Does anybody have a good solution for the "Sharing Coroutine State Sucks"-problem? I've thought a very long time about this (in my case, using continuations in FP instead of coroutines in Lua), but I still can't seem to come up with a good answer.
I guess one way to deal with it is by mechanically transforming the co-routines into a FSM. This is very similar to defunctionalization. However, I don't know of a language that does this well. Any suggestions?
With Stackless Python you can pickle (serialize) tasklets (coroutines). I built a Seaside-style web app in Stackless where each response would get pickled and saved to disk. When a new request with that id comes in you just unpickle it back into a tasklet and resume where you left off. You can do this between processes and machines. I don't see why you couldn't put them in a db but I was just using shared disk. What you're looking for are serializable continuations which some languages can handle.
I guess one way to deal with it is by mechanically transforming the co-routines into a FSM. This is very similar to defunctionalization. However, I don't know of a language that does this well. Any suggestions?