protected function findVariable($i, $escape)
    {
        $close = $this->bars[1] . $this->bars[1];

        if ($escape) {
            $close = $close . $this->bars[1];
        }

        for (; substr($this->source, $i, strlen($close)) !== $close;
        $i++) {
        }

        return $i + strlen($close);
    }