I started reading Deriving Backtracking Monad Transformers, by Ralf Hinze, this afternoon (or, rather, yesterday afternoon). It’s already been valuable, though that was more of a side effect.
I’ve haven’t read too much of it yet, but I’ve been able to understand what I have read, which means either- I’m learning; or
- Hinze is a good writer; or
- deriving backtracking monad transformers is simple.
I hope that it’s due to an increase in my understanding, but either of the other two cases might be true as well.
Next on the list is Backtracking, Interleaving, and Terminating Monad Transformers by Oleg Kiselyov, Chung-chieh Shan, Daniel P. Friedman and Amr Sabry.