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Alexander Belopolsky wrote:
> 
> Alexander Belopolsky <belopolsky@users.sourceforge.net> added the comment:
> 
> On Fri, Jul 2, 2010 at 6:00 PM, Tim Peters <report@bugs.python.org> wrote:
>>
>> Tim Peters <tim.peters@gmail.com> added the comment:
>>
>>> Do you remember why it was a good idea to
>>> derive datetime from date?
>>
>> Why not? A datetime is a date, but with additional behavior. Makes inheritance conceptually natural.
> 
> It is also time with additional behavior. In the face of ambiguity ...
> 
> Why not? See issue #5516. Most of datetime comparison code is
> devoted to fighting inheritance from date. There is hardly any
> non-trivial method that benefits from this inheritance.
> 
> To me, conceptually, datetime is a container of date, time and
> optionally time zone, it is not a date.
Just an aside:
Conceptually, you don't need date and time, only an object to
reference a point in time and another one to describe the
difference between two points in time. In mxDateTime I
called them DateTime and DateTimeDelta.
What we commonly refer to as date is really the combination of
a DateTime value pointing to the start of the day together with
a DateTimeDelta value representing one full turn of the Earth.
That said, I don't think redesigning the datetime module is part
of this ticket, just adding a second implementation of what we
already have in CPython :-)