Okay, I've been thinking about closures, continuations, and coroutines, and one of the interfering points has been threads.
What's the P6 thread model going to be? As I see it, parrot gives us the opportunity to implement preemptive threading at the VM level, even if it's not available via the OS. Thinking about coroutines and continuations leads to the conclusion that you need a segmented stack (duh). But it also makes you wonder about how that stack interoperates with the threading subsystem. If there's one stack per thread (obvious) then you're committing to an "overt threading" model (user declares threads). If the stacks are allowed to fork (which they must, to support even Damian's generator-style coroutines) then there's the possibility of supporting a "single, unified stack-tree" which means that generators might contain their state across threads, and full coroutines may run in parallel. Anyway, I though the list was too quiet... =Austin
