monkeyed_ruby_mixin.rb

module Monkeyedwith
  def monkeyed
    puts "Invisible Cavemen!"
  end
end
 
class MonkeyString < String
  include Monkeyedwith
end
 
madness = MonkeyString.new("madness") # => "madness" 

madness.monkeyed
# Invisible Cavemen!
# => nil