> > Is there a reason mypy could not assume that all AtomicStr methods that > return strings actually return an AtomicStr, without impacting runtime > behavior...? Maybe it's not possible and I'm just not familiar enough with > the behavior of the type checkers. >
I don't know but I could say that being problematic if parts of a project expects strings to be iterable and some expect them to atomic. If mypy assumes `isinstance(obj, Iterable)` returns false on `str` then its not really helping in the case where `obj: Union[str, Iterable[str]]` And while I don't really know much about mypy, I do know it understands stuff like `if isisnstance`, it seems like it would take tremendous hackery to get it to understand that when `isinstance(obj, Iterable)` returns True, you still can't pass that object to a function that consumes an iterable without also checking `not isinstance(obj, (str, bytes))`. assert """ > In practice this would be a very odd decision given that the definition of > Iterable is "has an __iter__". And there are plenty of times people will > find the resulting behavior surprising since str DOES have an __iter__ > method and there are plenty of times you might want to iterate on sequences > and strs in the same context. """ in set_of_draw_backs On Tue, Feb 25, 2020 at 4:28 AM Rhodri James <rho...@kynesim.co.uk> wrote: > On 24/02/2020 21:07, Alex Hall wrote: > > This response honestly seems to ignore most of the paragraph that it's > > responding to. It being a sharp distinction doesn't matter because > > consistency isn't axiomatically valuable. > > Actually I think it is. Or more precisely, I think inconsistency is > axiomatically has negative value. An inconsistency breaks your > expectation of how a language works. Each inconsistency creates a > special case that you simply have to learn in order to use the language. > The more inconsistencies you have, the more of those exceptions you > have to know, and the harder the language is to learn. Just consider > how hard English is to learn as an adult, and notice just how much of > the language is inconsistency after inconsistency. > > -- > Rhodri James *-* Kynesim Ltd > _______________________________________________ > 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/5ZIK4ESPNPX2YL4MNGGMNIFE56YIHCAP/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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