Haskell parser with GHC API

gistfile1.hs

-- ghc Main.hs -package ghc

module Main where

import DynFlags
import FastString
import HsSyn
import Lexer
import Outputable
import Parser
import RdrName
import SrcLoc
import StaticFlags
import StringBuffer

import System.Environment

main :: IO ()
main = do
    [file] <- getArgs
    mp <- parseHaskell file
    case mp of
        Nothing  -> putStrLn "Parse failed"
        Just mdl -> print $ map (showSDoc . ppr) $ hsmodDecls mdl

parseHaskell :: FilePath -> IO (Maybe (HsModule RdrName))
parseHaskell file = do
    initStaticOpts
    sbuf <- hGetStringBuffer file
    let srcloc = mkSrcLoc (mkFastString file) 1 1
    return $ case unP parseModule (mkPState defaultDynFlags sbuf srcloc) of
        POk _ (L _ mdl) -> Just mdl
        PFailed _ _     -> Nothing