From: Robert Dober <robert.dober@...>
Date: 2006-04-11T02:19:30+09:00
Subject: Re: Adding in class attribute with a Module

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On 4/10/06, Gregory Seidman <gsslist+ruby@anthropohedron.net> wrote:
>
> On Mon, Apr 10, 2006 at 11:58:43PM +0900, TRANS wrote:
> } > Is it possible to add class attributes (cattr_accessor) using a
> module?
> } > If so could you give an example?
> }
> } There is no "Ruby Way" to do this b/c Ruby's module methods aren't
> } inherited by classes that include them. Though I've asked for a way
> } man times now!
> [...]
> } Only ugly meta-programming hacks will give the sought behavior --and
> } even then their are corner-case complications.
>
> Does this count as ugly meta-programming?
>
> module M
>   def self.included(klass)
>     class << klass
>       attr_accessor :m
>     end
>   end
> end


It is much prettier than the following ugly meta-programming, but I have no
clue how it works !!!
Could you explain please?
Thx
Robert

} T.
> --Greg




class Module
>         def cattr( *names )
>                 names.map{ |name| name.to_s }.each do
>                         |name|
>                         eval <<-EOEval
>         def self.#{name}; @#{name}; end
>         def self.#{name}=3D(x); @#{name}=3Dx; end
>                         EOEval
>                         define_method( name ){ self.class.send( name ) }
>                         define_method( name + "=3D"){ |v| self.class.send=
(
> name + "=3D", v ) }
>                 end
>         end
> end
>
>


--
Deux choses sont infinies : l'univers et la b=EAtise humaine ; en ce qui
concerne l'univers, je n'en ai pas acquis la certitude absolue.

- Albert Einstein

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