From: transfire@...
Date: 2006-06-15T21:47:02+09:00
Subject: Re: Why the lack of mixing-in support for Class methods?


Daniel Schierbeck wrote:
> Simplification. Tell me if I should stop spamming.
>
>    class Module
>      def class_extension(&block)
>        @class_extension ||= Module.new do
>          def self.included(mod); end
>        end
>        @class_extension.module_eval(&block) if block_given?
>        @class_extension
>      end
>
>      def included(mod)
>        mod.extend(class_extension)
>        if mod.instance_of? Module and mod.respond_to? :class_extension
>          mod.send(:class_extension).send(:include, class_extension)
>        end
>      end
>    end
>
> The code might need a change if we decide to make #class_extension private.

Daniel,

I assume you are doing this for the challenge / learning expience....

#included is not the best method to use since it is a callback. While
you could override #include itself, probably the most appropriate
method to use is #append_features. This is the method include calls to
do it's "magic".

Also, after defining the class_extension method for Module, you'll want
to undefine it for Class, since it has no relevance there:

  class Class
    undef_method :class_extension
  end

HTH,
T.