From: Trans <transfire@...>
Date: 2008-03-23T04:40:44+09:00
Subject: Re: #meta



On Mar 22, 2:39 pm, "Rick DeNatale" <rick.denat...@gmail.com> wrote:
> On 3/22/08, Ryan Davis <ryand-r...@zenspider.com> wrote:
>
>
>
> >  On Mar 22, 2008, at 06:39 , Robert Klemme wrote:
> >  > I am feeling stupid because I seem to overlook something: what is
> >  > the advantage of your approach vs.
>
> >  > class Object
> >  >  def meta
> >  >    class<<self;self;end
> >  >  end
> >  > end
>
> > Your approach mentarbates less, so trans doesn't like it as much.
>
> Along these lines, note Stu Halloway's blog post about the definition
> of  Object#metaclass in facets vs. other places and the ensuing
> commentary:
>
> http://blog.thinkrelevance.com/2008/2/12/how-should-metaclass-work
>
> I'd seen lots of examples of metaclass being defined the same way as
> Robert's proposed meta method above, and had never seen the more
> complex implementation in facets until Stu bumped into problems
> because use was using facets 'feature' of taking a block.
>
> I totally agree with the consensus in the comments that the simpler
> definition is better.

Actually in Facets, #singelton_class is defined witht the simpler
definition. #meta_class is not. However, I don't agree that the
simplier case is somehow better. The issue is that Ruby will no-op a
block regardless. For example:

 def x; "1"; end
 x{"whatever"} #=> 1

So it has nothing per se to do with the definition of #meta_class.
It's an aspect of Ruby, and the fact that there are two definitions of
this floating around out there. So between the two, I tend toward not
wasting name space. If supporting the block takes nothing away from
the regular usage, and it reads better, then whats the issue exactly?

> I also side with Jim Weirich about the
> distinction between metaclass and singleton class or eigenclass or
> whatever you want to call them.

That's Smalltalk not Ruby. I understand the distinction people want to
draw, but in Ruby they are the same construct.

T.