module M where

import Control.Monad (ap, liftM)
import Control.Monad.Trans.Class (MonadTrans, lift)

newtype ComposeT t1 t2 m a = MkComposeT (t1 (t2 m) a)


instance (MonadTrans t1, MonadTrans t2, Monad m) => Monad (ComposeT t1 t2 m) where
  MkComposeT m >>= f = MkComposeT $ do
    x <- m
    let MkComposeT result = f x
    result

instance (MonadTrans t1, MonadTrans t2, Monad m) => Applicative (ComposeT t1 t2 m) where
  (<*>) = ap
  pure x = MkComposeT (pure x)
  
instance (MonadTrans t1, MonadTrans t2, Monad m) => Functor (ComposeT t1 t2 m) where
  fmap = liftM