[Python-Dev] Add aware local time support to datetime module

[Alexander Belopolsky]

It looks like this response has slipped under my radar.  Sorry.

On Sun, Aug 8, 2010 at 4:37 AM, Lennart Regebro <regebro at gmail.com> wrote:
[skipped description of two alternative solutions]
..
> For all of the reasons you give above, I think it's a bad idea. :-)
>
I did not give any reason for not having access to the information
that is readily available through reasonably cross-platform C API.
Can you elaborate on what you think is a bad idea?


> You need a proper time zone database to solve these issues, like pytz.

Pytz is more ambitious than what I propose.  I don't propose adding a
timezone database to python or even a functionality to access system
timezone database.  All I want to add is a method to get aware local
time in the system timezone.

> Which incidentally solves the ambiguity problem as well. so the
> solution is pytz. :-)

No, it does not.  In order to resolve the ambiguity, pytz adds a
non-standard argument to tzinfo methods, but datetime objects don't
know how to pass this argument and don't have data to determine its
value to begin with.

> What pytz doesn't have (but dateutil.tz does) is a timezone object
> that uses the operating systems local timezone data, like
> /etc/localzone on unix. That could be interesting to include,
> possibly. Having a fixed time zone offset object for the localtime
> seems a bad idea. The problem it solves is easy to get around, but the
> problems created are not.

This sounds like an argument against my "second alternative."  As I
explained, my preference is the same.  Do you have an opinion on the
localtime([t]) alternative?