protected function parseShortOption(string $token) : array
    {
        if (mb_substr($token, 0, 1) !== '-') {
            throw new RuntimeException("Invalid short option \"$token\"");
        }

        // Trim the "-"
        $token = mb_substr($token, 1);

        $options = [];

        // Each character in a short option is an option
        $tokens = preg_split('//u', $token, -1, PREG_SPLIT_NO_EMPTY);

        foreach ($tokens as $singleToken) {
            $options[] = [$singleToken, null];
        }

        return $options;
    }