public function getParentTemplateFilename() {

		if(empty($this->parentTemplateFilename)) {
		
			if(preg_match($this->extendRex, $this->bufferInstance->__rawContents, $matches)) {

				$this->parentTemplateFilename = $matches[1];

			}
		}

		return $this->parentTemplateFilename;
		
	}