Personally I think returning None is a fine API design, and IMO the concerns about this pattern are overblown. Note that X|None is no different than the "Maybe X" pattern that functional programmers are so fond of.
On Mon, Sep 19, 2022 at 8:02 AM Philipp Burch <p...@hb9etc.ch> wrote: > Hi all, > > I've only here found out that there is a discussion going on about those > none-aware operators and my first thought was "great, finally!". FWIW, > I'd be happy with the syntax suggestion in the PEP, since '?' looks > rather intuitive to me to mean something like "maybe". > > However, I then read the mentioned post of Steve Dower, with the final > summary: > > > So to summarise my core concern - allowing an API designer to "just > use None" is a cop out, and it lets people write lazy/bad APIs rather > than coming up with good ones. > > This is a very good point. In fact, I've never really thought about it > that way and of course he's totally right that "SomeType | None" (or > Optional[SomeType], which also somehow made me feel that this usage is > fairly intended) is not optimal, at least for user defined > types/classes. The problem is, that I never actually thought about his > suggested way. And I wouldn't be surprised if this holds for many other > people as well. > > Maybe it would be great to boldly mention these thoughts in the > documentation at an appropriate place. In my opinion, there are at least > the following good places where this would fit nicely: > > - The documentation of the dataclasses > (https://docs.python.org/3/library/dataclasses.html), since this is > probably the most common use case for the "| None" pattern. Going > further, the dataclasses functionality might even be extended to make it > simpler to generate such null-types (or however they are called), so > that it is no longer "a tonne more work". > > - Linters like pylint could emit a note when seeing the "| None" > pattern, linking to the explanation about why it is possibly not the > best way to do it. > > - The documentation of the discussed None-aware operators. Since these > new operators are closely coupled to the arguably suboptimal "| None" > pattern, it is probably good to tell folks right there why they should > consider better alternatives. > > As mentioned, I absolutely see Steve's point. However, there are many > Python scripts/programs working without a complex API, where this "| > None" pattern may still have its legitimate uses and the none-aware > operators can make code easier to read (and write). > > Best regards, > Philipp > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@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/Q2MOF5CJ7LSSZMEMB43YVEXD6PFATYTA/ > Code of Conduct: http://python.org/psf/codeofconduct/ > -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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