public function visitEnterSelectorSequence()
{
if ($this->_current === $this->_dom->documentElement && $this->_current->hasChildNodes()) {
$this->_current->appendChild($this->_dom->createElementNs($this->_xmlns, 'text'))->appendChild($this->_dom->createCDATASection(', '));
}
return $this->start($this->appendElement('selector'));
}