That might work (though not for older Python versions). What kind of API were you thinking of for adding and deleting abstract methods?
On Thu, Oct 1, 2020 at 01:07 Ben Avrahami <avrahami....@gmail.com> wrote: > > > I suppose it's better than nothing, since right now libraries are > (rightfully) afraid to modify it or rely on its behaviour. Although I > expect this will lead to a lot of repeated code, that looks a lot like the > `__abstractmethods__` population in `_py_abc`. I think it's preferable to > ease abstract method re-population for 3rd (and 1st) party libraries, but > the dev team probably knows better. If this is an accepted solution, I'd be > happy to write a BPO and PR. > > On Wed, Sep 30, 2020 at 5:30 PM Guido van Rossum <gu...@python.org> wrote: > >> Would it help if ‘__abstractmethods__’ was documented, overruling >> whatever the PEP says? >> >> On Wed, Sep 30, 2020 at 00:01 Ben Avrahami <avrahami....@gmail.com> >> wrote: >> >>> I encountered this problem when I needed to implement a class that >>> defined all 4 of the comparison operators, once with `dataclass` (for one >>> implementation) and once with `total_order` (for another).Also, 3rd party >>> libs are expected to fall down this rabbit hole, and unless they're >>> expected to modify `__abstractmethods__` and perform abstract logic on >>> their own- I don't see why the standard library should keep such >>> computations unavailable. >>> >>> On Tue, Sep 29, 2020 at 6:41 PM Eric V. Smith <e...@trueblade.com> >>> wrote: >>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> On 9/29/2020 10:49 AM, Ben Avrahami >>>> >>>> wrote: >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> On Tue, Sep 29, 2020 at 4:53 >>>> >>>> PM Bar Harel <bzvi7...@gmail.com> wrote: >>>> >>>> >>>> >>>> >>>> >>>>> >>>>> I'd like to bring another insight to the >>>>> >>>>> table: According to the pep, "Dynamically >>>>> >>>>> adding abstract methods to a class, or attempting to >>>>> >>>>> modify the abstraction status of a method or class once >>>>> >>>>> it is created, are not supported." >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> The notice exists both in the pep and at the abc module's >>>>> >>>>> docs, and is exactly what this idea is all about. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> My question is why? Was there an objection for >>>>> >>>>> implementing such a thing, or was it complex enough to >>>>> >>>>> postpone for the time being? >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> I think this is fine. The "abstract-ness" of a class is not >>>> >>>> supposed to change throughout its lifetime. The problem >>>> >>>> arises when decorators change the class before it's ever >>>> >>>> used, as that should still be considered its >>>> >>>> "initialization" as far as the user is concerned, so >>>> >>>> its "abstract-ness" should change accordingly. >>>> >>>> >>>> I agree with Guido in that the cleanest solution is to >>>> >>>> change the decorators. Perhaps a module function to >>>> >>>> recalculate a class's __abstractmethods __, that mixin >>>> >>>> decorators can call prior to returning the class. I can't >>>> >>>> really think of standard library class decorators that would >>>> >>>> use this global function other than `dataclass` and >>>> >>>> `total_ordering`, but in this way, 3rd party decorators can >>>> >>>> easily support implementing abstract functions. >>>> >>>> >>>> The one downside to this solution is that it can easily >>>> >>>> be abused by calling it in the middle of a class's lifetime. >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> I think I'd like to see dataclasses handle this directly, so as >>>> >>>> to keep it easy to use. But I can be argued with: it's not like a >>>> >>>> beginner would stumble over this issue. >>>> >>>> >>>> >>>> >>>> Eric >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> >>>> >>>> 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/EQQVNE4IVG5ZLWZHY3HCIATUY32PHWJG/ >>>> >>>> >>>> Code of Conduct: http://python.org/psf/codeofconduct/ >>>> >>>> >>>> >>> >>> _______________________________________________ >>> >>> 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/ASPJKUZ46MAD5FT6HOLIFSQDFZR7IFGY/ >>> >>> Code of Conduct: http://python.org/psf/codeofconduct/ >>> >>> -- >> --Guido (mobile) >> >> >> > > -- --Guido (mobile)
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