Free monads

[Andres Löh]

Hi everyone.

I'll follow Simon's lead, and ask a similar question with a similar
motivation. I'm going to talk about free monads at the upcoming
Haskell eXchange next Wednesday. I'll not limit myself to a particular
library, and I'm open to related approaches (e.g. "operational") as
well.

I'm also looking for as many compelling examples as possible. Like
Simon, I don't want to know anything secret or anything that you
wouldn't like me to include in my talk. Most useful are pointers to
existing libraries using free monads that I might have missed (for
example, because they're new or very specialized).

Thanks a lot for your help in advance.

Cheers,
  Andres

-- 
Andres L?h, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com