# File lib/rbreadline.rb, line 2190
  def parser_else(args)
    if @if_stack.empty?
      #_rl_init_file_error ("$else found without matching $if")
      return 0
    end

    # Check the previous (n) levels of the stack to make sure that
    #   we haven't previously turned off parsing.
    return 0 if @if_stack.detect {|x| x }

    # Invert the state of parsing if at top level.
    @_rl_parsing_conditionalized_out = !@_rl_parsing_conditionalized_out
    return 0
  end