1 module PascalPreprocessor where

     2 

     3 import Text.Parsec

     4 import Control.Monad.IO.Class

     5 import System.IO

     6 import qualified Data.Map as Map

     7 

     8 preprocess :: String -> IO String

     9 preprocess fn = do

    10     r <- runParserT (preprocessFile fn) Map.empty "" ""

    11     case r of

    12          (Left a) -> do

    13              hPutStrLn stderr (show a)

    14              return ""

    15          (Right a) -> return a

    16     

    17     where

    18     preprocessFile :: String -> ParsecT String (Map.Map String String) IO String

    19     preprocessFile fn = do

    20         f <- liftIO (readFile fn)

    21         setInput f

    22         preprocessor

    23     preprocessor, codeBlock, switch :: ParsecT String (Map.Map String String) IO String

    24     preprocessor = chainl codeBlock (return (++)) ""

    25     codeBlock = choice [

    26             switch

    27             --, comment

    28             , char '\'' >> many (noneOf "'") >>= \s -> char '\'' >> return ('\'' : s ++ "'")

    29             , many1 $ noneOf "{'"

    30             ]

    31     switch = do

    32         try $ string "{$"

    33         s <- choice [

    34             include

    35             , unknown

    36             ]

    37         return s

    38     include = do

    39         try $ string "INCLUDE"

    40         spaces

    41         (char '"')

    42         fn <- many1 $ noneOf "\"\n"

    43         char '"'

    44         spaces

    45         char '}'

    46         f <- liftIO (readFile fn)

    47         c <- getInput

    48         setInput $ f ++ c

    49         return ""

    50 

    51     unknown = do

    52         fn <- many1 $ noneOf "}\n"

    53         char '}'

    54         return ""

    55