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

[Raymond Hettinger]

FWIW, my viewpoint on this is softening over time
and I no longer feel a need to push for a new context flag.

It is probably simplest for users if implicit coercions didn't come
with control knobs.  We already have Fraction+float-->float
occurring without any exceptions or warnings, and nothing
bad has happened as a result.

Also, I'm reminded of Tim Peter's admonition to resist
extending the decimal spec.  

I used to worry that any decimal/float interactions were
most likely errors and shouldn't pass silently.  Now, I've
just stopped worrying and I feel better already ;-)
Adding a FAQ entry is simpler than building-out
Context object circuitry and documenting it in an
understandable way.

Raymond



On Mar 24, 2010, at 12:36 PM, Stefan Krah wrote:

> Nick Coghlan <ncoghlan at gmail.com> wrote:
>> Raymond Hettinger wrote:
>>> The decimal module is already drowning in complexity,
>>> so it would be best to keep it simple:  one boolean flag
>>> that if set would warn about any implicit decimal/float
>>> interaction.
>> 
>> Agreed - those that want exceptions instead can use the usual warnings
>> module mechanisms to trigger them.
> 
> 
> I'm not sure about the warnings module. If lower complexity is a goal,
> I would prefer Facundo's original proposal of just adding a single new
> signal. Users who just want to know if a NonIntegerConversion has occurred
> can check the flags, users who want an exception set the trap.
> 
> With the warnings module, users have to know (and deal with) two exception
> handling/suppressing mechanisms.
> 
> 
> Stefan Krah