stackless python

Christian Tismer tismer at
Tue Jan 1 17:13:40 EST 2002

Donn Cave wrote:

> Quoth Christian Tismer <tismer at>:
> ...
> | Continuations can do even more, they are able to create new
> | control structures for your language. And exactly that it the point
> | which makes them insuitable for Python: They are too powerful.
> | Python has its own control structures, and we don't need a construct
> | with the power to build some. This is oversized, and very oversized
> | construct turns out to be a drawback at some future.
> | What Python needs is a secure mechanism to switch frame changes
> | at certain times. This is not continuations, but microthreads with
> | explicit or implicit switching.
> |
> | I will implement this for Python 2.2, probably with some help
> | of volunteers.
> Could Gordon McMillan's "asyncore turned right-side out" select
> dispatcher have been written with the microthread facility you
> have in mind?

Yes, I'm pretty sure.

> I am sure there's some way to present that capability in terms of
> a pre-defined control structure, instead of raw continuations, but
> it's a pity if it has to be given up because it's too powerful.

No, I no longer think so.
It has to be shrunk down to the capabilities needed.
Having continuations where one-shot continuations (aka frames with
state) are sufficient is not healthy.
I've been thinking of this since a year now, and finally Guido
convinced me.

ciao - chris

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