[Datetime-SIG] PEP 495 (Local Time Disambiguation) is ready for pronouncement

Alexander Belopolsky alexander.belopolsky at gmail.com
Sun Aug 16 05:17:19 CEST 2015

On Sat, Aug 15, 2015 at 10:58 PM, Ethan Furman <ethan at stoneleaf.us> wrote:
> Correction to PEP:
> ----------------------------------
> [about halfway down]
> The value returned by dt.timestamp() given a missing dt will be the larger
> of the two "nice to know" values if dt.first  == True and the larger
> otherwise.
> Presumably the first "larger" should be "smaller".
> ----------------------------------

No.  The rule for the missing time is the opposite to that for the
ambiguous time.
This allows a program that probes the TZ database by calling timestamp with
two different values of the "first" flag to avoid any additional calls
to differentiate
between the gap and the fold.

> [about three/fourths of the way down]
> Temporal Arithmetics
> The value of "first" will be ignored in all operations except those that
> involve conversion between timezones. [2] As a consequence,
> datetime.datetime` or datetime.time instances ...
> "datetime.datetime" is missing a leading backtick.
> ----------------------------------

Will fix. Thanks.

> The PEP should be presented on py-dev for discussion (or at least for
> pronouncement).

According to PEP 1:

"PEP review and resolution may also occur on a list other than
python-dev (for example, distutils-sig for packaging related PEPs that
don't immediately affect the standard library). In this case, the
"Discussions-To" heading in the PEP will identify the appropriate
alternative list where discussion, review and pronouncement on the PEP
will occur." [1]

PEP 495 has  "Discussions-To" heading set to this mailing list.  I
have no problem cross-posting to python-dev, but I am not sure this is
the right thing to do.  This SIG was created for a reason.

> Are the strict tzinfo's for a different PEP?

Yes, PEP-0500.

[1]: https://www.python.org/dev/peps/pep-0001/#pep-review-resolution

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