ruby meta brainfuck.rb

module Speech
  def self.included(base)
    base.send :include, Speech::Support
  end
end

module Speech::Support
  def self.included(base)
    base.extend(ClassMethods)
  end
  
  module ClassMethods
    def singleton_class
      class << self; self; end
    end
    
    def speak
      puts "in #{__LINE__} from #{caller[0]}"
      puts 'say: module method'
      super
    end
    
    def can_speak
      class_eval do
        def self.speak
          puts "say: class_eval"
          super
        end
      end
      
      class << self
        define_method :speak do
          puts "in #{__LINE__} from #{caller[0]}"
          puts "say: class << self"
          super()
        end
      end
      
      self.class.instance_eval do
        define_method :speak do
          puts "in #{__LINE__} from #{caller[0]}"
          puts "say: class.instance_eval"
        end
      end
    end
  end
end

class Matt
  def self.speak
    puts "real class method"
    super
  end
  
  include Speech
  can_speak
end

Matt.speak