@hackage MonadCompose0.8.4.2

Methods for composing monads.

The IO monad transformer solves the problem of combining two IO-performing monads, so that both may be transformed separately.

A monad transformer can transform another monad, but if you have two monads both lacking a transformer, one can define an extended distributive law which allows a monad to arise - see Control.Monad.PlusMonad.