Example Singleton for #ruby IRC

base.rb

require 'singleton'

module Base
  attr_reader :properties

  def self.included(base)
    base.instance.instance_variable_set(:@properties, [])
    base.instance_eval do
      def property(name)
        instance.properties << name
      end
    end
  end
end

class Sub
  include Singleton
  include Base

  property :foo
end

Sub.instance.properties
#=> [:foo]

sub.rb

module Base
  attr_reader :properties

  def property(name)
    @properties << name
  end
 
  def self.extended(base)
    base.instance_eval do
      @properties = []
    end
  end
end

class Sub
  extend Base

  property :foo
end
 
p Sub.properties
#=> [:foo]