protected function getLabels()
	{
		preg_match_all(
			'/\\[((?:[^\\x17[\\]]|\\[[^\\x17[\\]]*\\])*)\\]/',
			$this->text,
			$matches,
			PREG_OFFSET_CAPTURE
		);
		$labels = [];
		foreach ($matches[1] as $m)
		{
			$labels[$m[1] - 1] = strtolower($m[0]);
		}

		return $labels;
	}