{- |

Module : $Header$

Description : extract Haskell code in structured specs

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.Parsec

hStuff :: CharParser st String

hStuff = flat $ many stuff

stuff :: CharParser st String

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

<|> balanced "{}"

<|> balanced "()"

<|> balanced "[]"

<|> letter <:> many (alphaNum <|> char '\'')

<|> 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 :: CharParser st String

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

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

stringLit :: CharParser st String

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

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

charLit :: CharParser st String

charLit = tryString "'''" <|>

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

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

(char '\'')