decorate w/ Module

gistfile1.rb

class SimpleWriter

  def write(text)
    puts text
  end

end

module TimeStampingWriter

  def write(text)
    super("#{Time.now}: #{text}")
  end

end

module NumberingWriter

  attr_reader :line_number

  def write(text)
    @line_number = 1 unless @line_number
    super("#{@line_number}: #{text}")
    @line_number += 1
  end

end

w = SimpleWriter.new
w.write("Hello")

w.extend(NumberingWriter)
w.extend(TimeStampingWriter)
w.write("Hello")