package Module2(Module2(..), unMod2) where

data Module2 i = Mod2 (Module i)

unMod2 :: Module2 i -> Module i
unMod2 (Mod2 x) = x

instance Monad Module2
  where
    return x = Mod2 (return x)
    bind (Mod2 x) f =
      let f' x = unMod2 (f x)
      in Mod2 (bind x f')

instance IsModule Module2 Id
  where
    liftModule m = Mod2 m
    liftModuleOp f m = Mod2 (f (unMod2 m))