Hi list, I am *still* cursing the fact that I like where Haskell is taking me but that I am too dumb to get it into my head as quickly as I'd like! I will not give up and in that vein I have been beating myself up trying to run before I can walk as usual by attempting to write an FFI wrapper around the Ubuntu libcwiimote library! Having been inspired by johnnylee.net and having found his code is for Windows and C# I have taken it on myself to reproduce what he's done but using Haskell and OpenGL. Laugh, I nearly cried because it's taken hours of frustration just to get this far! I've built the hardware and now I need the software as usual. So, here we go... what I post here is the beginnings of a Wiimote wrapper. I *think* I understand Monads properly now, Brian Beck video on C9 (MSDN) really really helped a lot, I'd recommend that to anybody still struggling with the concept. What I want to know is can my code be improved by using monadic chaining and if so, with what and how (LMAO) and also have I overlooked or otherwise not used the correct forms, idioms etc. to achieve what I have so far ? I am really keen to know how the real gurus out there could reduce this code down or make it 'more haskell like'. Basically, I want you to correct it, improve it, show me and others how to do it right! I want it de-constructed, ripped to pieces, laughed at, openly mocked and I will learn from it and enjoy it because I am a developer! ;) LOL It compiles with ... ghc --make -lcwiimote -o wmscan WiiMote.hs and runs like so ... sean@sean-desktop:~/Documents/bluetooth$ ./wmscan 00:21:BD:A3:97:C7 Connecting to 00:21:BD:A3:97:C7 00:21:BD:A3:97:C7connected OK, disconnecting ...OK sean@sean-desktop:~/Documents/bluetooth$ ...and I was proud as hell, almost as proud as watching my son born but without the goo. Many thanks. Sean ---- {-# LANGUAGE ForeignFunctionInterface #-} import Foreign import Foreign.C.Types import Foreign.Ptr import Foreign.C.String import System #include "wiimote_api.h" foreign import ccall unsafe "wiimote_api.h wiimote_open" c_wiimote_open :: CString -> IO (Ptr Word8) foreign import ccall unsafe "wiimote_api.h wiimote_close" c_wiimote_close :: (Ptr Word8) -> IO CInt wiiOpen :: String -> IO (Maybe (Ptr Word8)) wiiOpen wid = do handle <- withCString wid c_wiimote_open case handle of nullPtr -> return Nothing handle -> return (Just handle) wiiClose :: Ptr Word8 -> IO Bool wiiClose wptr = do response <- c_wiimote_close wptr case response of 0 -> return True _ -> return False -- Open the wiiremote, print the handle and close it test :: String -> IO () test wiiHID = do wiimote <- wiiOpen wiiHID case wiimote of Just handle -> do putStr (wiiHID ++ " connected OK, disconnecting ... ") status <- wiiClose handle case status of True -> putStrLn "OK" False -> putStrLn "FAIL" Nothing -> putStrLn "FAIL" return () -- expects a single HID string on the command line ... main :: IO () main = do args <- getArgs case args of [hid] -> do putStrLn ("Connecting to " ++ hid) test hid _ -> putStrLn "Supply ONE Wiimote HID address!"