[Christian]
... Full continuations cannot be expressed by coroutines. All the rest is true.
[Gordon]
I beg enlightenment from someone more familiar with these high-falutin' concepts. Would the following characterization be accurate?
All these beasts (continuations, coroutines, generators) involve the idea of "resumable", but:
A generator's state is wholly self-contained A coroutines's state is not necessarily self-contained but it is stable Continuations may have volatile state.
Is this right, wrong, necessary, sufficient...??
I still don't understand all of this (I have not much of an idea of what Christian's search for hidden registers is about and what kind of analysis he needs) but I think of continuations as requiring (theoretically) coping the current stack (to and from), while generators and coroutines just need their own piece of stack set aside. The difference between any of these and threads (fake or real) is that they pass control explicitly, while threads (typically) presume pre-emptive scheduling, i.e. they make independent parallel progress without explicit synchronization. (Hmm, how do you do this with fake threads? Or are these only required to switch whenever you touch a mutex?) I'm not sure if there's much of a difference between generators and coroutines -- it seems just the termination convention. (Hmm... would/should a generator be able to raise an exception in its caller? A coroutine?) --Guido van Rossum (home page: http://www.python.org/~guido/)