[Python-Dev] Issue 2736: datetimes and Unix timestamps

[Terry Reedy]

On 6/5/2012 3:17 PM, Guido van Rossum wrote:
> On Tue, Jun 5, 2012 at 12:15 PM, Alexander Belopolsky
> <alexander.belopolsky at gmail.com>  wrote:
>> On Tue, Jun 5, 2012 at 3:01 PM, Antoine Pitrou<solipsis at pitrou.net>  wrote:
>>> You could say the same about equally "confusing" results, yet equality never
>>> raises TypeError (except between datetime instances):
>>>
>>>>>> () == []
>>> False
>>
>> And even closer to home,
>>
>>>>> date(2012,6,1) == datetime(2012,6,1)
>> False
>>
>> I agree, equality comparison should not raise an exception.
>
> Let's make it so.

3.3 enhancement or backported bugfix? The doc strongly suggests that 
rich comparisons should return *something* and by implication, not 
raise. In particular, return NotImplemented instead of raising a 
TypeError for mis-matched arguments.

"A rich comparison method may return the singleton NotImplemented if it 
does not implement the operation for a given pair of arguments. By 
convention, False and True are returned for a successful comparison. 
However, these methods can return any value,"

-- 
Terry Jan Reedy