从动态元素中读取节点值

Is it possible to read node values from a dynamic element in a xml file using variables?

XML file:

<plugin_permission>
    <plugin1>true</plugin1>
    <plugin2>false</plugin2>
    <plugin3>true</plugin3>
    ...
</plugin_permission>

PHP file:

$xml = simplexml_load_file('settings/groep/permissions/'.$groep.'.xml');
$pluginIdName = $pluginObj->getIdName();
return $xml->plugin_permission->$pluginIdName;

The output should be "true" or "false", but get literally nothing.

Problem solved

I solved my problem using xpath

$xml = simplexml_load_file('settings/groep/permissions/'.$groep.'.xml');
return $xml->xpath('/plugin_permission/'.$plugin->getIdName());