On Wed, Jul 8, 2020 at 6:17 PM Inada Naoki <songofaca...@gmail.com> wrote: > > Since this is very new system, can we have some restriction > to allow aggressive optimization than regular Python code? > > # Class Pattern > > Example: > > match val: > case Point(0, y): ... > case Point(x, 0): ... > case Point(x, y): ... > > * Can VM cache the "Point" at first execution, and never lookup in > next time? (e.g. function executed many times)
I'd prefer not - that seems very confusing. > # Constant value pattern > > Example: > > match val: > case Sides.SPAM: ... > case Sides.EGGS: ... > > * Can VM cache the value of "Sides.SPAM" and "Sides.EGGS" for next execution? > Similar, but with the additional consideration that you can create a "pre-baked pattern" by using a dict, so if you're worried about performance, use the slightly uglier notation (assuming that Sides.SPAM and Sides.EGGS are both hashable - and if they're not, the risk of prebaking is way too high). > * Can VM lookup "Point" only once per executing `match`, instead three times? > * Can VM lookup "Sides" only once, instead of two? These two I would be less averse to, but the trouble is that they make the semantics a bit harder to explain. "Dotted names are looked up if not already looked up, otherwise they use the same object from the previous lookup". If you have (say) "case socket.AddressFamily.AF_INET", does it cache "socket", "socket.AddressFamily", or both? ChrisA _______________________________________________ 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/IR5UUBLXBAZDT45MGYD2CX42K2R7Z5LB/ Code of Conduct: http://python.org/psf/codeofconduct/
