You appear to be making a connection between star-args in a call and in a function definition. They are unrelated. The more I hear about this the more I favor not supporting it in the subscript syntax.
On Sun, Aug 30, 2020 at 08:44 Joseph Martinot-Lagarde <contreba...@gmail.com> wrote: > Guido van Rossum wrote: > > > > > > Do we want to support d[**kwargs]? It can be done, alternatively we could > > > just ask the user to write the __getitem__/__setitem__ call explicitly. > > > I think we should say no to d[*args], because that will just become > > > d[(args)], with awkward questions around what if args == (1,). Maybe then > > > for consistency we needn't bother with **kwargs, though the case for that > > > is definitely stronger. > > > Sorry for telegraphing this -- I am way past my bedtime but looking at > this > > > from the C API POV definitely made some things clear to me. I'm probably > > > posting this in the wrong thread -- I can't keep up (and GMail splits > > > threads after 100 messages, which doesn't help). > > > > I hope I understood correctly because Mailman eats the * signs for > formatting, but is it possible (and desirable) to have a different > behaviour for *args and index when there is only one positional value ? > Using "index" would keep the current behaviour : pass a tuple except when > there is only one value, in that case the value is passes as-is. On the > other hand if *args is passed in the signature, it always gets the > positional arguments in a tuple, whatever their number. It would avoid the > classical isinstance(index, tuple) check. Here are some examples of what I > mean: > > > > # Usual signature > > class Simple: > > def __getitem__(self, index): > > print(index) > > simple = Simple() > > simple[0] # 0 > > simple[0, 1] # (0, 1) > > > > # This is valid python, but useless ? > > class Star: > > def __getitem__(self, *index): > > print(index) > > star = Star() > > star[0] # (0,) > > star[0, 1] # ((0, 1),) > > > > # I propose this breaking change > > class NewStar: > > def __getitem__(self, *index): > > print(index) > > star = Star() > > star[0] # (0,) > > star[0, 1] # (0, 1) > > > > This is theoretically a breaking change, but who in his right mind would > write such a Star class with the current python ? > > > > Any thoughts ? > > _______________________________________________ > > Python-ideas mailing list -- python-ideas@python.org > > To unsubscribe send an email to python-ideas-le...@python.org > > https://mail.python.org/mailman3/lists/python-ideas.python.org/ > > Message archived at > https://mail.python.org/archives/list/python-ideas@python.org/message/HYGUIAYR5OGACHUHOIXN22YJWFMCE7IG/ > > Code of Conduct: http://python.org/psf/codeofconduct/ > > -- --Guido (mobile)
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