Don't forget leap seconds! :-) On Thu, Feb 10, 2022, 11:45 AM Christopher Barker <python...@gmail.com> wrote:
> Since a started this:-) > > 1) the complexities are exactly why this *might* be a candidate for the > stdlib. Those are the things that someone is likely to get wrong, or not > think of, when they write something quick themselves, and only lightly > test. > > 2) it doesn’t have to be everything for everyone- it has to be many things > for many (most) people. > > 3) DST is a nightmare, plain and simple. The datetime module was useful > for years even before it gained the ability to deal with it at all.[*] > > An educational thing to explore, in any case. > > -CHB > > [*] now that I think about it, I would probably only do this without DST — > including DST would require a DST database, which the stdlib doesn’t > include. > > On Thu, Feb 10, 2022 at 7:48 AM Paul Moore <p.f.mo...@gmail.com> wrote: > >> On Thu, 10 Feb 2022 at 15:21, Aman Pandey <amanpandey5...@gmail.com> >> wrote: >> > >> > Hello Stephen, I think you misunderstood it. we are not talking about >> modifying the existing built-in function range rather adding a new function >> in datetime module that will generate the date and time between two periods. >> > if we add a function like that in the datetime module the code will be >> exactly like the one you gave. >> > Christopher was mentioning that he visualizes that function in the >> datetime module as something similar in syntax and execution like the >> built-in range function. >> > >> > what do you think if we add some function like that in datetime module >> wouldn't it be helpful? >> >> I think something like this might occasionally be helpful. However, >> for simple examples, it's pretty easy to write your own, sufficiently >> so that people would expect more of a stdlib version. And >> understanding the edge cases, correctly handling them, and designing >> an API which makes the function easy to use while still having the >> power to cover everyone's use cases, is a *lot* harder. It's that part >> of the problem that is receiving the pushback here. >> >> To give a concrete example, consider a range with a start of 1:30am on >> a particular day, and a step of 1 day. If the range extends over a DST >> change, then there's one day in the range where either there are no >> valid 1:30am times, or there are *two*, equally valid 1:30am times >> (depending on whether the clock is "going forwards" or "going >> backwards"). What should the stdlib function do in this case? How >> should the function deal with the fact that people can legitimately >> expect different behaviours (for some applications "raise an >> exception" could be the only safe option, for others, "use the nearest >> valid time" might be)? Having flags that pick between different >> behaviours scales badly, and is typically not a good design. >> >> For your own code, you can write the behaviour that works best for >> you, and for your application. For the stdlib, the behaviour has to >> address the needs of *everyone*. >> >> My feeling is that the complexity of a "does the right thing for >> everyone" stdlib implementation would outweigh any benefit gained from >> not having to write your own short function, tailored to your >> particular needs. >> >> Paul >> _______________________________________________ >> 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/5BNPSKGEJ6WE2GBYO4FGG5NMXXRJHJ7S/ >> Code of Conduct: http://python.org/psf/codeofconduct/ >> > -- > Christopher Barker, PhD (Chris) > > 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/YBSYFBVT4MEFSCS76UX2LSGJYU64O5ZK/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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