From: Dreamcat Four <dreamcat4@...>
Date: 2009-10-12T21:54:37+09:00
Subject: Re: Class Level inheritable attributes - are we there yet?

Ah,

dreamcat four wrote:
> * Use the activeresource class inheritable accessor. I guess that's
> not so much of a stretch if you are already depending upon
> activeresource for other things.
> 
> * Request a real language implementation in ruby core because class is
> an object. It would be entirely a matter for the ruby development team
> to decide whether they would want to implement it, and/or how. I'm
> very surprised no-one has asked for this on 1.9 line, or to change the
> existing @@ behaviour since are changed the block level variable
> scoping and many other things.
> 

I seem to have been wrong about recommending these
activesupport/class_inheritable_accessor. They are not fully up to
scratch.

require "activesupport"
class Cartoon
  self.class_inheritable_accessor :_
  self._ = "deputy dawg"

  def initialize(*args, &block)
    puts self.class._.inspect
    puts self._.inspect
    self._ = "the lazy cat"
    puts self._.inspect
    puts self.class._.inspect
  end
end
Cartoon.new

=>
"deputy dawg"
"deputy dawg"
"the lazy cat"
"the lazy cat"

As you can see, modifying the value in the instantiated object also
modifies the value back in the class object.


So back to 'clia.rb' like in the first 2 posts. I was maybe going to
suggest that we should make a new accessor method. But digging deeper we
can see activesupport have already defined 'cattr_accessor' aswell (this
time for attributes which aren't inherited and passed on to either
instances or subclasses).

Then i searched for 'ciattr_accessor' in case someone had already made
an inheritable version.
http://atomos.rubyforge.org/svn/atomos/lib/extra.rb Does it do the
required job? No (is another duplication of cattr). Potential namespace
conflict? Yes.


David has shown that we should 'extend' and not define any accessor
method. So I guess its the better choice (since pointing out about the
@=nil). Im definately coming around to understand better and appreciate
more David's solution here. Thank you.


Best regards,

dreamcat4
dreamcat4@gmail.com
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