Netwire - console cursor moving

cursor.hs

import Control.Wire
import Prelude hiding ((.), id)
import System.Console.ANSI
import Data.Maybe
import Control.Applicative ((<$>))

control whenInhibited whenProduced wire = loop wire clockSession
   where
     loop w' session' = do
         (mx, w, session) <- stepSession w' session' ()
         case mx of
           Left ex -> whenInhibited ex
           Right x -> whenProduced x
         loop w session

foreign import ccall unsafe "conio.h getch" c_getch :: IO Char
foreign import ccall unsafe "conio.h kbhit" c_kbhit :: IO Bool
keyPressed = do isKey <- c_kbhit
                if isKey then Just <$> c_getch
                         else return Nothing

                         
pressedKeyMaybe = mkFixM $
     \_ _ -> Right <$> keyPressed

moveCursor = mkFixM $ 
    \_ coords@(x,y) -> setCursorPosition y x >> return (Right coords)

cursorWire = accum (\(a,b) (c,d) -> (a+c, b+d)) (0,0)
    . (    pure ((-1),  0 ) . when (== Just 'K') 
       <|> pure (  1,   0 ) . when (== Just 'M')
       <|> pure (  0, (-1)) . when (== Just 'H')
       <|> pure (  0,   1 ) . when (== Just 'P')
       )
    . edge ((/=) 224 . fromEnum . fromMaybe ' ') . pressedKeyMaybe

main = control return (const (return ())) $
    moveCursor . cursorWire