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Character classification
\begin{code}
module Ctype
( is_ident -- Char# -> Bool
, is_symbol -- Char# -> Bool
, is_any -- Char# -> Bool
, is_space -- Char# -> Bool
, is_lower -- Char# -> Bool
, is_upper -- Char# -> Bool
, is_digit -- Char# -> Bool
, is_alphanum -- Char# -> Bool
, is_decdigit, is_hexdigit, is_octdigit
, hexDigit, octDecDigit
) where
#include "HsVersions.h"
import Data.Int ( Int32 )
import Data.Bits ( Bits((.&.)) )
import Data.Char ( ord, chr )
import Panic
\end{code}
Bit masks
\begin{code}
cIdent, cSymbol, cAny, cSpace, cLower, cUpper, cDigit :: Int
cIdent = 1
cSymbol = 2
cAny = 4
cSpace = 8
cLower = 16
cUpper = 32
cDigit = 64
\end{code}
The predicates below look costly, but aren't, GHC+GCC do a great job
at the big case below.
\begin{code}
{-# INLINE is_ctype #-}
is_ctype :: Int -> Char -> Bool
is_ctype mask c = (fromIntegral (charType c) .&. fromIntegral mask) /= (0::Int32)
is_ident, is_symbol, is_any, is_space, is_lower, is_upper, is_digit,
is_alphanum :: Char -> Bool
is_ident = is_ctype cIdent
is_symbol = is_ctype cSymbol
is_any = is_ctype cAny
is_space = is_ctype cSpace
is_lower = is_ctype cLower
is_upper = is_ctype cUpper
is_digit = is_ctype cDigit
is_alphanum = is_ctype (cLower+cUpper+cDigit)
\end{code}
Utils
\begin{code}
hexDigit :: Char -> Int
hexDigit c | is_decdigit c = ord c - ord '0'
| otherwise = ord (to_lower c) - ord 'a' + 10
octDecDigit :: Char -> Int
octDecDigit c = ord c - ord '0'
is_decdigit :: Char -> Bool
is_decdigit c
= c >= '0' && c <= '9'
is_hexdigit :: Char -> Bool
is_hexdigit c
= is_decdigit c
|| (c >= 'a' && c <= 'f')
|| (c >= 'A' && c <= 'F')
is_octdigit :: Char -> Bool
is_octdigit c = c >= '0' && c <= '7'
to_lower :: Char -> Char
to_lower c
| c >= 'A' && c <= 'Z' = chr (ord c - (ord 'A' - ord 'a'))
| otherwise = c
\end{code}
We really mean .|. instead of + below, but GHC currently doesn't do
any constant folding with bitops. *sigh*
\begin{code}
charType :: Char -> Int
charType c = case c of
'\0' -> 0 -- \000
'\1' -> 0 -- \001
'\2' -> 0 -- \002
'\3' -> 0 -- \003
'\4' -> 0 -- \004
'\5' -> 0 -- \005
'\6' -> 0 -- \006
'\7' -> 0 -- \007
'\8' -> 0 -- \010
'\9' -> cSpace -- \t (not allowed in strings, so !cAny)
'\10' -> cSpace -- \n (ditto)
'\11' -> cSpace -- \v (ditto)
'\12' -> cSpace -- \f (ditto)
'\13' -> cSpace -- ^M (ditto)
'\14' -> 0 -- \016
'\15' -> 0 -- \017
'\16' -> 0 -- \020
'\17' -> 0 -- \021
'\18' -> 0 -- \022
'\19' -> 0 -- \023
'\20' -> 0 -- \024
'\21' -> 0 -- \025
'\22' -> 0 -- \026
'\23' -> 0 -- \027
'\24' -> 0 -- \030
'\25' -> 0 -- \031
'\26' -> 0 -- \032
'\27' -> 0 -- \033
'\28' -> 0 -- \034
'\29' -> 0 -- \035
'\30' -> 0 -- \036
'\31' -> 0 -- \037
'\32' -> cAny + cSpace --
'\33' -> cAny + cSymbol -- !
'\34' -> cAny -- "
'\35' -> cAny + cSymbol -- #
'\36' -> cAny + cSymbol -- $
'\37' -> cAny + cSymbol -- %
'\38' -> cAny + cSymbol -- &
'\39' -> cAny + cIdent -- '
'\40' -> cAny -- (
'\41' -> cAny -- )
'\42' -> cAny + cSymbol -- *
'\43' -> cAny + cSymbol -- +
'\44' -> cAny -- ,
'\45' -> cAny + cSymbol -- -
'\46' -> cAny + cSymbol -- .
'\47' -> cAny + cSymbol -- /
'\48' -> cAny + cIdent + cDigit -- 0
'\49' -> cAny + cIdent + cDigit -- 1
'\50' -> cAny + cIdent + cDigit -- 2
'\51' -> cAny + cIdent + cDigit -- 3
'\52' -> cAny + cIdent + cDigit -- 4
'\53' -> cAny + cIdent + cDigit -- 5
'\54' -> cAny + cIdent + cDigit -- 6
'\55' -> cAny + cIdent + cDigit -- 7
'\56' -> cAny + cIdent + cDigit -- 8
'\57' -> cAny + cIdent + cDigit -- 9
'\58' -> cAny + cSymbol -- :
'\59' -> cAny -- ;
'\60' -> cAny + cSymbol -- <
'\61' -> cAny + cSymbol -- =
'\62' -> cAny + cSymbol -- >
'\63' -> cAny + cSymbol -- ?
'\64' -> cAny + cSymbol -- @
'\65' -> cAny + cIdent + cUpper -- A
'\66' -> cAny + cIdent + cUpper -- B
'\67' -> cAny + cIdent + cUpper -- C
'\68' -> cAny + cIdent + cUpper -- D
'\69' -> cAny + cIdent + cUpper -- E
'\70' -> cAny + cIdent + cUpper -- F
'\71' -> cAny + cIdent + cUpper -- G
'\72' -> cAny + cIdent + cUpper -- H
'\73' -> cAny + cIdent + cUpper -- I
'\74' -> cAny + cIdent + cUpper -- J
'\75' -> cAny + cIdent + cUpper -- K
'\76' -> cAny + cIdent + cUpper -- L
'\77' -> cAny + cIdent + cUpper -- M
'\78' -> cAny + cIdent + cUpper -- N
'\79' -> cAny + cIdent + cUpper -- O
'\80' -> cAny + cIdent + cUpper -- P
'\81' -> cAny + cIdent + cUpper -- Q
'\82' -> cAny + cIdent + cUpper -- R
'\83' -> cAny + cIdent + cUpper -- S
'\84' -> cAny + cIdent + cUpper -- T
'\85' -> cAny + cIdent + cUpper -- U
'\86' -> cAny + cIdent + cUpper -- V
'\87' -> cAny + cIdent + cUpper -- W
'\88' -> cAny + cIdent + cUpper -- X
'\89' -> cAny + cIdent + cUpper -- Y
'\90' -> cAny + cIdent + cUpper -- Z
'\91' -> cAny -- [
'\92' -> cAny + cSymbol -- backslash
'\93' -> cAny -- ]
'\94' -> cAny + cSymbol -- ^
'\95' -> cAny + cIdent + cLower -- _
'\96' -> cAny -- `
'\97' -> cAny + cIdent + cLower -- a
'\98' -> cAny + cIdent + cLower -- b
'\99' -> cAny + cIdent + cLower -- c
'\100' -> cAny + cIdent + cLower -- d
'\101' -> cAny + cIdent + cLower -- e
'\102' -> cAny + cIdent + cLower -- f
'\103' -> cAny + cIdent + cLower -- g
'\104' -> cAny + cIdent + cLower -- h
'\105' -> cAny + cIdent + cLower -- i
'\106' -> cAny + cIdent + cLower -- j
'\107' -> cAny + cIdent + cLower -- k
'\108' -> cAny + cIdent + cLower -- l
'\109' -> cAny + cIdent + cLower -- m
'\110' -> cAny + cIdent + cLower -- n
'\111' -> cAny + cIdent + cLower -- o
'\112' -> cAny + cIdent + cLower -- p
'\113' -> cAny + cIdent + cLower -- q
'\114' -> cAny + cIdent + cLower -- r
'\115' -> cAny + cIdent + cLower -- s
'\116' -> cAny + cIdent + cLower -- t
'\117' -> cAny + cIdent + cLower -- u
'\118' -> cAny + cIdent + cLower -- v
'\119' -> cAny + cIdent + cLower -- w
'\120' -> cAny + cIdent + cLower -- x
'\121' -> cAny + cIdent + cLower -- y
'\122' -> cAny + cIdent + cLower -- z
'\123' -> cAny -- {
'\124' -> cAny + cSymbol -- |
'\125' -> cAny -- }
'\126' -> cAny + cSymbol -- ~
'\127' -> 0 -- \177
_ -> panic ("charType: " ++ show c)
\end{code}
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