code: private function getMeaningfulTokenSibling($index, $direction)
      {
          while (true) {
              $index += $direction;
  
              if (!$this->offsetExists($index)) {
                  break;
              }
  
              if (!$this[$index]->isType(DocLexer::T_NONE)) {
                  return $index;
              }
          }
  
          return null;
      }
docs: @param int $index
  @param int $direction
  
  @return null|int