public function getParametersByName() {
    $param_tags = $this->getDocBlock()->getTagsByName('param');
    $parameters = array();
    /** @var \phpDocumentor\Reflection\DocBlock\Tag\ParamTag $param_tag */
    foreach ($param_tags as $param_tag) {
      $name = ltrim($param_tag->getVariableName(), '$');
      $parameters[$name] = $param_tag;
    }
    return $parameters;
  }