PHPCMS V9{loop subcat(0,0,0,$siteid) $r}怎么解释？

{loop subcat(0,0,0,$siteid) $r}{/loop}

/**

* 获取子栏目
* @param $parentid 父级id 
* @param $type 栏目类型
* @param $self 是否包含本身 0为不包含
* @param $siteid 站点id
*/
function subcat($parentid = NULL, $type = NULL,$self = '0', $siteid = '') {
        if (empty($siteid)) $siteid = get_siteid();
        $category = getcache('category_content_'.$siteid,'commons');
        foreach($category as $id=>$cat) {
                if($cat['siteid'] == $siteid && ($parentid === NULL || $cat['parentid'] == $parentid) && ($type === NULL || $cat['type'] == $type)) $subcat[$id] = $cat;
                if($self == 1 && $cat['catid'] == $parentid && !$cat['child'])  $subcat[$id] = $cat;
        }
        return $subcat;
}