wrapping_methods.rb

module Animal
  def self.included(base)
    class << base
      def method_added(name)
        unless (@wrapped_methods ||= []).include? name
          @wrapped_methods.push name
          puts "Defined #{name}"
          wrap_method name
        end
      end

      def wrap_method(method_name)
        method = instance_method(method_name)
        define_method(method_name) do |*args|
          puts "#{method_name} called"
          method.bind(self).call(*args)
        end
      end
    end
    [:miow].each {|m| base.wrap_method m if base.method_defined? m}
  end
end

class Cat
  def miow
    puts "#{@name} miows"
  end

  include Animal

  def initialize(name)
    @name = name
  end

  def miow
    puts "#{@name} miows"
  end
end

Cat.new("Eric").miow