织梦DEDECMS扩展标签怎么用

if(!defined('DEDEINC'))  {  exit("Request Error!");  }  function lib_demotag(&$ctag,&$refObj)  {  global $dsql,$envs;    $attlist="row|12,titlelen|24";  FillAttsDefault($ctag->CAttribute->Items,$attlist);  extract($ctag->CAttribute->Items, EXTR_SKIP);  $revalue = '';    //------------------------------------------------------  $revalue = 'Hello Word!';  //------------------------------------------------------  return $revalue;  }  ?>