I think I recall that discussion -- but don't recall how it ended. Did it just peter out?
Anyway, +1 form me -- I've actually got my own implementation as well. So it certainly has a use case, and it's really better to have one version in the stdlib. I haven't had a chance to review your implementation, but if it looks like you're getting support, I'll be sure to do so. -CHB On Tue, Jun 16, 2020 at 5:45 AM Alexander Hill <a...@hill.net.au> wrote: > Hi all, > > I’d like to propose support for infinite dates, datetimes and timedeltas. > They're very useful when you need to model ranges with one or both ends > unbounded (e.g. “forever starting from June 15th 2020”). > > Without first-class infinite values, you can use None, or you can use the > `min` and `max` attributes of Python’s datetime types, or some other > arbitrary large values. Using None means you need to implement a path for > None, and a path for everything else, and your various infinite values are > indistinguishable. Using max/min means comparisons just work, but > calculations need special treatment and you’re fundamentally > misrepresenting your meaning. > > Temporal infinities give the best of both worlds: infinite values that > interoperate seamlessly with the built-in types and behave sensibly and > predictably. They’re also supported by Postgres! > > Usage examples: > > >>> from temporal_infinities import * > >>> from datetime import * > >>> DATETIME_POS_INF - datetime(2020, 6, 15) > TIMEDELTA_POS_INF > >>> DATETIME_NEG_INF < date(2020, 6, 15) > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > TypeError: '<' not supported between instances of 'DatetimeInfinity' and > 'datetime.date' > >>> DATE_NEG_INF < date(2020, 6, 15) > True > >>> date(2020, 6, 15) + TIMEDELTA_POS_INF > DATE_POS_INF > >>> TIMEDELTA_NEG_INF == TIMEDELTA_NEG_INF > True > > My implementation is at > https://github.com/AlexHillAlexHill/temporal-infinities > <https://github.com/AlexHill/temporal-infinities> and is designed to be > as consistent with the behaviour of floating-point infinities as possible. > The expected behaviour of the various types is captured in test_matrix.csv, > which is used to produce test cases. Blank cells indicate that a TypeError > should be raised. It's tested back to Python 3.4. > > Previous discussion: > https://mail.python.org/pipermail/python-ideas/2015-January/031414.html > > Thanks for your time! > > Alex > _______________________________________________ > 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/S4H553FNZPX62RJLHVKCF4JFXBWQWXS6/ > 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
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