# File lib/mail/parsers/rfc2822_obsolete.rb, line 1226
    def _nt_obs_domain_list
      start_index = index
      if node_cache[:obs_domain_list].has_key?(index)
        cached = node_cache[:obs_domain_list][index]
        @index = cached.interval.end if cached
        return cached
      end

      i0, s0 = index, []
      if has_terminal?("@", false, index)
        r1 = instantiate_node(SyntaxNode,input, index...(index + 1))
        @index += 1
      else
        terminal_parse_failure("@")
        r1 = nil
      end
      s0 << r1
      if r1
        r2 = _nt_domain
        s0 << r2
        if r2
          s3, i3 = [], index
          loop do
            i4, s4 = index, []
            s5, i5 = [], index
            loop do
              if has_terminal?(",", false, index)
                r6 = instantiate_node(SyntaxNode,input, index...(index + 1))
                @index += 1
              else
                terminal_parse_failure(",")
                r6 = nil
              end
              if r6
                s5 << r6
              else
                break
              end
            end
            r5 = instantiate_node(SyntaxNode,input, i5...index, s5)
            s4 << r5
            if r5
              r8 = _nt_CFWS
              if r8
                r7 = r8
              else
                r7 = instantiate_node(SyntaxNode,input, index...index)
              end
              s4 << r7
              if r7
                if has_terminal?("@", false, index)
                  r9 = instantiate_node(SyntaxNode,input, index...(index + 1))
                  @index += 1
                else
                  terminal_parse_failure("@")
                  r9 = nil
                end
                s4 << r9
                if r9
                  r10 = _nt_domain
                  s4 << r10
                end
              end
            end
            if s4.last
              r4 = instantiate_node(SyntaxNode,input, i4...index, s4)
              r4.extend(ObsDomainList0)
            else
              @index = i4
              r4 = nil
            end
            if r4
              s3 << r4
            else
              break
            end
          end
          r3 = instantiate_node(SyntaxNode,input, i3...index, s3)
          s0 << r3
        end
      end
      if s0.last
        r0 = instantiate_node(SyntaxNode,input, i0...index, s0)
        r0.extend(ObsDomainList1)
      else
        @index = i0
        r0 = nil
      end

      node_cache[:obs_domain_list][start_index] = r0

      r0
    end