+8  A: 

Oleg's work on "concurrent" zippers via delimited continuations is the main reference.

Don Stewart
Thank you, that does seem like the answer to my question. It's just a shame that they use all the constructs a newbie fears the most (Monads, Monad Transformers, Continuations, -fglasgow-exts). They even made things harder by adjusting the continuation library. So it's gonna take me a while to grok that. If I may another question, you seem to have been on Haskell scene for a while now, will I ever stop feeling like I'm shooting myself in a foot by learning Haskell :) (in a sense that this would have been so easy to achieve in a OO language)?
inetic
@inetic, it depends only on you, it takes dedication in learning but the rewards are worth it.Also, you don't have to fully understand all the higher level concepts they talk about to enjoy programming in Haskell.
David V.
+2  A: 

See this paper . I seem to recall reading somewhere that the second derivative has two holes, which is probably what you want.

Paul Johnson