From: Michel Demazure <michel@...>
Date: 2007-10-31T19:56:29+09:00
Subject: Re: Code to DRY

Robert Klemme wrote:
> 2007/10/31, Michel Demazure <michel@demazure.com>:
>> >>   end
>> >> end
>> >
>> > And instead of #le?, why not #<, #==, #>, #<=>?
>>
>> #< looks good. Thanks.
> 
> Also keep attention to module Comparable
> http://www.ruby-doc.org/core/classes/Comparable.html
> 
> Basically you need to only implement <=> and get all other operators for 
> free.
> 
> Btw, what do you need min and max for?
> 
> Kind regards
> 
> robert

Robert,

Actually, I have partial orders ("pr辿ordre" in french) and not orders 
("ordre total" in french), so <=> does not work well. For instance, you 
can have a.le?(b) and b.le?(a), but not a = b. Or neither a.le?(b), nor 
b.le?(a). For instance a.lt?(b) is "a.le?(b) and not b.le?(a)" but not 
"a.le?(B) and a != b".

I need min and max for semantic reasons, analogous to Scott's semantics 
for programming languages : 'min' is something like 'undefined' 
(definitely less than 'defined with value nil' for instance) and 'max' 
is something like 'overdefined' or 'impossible'. All this for some try 
at a "fuzzy knowledge" management program...which actually works quite 
well!

Best,
Michel
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