I created an elevator to navigate a monad transformer stack, liberating us from creating a Monad* class and instances.

The key function, elevate, can be whatever you need:

elevate :: IO a -> IO a

elevate :: IO a -> StateT s IO a

elevate :: State s a -> StateT s IO a

elevate :: IO a -> MaybeT (StateT s IO) a

If you want to elevate actions above your monad, just write

instance Tower YourMonad

to declare that YourMonad is one-storied.

Hackage: http://hackage.haskell.org/package/elevator-0.1/docs/Control-Elevator.html

Cheers

Fumiaki Kinoshita