[Python-Dev] proposal: add basic time type to the standard library

M.-A. Lemburg mal@lemburg.com
Wed, 27 Feb 2002 10:36:05 +0100

Anthony Baxter wrote:
> >>> "M.-A. Lemburg" wrote
> > I tried that in early version of mxDateTime -- it fails
> > badly. I switched to the local time assumption very
> > early in the development.
> If you must store stuff without timezones, _please_ don't use
> localtime. localtime is a variable thing (think what happens
> when daylight savings goes on and off).

You probably didn't notice the "assumption" -- mxDateTime
has a few APIs which make assumptions about the value
stored in DateTime objects; however, you can just as well
store UTC in them. In that case, the APIs making the
local time assumption will produce wrong data of course.

>>> from mx.DateTime import *
>>> now() # local time
<DateTime object for '2002-02-27 10:33:52.63' at 8199ec0>
>>> now().gmtime() # in UTC
<DateTime object for '2002-02-27 09:33:55.72' at 8196b38>

In the end, it's better to leave the decision what to store
in a DateTime object to the programmer. Timezones, DST and
leap seconds sometimes have their application and sometimes
just cause plain confusion. 

IMHO, the application should decide what to do about them 
and manage the data storage aspects of its decision.
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
Company & Consulting:                           http://www.egenix.com/
Python Software:                   http://www.egenix.com/files/python/