On Thu, Apr 22, 2021 at 7:53 PM Paul Moore <[email protected]> wrote: > I wonder whether type checkers could handle a "magic" type (let's call > it DuckTyped for now :-)) which basically means "infer a protocol > based on usage in this function". So if I do: > > def my_fn(f: DuckTyped): > with f: > data = f.read() > for line in f: > print(line) > f.close() > > then the type checker would automatically build a protocol type like > the one I defined above and use that as the type of f? That would make > it much easier to include duck typed arguments in function signatures > while keeping the benefits of static type checking. >
Someone will likely correct me if this is inaccurate, but my understanding is that that's exactly what you get if you just don't give a type hint. The point of type hints is to give more information to the type checker when it's unable to simply infer from usage and context. ChrisA _______________________________________________ Python-Dev mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/[email protected]/message/RW5ACSLJP2RLBZWDGQRGBD6ZAVRUQWMG/ Code of Conduct: http://python.org/psf/codeofconduct/