I've done something similar in the monad-classes library [1]; and there's an ongoing series of articles about it [2]. [1]: https://github.com/feuerbach/monad-classes [2]: http://ro-che.info/articles/extensible-effects On 17/11/14 08:37, Fumiaki Kinoshita wrote:
Hello everybody,
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
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