From: Eric Hodel <drbrain@...7.net>
Date: 2005-11-10T03:45:56+09:00
Subject: Re: Numeric <=>

On Nov 9, 2005, at 8:47 AM, Robert Klemme wrote:

> Christophe Grandsire wrote:
>> Selon ChrisH <chris.hulan@gmail.com>:
>>
>>> Thanks Eric.  I just wonder why Numeric doesn't implement it
>>> properly?
>>
>> Probably because it can't. I'm not completely up-to-date with the
>> Numeric inheritance chain, but I guess for instance Complex numbers
>> also inherit from Numeric. Being Numeric doesn't necessarily mean
>> that there is a meaningful order among the objects.
>
> Although I agree with your analysis that Numeric can't properly  
> implement
> <=> the question remains why <=> is actually implemented in  
> Numeric.  ATM
> I cannot see what necessitates it.  Including Comparable is not a  
> reason
> IMHO because that will break either way (i.e. with missing <=> and  
> with
> incomplete implemented <=>).
>
>> Then again, I'm out on a limb here, and may be completely wrong.
>
> Not completely but I have the feeling we're still not there.  Someone
> probably needs to take the time and have a look at the sources...

If you forget to define #<=> in your Numeric subclass you have a  
safety net and your code won't mysteriously die.

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
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