{- |

Module: $Header$

Copyright : (c) C. Maeder, Uni Bremen 2003

License : similar to LGPL, see HetCATS/LICENSE.txt or LIZENZ.txt

Maintainer : Christian.Maeder@dfki.de

Stability : provisional

Portability : portable

extract Haskell code from String

-}

{-

stops at unbalanced "}"

"then" may be recognized if it is not preceded by "if"

but that's not worth the trouble, because ...

"and" is used by Haskell,

"with", "hide", "reveal", "within", "end"

may be userdefined in Haskell

-}

module Haskell.Wrapper where

import Text.ParserCombinators.Parsec

import Common.Lexer

import Data.Char

hStuff, stuff :: CharParser st String

hStuff = flat $ many stuff

stuff = lineComment <|> nestComment <|> stringLit <|> charLit

<|> balanced "{}"

<|> balanced "()"

<|> balanced "[]"

<|> satisfy isAlpha <:> many (satisfy isAlphaNum <|> prime)

<|> single (noneOf "])}") <?> ""

balanced :: String -> CharParser st String

balanced [o, c] = char o <:> hStuff <++> string [c]

balanced _ = error "balanced"

nestComment :: CharParser st String

nestComment = nestedComment "{-" "-}"

lineComment, stringLit, charLit :: CharParser st String

lineComment = try (string "--") <++> many (noneOf "\n\r")

<++> many (oneOf "\n\r")

stringLit = enclosedBy (flat $ many $ single (noneOf "\\\"")

<|> char '\\' <:> single anyChar) $ char '\"'

charLit = try (string "'''") <|>

enclosedBy (flat $ many $ single (noneOf "\\\'")

<|> char '\\' <:> single anyChar)

(char '\'')