From: Christoph <swap@...> (news_chr)
Date: 2003-10-03T15:50:27+09:00
Subject: Re: mixing in class methods

"Mark J. Reed"  wrote:
....
>
> Thanks to all.  The :append_features solution was giving me trouble
> with modules that included other modules; :included may help there.

On a serious note: The following might give you an idea on
dealing with the ``include Modules in other Module'' issue.

----
class MModule < Module # the name is arbitrary
  def initialize
    @class_module = Module.new
    super
  end
   private
  def class_methods(&b)
    @class_module.module_eval &b
  end
  def included(mod)
    if mod.is_a? Class
      mod.extend @class_module
    else mod.is_a? MModule
      mod.class_module.__send__(:include,@class_module)
    end
  end
  protected
  attr_reader :class_module
end




# usage #
M = MModule.new do
  def instance_method1
    p "instance_method1"
  end
  class_methods do
    def class_method1
      p "class_method1"
    end
  end
end

# a MModule constant can be used like regular Module constant
module M
  def instance_method2
    p "instance_method2"
  end
  class_methods do
    def class_method2
      p "class_method2"
    end
  end
end


# include example
N = MModule.new do
  include M
  def instance_method3
    p "instance_method1"
  end

  class_methods do
    def class_method3
      p "class_method3"
    end
  end
end


class C
  include N
end


C.new.instance_method1 # instance_method1
C.new.instance_method2 # instance_method2
C.new.instance_method3 # instance_method3
C.class_method1        # class_method1
C.class_method2        # class_method2
C.class_method3        # class_method3
----

/Christoph