Hello everyone, I am trying to compile some code that I have written a long time ago (might have been for ghc 6.3), and I have not done much Haskell in the meantime. I have trouble compiling the code, maybe only because I do not remember the necessary flags (yes, these should be in the source files), maybe because ghc has changed. I do for example have functions like this: getnArray :: Int -> [Word8] -> Maybe (UArray Int Word8, [Word8]) getnArrayST :: Int -> [Word8] -> (forall s . ST s (Maybe (UArray Int Word8, [Word8]))) getnArrayST n bs :: ST s (Maybe (UArray Int Word8, [Word8])) = do (a :: STUArray s Int Word8) <- newArray_ (0,n-1) let loop k bs | k == n = do fa <- freeze a return $ Just (fa, bs) | k < n = case bs of (b:bs) -> do writeArray a k b loop (k+1) bs [] -> return Nothing loop 0 bs getnArray n bs = runST (getnArrayST n bs) Can someone suggest compiler flags which will make this compile with 6.8 and 6.12? I have tried -XRankNTypes -XScopedTypeVariables -fglasgow-exts but still get "Parse error in pattern" for the definition of getnArrayST. Thanks for helping. As soon as I have overcome this problem, the real fun will begin, because my program uses Template Haskell ;) Carsten