# File lib/diff/lcs/change.rb, line 116
  def <=>(other)
    r = @action <=> other.action
    r = @old_position <=> other.old_position if r.zero?
    r = @new_position <=> other.new_position if r.zero?
    r = @old_element <=> other.old_element if r.zero?
    r = @new_element <=> other.new_element if r.zero?
    r
  end