gistfile1.txt

  def self.process_randoms(text)
    stack          = []
    stored_string  = ""
    random_choices = []

    scanner = StringScanner.new(text)
    while match = scanner.scan_until(/[\{\}\|]|\[(one of|or|at random)\]/)
      stored_string << match.slice(0, match.length - scanner.matched_size)
      case scanner.matched
      when "{", "[one of]"
        stack.push([random_choices, stored_string])
        random_choices = []
        stored_string  = ""
      when "|", "[or]"
        if stack.empty?
          stored_string << "|"
        else
          random_choices.push(stored_string)
          stored_string = ""
        end
      when "}", "[at random]"
        unless stack.empty?
          random_choices.push(stored_string)
          selected_choice = random_choices[rand(random_choices.length)]
          (random_choices, stored_string) = stack.pop
          stored_string << selected_choice
        end
      end
    end
    stored_string << scanner.rest if scanner.rest?
    stored_string
  end