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Python and Boehm-Demers GC, I have code.

Christian Tismer tismer at appliedbiometrics.com
Tue Jul 20 08:30:19 EDT 1999 
Michael Hudson wrote:
> 
> On 20 Jul 1999, Markus Kohler wrote:
> [snippety snip]
> >
> > Is there anything that would prevent someone to reimplement loops such
> > that only one variable is allocated ?
> >
> 
> Yes. The fact that ints are immutable. Consider:
> 
> for i in xrange(10):
>     if i == 2:
>         j = i
> 
> if the loop only allocated one variable, then at the end of the loop
> 'print j' would give the answer '9'!
> 
> I guess this could be worked around by inspecting refcounts and such...
> but not easily.

FYI, stackless Python already saves the internal loop count into
a counter object. The explicit creation of "i" is still there,
of course. But you might know that inteegr allocation is completely
handled through a cache, and I see not much benefit coming from
making my mutable integer object public.
This look to cheap for me, to be replaced by the hair of extra
refcount tracking.

ciao - chris

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