[pypy-dev] Stackless PyPy mini sprint 2007

Christian Tismer tismer at stackless.com
Mon Sep 17 03:42:10 CEST 2007

Erik Gorset wrote:
> On Sep 16, 2007, at 8:13 PM, Christian Tismer wrote:
>> Erik Gorset wrote:
>>> I'm wondering if there is any plans for pypy/stackless to support
>>> true continuations as first class citizen in the future? It would be 
>>> easy
>>> to implement coroutines and exceptions in normal python code if
>>> call/cc was supported. After all, ruby, scheme and smalltalk can
>>> support this :-)
>> Maybe this is possible, but that's not a reason to do it.
>> I have spent a little too much of my lifetime with taming
>> continuations. And since Python has all the control flow
>> it needs, it does not make sense to add continuations, which
>> impose extra complications for no gain.
>> I think to stick with coroutines as the building block,
>> unless there is a real need for continuations.
> Actually, having continuations as a fundamental building block is a
> big simplification as all other control flows can be expressed by it.

It is a complication, since continuation support is not
trivial. The demands are much harder than for coroutines.

> The only "flaw" is that you can't use the c stack in a normal way
> since the executing contexts will form a tree instead of a linear
> structure.

Please don't continue this discussion on this list.
This is a stackless issue in the first place, not PyPy's.
I was just inviting people here to a sprint.
Stackless matters go to the stackless list.

See http://www.stackless.com/mailman/listinfo/stackless

Also the issue of continuations has been discussed at length there.
Please use this list for question about PyPy.

cheers - chris
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