[Python-Dev] Status on PEP-431 Timezones

Tim Peters tim.peters at gmail.com
Mon Jul 27 22:10:00 CEST 2015

[Terry Reedy <tjreedy at udel.edu>]
> To me, having 1 day be 23 or 25 hours of elapsed time on the DST transition
> days, as in Paul's alarm example, hardly ignores the transition point.

It's 2:56PM.  What time will it be 24 hours from now?  If your answer
is "not enough information to say, but it will be some minute between
1.56PM and 3:56PM inclusive", you want to call _that_ "naive"?  I sure
don't.  You can only give such an answer if you're acutely aware of
(for example) DST transitions.

If you're truly naive, utterly unaware of the possibility of
occasional time zone adjustments, then you give the obvious answer:
2:56PM.  That's what Python's datetime arithmetic gives.  That's naive
in both technical and colloquial senses.

You're only aware of that "2:56PM tomorrow" may be anywhere between 23
and 25 hours away from "2:56PM today" because you're _not_ ignoring
possible transitions.  So,. sure, I agree that your pointing it out
"hardly ignores the transition point".  But I wasn't talking about you
;-)  I was talking about the arithmetic, which does thoroughly ignore

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