module Char(
isAscii, isLatin1, isControl, isPrint, isSpace, isUpper, isLower,
isAlpha, isDigit, isOctDigit, isHexDigit, isAlphaNum,
digitToInt, intToDigit,
toUpper, toLower,
ord, chr,
readLitChar, showLitChar, lexLitChar,
Char,String
)
where
import Prelude
import PreludeBuiltin
import Numeric(readDec, readOct, lexDigits, readHex)
import Array
-- * Character classification
isAscii, isControl, isPrint, isSpace :: Char -> Bool
isUpper, isLower, isAlpha, isDigit, isAlphanum :: Char -> Bool
isAscii c = c < '\x80'
isLatin1 c = c <= '\xff'
isControl c = c < ' ' || c >= '\DEL' && c <= '\x9f'
isPrint c = c >= ' ' && c <= '~' || c >= '\xa0' -- hmm
isSpace c = c == ' ' || c == '\t' || c == '\n' || c == '\r' ||
c == '\f' || c == '\v' || c=='\xa0'
isUpper c =
c >= 'A' && c <= 'Z' ||
c >= 'À' && c <= 'Ö' ||
c >= 'Ø' && c <= 'Þ'
isLower c =
c >= 'a' && c <= 'z' || c=='µ' ||
c >= 'ß' && c <= 'ö' ||
c >= 'ø' && c <= 'ÿ'
isAlpha c = isUpper c || isLower c
isDigit c = c >= '0' && c <= '9'
isAlphanum c = isAlpha c || isDigit c
isAlphaNum = isAlphanum
isOctDigit c = c >= '0' && c <= '7'
isHexDigit c = isDigit c || c >= 'A' && c <= 'F' ||
c >= 'a' && c <= 'f'
-- * Case conversion
toUpper, toLower :: Char -> Char
toUpper c | isLower c = chr (ord c - ord 'a' + ord 'A')
| otherwise = c
toLower c | isUpper c = chr (ord c - ord 'A' + ord 'a')
| otherwise = c
{-
minChar, maxChar :: Char
minChar = chr 0
maxChar = chr 255
-}
-- * Digit conversion operations
digitToInt :: Char -> Int
digitToInt c
| isDigit c = fromEnum c - fromEnum '0'
| c >= 'a' && c <= 'f' = fromEnum c - fromEnum 'a' + 10
| c >= 'A' && c <= 'F' = fromEnum c - fromEnum 'A' + 10
| otherwise = error "Char.digitToInt: not a digit"
intToDigit :: Int -> Char
intToDigit i
| i >= 0 && i <= 9 = toDigit i
| i >= 10 && i <= 15 = chr (ord 'a' + i - 10)
| otherwise = error "Char.intToDigit: not a digit"
toDigit i = chr (ord '0' + i)
-- * Numeric representations
ord c = primCharToInt c
chr n = primIntToChar n
-- * Text functions
readLitChar :: ReadS Char
readLitChar ('\\':s) = readEsc s
where
readEsc ('a':s) = [('\a',s)]
readEsc ('b':s) = [('\b',s)]
readEsc ('f':s) = [('\f',s)]
readEsc ('n':s) = [('\n',s)]
readEsc ('r':s) = [('\r',s)]
readEsc ('t':s) = [('\t',s)]
readEsc ('v':s) = [('\v',s)]
readEsc ('\\':s) = [('\\',s)]
readEsc ('"':s) = [('"',s)]
readEsc ('\'':s) = [('\'',s)]
readEsc ('^':c:s) | c >= '@' && c <= '_'
= [(chr (ord c - ord '@'), s)]
readEsc s@(d:_) | isDigit d
= [(chr n, t) | (n,t) <- readDec s]
readEsc ('o':s) = [(chr n, t) | (n,t) <- readOct s]
readEsc ('x':s) = [(chr n, t) | (n,t) <- readHex s]
readEsc s@(c:_) | isUpper c
= let table = ('\DEL', "DEL") : assocs asciiTab
in case [(c,s') | (c, mne) <- table,
([],s') <- [match mne s]]
of (pr:_) -> [pr]
[] -> []
readEsc _ = []
match :: (Eq a) => [a] -> [a] -> ([a],[a])
match (x:xs) (y:ys) | x == y = match xs ys
match xs ys = (xs,ys)
readLitChar (c:s) = [(c,s)]
--}
showLitChar :: Char -> ShowS
showLitChar c | c > '\DEL' = showChar '\\' .
protectEsc isDigit (shows (ord c))
showLitChar '\DEL' = showString "\\DEL"
showLitChar '\\' = showString "\\\\"
showLitChar c | c >= ' ' = showChar c
showLitChar '\a' = showString "\\a"
showLitChar '\b' = showString "\\b"
showLitChar '\f' = showString "\\f"
showLitChar '\n' = showString "\\n"
showLitChar '\r' = showString "\\r"
showLitChar '\t' = showString "\\t"
showLitChar '\v' = showString "\\v"
showLitChar '\SO' = protectEsc (== 'H') (showString "\\SO")
showLitChar c = showString ('\\' : asciiTab!c)
protectEsc p f = f . cont
where cont s@(c:_) | p c = "\\&" ++ s
cont s = s
asciiTab = listArray ('\NUL', ' ')
["NUL", "SOH", "STX", "ETX", "EOT", "ENQ", "ACK", "BEL",
"BS", "HT", "LF", "VT", "FF", "CR", "SO", "SI",
"DLE", "DC1", "DC2", "DC3", "DC4", "NAK", "SYN", "ETB",
"CAN", "EM", "SUB", "ESC", "FS", "GS", "RS", "US",
"SP"]
--lexLitChar :: ReadS String
lexLitChar ('\\':s) = [('\\':esc, t) | (esc,t) <- lexEsc s]
where
lexEsc (c:s) | c `elem` "abfnrtv\\\"'" = [([c],s)]
lexEsc s@(d:_) | isDigit d = lexDigits s
lexEsc ('x':c:s) | isHexDigit c = [('x':c:ds,r)]
where (ds,r) = span isHexDigit s
lexEsc ('^':c:s) | c >= '@' && c <= '_' = [(['^',c],s)]
-- Very crude approximation to \XYZ. Let readers work this out.
lexEsc s@(c:_) | isUpper c = [span isCharName s]
lexEsc _ = []
isCharName c = isUpper c || isDigit c
lexLitChar (c:s) = [([c],s)]
lexLitChar "" = []