From: Victor Shepelev <vshepelev@...>
Date: 2006-04-14T16:29:19+09:00
Subject: Re: Rubyesque way to do multiple <=>



> > You haven't got it. I already USED first version, but I CAN'T if
> > comparison
> > is done through stand-alone function instead of <=>
> 
> 
> I have not, you are right! really sorry, I just *could* not immagine that
> someone would implement a Custom Compare without defining <=>.
> But as it is you have of course a problem.
> Forgive my answer sometimes there are beginners posting.
> The next time however, before replying, I might read the question.

I thinks, there is a bit of irony :)
If my uppercased words have hurt your feelings, I must apoligize :(
Uppercase was only logical stress (moreover, my English is not so good, so
maybe I said something terrible, but I have no intention to show my "great
mind" :)
Sorry my bad manners, please

> What you have done is nice, but condider this too in case you can
> determine
> a reasonable BaseClass of sex.
> 
> class SexBaseClass
>    def <=>(other)
>       ComplexCompareFunction self, other
>    end
> end

Yes, I know this way, but I really can't use it. Here is more real example:

class Product
  attr_accessor :type, :field1, :field2, field3
end

If @type is "HDD", @field1 is string representing hdd size (120 Gb, 80 Gb
and so on): comparison must be done as field1.to_i <=> other.field1.to_i

If @type is "drive", @field1 is drive type ("cd-r", "cd-rw", "dvd" ...) and
comparison must be done in a strange way ("cd-XXX" > "dvd-XXXX", but
"cd-rom" < "cd-r" < "cd-rw").

OK, you would ask, why I've used one "general" class Product instead of
concrete HDD, CPU, Drive and so on? Because product type can be changed
dynamically (it is guessed by product full name, on wrong guess user can
change @type manually through GUI).

So, my question is still actual.

> Hope I got it
> Robert

Victor.