[Python-Dev] Mixing float and Decimal -- thread reboot

[Guido van Rossum]

On Mon, Mar 22, 2010 at 10:22 AM, Alexander Belopolsky
<alexander.belopolsky at gmail.com> wrote:
> On Mon, Mar 22, 2010 at 1:56 PM, Raymond Hettinger
> <raymond.hettinger at gmail.com> wrote:
>>
>> On Mar 22, 2010, at 10:00 AM, Guido van Rossum wrote:
>>
>>   Decimal + float --> Decimal
>>
>> If everybody associated with the Decimal implementation wants this I
>> won't stop you; as I repeatedly said my intuition about this one (as
>> opposed to the other two above) is very weak.
>>
>> That's my vote.
>
> I've been lurking on this thread so far, but let me add my +1 to this
> option.  My reasoning is that Decimal is a "better" model of Real than
> float and mixed operations should not degrade the result.   "Better"
> can mean different things to different people, but to me the tie
> breaker is the support for contexts.  I would not want precision to
> suddenly change in the middle of calculation I add 1.0 instead of 1.
>
> This behavior will also be familiar to users of other "enhanced"
> numeric types such as NumPy scalars.   Note that in the older Numeric,
> it was the other way around, but after considerable discussion, the
> behavior was changed.

Thanks, "better" is a great way to express this.

-- 
--Guido van Rossum (python.org/~guido)