Author ncoghlan
Recipients Jeremy.Hylton, Trundle, alex, benjamin.peterson, brett.cannon, daniel.urban, dmalcolm, eltoder, eric.snow, georg.brandl, gregory.p.smith, haypo, jcon, mark.dickinson, meador.inge, nadeem.vawda, ncoghlan, pitrou, rhettinger, santoso.wijaya, techtonik, terry.reedy
Date 2012-09-06.01:45:35
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Message-id <1346895936.78.0.623295097149.issue11549@psf.upfronthosting.co.za>
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The peephole optimiser already makes optimisations like that in a couple of places (e.g. set -> frozenset):

>>> def f(x):
...    if x in {1, 2}: pass
...
>>> f.__code__.co_consts
(None, 1, 2, frozenset({1, 2}))

It's name lookup semantics that are the real minefield. It's one of the reasons PyPy's JIT can be so much more effective than a static optimiser - because it's monitoring real execution and inserting the appropriate guards it's not relying on invalid assumptions about name bindings.
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Date User Action Args
2012-09-06 01:45:36ncoghlansetrecipients: + ncoghlan, brett.cannon, georg.brandl, rhettinger, terry.reedy, gregory.p.smith, mark.dickinson, pitrou, haypo, techtonik, nadeem.vawda, benjamin.peterson, alex, Trundle, dmalcolm, meador.inge, daniel.urban, Jeremy.Hylton, santoso.wijaya, eltoder, eric.snow, jcon
2012-09-06 01:45:36ncoghlansetmessageid: <1346895936.78.0.623295097149.issue11549@psf.upfronthosting.co.za>
2012-09-06 01:45:36ncoghlanlinkissue11549 messages
2012-09-06 01:45:35ncoghlancreate