-----------------------------------------------------------------------------
-- |
-- Module      :  ParsecChar
-- Copyright   :  (c) Daan Leijen 1999-2001
-- License     :  BSD-style (see the file LICENSE)
--
-- Maintainer  :  daan@cs.uu.nl
-- Stability   :  provisional
-- Portability :  portable
--
-- Commonly used character parsers.
--
-----------------------------------------------------------------------------

module ParsecChar
                  ( CharParser
                  , spaces, space
                  , newline, tab
                  , upper, lower, alphaNum, letter
                  , digit, hexDigit, octDigit
                  , char, string
                  , anyChar, oneOf, noneOf
                  , satisfy
                  ) where

import Prelude
import Data.Char
import ParsecPrim
import Position -- from BSC

-----------------------------------------------------------
-- Type of character parsers
-----------------------------------------------------------
type CharParser st a    = GenParser Char st a

-----------------------------------------------------------
-- Character parsers
-----------------------------------------------------------
oneOf, noneOf :: [Char] -> CharParser st Char
oneOf cs            = satisfy (`elem` cs)
noneOf cs           = satisfy (`notElem` cs)

spaces :: CharParser st ()
spaces              = skipMany space        <?> "white space"

space, newline, tab :: CharParser st Char
space               = satisfy (isSpace)     <?> "space"
newline             = char '\n'             <?> "new-line"
tab                 = char '\t'             <?> "tab"

upper, lower, alphaNum, letter, digit, hexDigit, octDigit :: CharParser st Char
upper               = satisfy (isUpper)     <?> "uppercase letter"
lower               = satisfy (isLower)     <?> "lowercase letter"
alphaNum            = satisfy (isAlphaNum)  <?> "letter or digit"
letter              = satisfy (isAlpha)     <?> "letter"
digit               = satisfy (isDigit)     <?> "digit"
hexDigit            = satisfy (isHexDigit)  <?> "hexadecimal digit"
octDigit            = satisfy (isOctDigit)  <?> "octal digit"

char :: Char -> CharParser st Char
char c              = satisfy (==c)  <?> show [c]

anyChar :: CharParser st Char
anyChar             = satisfy (const True)

-----------------------------------------------------------
-- Primitive character parsers
-----------------------------------------------------------
satisfy :: (Char -> Bool) -> CharParser st Char
satisfy f           = tokenPrim (\c -> show [c])
                                (\pos c cs -> updatePosChar pos c)
                                (\c -> if f c then Just c else Nothing)

string :: String -> CharParser st String
string s            = tokens show updatePosString s