private function instantiatTag($tag)
{
if (!$this->hasTag($tag)) {
throw new Exception("Unable to find requested TagParser tag '{$tag}'.");
}
if (!is_object($this->tags[$tag])) {
$this->tags[$tag] = Yii::createObject($this->tags[$tag]);
Yii::trace('tag parser object generated for:' . $tag, __CLASS__);
}
}