[Python-Dev] Optimizing literal comparisons and contains
Many operations involving two literals are optimized (to a certain level). So it sort of surprises me that literal comparisons are not optimized and literal contains only convert the right operand to a constant if possible. I'd like to implement optimizations for these especially for the literal contains. There is a TODO in the ast optimizer for literal comparisons as well, and that's another reason I would like to have these added. ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/5I2GXLMVZ6OOLACL2BB2ER4L2RKEGWIJ/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-Dev] Re: Optimizing literal comparisons and contains
> Many operations involving two literals are optimized (to a certain level). So > it sort of surprises me that literal comparisons are not optimized and > literal contains only convert the right operand to a constant if possible. > I'd like to implement optimizations for these especially for the literal > contains. There is a TODO in the ast optimizer for literal comparisons as > well, and that's another reason I would like to have these added. Though not having paid much attention to this over the years, I'm pretty sure I've seen the topic float past from time-to-time. As I recall, optimizing expressions involving two constants isn't a big win in Python because that sort of expression occurs rarely in anything other than test code. In C/C++ and its cousins, preprocessors routinely expand names to constants, so 2 == 2 might well be seen by the compiler even though the author actually wrote MUMBLE == FRAZZLE If a Python programmer wrote such an expression, MUMBLE and FRAZZLE would be names bound to a particular object, and could — theoretically — be rebound at runtime, so such an expression couldn't safely be optimized. So, while you could optimize expressions involving just constants, the benefit would be exceedingly small compared to the effort to write and maintain the optimization code. Skip ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/4TFW3Q2X42XKP4IK263ZXOGAZ3XXYUH4/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-Dev] Re: The current state of typing PEPs
On Fri, Nov 26, 2021 at 5:47 PM Jim J. Jewett wrote: > Steven D'Aprano wrote: > > Maybe PEP 563 could include a decorator in the typing module to > > destringify all the annotations in a class or function? > > If it were in an annotations module, that would probably be sufficient. > > If it is in typing, then it is a very heavyweight dependency -- As of Py 3.10 there is: inspect.get_annotations one could write a decorator around that, but I think the real question is when do you want the annotations to be "finalized"? -CHB heavy enough that even the people actually using that module for > development (and not for production runs) are worried about the costs. If > the costs of the typing module are that high, it is not acceptable to > impose them on people not otherwise using the module. > > -jJ > ___ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/ZQHP24T2PKRTDBGZ36KLBHLLOKITP5ON/ > Code of Conduct: http://python.org/psf/codeofconduct/ > ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/OID2CGJ2L5IA7WGDRPO45BAPECFGWO7B/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-Dev] Re: Optimizing literal comparisons and contains
For the benefit of the audience on python-dev, you should also mention that this proposal and associated PR has been twice discussed and rejected on the tracker: https://bugs.python.org/issue45907 https://bugs.python.org/issue45843 The response just given by Skip pretty much matches the comments already given by Batuhan, Pablo, and Serhiy. So far, no one who has looked at this thinks this should be done. ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/QQ7TBTIQSCXZ66E3WLLT77EUKIQOO3FN/ Code of Conduct: http://python.org/psf/codeofconduct/
