, d, e, f, g, h, i)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i) -> ShowS Source #

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

showList :: [(a, b, c, d, e, f, g, h, i)] -> ShowS Source #

(Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j) => Show (a, b, c, d, e, f, g, h, i, j)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j) -> ShowS Source #

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

showList :: [(a, b, c, d, e, f, g, h, i, j)] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

showsPrec :: Int -> (a, b, c, d, e, f, g, h, i, j, k) -> ShowS Source #

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

showList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

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

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

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

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

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

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

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

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

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> ShowS Source #

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Methods

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

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

showList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> ShowS Source #

class Eq a where Source #

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

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

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

Minimal complete definition

(==) | (/=)

Methods

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

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

Instances

Instances details
Eq ByteArray

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Eq Timeout 
Instance details

Defined in System.Timeout

Eq ByteString 
Instance details

Defined in Data.ByteString.Internal.Type

Eq ByteString 
Instance details

Defined in Data.ByteString.Lazy.Internal

Eq ShortByteString 
Instance details

Defined in Data.ByteString.Short.Internal

Eq IntSet 
Instance details

Defined in Data.IntSet.Internal

Eq BigNat 
Instance details

Defined in GHC.Num.BigNat

Eq Void

Since: base-4.8.0.0

Instance details

Defined in GHC.Internal.Base

Methods

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

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

Eq ByteOrder

Since: base-4.11.0.0

Instance details

Defined in GHC.Internal.ByteOrder

Eq SomeTypeRep 
Instance details

Defined in GHC.Internal.Data.Typeable.Internal

Eq ErrorCall

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Exception

Eq ArithException

Since: base-3.0

Instance details

Defined in GHC.Internal.Exception.Type

Eq CBool 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CClock 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CDouble 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CFloat 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CIntMax 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CLLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CPtrdiff 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CSChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CSUSeconds 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CShort 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CSigAtomic 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CSize 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CTime 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CUChar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CUInt 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Methods

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

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

Eq CUIntMax 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CUIntPtr 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CULLong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CULong 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CUSeconds 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CUShort 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq CWchar 
Instance details

Defined in GHC.Internal.Foreign.C.Types

Eq IntPtr 
Instance details

Defined in GHC.Internal.Foreign.Ptr

Eq WordPtr 
Instance details

Defined in GHC.Internal.Foreign.Ptr

Eq Associativity

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

Eq DecidedStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Eq Fixity

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

Eq SourceStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Eq SourceUnpackedness

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Eq MaskingState

Since: base-4.3.0.0

Instance details

Defined in GHC.Internal.IO

Eq BufferMode

Since: base-4.2.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Eq Handle

Since: base-4.1.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Eq Newline

Since: base-4.2.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Eq NewlineMode

Since: base-4.2.0.0

Instance details

Defined in GHC.Internal.IO.Handle.Types

Eq Int16

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Methods

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

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

Eq Int32

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Methods

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

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

Eq Int64

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Methods

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

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

Eq Int8

Since: base-2.1

Instance details

Defined in GHC.Internal.Int

Methods

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

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

Eq SrcLoc

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Stack.Types

Eq SomeChar 
Instance details

Defined in GHC.Internal.TypeLits

Eq SomeSymbol

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.TypeLits

Eq Word16

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word32

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word64

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Eq Word8

Since: base-2.1

Instance details

Defined in GHC.Internal.Word

Methods

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

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

Eq Module 
Instance details

Defined in GHC.Classes

Eq Ordering 
Instance details

Defined in GHC.Classes

Eq TrName 
Instance details

Defined in GHC.Classes

Eq TyCon 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq AttrOpTag Source # 
Instance details

Defined in Data.GI.Base.Attributes

Eq GType Source # 
Instance details

Defined in Data.GI.Base.BasicTypes

Methods

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

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

Eq DVKey Source # 
Instance details

Defined in Data.GI.Base.DynVal

Methods

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

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

Eq GParamFlag Source # 
Instance details

Defined in Data.GI.Base.GParamSpec

Eq GVariantHandle Source # 
Instance details

Defined in Data.GI.Base.GVariant

Eq GVariantObjectPath Source # 
Instance details

Defined in Data.GI.Base.GVariant

Eq GVariantSignature Source # 
Instance details

Defined in Data.GI.Base.GVariant

Eq UnicodeException 
Instance details

Defined in Data.Text.Encoding.Error

Eq I8 
Instance details

Defined in Data.Text.Foreign

Methods

(==) :: I8 -> I8 -> Bool Source #

(/=) :: I8 -> I8 -> Bool Source #

Eq Text 
Instance details

Defined in Data.Text

Methods

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

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

Eq Builder 
Instance details

Defined in Data.Text.Internal.Builder

Eq PartialUtf8CodePoint 
Instance details

Defined in Data.Text.Internal.Encoding

Methods

(==) :: PartialUtf8CodePoint -> PartialUtf8CodePoint -> Bool Source #

(/=) :: PartialUtf8CodePoint -> PartialUtf8CodePoint -> Bool Source #

Eq Utf8State 
Instance details

Defined in Data.Text.Internal.Encoding

Eq DecoderState 
Instance details

Defined in Data.Text.Internal.Encoding.Utf8

Eq Size 
Instance details

Defined in Data.Text.Internal.Fusion.Size

Methods

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

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

Eq Integer 
Instance details

Defined in GHC.Num.Integer

Eq Natural 
Instance details

Defined in GHC.Num.Natural

Eq () 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Bool 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Char 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Double

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

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

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

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

Defined in GHC.Classes

Eq Float

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

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

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

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

Defined in GHC.Classes

Methods

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

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

Eq Int 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq Word 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq (Chan a)

Since: base-4.4.0.0

Instance details

Defined in Control.Concurrent.Chan

Methods

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

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

Eq (MutableByteArray s)

Since: base-4.17.0.0

Instance details

Defined in Data.Array.Byte

Eq a => Eq (Complex a)

Since: base-2.1

Instance details

Defined in Data.Complex

Methods

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

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

Eq a => Eq (First a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

Eq a => Eq (Last a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

Eq a => Eq (Max a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

Eq a => Eq (Min a)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

Eq m => Eq (WrappedMonoid m)

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Eq vertex => Eq (SCC vertex)

Since: containers-0.5.9

Instance details

Defined in Data.Graph

Methods

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

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

Eq a => Eq (IntMap a) 
Instance details

Defined in Data.IntMap.Internal

Methods

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

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

Eq a => Eq (Seq a) 
Instance details

Defined in Data.Sequence.Internal

Methods

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

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

Eq a => Eq (ViewL a) 
Instance details

Defined in Data.Sequence.Internal

Methods

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

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

Eq a => Eq (ViewR a) 
Instance details

Defined in Data.Sequence.Internal

Methods

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

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

Eq a => Eq (Intersection a) 
Instance details

Defined in Data.Set.Internal

Eq a => Eq (Set a) 
Instance details

Defined in Data.Set.Internal

Methods

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

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

Eq a => Eq (Tree a) 
Instance details

Defined in Data.Tree

Methods

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

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

Eq a => Eq (NonEmpty a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

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

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

Eq (ForeignPtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.ForeignPtr

Eq p => Eq (Par1 p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (IORef a)

Pointer equality.

Since: base-4.0.0.0

Instance details

Defined in GHC.Internal.IORef

Methods

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

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

Eq (FunPtr a) 
Instance details

Defined in GHC.Internal.Ptr

Methods

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

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

Eq (Ptr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Ptr

Methods

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

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

Eq a => Eq (Ratio a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Real

Methods

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

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

Eq (StablePtr a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Stable

Eq (SChar c)

Since: base-4.19.0.0

Instance details

Defined in GHC.Internal.TypeLits

Methods

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

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

Eq (SSymbol s)

Since: base-4.19.0.0

Instance details

Defined in GHC.Internal.TypeLits

Methods

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

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

Eq (ManagedPtr a) Source #

Two ManagedPtrs are equal if they wrap the same underlying C Ptr.

Instance details

Defined in Data.GI.Base.BasicTypes

Eq a => Eq (HValue a) Source # 
Instance details

Defined in Data.GI.Base.GValue

Methods

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

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

Eq a => Eq (GVariantSinglet a) Source # 
Instance details

Defined in Data.GI.Base.GVariant

Eq a => Eq (Stream a) 
Instance details

Defined in Data.Text.Internal.Fusion.Types

Methods

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

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

Eq a => Eq (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Maybe

Methods

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

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

Eq a => Eq (Solo a) 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq a => Eq [a] 
Instance details

Defined in GHC.Classes

Methods

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

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

Eq (Fixed a)

Since: base-2.1

Instance details

Defined in Data.Fixed

Methods

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

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

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 Source #

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

(Eq k, Eq a) => Eq (Map k a) 
Instance details

Defined in Data.Map.Internal

Methods

(==) :: Map k a -> Map k a -> Bool Source #

(/=) :: Map k a -> Map k a -> Bool Source #

Eq (Proxy s)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Data.Proxy

Methods

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

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

Eq (TypeRep a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Data.Typeable.Internal

Methods

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

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

Eq (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

(Eq key, Eq value) => Eq (GVariantDictEntry key value) Source # 
Instance details

Defined in Data.GI.Base.GVariant

Methods

(==) :: GVariantDictEntry key value -> GVariantDictEntry key value -> Bool Source #

(/=) :: GVariantDictEntry key value -> GVariantDictEntry key value -> Bool Source #

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

Defined in GHC.Classes

Methods

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

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

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

Since: base-4.18.0.0

Instance details

Defined in GHC.Internal.Generics

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

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (URec (Ptr ()) p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (URec Char p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (URec Int p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq (URec Word p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

(Eq1 f, Eq a) => Eq (Backwards f a) 
Instance details

Defined in Control.Applicative.Backwards

Methods

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

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

(Eq1 f, Eq a) => Eq (IdentityT f a) 
Instance details

Defined in Control.Monad.Trans.Identity

Methods

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

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

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

Defined in Data.Functor.Constant

Methods

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

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

(Eq1 f, Eq a) => Eq (Reverse f a) 
Instance details

Defined in Data.Functor.Reverse

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Product

Methods

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

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

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

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Sum

Methods

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

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

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

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

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

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Eq c => Eq (K1 i c p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Since: base-4.18.0.0

Instance details

Defined in Data.Functor.Compose

Methods

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

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

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

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

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

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

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

Defined in GHC.Classes

Methods

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

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

data IO a Source #

A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a.

There is really only one way to "perform" an I/O action: bind it to Main.main in your program. When your program is run, the I/O will be performed. It isn't possible to perform I/O from an arbitrary function, unless that function is itself in the IO monad and called at some point, directly or indirectly, from Main.main.

IO is a monad, so IO actions can be combined using either the do-notation or the >> and >>= operations from the Monad class.

Instances

Instances details
MonadIO IO

Since: base-4.9.0.0

Instance details

Defined in Control.Monad.IO.Class

Methods

liftIO :: IO a -> IO a Source #

Alternative IO

Takes the first non-throwing IO action's result. empty throws an exception.

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

empty :: IO a Source #

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

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

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

Applicative IO

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

pure :: a -> IO a Source #

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

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

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

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

Functor IO

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

Monad IO

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> IO a Source #

MonadPlus IO

Takes the first non-throwing IO action's result. mzero throws an exception.

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

mzero :: IO a Source #

mplus :: IO a -> IO a -> IO a Source #

MonadFail IO

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Control.Monad.Fail

Methods

fail :: String -> IO a Source #

MonadFix IO

Since: base-2.1

Instance details

Defined in GHC.Internal.Control.Monad.Fix

Methods

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

a ~ () => HPrintfType (IO a)

Since: base-4.7.0.0

Instance details

Defined in Text.Printf

Methods

hspr :: Handle -> String -> [UPrintf] -> IO a

a ~ () => PrintfType (IO a)

Since: base-4.7.0.0

Instance details

Defined in Text.Printf

Methods

spr :: String -> [UPrintf] -> IO a

Monoid a => Monoid (IO a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

mempty :: IO a Source #

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

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

Semigroup a => Semigroup (IO a)

Since: base-4.10.0.0

Instance details

Defined in GHC.Internal.Base

Methods

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

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

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

class Applicative m => Monad (m :: Type -> Type) where Source #

The Monad class defines the basic operations over a monad, a concept from a branch of mathematics known as category theory. From the perspective of a Haskell programmer, however, it is best to think of a monad as an abstract datatype of actions. Haskell's do expressions provide a convenient syntax for writing monadic expressions.

Instances of Monad should satisfy the following:

Left identity
return a >>= k = k a
Right identity
m >>= return = m
Associativity
m >>= (\x -> k x >>= h) = (m >>= k) >>= h

Furthermore, the Monad and Applicative operations should relate as follows:

The above laws imply:

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

The instances of Monad for List, Maybe and IO defined in the Prelude satisfy these laws.

Minimal complete definition

(>>=)

Methods

(>>=) :: m a -> (a -> m b) -> m b infixl 1 Source #

Sequentially compose two actions, passing any value produced by the first as an argument to the second.

'as >>= bs' can be understood as the do expression

do a <- as
   bs a

An alternative name for this function is 'bind', but some people may refer to it as 'flatMap', which results from it being equivialent to

\x f -> join (fmap f x) :: Monad m => m a -> (a -> m b) -> m b

which can be seen as mapping a value with Monad m => m a -> m (m b) and then 'flattening' m (m b) to m b using join.

(>>) :: m a -> m b -> m b infixl 1 Source #

Sequentially compose two actions, discarding any value produced by the first, like sequencing operators (such as the semicolon) in imperative languages.

'as >> bs' can be understood as the do expression

do as
   bs

or in terms of (>>=) as

as >>= const bs

return :: a -> m a Source #

Inject a value into the monadic type. This function should not be different from its default implementation as pure. The justification for the existence of this function is merely historic.

Instances

Instances details
Monad Complex

Since: base-4.9.0.0

Instance details

Defined in Data.Complex

Methods

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

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

return :: a -> Complex a Source #

Monad First

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

return :: a -> First a Source #

Monad Last

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

return :: a -> Last a Source #

Monad Max

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

return :: a -> Max a Source #

Monad Min

Since: base-4.9.0.0

Instance details

Defined in Data.Semigroup

Methods

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

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

return :: a -> Min a Source #

Monad Put 
Instance details

Defined in Data.ByteString.Builder.Internal

Methods

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

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

return :: a -> Put a Source #

Monad Seq 
Instance details

Defined in Data.Sequence.Internal

Methods

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

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

return :: a -> Seq a Source #

Monad Tree 
Instance details

Defined in Data.Tree

Methods

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

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

return :: a -> Tree a Source #

Monad NonEmpty

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> NonEmpty a Source #

Monad Par1

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

(>>=) :: Par1 a -> (a -> Par1 b) -> Par1 b Source #

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

return :: a -> Par1 a Source #

Monad IO

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> IO a Source #

Monad Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> Maybe a Source #

Monad Solo

Since: base-4.15

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> Solo a Source #

Monad []

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> [a] Source #

Monad m => Monad (WrappedMonad m)

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Methods

(>>=) :: WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b Source #

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

return :: a -> WrappedMonad m a Source #

Monad (SetM s) 
Instance details

Defined in Data.Graph

Methods

(>>=) :: SetM s a -> (a -> SetM s b) -> SetM s b Source #

(>>) :: SetM s a -> SetM s b -> SetM s b Source #

return :: a -> SetM s a Source #

Monad (Proxy :: Type -> Type)

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Data.Proxy

Methods

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

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

return :: a -> Proxy a Source #

Monad (U1 :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

(>>=) :: U1 a -> (a -> U1 b) -> U1 b Source #

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

return :: a -> U1 a Source #

Monad (IParser t) 
Instance details

Defined in Data.Text.Internal.Read

Methods

(>>=) :: IParser t a -> (a -> IParser t b) -> IParser t b Source #

(>>) :: IParser t a -> IParser t b -> IParser t b Source #

return :: a -> IParser t a Source #

Monoid a => Monad ((,) a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

(>>=) :: (a, a0) -> (a0 -> (a, b)) -> (a, b) Source #

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

return :: a0 -> (a, a0) Source #

(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 Source #

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

return :: a -> WhenMissing f x a Source #

Monad f => Monad (Rec1 f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

(>>=) :: Rec1 f a -> (a -> Rec1 f b) -> Rec1 f b Source #

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

return :: a -> Rec1 f a Source #

Monad m => Monad (IdentityT m) 
Instance details

Defined in Control.Monad.Trans.Identity

Methods

(>>=) :: IdentityT m a -> (a -> IdentityT m b) -> IdentityT m b Source #

(>>) :: IdentityT m a -> IdentityT m b -> IdentityT m b Source #

return :: a -> IdentityT m a Source #

Monad m => Monad (ReaderT r m) 
Instance details

Defined in Control.Monad.Trans.Reader

Methods

(>>=) :: ReaderT r m a -> (a -> ReaderT r m b) -> ReaderT r m b Source #

(>>) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m b Source #

return :: a -> ReaderT r m a Source #

Monad m => Monad (StateT s m) 
Instance details

Defined in Control.Monad.Trans.State.Lazy

Methods

(>>=) :: StateT s m a -> (a -> StateT s m b) -> StateT s m b Source #

(>>) :: StateT s m a -> StateT s m b -> StateT s m b Source #

return :: a -> StateT s m a Source #

Monad m => Monad (Reverse m)

Derived instance.

Instance details

Defined in Data.Functor.Reverse

Methods

(>>=) :: Reverse m a -> (a -> Reverse m b) -> Reverse m b Source #

(>>) :: Reverse m a -> Reverse m b -> Reverse m b Source #

return :: a -> Reverse m a Source #

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

Since: base-4.14.0.0

Instance details

Defined in GHC.Internal.Base

Methods

(>>=) :: (a, b, a0) -> (a0 -> (a, b, b0)) -> (a, b, b0) Source #

(>>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0) Source #

return :: a0 -> (a, b, a0) Source #

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

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Product

Methods

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

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

return :: a -> Product f g a Source #

(Monad f, 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 Source #

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

return :: a -> WhenMatched f x y a Source #

(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 Source #

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

return :: a -> WhenMissing f k x a Source #

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

(>>=) :: (f :*: g) a -> (a -> (f :*: g) b) -> (f :*: g) b Source #

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

return :: a -> (f :*: g) a Source #

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

Since: base-4.14.0.0

Instance details

Defined in GHC.Internal.Base

Methods

(>>=) :: (a, b, c, a0) -> (a0 -> (a, b, c, b0)) -> (a, b, c, b0) Source #

(>>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0) Source #

return :: a0 -> (a, b, c, a0) Source #

Monad ((->) r)

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> r -> a Source #

(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 Source #

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

return :: a -> WhenMatched f k x y a Source #

Monad f => Monad (M1 i c f)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

return :: a -> M1 i c f a Source #

data Maybe a Source #

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

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

Constructors

Nothing 
Just a 

Instances

Instances details
MonadZip Maybe

Since: base-4.8.0.0

Instance details

Defined in Control.Monad.Zip

Methods

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

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

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

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 Source #

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 Source #

Read1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

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 Source #

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

Alternative Maybe

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

empty :: Maybe a Source #

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

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

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

Applicative Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

pure :: a -> Maybe a Source #

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

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

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

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

Functor Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

Monad Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

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

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

return :: a -> Maybe a Source #

MonadPlus Maybe

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

Since: base-2.1

Instance details

Defined in GHC.Internal.Base

Methods

mzero :: Maybe a Source #

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

MonadFail Maybe

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Control.Monad.Fail

Methods

fail :: String -> Maybe a Source #

MonadFix Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Control.Monad.Fix

Methods

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

Foldable Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Data.Foldable

Methods

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

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

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

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

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

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

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

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

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

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

null :: Maybe a -> Bool Source #

length :: Maybe a -> Int Source #

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

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

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

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

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

Traversable Maybe

Since: base-2.1

Instance details

Defined in GHC.Internal.Data.Traversable

Methods

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

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

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

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

Generic1 Maybe 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep1 Maybe

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

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

Methods

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

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

Eq a => EqMaybe a (Maybe a) Source # 
Instance details

Defined in Data.GI.Base.Attributes

Methods

eqMaybe :: a -> Maybe a -> Bool Source #

Each () (Maybe a) (Maybe b) a b
each :: IxTraversal () (Maybe a) (Maybe b) a b
Instance details

Defined in Optics.Each.Core

Methods

each :: IxTraversal () (Maybe a) (Maybe b) a b Source #

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.Internal.Base

Methods

mempty :: Maybe a Source #

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

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

Semigroup a => Semigroup (Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Base

Methods

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

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

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

Generic (Maybe a) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep (Maybe a)

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

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

Methods

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

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

SingKind a => SingKind (Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Associated Types

type DemoteRep (Maybe a) 
Instance details

Defined in GHC.Internal.Generics

type DemoteRep (Maybe a) = Maybe (DemoteRep a)

Methods

fromSing :: forall (a0 :: Maybe a). Sing a0 -> DemoteRep (Maybe a)

Show a => Show (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Eq a => Eq (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Maybe

Methods

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

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

Ord a => Ord (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Internal.Maybe

Methods

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

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

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

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

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

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

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

IsGValue (Maybe GParamSpec) Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGValue (Maybe Text) Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGValue (Maybe String) Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGVariant a => IsGVariant (Maybe a) Source # 
Instance details

Defined in Data.GI.Base.GVariant

At (Maybe a) 
Instance details

Defined in Optics.At.Core

Methods

at :: Index (Maybe a) -> Lens' (Maybe a) (Maybe (IxValue (Maybe a))) Source #

Ixed (Maybe a) 
Instance details

Defined in Optics.At.Core

Associated Types

type IxKind (Maybe a) 
Instance details

Defined in Optics.At.Core

Methods

ix :: Index (Maybe a) -> Optic' (IxKind (Maybe a)) NoIx (Maybe a) (IxValue (Maybe a)) Source #

AsEmpty (Maybe a) 
Instance details

Defined in Optics.Empty.Core

Methods

_Empty :: Prism' (Maybe a) () Source #

SingI ('Nothing :: Maybe a)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

sing :: Sing ('Nothing :: Maybe a)

SingI a2 => SingI ('Just a2 :: Maybe a1)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

sing :: Sing ('Just a2)

type Rep1 Maybe

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 Maybe = D1 ('MetaData "Maybe" "GHC.Internal.Maybe" "ghc-internal" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))
type DemoteRep (Maybe a) 
Instance details

Defined in GHC.Internal.Generics

type DemoteRep (Maybe a) = Maybe (DemoteRep a)
type Rep (Maybe a)

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep (Maybe a) = D1 ('MetaData "Maybe" "GHC.Internal.Maybe" "ghc-internal" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: 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.Internal.Generics

data Sing (b :: Maybe a) where
type Index (Maybe a) 
Instance details

Defined in Optics.At.Core

type Index (Maybe a) = ()
type IxKind (Maybe a) 
Instance details

Defined in Optics.At.Core

type IxValue (Maybe a) 
Instance details

Defined in Optics.At.Core

type IxValue (Maybe a) = a

(.) :: (b -> c) -> (a -> b) -> a -> c infixr 9 Source #

Right to left function composition.

(f . g) x = f (g x)
f . id = f = id . f

Examples

Expand
>>> map ((*2) . length) [[], [0, 1, 2], [0]]
[0,6,2]
>>> foldr (.) id [(+1), (*3), (^3)] 2
25
>>> let (...) = (.).(.) in ((*2)...(+)) 5 10
30

($) :: (a -> b) -> a -> b infixr 0 Source #

($) is the function application operator.

Applying ($) to a function f and an argument x gives the same result as applying f to x directly. The definition is akin to this:

($) :: (a -> b) -> a -> b
($) f x = f x

This is id specialized from a -> a to (a -> b) -> (a -> b) which by the associativity of (->) is the same as (a -> b) -> a -> b.

On the face of it, this may appear pointless! But it's actually one of the most useful and important operators in Haskell.

The order of operations is very different between ($) and normal function application. Normal function application has precedence 10 - higher than any operator - and associates to the left. So these two definitions are equivalent:

expr = min 5 1 + 5
expr = ((min 5) 1) + 5

($) has precedence 0 (the lowest) and associates to the right, so these are equivalent:

expr = min 5 $ 1 + 5
expr = (min 5) (1 + 5)

Examples

Expand

A common use cases of ($) is to avoid parentheses in complex expressions.

For example, instead of using nested parentheses in the following Haskell function:

-- | Sum numbers in a string: strSum "100  5 -7" == 98
strSum :: String -> Int
strSum s = sum (mapMaybe readMaybe (words s))

we can deploy the function application operator:

-- | Sum numbers in a string: strSum "100  5 -7" == 98
strSum :: String -> Int
strSum s = sum $ mapMaybe readMaybe $ words s

($) is also used as a section (a partially applied operator), in order to indicate that we wish to apply some yet-unspecified function to a given value. For example, to apply the argument 5 to a list of functions:

applyFive :: [Int]
applyFive = map ($ 5) [(+1), (2^)]
>>> [6, 32]

Technical Remark (Representation Polymorphism)

Expand

($) is fully representation-polymorphic. This allows it to also be used with arguments of unlifted and even unboxed kinds, such as unboxed integers:

fastMod :: Int -> Int -> Int
fastMod (I# x) (I# m) = I# $ remInt# x m

(++) :: [a] -> [a] -> [a] infixr 5 Source #

(++) appends two lists, i.e.,

[x1, ..., xm] ++ [y1, ..., yn] == [x1, ..., xm, y1, ..., yn]
[x1, ..., xm] ++ [y1, ...] == [x1, ..., xm, y1, ...]

If the first list is not finite, the result is the first list.

Performance considerations

Expand

This function takes linear time in the number of elements of the first list. Thus it is better to associate repeated applications of (++) to the right (which is the default behaviour): xs ++ (ys ++ zs) or simply xs ++ ys ++ zs, but not (xs ++ ys) ++ zs. For the same reason concat = foldr (++) [] has linear performance, while foldl (++) [] is prone to quadratic slowdown

Examples

Expand
>>> [1, 2, 3] ++ [4, 5, 6]
[1,2,3,4,5,6]
>>> [] ++ [1, 2, 3]
[1,2,3]
>>> [3, 2, 1] ++ []
[3,2,1]

(=<<) :: Monad m => (a -> m b) -> m a -> m b infixr 1 Source #

Same as >>=, but with the arguments interchanged.

as >>= f == f =<< as

(>=>) :: Monad m => (a -> m b) -> (b -> m c) -> a -> m c infixr 1 Source #

Left-to-right composition of Kleisli arrows.

'(bs >=> cs) a' can be understood as the do expression

do b <- bs a
   cs b

or in terms of (>>=) as

bs a >>= cs

data Bool Source #

Instances

Instances details
Bits Bool

Interpret Bool as 1-bit bit-field

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Bits

FiniteBits Bool

Since: base-4.7.0.0

Instance details

Defined in GHC.Internal.Bits

Bounded Bool

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Enum Bool

Since: base-2.1

Instance details

Defined in GHC.Internal.Enum

Storable Bool

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Generic Bool 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep Bool

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

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

Methods

from :: Bool -> Rep Bool x Source #

to :: Rep Bool x -> Bool Source #

SingKind Bool

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Associated Types

type DemoteRep Bool 
Instance details

Defined in GHC.Internal.Generics

type DemoteRep Bool = Bool

Methods

fromSing :: forall (a :: Bool). Sing a -> DemoteRep Bool

Show Bool

Since: base-2.1

Instance details

Defined in GHC.Internal.Show

Eq Bool 
Instance details

Defined in GHC.Classes

Methods

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

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

Ord Bool 
Instance details

Defined in GHC.Classes

IsGValue Bool Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGVariant Bool Source # 
Instance details

Defined in Data.GI.Base.GVariant

IsGVariantBasicType Bool Source # 
Instance details

Defined in Data.GI.Base.GVariant

SingI 'False

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

sing :: Sing 'False

SingI 'True

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

sing :: Sing 'True

type DemoteRep Bool 
Instance details

Defined in GHC.Internal.Generics

type DemoteRep Bool = Bool
type Rep Bool

Since: base-4.6.0.0

Instance details

Defined in GHC.Internal.Generics

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

Defined in GHC.Internal.Generics

data Sing (a :: Bool) where

data Float Source #

Single-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE single-precision type.

Instances

Instances details
PrintfArg Float

Since: base-2.1

Instance details

Defined in Text.Printf

Enum Float

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5 :: Float]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Floating Float

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

RealFloat Float

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Storable Float

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Num Float

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:

>>> (0.1 + 0.1 :: Float) + 0.5 == 0.1 + (0.1 + 0.5)
False
>>> (0.1 + 0.2 :: Float) * 0.9 == 0.1 * 0.9 + 0.2 * 0.9
False
>>> (0.1 * 0.1 :: Float) * 0.9 == 0.1 * (0.1 * 0.9)
False

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Fractional Float

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.

>>> 0 == (-0 :: Float)
True
>>> recip 0 == recip (-0 :: Float)
False
>>> map (/ 0) [-1, 0, 1 :: Float]
[-Infinity,NaN,Infinity]
>>> map (* 0) $ map (/ 0) [-1, 0, 1 :: Float]
[NaN,NaN,NaN]

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Real Float

Beware that toRational generates garbage for non-finite arguments:

>>> toRational (1/0 :: Float)
340282366920938463463374607431768211456 % 1
>>> toRational (0/0 :: Float)
510423550381407695195061911147652317184 % 1

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

RealFrac Float

Beware that results for non-finite arguments are garbage:

>>> [ f x | f <- [round, floor, ceiling], x <- [-1/0, 0/0, 1/0 :: Float] ] :: [Int]
[0,0,0,0,0,0,0,0,0]
>>> map properFraction [-1/0, 0/0, 1/0] :: [(Int, Float)]
[(0,0.0),(0,0.0),(0,0.0)]

and get even more non-sensical if you ask for Integer instead of Int.

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Methods

properFraction :: Integral b => Float -> (b, Float) Source #

truncate :: Integral b => Float -> b Source #

round :: Integral b => Float -> b Source #

ceiling :: Integral b => Float -> b Source #

floor :: Integral b => Float -> b Source #

Show Float

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Eq Float

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

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

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

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

Defined in GHC.Classes

Methods

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

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

Ord Float

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

Instance details

Defined in GHC.Classes

IsGValue Float Source # 
Instance details

Defined in Data.GI.Base.GValue

Generic1 (URec Float :: k -> Type) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 (URec Float :: k -> Type) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: k -> Type)))

Methods

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

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

Foldable (UFloat :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Foldable

Methods

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

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

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

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

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

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

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

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

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

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

null :: UFloat a -> Bool Source #

length :: UFloat a -> Int Source #

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

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

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

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

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

Traversable (UFloat :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Traversable

Methods

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

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

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

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

Functor (URec Float :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Generic (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

type Rep (URec Float p) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: Type -> Type)))

Methods

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

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

Show (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

Eq (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Ord (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

data URec Float (p :: k)

Used for marking occurrences of Float#

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

data URec Float (p :: k) = UFloat {}
type Rep1 (URec Float :: k -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 (URec Float :: k -> Type) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: k -> Type)))
type Rep (URec Float p) 
Instance details

Defined in GHC.Internal.Generics

type Rep (URec Float p) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UFloat" 'PrefixI 'True) (S1 ('MetaSel ('Just "uFloat#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UFloat :: Type -> Type)))

data Double Source #

Double-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE double-precision type.

Instances

Instances details
PrintfArg Double

Since: base-2.1

Instance details

Defined in Text.Printf

Enum Double

fromEnum just truncates its argument, beware of all sorts of overflows.

List generators have extremely peculiar behavior, mandated by Haskell Report 2010:

>>> [0..1.5]
[0.0,1.0,2.0]

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Floating Double

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

RealFloat Double

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Storable Double

Since: base-2.1

Instance details

Defined in GHC.Internal.Foreign.Storable

Num Double

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero. Neither addition nor multiplication are associative or distributive:

>>> (0.1 + 0.1) + 0.4 == 0.1 + (0.1 + 0.4)
False
>>> (0.1 + 0.2) * 0.3 == 0.1 * 0.3 + 0.2 * 0.3
False
>>> (0.1 * 0.1) * 0.3 == 0.1 * (0.1 * 0.3)
False

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Fractional Double

This instance implements IEEE 754 standard with all its usual pitfalls about NaN, infinities and negative zero.

>>> 0 == (-0 :: Double)
True
>>> recip 0 == recip (-0 :: Double)
False
>>> map (/ 0) [-1, 0, 1]
[-Infinity,NaN,Infinity]
>>> map (* 0) $ map (/ 0) [-1, 0, 1]
[NaN,NaN,NaN]

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Real Double

Beware that toRational generates garbage for non-finite arguments:

>>> toRational (1/0)
179769313 (and 300 more digits...) % 1
>>> toRational (0/0)
269653970 (and 300 more digits...) % 1

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

RealFrac Double

Beware that results for non-finite arguments are garbage:

>>> [ f x | f <- [round, floor, ceiling], x <- [-1/0, 0/0, 1/0] ] :: [Int]
[0,0,0,0,0,0,0,0,0]
>>> map properFraction [-1/0, 0/0, 1/0] :: [(Int, Double)]
[(0,0.0),(0,0.0),(0,0.0)]

and get even more non-sensical if you ask for Integer instead of Int.

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Show Double

Since: base-2.1

Instance details

Defined in GHC.Internal.Float

Eq Double

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

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

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

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

Defined in GHC.Classes

Ord Double

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

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

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

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

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

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

Instance details

Defined in GHC.Classes

IsGValue Double Source # 
Instance details

Defined in Data.GI.Base.GValue

IsGVariant Double Source # 
Instance details

Defined in Data.GI.Base.GVariant

IsGVariantBasicType Double Source # 
Instance details

Defined in Data.GI.Base.GVariant

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

Defined in GHC.Internal.Generics

Associated Types

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 (URec Double :: k -> Type) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UDouble" 'PrefixI 'True) (S1 ('MetaSel ('Just "uDouble#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UDouble :: k -> Type)))

Methods

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

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

Foldable (UDouble :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Foldable

Methods

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

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

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

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

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

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

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

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

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

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

null :: UDouble a -> Bool Source #

length :: UDouble a -> Int Source #

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

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

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

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

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

Traversable (UDouble :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Traversable

Methods

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

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

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

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

Functor (URec Double :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Generic (URec Double p) 
Instance details

Defined in GHC.Internal.Generics

Associated Types

type Rep (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

Methods

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

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

Show (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Eq (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

Methods

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

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

Ord (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

data URec Double (p :: k)

Used for marking occurrences of Double#

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

type Rep1 (URec Double :: k -> Type) = D1 ('MetaData "URec" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "UDouble" 'PrefixI 'True) (S1 ('MetaSel ('Just "uDouble#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UDouble :: k -> Type)))
type Rep (URec Double p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Internal.Generics

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

undefined :: HasCallStack => a Source #

A special case of error. It is expected that compilers will recognize this and insert error messages which are more appropriate to the context in which undefined appears.

error :: HasCallStack => [Char] -> a Source #

error stops execution and displays an error message.

map :: (a -> b) -> [a] -> [b] Source #

\(\mathcal{O}(n)\). map f xs is the list obtained by applying f to each element of xs, i.e.,

map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
map f [x1, x2, ...] == [f x1, f x2, ...]

this means that map id == id

Examples

Expand
>>> map (+1) [1, 2, 3]
[2,3,4]
>>> map id [1, 2, 3]
[1,2,3]
>>> map (\n -> 3 * n + 1) [1, 2, 3]
[4,7,10]

length :: Foldable t => t a -> Int Source #

Returns the size/length of a finite structure as an Int. The default implementation just counts elements starting with the leftmost. Instances for structures that can compute the element count faster than via element-by-element counting, should provide a specialised implementation.

Examples

Expand

Basic usage:

>>> length []
0
>>> length ['a', 'b', 'c']
3
>>> length [1..]
* Hangs forever *

Since: base-4.8.0.0

mapM :: (Traversable t, Monad m) => (a -> m b) -> t a -> m (t b) Source #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see mapM_.

Examples

Expand

mapM is literally a traverse with a type signature restricted to Monad. Its implementation may be more efficient due to additional power of Monad.

mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m () Source #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM.

mapM_ is just like traverse_, but specialised to monadic actions.

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

Conditional execution of Applicative expressions. For example,

Examples

Expand
when debug (putStrLn "Debugging")

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

>>> putStr "pi:" >> when False (print 3.14159)
pi:

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

General coercion from Integral types.

WARNING: This function performs silent truncation if the result type is not at least as big as the argument's type.

realToFrac :: (Real a, Fractional b) => a -> b Source #

General coercion to Fractional types.

WARNING: This function goes through the Rational type, which does not have values for NaN for example. This means it does not round-trip.

For Double it also behaves differently with or without -O0:

Prelude> realToFrac nan -- With -O0
-Infinity
Prelude> realToFrac nan
NaN

class a ~# b => (a :: k) ~ (b :: k) infix 4 Source #

Lifted, homogeneous equality. By lifted, we mean that it can be bogus (deferred type error). By homogeneous, the two types a and b must have the same kinds.