# File lib/mail/parsers/content_disposition.rb, line 269
    def _nt_attribute
      start_index = index
      if node_cache[:attribute].has_key?(index)
        cached = node_cache[:attribute][index]
        @index = cached.interval.end if cached
        return cached
      end

      s0, i0 = [], index
      loop do
        r1 = _nt_token
        if r1
          s0 << r1
        else
          break
        end
      end
      if s0.empty?
        @index = i0
        r0 = nil
      else
        r0 = instantiate_node(SyntaxNode,input, i0...index, s0)
      end

      node_cache[:attribute][start_index] = r0

      r0
    end