Safe Haskell	None
Language	Haskell2010

Char

Contents

Characters
ASCII Letters
Digits
Conversion
Unicode Code Points

Description

Functions for working with characters. Character literals are enclosed in 'a' pair of single quotes.

Since we don't have a browser and we don't have a default locale, functions like toLocaleUpper and toLocaleUpper are not supported. If you need something like that you can check out the 'text-icu' package which provides functions like toUpper :: LocaleName -> Text -> Text.

Synopsis

Characters

data Char #

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

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

Instances

Bounded Char	Since: base-2.1
Instance details Defined in GHC.Enum Methods minBound :: Char # maxBound :: Char #
Enum Char	Since: base-2.1
Instance details Defined in GHC.Enum Methods succ :: Char -> Char # pred :: Char -> Char # toEnum :: Int -> Char # fromEnum :: Char -> Int # enumFrom :: Char -> [Char] # enumFromThen :: Char -> Char -> [Char] # enumFromTo :: Char -> Char -> [Char] # enumFromThenTo :: Char -> Char -> Char -> [Char] #
Eq Char
Instance details Defined in GHC.Classes Methods (==) :: Char -> Char -> Bool # (/=) :: Char -> Char -> Bool #
Ord Char
Instance details Defined in GHC.Classes Methods compare :: Char -> Char -> Ordering # (<) :: Char -> Char -> Bool # (<=) :: Char -> Char -> Bool # (>) :: Char -> Char -> Bool # (>=) :: Char -> Char -> Bool # max :: Char -> Char -> Char # min :: Char -> Char -> Char #
Read Char	Since: base-2.1
Instance details Defined in GHC.Read Methods readsPrec :: Int -> ReadS Char # readList :: ReadS [Char] # readPrec :: ReadPrec Char # readListPrec :: ReadPrec [Char] #
Show Char	Since: base-2.1
Instance details Defined in GHC.Show Methods showsPrec :: Int -> Char -> ShowS # show :: Char -> String # showList :: [Char] -> ShowS #
Ix Char	Since: base-2.1
Instance details Defined in GHC.Arr Methods range :: (Char, Char) -> [Char] # index :: (Char, Char) -> Char -> Int # unsafeIndex :: (Char, Char) -> Char -> Int inRange :: (Char, Char) -> Char -> Bool # rangeSize :: (Char, Char) -> Int # unsafeRangeSize :: (Char, Char) -> Int
Lift Char
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Char -> Q Exp #
Hashable Char
Instance details Defined in Data.Hashable.Class Methods hashWithSalt :: Int -> Char -> Int # hash :: Char -> Int #
ToJSON Char
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Char -> Value # toEncoding :: Char -> Encoding # toJSONList :: [Char] -> Value # toEncodingList :: [Char] -> Encoding #
ToJSONKey Char
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSONKey :: ToJSONKeyFunction Char # toJSONKeyList :: ToJSONKeyFunction [Char] #
Storable Char	Since: base-2.1
Instance details Defined in Foreign.Storable Methods sizeOf :: Char -> Int # alignment :: Char -> Int # peekElemOff :: Ptr Char -> Int -> IO Char # pokeElemOff :: Ptr Char -> Int -> Char -> IO () # peekByteOff :: Ptr b -> Int -> IO Char # pokeByteOff :: Ptr b -> Int -> Char -> IO () # peek :: Ptr Char -> IO Char # poke :: Ptr Char -> Char -> IO () #
Prim Char
Instance details Defined in Data.Primitive.Types Methods sizeOf# :: Char -> Int# # alignment# :: Char -> Int# # indexByteArray# :: ByteArray# -> Int# -> Char # readByteArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Char#) # writeByteArray# :: MutableByteArray# s -> Int# -> Char -> State# s -> State# s # setByteArray# :: MutableByteArray# s -> Int# -> Int# -> Char -> State# s -> State# s # indexOffAddr# :: Addr# -> Int# -> Char # readOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Char#) # writeOffAddr# :: Addr# -> Int# -> Char -> State# s -> State# s # setOffAddr# :: Addr# -> Int# -> Int# -> Char -> State# s -> State# s #
ErrorList Char
Instance details Defined in Control.Monad.Trans.Error Methods listMsg :: String -> [Char] #
Unbox Char
Instance details Defined in Data.Vector.Unboxed.Base
Pretty Char
Instance details Defined in Text.PrettyPrint.Annotated.WL Methods pretty :: Char -> Doc b # prettyList :: [Char] -> Doc b #
Vector Vector Char
Instance details Defined in Data.Vector.Unboxed.Base Methods basicUnsafeFreeze :: PrimMonad m => Mutable Vector (PrimState m) Char -> m (Vector Char) # basicUnsafeThaw :: PrimMonad m => Vector Char -> m (Mutable Vector (PrimState m) Char) # basicLength :: Vector Char -> Int # basicUnsafeSlice :: Int -> Int -> Vector Char -> Vector Char # basicUnsafeIndexM :: Monad m => Vector Char -> Int -> m Char # basicUnsafeCopy :: PrimMonad m => Mutable Vector (PrimState m) Char -> Vector Char -> m () # elemseq :: Vector Char -> Char -> b -> b #
MVector MVector Char
Instance details Defined in Data.Vector.Unboxed.Base Methods basicLength :: MVector s Char -> Int # basicUnsafeSlice :: Int -> Int -> MVector s Char -> MVector s Char # basicOverlaps :: MVector s Char -> MVector s Char -> Bool # basicUnsafeNew :: PrimMonad m => Int -> m (MVector (PrimState m) Char) # basicInitialize :: PrimMonad m => MVector (PrimState m) Char -> m () # basicUnsafeReplicate :: PrimMonad m => Int -> Char -> m (MVector (PrimState m) Char) # basicUnsafeRead :: PrimMonad m => MVector (PrimState m) Char -> Int -> m Char # basicUnsafeWrite :: PrimMonad m => MVector (PrimState m) Char -> Int -> Char -> m () # basicClear :: PrimMonad m => MVector (PrimState m) Char -> m () # basicSet :: PrimMonad m => MVector (PrimState m) Char -> Char -> m () # basicUnsafeCopy :: PrimMonad m => MVector (PrimState m) Char -> MVector (PrimState m) Char -> m () # basicUnsafeMove :: PrimMonad m => MVector (PrimState m) Char -> MVector (PrimState m) Char -> m () # basicUnsafeGrow :: PrimMonad m => MVector (PrimState m) Char -> Int -> m (MVector (PrimState m) Char) #
Generic1 (URec Char :: k -> Type)
Instance details Defined in GHC.Generics Associated Types type Rep1 (URec Char) :: k -> Type # Methods from1 :: URec Char a -> Rep1 (URec Char) a # to1 :: Rep1 (URec Char) a -> URec Char a #
Functor (URec Char :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods fmap :: (a -> b) -> URec Char a -> URec Char b # (<$) :: a -> URec Char b -> URec Char a #
Foldable (URec Char :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in Data.Foldable Methods fold :: Monoid m => URec Char m -> m # foldMap :: Monoid m => (a -> m) -> URec Char a -> m # foldr :: (a -> b -> b) -> b -> URec Char a -> b # foldr' :: (a -> b -> b) -> b -> URec Char a -> b # foldl :: (b -> a -> b) -> b -> URec Char a -> b # foldl' :: (b -> a -> b) -> b -> URec Char a -> b # foldr1 :: (a -> a -> a) -> URec Char a -> a # foldl1 :: (a -> a -> a) -> URec Char a -> a # toList :: URec Char a -> [a] # null :: URec Char a -> Bool # length :: URec Char a -> Int # elem :: Eq a => a -> URec Char a -> Bool # maximum :: Ord a => URec Char a -> a # minimum :: Ord a => URec Char a -> a # sum :: Num a => URec Char a -> a # product :: Num a => URec Char a -> a #
Traversable (URec Char :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in Data.Traversable Methods traverse :: Applicative f => (a -> f b) -> URec Char a -> f (URec Char b) # sequenceA :: Applicative f => URec Char (f a) -> f (URec Char a) # mapM :: Monad m => (a -> m b) -> URec Char a -> m (URec Char b) # sequence :: Monad m => URec Char (m a) -> m (URec Char a) #
Eq (URec Char p)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods (==) :: URec Char p -> URec Char p -> Bool # (/=) :: URec Char p -> URec Char p -> Bool #
Ord (URec Char p)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods compare :: URec Char p -> URec Char p -> Ordering # (<) :: URec Char p -> URec Char p -> Bool # (<=) :: URec Char p -> URec Char p -> Bool # (>) :: URec Char p -> URec Char p -> Bool # (>=) :: URec Char p -> URec Char p -> Bool # max :: URec Char p -> URec Char p -> URec Char p # min :: URec Char p -> URec Char p -> URec Char p #
Show (URec Char p)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods showsPrec :: Int -> URec Char p -> ShowS # show :: URec Char p -> String # showList :: [URec Char p] -> ShowS #
Generic (URec Char p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec Char p) :: Type -> Type # Methods from :: URec Char p -> Rep (URec Char p) x # to :: Rep (URec Char p) x -> URec Char p #
newtype Vector Char
Instance details Defined in Data.Vector.Unboxed.Base newtype Vector Char = V_Char (Vector Char)
data URec Char (p :: k)	Used for marking occurrences of `Char#` Since: base-4.9.0.0
Instance details Defined in GHC.Generics data URec Char (p :: k) = UChar { uChar# :: Char# }
newtype MVector s Char
Instance details Defined in Data.Vector.Unboxed.Base newtype MVector s Char = MV_Char (MVector s Char)
type Rep1 (URec Char :: k -> Type)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics type Rep1 (URec Char :: k -> Type) = D1 (MetaData "URec" "GHC.Generics" "base" 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.Generics type Rep (URec Char p) = D1 (MetaData "URec" "GHC.Generics" "base" False) (C1 (MetaCons "UChar" PrefixI True) (S1 (MetaSel (Just "uChar#") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (UChar :: Type -> Type)))

ASCII Letters

isUpper :: Char -> Bool Source #

Detect upper case ASCII characters.

isUpper 'A' == True
isUpper 'B' == True
...
isUpper 'Z' == True

isUpper '0' == False
isUpper 'a' == False
isUpper '-' == False
isUpper 'Σ' == False

isLower :: Char -> Bool Source #

Detect lower case ASCII characters.

isLower 'a' == True
isLower 'b' == True
...
isLower 'z' == True

isLower '0' == False
isLower 'A' == False
isLower '-' == False
isLower 'π' == False

isAlpha :: Char -> Bool Source #

Detect upper case and lower case ASCII characters.

isAlpha 'a' == True
isAlpha 'b' == True
isAlpha 'E' == True
isAlpha 'Y' == True

isAlpha '0' == False
isAlpha '-' == False
isAlpha 'π' == False

isAlphaNum :: Char -> Bool Source #

Detect upper case and lower case ASCII characters.

isAlphaNum 'a' == True
isAlphaNum 'b' == True
isAlphaNum 'E' == True
isAlphaNum 'Y' == True
isAlphaNum '0' == True
isAlphaNum '7' == True

isAlphaNum '-' == False
isAlphaNum 'π' == False

Digits

isDigit :: Char -> Bool Source #

Detect digits 0123456789

isDigit '0' == True
isDigit '1' == True
...
isDigit '9' == True

isDigit 'a' == False
isDigit 'b' == False
isDigit 'A' == False

isOctDigit :: Char -> Bool Source #

Detect octal digits 01234567

isOctDigit '0' == True
isOctDigit '1' == True
...
isOctDigit '7' == True

isOctDigit '8' == False
isOctDigit 'a' == False
isOctDigit 'A' == False

isHexDigit :: Char -> Bool Source #

Detect hexadecimal digits 0123456789abcdefABCDEF

Conversion

toUpper :: Char -> Char Source #

Convert to upper case.

toLower :: Char -> Char Source #

Convert to lower case.

Unicode Code Points

toCode :: Char -> Int Source #

Convert to the corresponding Unicode code point.

toCode 'A' == 65
toCode 'B' == 66
toCode '木' == 26408
toCode '𝌆' == 0x1D306
toCode '😃' == 0x1F603

fromCode :: Int -> Char Source #

Convert a Unicode code point to a character.

fromCode 65      == 'A'
fromCode 66      == 'B'
fromCode 0x6728  == '\26408'  -- '木'
fromCode 0x1D306 == '\119558' -- '𝌆'
fromCode 0x1F603 == '\128515' -- '😃'
fromCode (-1)    == '\65533'  -- '�'

The full range of unicode is from 0 to 0x10FFFF. With numbers outside that range, you get the replacement character#Replacement_character).