Automattic / jetpack

	// a bunch of guards that are and'd together

	// TODO rename to guardGroup

	protected function guardGroup(&$guardGroup) {

		$s = $this->seek();

		$guardGroup = array();

		while ($this->guard($guard)) {

			$guardGroup[] = $guard;

			if (!$this->literal("and")) break;

		}

		if (count($guardGroup) == 0) {

			$guardGroup = null;

			$this->seek($s);

			return false;

		}

		return true;

	}

	protected function guard(&$guard) {

		$s = $this->seek();

	}

	// comma separated list of selectors

	protected function selectors(&$out) {

		$s = $this->seek();

		$selectors = array();

		while ($this->selector($sel)) {

			$selectors[] = $sel;

			if (!$this->literal(",")) break;

			while ($this->literal(",")); // ignore extra

		}

		if (count($selectors) == 0) {

			$this->seek($s);

			return false;

		}

		$out = $selectors;

		return true;

	}

	// whitespace separated list of selectorSingle

	protected function selector(&$out) {