# File lib/mail/parsers/content_type.rb, line 240
    def _nt_composite_type
      start_index = index
      if node_cache[:composite_type].has_key?(index)
        cached = node_cache[:composite_type][index]
        @index = cached.interval.end if cached
        return cached
      end

      i0 = index
      if has_terminal?("message", false, index)
        r1 = instantiate_node(SyntaxNode,input, index...(index + 7))
        @index += 7
      else
        terminal_parse_failure("message")
        r1 = nil
      end
      if r1
        r0 = r1
      else
        if has_terminal?("multipart", false, index)
          r2 = instantiate_node(SyntaxNode,input, index...(index + 9))
          @index += 9
        else
          terminal_parse_failure("multipart")
          r2 = nil
        end
        if r2
          r0 = r2
        else
          r3 = _nt_extension_token
          if r3
            r0 = r3
          else
            @index = i0
            r0 = nil
          end
        end
      end

      node_cache[:composite_type][start_index] = r0

      r0
    end