配列を XML 形式に変換することについてマスターに質問する

<?xml version="1.0" encoding="utf-8"?><nodes>    <node id="c5569e2c-0f4a-4ec2-86ba-736b79eca18c" name="A公司"        type="0">        <node id="4f2b55e9-e10a-496b-8bca-60e6f26daee5" name="部门1" type="1">            <node id="363" name="叶子1" type="2" playurl="http://XXXXXXX363" />        </node>        <node id="0c5ce42f-ba31-4b7a-8173-79ecae4a73ca" name="部门2" type="1">            <node id="241" name="叶子1" type="2"    playurl="http://xxxxx=241" />            <node id="356" name="叶子1" type="2" playurl="xxxxxxxxx=356" />        </node>    </node></nodes>

	function arrayToXml($arr, $xmlDoc = 0, $item = 0)	{		/*判断是否已为xml*/		if (!$xmlDoc)		{			$xmlDoc = new DOMDocument("1.0");		}		/*判断是否为子节点*/		if (!$item)		{			$item = $xmlDoc->createElement("nodes","UTF-8");			$xmlDoc->appendChild($item);		}		/*将数组数据按“键=>值”方式，循环取出并写入dom树*/		foreach ($arr as $key=>$val)		{			/*增加子节点名和值*/			$itemX = $xmlDoc->createElement(is_string($key) ? $key:"node");			$item->appendChild($itemX);			/*如果数组内某一元素的值也是数组，则进行递归*/			if (!is_array($val))			{				$text = $xmlDoc->createTextNode($val);				$itemX->appendChild($text);			}			else			{				$this->arrayToXml($val,$xmlDoc,$itemX); //在类中调用需加$this->			}		}		return $xmlDoc->saveXML(); //返回xml数据，可以把返回数据直接写入*.xml文件即可生成xml文件	}

$ar = array(  array( 'id' => "c5569e2c-0f4a-4ec2-86ba-736b79eca18c", 'name' => "A公司", 'type' => "0",    array( 'id' => "4f2b55e9-e10a-496b-8bca-60e6f26daee5", 'name' => "部门1", 'type' => "1",      array( 'id' => "363", 'name' => "叶子1", 'type' => "2", 'playurl' => "http://XXXXXXX363"),    ),    array( 'id' => "0c5ce42f-ba31-4b7a-8173-79ecae4a73ca", 'name' => "部门2", 'type' => "1",      array( 'id' => "241", 'name' => "叶子1", 'type' => "2", 'playurl' => "http://xxxxx=241"),      array( 'id' => "356", 'name' => "叶子1", 'type' => "2", 'playurl' => "xxxxxxxxx=356"),    ),  ));$xml = simplexml_load_string('<nodes/>');arrayToXml($ar, $xml);echo $xml->asXML();function arrayToXml($ar, $xml) {  foreach($ar as $k=>$v) {    if(is_array($v)) arrayToXml($v, $xml->addChild('node'));    else $xml->addAttribute($k, $v);  }}