On Thu, Jun 25, 2020 at 6:53 PM Antoine Pitrou <solip...@pitrou.net> wrote: > > On Wed, 24 Jun 2020 12:38:52 -0700 > Guido van Rossum <gu...@python.org> wrote: > > Everyone, > > > > If you've commented and you're worried you haven't been heard, please add > > your issue *concisely* to this new thread. Note that the following issues > > are already open and will be responded to separately; please don't bother > > commenting on these until we've done so: > > > > - Alternative spellings for '|' > > - Whether to add an 'else' clause (and how to indent it) > > - A different token for wildcards instead of '_' > > - What to do about the footgun of 'case foo' vs. 'case .foo' > > > > (Note that the last two could be combined, e.g. '?foo' or 'foo?' to mark a > > variable binding and '?' for a wildcard.) > > I don't know if you read it, so I'll reiterate what I said :-) > > """ > Overall, my main concern with this PEP is that the matching semantics > and pragmatics are different from everything else in the language. > When reading and understanding a match clause, there's a cognitive > overhead because suddently `Point(x, 0)` means something entirely > different (it doesn't call Point.__new__, it doesn't lookup `x` in the > locals or globals...). Obviously, there are cases where this is > worthwhile, but still. >
AIUI, the case clauses are far more akin to *assignment targets* than they are to expressions. If you see something like this: [x, y] = foo() then you don't expect it to look up x or y in the current scope, nor to construct a list. Is there any way to make the syntax look more like assignment? Or maybe this won't even matter - people will simply get used to it with a bit of experience, same as "for x, y in stuff" has an assignment target in it. 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/JGX7PZ6LMSDNS4OWQIJBWGGM6E7V4XO7/ Code of Conduct: http://python.org/psf/codeofconduct/
