From: Christophe Grandsire <christophe.grandsire@...>
Date: 2005-10-26T18:33:37+09:00
Subject: Re: Comparing Classes with Case ?

Selon Robert Klemme <bob.news@gmx.net>:

> >
> > Yes, and although the order makes sense, from a functional point of
> > view, it is difficult to get my head around the idea that case
> > indicates the argument rather than the receiver.
>
> If you think about it for a moment you'll see that it's the only
> reasonable approach: the expression after the case is the item to test and
> all expressions after when denomiate conditions.

Of course it is the only reasonable approach. I agree completely with it. But it
doesn't change that the order in which the case and the when parts read kind of
imply a left-to-right, rather than right-to-left, relationship, especially
since in other languages I know with a case/switch expression it's exactly what
happen under the hood :) .

So although I see why it *should* be the way it is in Ruby, I still can't
remember it reliably. It's not a Ruby problem, it's a me problem ;) .

  You can for example do
> this, which might make it clearer...
>
> def Condition(&b)
>   class <<b
>     alias === []
>   end
>   b
> end
>

Wow! Some of the things one can do with Ruby make my head spin! The worst is: I
can understand what it means!!! ;)

> case a_number
>   when Condition {|x| x < 10}
>   ...
> end
>

Cool trick indeed :) . But I'll just try to remember the order from now on, or
at least remember how to get back to it...
--
Christophe Grandsire.

http://rainbow.conlang.free.fr

It takes a straight mind to create a twisted conlang.