[carapace]

And there's the rub. I don't doubt this stuff is useful, and I'd like to know more. But it seems really hard to bring this stuff "down from the mountain" in a way that makes it easier to understand and utilize for us mere mortals.

[koloron]

Here are two blog posts on free monads that should be accessible for people who understand what a monad is and are able to read Haskell:

http://www.haskellforall.com/2012/06/you-could-have-invented...

http://www.haskellforall.com/2012/07/purify-code-using-free-...