module Id where

newtype I a = I a

unI :: I a  -> a
unI (I a) = a

instance Functor I where
  fmap f m = do { x <- m; return (f x) }

instance Applicative I where
  pure = I
  g <*> m = do { f <- g; x <- m; return (f x) }

instance Monad I where
  (I m) >>= k = k m

evalI m = unI m