ASCII.TemplateHaskell

Characters

charExp :: Char -> Q Exp

>>> $(toCharOrFail 'F' >>= charExp)
CapitalLetterF

>>> $(toCharOrFail '\DEL' >>= charExp)
Delete

charPat :: Char -> Q Pat

>>> :{
>>> case SmallLetterS of
>>> $(toCharOrFail 'r' >>= charPat) -> 1
>>> $(toCharOrFail 's' >>= charPat) -> 2
>>> _                               -> 3
>>> :}
2

This is the same as:

>>> :{
>>> case SmallLetterS of
>>> SmallLetterR -> 1
>>> SmallLetterS -> 2
>>> _            -> 3
>>> :}
2

Character lists

charListExp :: [Char] -> Q Exp

>>> $(charListExp [CapitalLetterH, SmallLetterI])
[CapitalLetterH,SmallLetterI]

charListPat :: [Char] -> Q Pat

>>> :{
>>> case [CapitalLetterH, SmallLetterI] of
>>> $(charListPat [CapitalLetterH, SmallLetterA]) -> 1
>>> $(charListPat [CapitalLetterH, SmallLetterI]) -> 2
>>> _                                             -> 3
>>> :}
2

Character supersets

isCharExp :: Char -> Q Exp

>>> $(isCharExp CapitalLetterA) :: ASCII.Char
CapitalLetterA

>>> $(isCharExp CapitalLetterA) :: Word8
65

>>> $(isCharExp CapitalLetterA) :: ASCII Word8
asciiUnsafe 65

isCharPat :: Char -> Q Pat

>>> :set -XViewPatterns

>>> :{
>>> case (66 :: Word8) of
>>> $(isCharPat CapitalLetterA) -> 1
>>> $(isCharPat CapitalLetterB) -> 2
>>> _                           -> 3
>>> :}
2

String supersets

isStringExp :: [Char] -> Q Exp

isStringPat :: [Char] -> Q Pat