{- |

Module: $Header$

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

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

Maintainer : maeder@tzi.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

hStuff, stuff :: GenParser Char st String

hStuff = flat $ many stuff

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

<|> balanced "{}"

<|> balanced "()"

<|> balanced "[]"

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

balanced :: String -> GenParser Char st String

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

balanced _ = error "balanced"

nestComment :: GenParser Char st String

nestComment = try (string "{-") <++>

flat (many (single (noneOf "-{")

<|> try (string "-" << notFollowedBy (char '}'))

<|> nestComment

<|> string "{" ))

<++> string "-}"

lineComment, stringLit, charLit :: GenParser Char st String

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

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

stringLit = char '\"' <:> flat (many (single (noneOf "\\\"")

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

<++> string "\""

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

char '\'' <:> flat (many (single (noneOf "\\\'")

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

<++> string "\'"