Monad transformers aren't quite the same thing as composed monads. (In fact, they're kind of a kludge to deal with the fact that monad composition isn't very we

Monad transformers aren't quite the same thing as composed monads. (In fact, they're kind of a kludge to deal with the fact that monad composition isn't very well behaved.) Some monad transformers, like `MaybeT m a`, are just wrappers around a composed `m (Maybe a)`, but others, like the continuation passing transformer `ContT r m a = (a -> m r) -> m r`, are very much not.