gistfile1.txt

{-# LANGUAGE FlexibleInstances, ImplicitParams #-}
import Control.Monad
import Control.Applicative

instance (Monad m, Num b) => Num (a -> m b) where
  a + b =  liftM2 (+) <$> a <*> b
  a * b = liftM2 (*) <$> a <*> b
  negate a = liftM negate <$> a
  abs a = liftM abs <$> a
  signum a = liftM signum <$> a
  fromInteger = const . return . fromInteger

main = print $ (m >>= 1) ()
  where m = const 0