class.rb

  def rule message, &block
    @rules ||= []
    @rules << Class.new {
      attr_reader :message

      def initialize(message, &block)
        @message = message
        @block = block
      end

      def matches?
        @block.call
      end
    }.new(message, &block)
  end



  def rule message, &block
    @rules << Class.new {
      define_method(:message)  { message }
      define_method(:matches?) { block.call }
    }.new
  end