# File lib/treetop/compiler/metagrammar.rb, line 3266
      def _nt_alphanumeric_char
        start_index = index
        if node_cache[:alphanumeric_char].has_key?(index)
          cached = node_cache[:alphanumeric_char][index]
          if cached
            cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
            @index = cached.interval.end
          end
          return cached
        end

        i0 = index
        r1 = _nt_alpha_char
        if r1
          r0 = r1
        else
          if has_terminal?('\G[0-9]', true, index)
            r2 = true
            @index += 1
          else
            r2 = nil
          end
          if r2
            r0 = r2
          else
            @index = i0
            r0 = nil
          end
        end

        node_cache[:alphanumeric_char][start_index] = r0

        r0
      end