+1 to what Jelle said -- I don't see anyone seriously using this except in code golf or obfuscated code contests. On Fri, Apr 23, 2021 at 11:51 AM Jelle Zijlstra wrote:

For what it's worth, Larry's PEP 649 branch currently prohibits yield, yield from, await, and the walrus operator in annotations. That seems like the right choice unless there's some realistic use case for any of these.

El vie, 23 abr 2021 a las 11:27, Batuhan Taskaya () escribió:

...

About 4 months ago, I've created bpo-42725 in order to resolve some of the points below though I decided to postpone it for various reasons that blocked it completely until the point of where we have a beta cut in a week or so. So I'm asking for comments regarding how should we resolve this behavior.

Even though PEP 563 blocks having all compiler-related activities for annotations by behaving them strings, this doesn't happen until the symbol is constructed which results with different problems. For example you can use yield in annotation, and since PEP 563 will stringify it you'd expect your function to act accordingly but it currently doesn't. Also references to the upper scope variables will still be contained as closures of the current function, and some other oddities that I've found regarding misc stuff (usage of super() etc).

Here is a quick demo:

def foo(): for number in range(5): foo: (yield number) return number

foo() # ======> this will be a generator

We could go with acting these as strings and letting them stay as annotations but making them no-op on the symbol table (which is the straight forward choice) or we could restrict usage of those inside of annotations and raise SyntaxErrors. I've drafted patches for both of those ideas, though it definitely needs more work and there is not much time left so any comments would be appreciated.

P.S: I intend to submit a PR with the most likely option by, at latest, end of saturday so that we can give reviewers enough time and also catch the beta freeze considering this is a clear behavioral change. _______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-leave@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/5NQH5GUR... Code of Conduct: http://python.org/psf/codeofconduct/

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