PHP模拟asp.net的StringBuilder类实现方法

/********************************************  *  * 函数名：StringBuilder  * 作 用：构造PHP下的StringBuilder类  *  ********************************************/class StringBuilder {   const LINE="<br/>";   protected $list= array('');   public function __construct( $str=NULL)   {     array_push($this->list,$str);   }   public function Append($str)   {     array_push($this->list,$str);     return $this;   }   public function AppendLine($str)   {     array_push($this->list,$str.self::LINE);     return $this;   }   public function AppendFormat( $str,mixed $args)   {     array_push($this->list, sprintf($str,$args));     return $this;   }   public function ToString()   {     return implode("",$this->list);   }   public function __destruct()   {     unset($this->list);   } }