module_inclusion.rb

module Wrapped
  # This is the wrapper class
  class Wrapper
    attr_accessor :content

    def initialize(content)
      @content = content
    end

    def content_value
      @content.value
    end
  end

  # So that module can be inluded as well as extended 
  def self.included(base)
    base.extend self
  end

  def new(*args)
    Wrapper.new(super)
  end
  
end


class Content

  include Wrapped

  attr_accessor :value

  def initialize(default)
    @value = default
  end

end

class ComplicatedContent < Content
  alias_method :simple_value, :value
  def value
    simple_value.reverse
  end
end

c = Content.new("a_to_z")
puts "Content.new(\"a_to_z\"):"
puts "- class = #{c.class}"
puts "- value = #{c.content_value}"

c = ComplicatedContent.new("a_to_z")
puts "ComplicatedContent.new(\"a_to_z\"):"
puts "- class = #{c.class}"
puts "- value = #{c.content_value}"

singleton_super_version.rb

class Wrapper
  attr_accessor :content

  def initialize(content)
    @content = content
  end

  def content_value
    @content.value
  end
end

class Content
  attr_accessor :value

  class << self
    def new(*args)
      Wrapper.new(super)
    end
  end

  def initialize(default)
    @value = default
  end

end

class ComplicatedContent < Content
  alias_method :simple_value, :value
  def value
    simple_value.reverse
  end
end

c = Content.new("a_to_z")
puts "Content.new(\"a_to_z\"):"
puts "- class = #{c.class}"
puts "- value = #{c.content_value}"

c = ComplicatedContent.new("a_to_z")
puts "ComplicatedContent.new(\"a_to_z\"):"
puts "- class = #{c.class}"
puts "- value = #{c.content_value}"