Spell: Class Extension Mixin

class_extension_mixin.rb

# ============================
# Spell: Class Extension Mixin
# ============================

# Enable a module to extend its includer through a Hook Method (http://gist.github.com/534994).

module M
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    def my_method
      'a class method'
    end
  end
end

class C
  include M
end

C.my_method # => "a class method"

# For more information: http://www.pragprog.com/titles/ppmetr/metaprogramming-ruby