Using monad-control with monad transformers

This article assumes familiarity with monads and monad transformers. If you’ve never had an occasion to use lift yet, you may want to come back to it later. It is also available on the School of Haskell: https://www.fpcomplete.com/user/jwiegley/monad-control. The Problem What is the problem that monad-control aims to solve? To answer that, let’s back up [...]