[Stackless] micro-threads & co-routines

Just van Rossum just at letterror.com
Fri Oct 13 12:49:49 CEST 2000

At 11:36 AM +0200 12-10-2000, Dirk-Ulrich Heise wrote:
>My comment on the ownership scheme Christian
>wants to introduce:
>It's perfectly okay.

Well, even Chris doesn't seem to be 100% sure it is, actually.

>Just, you should notice that "having
>a reference" doesn't mean "own" in the logical sense.

I know. The big issue seems to be that there can be more than one path
leading back to the same frame. Now who is _the_ owner?

[ ... ]

>A completely different question: All these concepts by
>Christian seem to be very complex. Did somebody
>consider modeling them using Python, that is, create a sort
>of prototype engine that would allow testing them before
>the C coding starts? Just asking for curiosity.

There needs to be _some_ C-level support for restartable frames (a.k.a.
continuations. Well, sortof.) to be able to experiment with this. But maybe
that support can be extremely minimal at first (maybe even so bare that
it's possible to crash Python if not used properly...). On the other hand,
Christian is a speed freak, and if his continuations can't be as fast as
can be, he won't have as much fun with them ;-)

For a while now I've been trying to convince Christian to make
continuations much more primitive -- less options, simpler semantics -- but
I'm not sure how much he is willing to give up. Everything that the current
continuations can do, should be modelable (is that a word?) with even
simpler building blocks. That, to me, is the essence of continuations:
they're (the most) primitive building blocks, and you use them to build
other control structures. IMHO, Chris' continuations are too close to
"other control structures": they're trying to do too much.


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