skip_optional_do_after_expression

# File lib/rdoc/parser/ruby.rb, line 2734
  def skip_optional_do_after_expression
    skip_tkspace(false)
    tk = get_tk
    case tk
    when TkLPAREN, TkfLPAREN
      end_token = TkRPAREN
    else
      end_token = TkNL
    end

    nest = 0
    @scanner.instance_eval{@continue = false}

    loop do
      case tk
      when TkSEMICOLON
        break
      when TkLPAREN, TkfLPAREN
        nest += 1
      when TkDO
        break if nest.zero?
      when end_token
        if end_token == TkRPAREN
          nest -= 1
          break if @scanner.lex_state == EXPR_END and nest.zero?
        else
          break unless @scanner.continue
        end
      end
      tk = get_tk
    end
    skip_tkspace(false)

    get_tk if TkDO === peek_tk
  end