[Patches] [ python-Patches-1548082 ] "if x in setliteral" peepholer optimization

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Patches item #1548082, was opened at 2006-08-28 17:38
Message generated for change (Comment added) made by gbrandl
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Category: Core (C code)
Group: Python 3000
Status: Open
Resolution: None
Priority: 5
Submitted By: Georg Brandl (gbrandl)
>Assigned to: Guido van Rossum (gvanrossum)
>Summary: "if x in setliteral" peepholer optimization

Initial Comment:
Like "for x in tuple_or_list", this patch rewrites "for
x in set" to use a constant frozenset.

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>Comment By: Georg Brandl (gbrandl)
Date: 2006-08-29 19:08

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Argh. Like in the py3k mail, I confusedly interchanged "for
x in set" and "if x in set".

if x in [1,2,3] does get special treatment, and optimizing
the "in" test does make sense.

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Comment By: Guido van Rossum (gvanrossum)
Date: 2006-08-29 18:24

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Um, "for x in [1,2,3]" doesn't get any treatment. What would
be the point of writing "for x in {1,2,3}" anyway?

I'd rather reject this as premature optimization.

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