On Tue, Aug 16, 2016 at 08:21:31PM +0200, Corentin Dupont wrote: > Hi guys, > is there some library with a Monad (+Applicative, Functor...) instance of > the following type: > > data Todo a b = Todo [a] | Done b What is the general idea behind the "todo monad"? As an unrepented procrastinator, I might learn something useful.