From: Trans <transfire@...>
Date: 2007-06-19T02:48:30+09:00
Subject: Means of Optional Expression

Have a look at this. Note that I'm not bothering to implement the
#shuffle method as it is not the point --it's just an foo example.

  module Kernel
    def express(name)
      extend self.class.const_get(name.to_s.capitalize)
    end
  end

  class Array
    module Random
      def shuffle
        [] # ...
      end

      def shuffle!
        replace(shuffle)
      end

      # ...
    end
  end

  a = [1,2,3]
  a.shuffle  #=> NoMethodError

  a.express(:Random)
  a.shuffle  #=> []

T.