[Python-Dev] datetime module enhancements

[Georg Brandl]

Robert Brewer schrieb:
> Brett Cannon wrote:
>> On 3/9/07, Collin Winter <collinw at gmail.com> wrote:
>> > On the subject of datetime enhancements, I came across an SF patch
>> > (#1673403) the other day that proposed making it possible to compare
>> > date and datetime objects...
>> 
>> I personally like the current solution.  The proposal to just assume
>> midnight goes against EIBTI in my mind.
> 
> Yeah, but the current solution goes against, um, APBP*. Not in my mind,
> but in my code. Repeatedly. I can't count how many times I've written
> code like:
> 
>     if created > fdate:
> 
> when I "should" have written:
> 
>     if isinstance(created, datetime.date):
>         date_version_of_created = created
>     else:
>         date_version_of_created = created.date()
>     if date_version_of_created > fdate:
> 
> But it gets better, because:
> 
>     >>> isinstance(datetime.datetime(x, y, z), datetime.date)
>     True
> 
> So the above won't work, you must remember to reverse the if/else:
> 
>     if isinstance(created, datetime.datetime):
>         date_version_of_created = created.date()
>     else:
>         date_version_of_created = created
>     if date_version_of_created > fdate:

Why not just give date objects a date() method that returns self?
That way you can write

if created.date() > fdate:

Georg