On Wed, Aug 26, 2020 at 9:46 AM David Mertz <me...@gnosis.cx> wrote: > In my mind, *anything* other than the straightforward and obvious > signature `__getitem__(self, index, **kws)` is a pointless distraction. > > ...
> Yes, it's slightly funny that square brackets convert to `index` rather > than `*index`, but that ship sailed very long ago, and it's no big deal. > There's no problem that needs solving and no need for code churn. > I disagree here -- sure, for full backwards compatibility and preservation of performance, we'll probably have to live with it. But the fact that the square brackets don't create a tuple makes it fundamentally odd and confusing to work with -- not too big a deal when [] only accepted a single expression, and therefor passed a single value on to the dunders, but it gets very odd when you have something that looks a lot like a function call, but is different. And it gets worse for __setitem__, which I guess will be: thing[ind1, ind2, kwd1=v1, kw2=v2] = value Translating to: thing.__setitem__(self, (ind1, ind2), value, kwd1=v1, kw2=v2) which is pretty darn weird -- particularly if you try to write the handler this way: def __setitem__(self, *args, **kwargs): so: args would always be a 2-tuple, something like: ((ind1, ind2), value) At least **kwargs would be "normal", yes? On the plus side, this weirdness is only really exposed to folks writing classes with complex custom indexing behavior, and would still look like the same semantics as a function call to the users of that class. well, almost -- it would not support [*args] -- would it support [**kwargs] ? And this kind of thing is very much a write once, use a lot situation. TL;DR -- let's watch the strong language here -- these proposals do attempt to address a real problem -- probably not worth the downsides, but this "doesn't solve any problem", "no one asked for it", etc, is really dismissive. -CHB > > _______________________________________________ > 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/IXGZNYZEKHBNE6E52WKTENNGOIKXOVV6/ > Code of Conduct: http://python.org/psf/codeofconduct/ > -- Christopher Barker, PhD Python Language Consulting - Teaching - Scientific Software Development - Desktop GUI and Web Development - wxPython, numpy, scipy, Cython
_______________________________________________ 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/YSQMO4ZLYI3OUGYL254ZIX6MK2CQ3DCU/ Code of Conduct: http://python.org/psf/codeofconduct/
