public function bracketSpecialChars($value, bool $will_force_match_all = false)
    {
        if (is_array($value) || is_object($value)) {
            foreach ($value as $_key => &$_value) {
                $_value = $this->bracketSpecialChars($_value, $will_force_match_all);
            } // unset($_key, $_value); // Housekeeping.
            return $value;
        }
        if (!($string = (string) $value)) {
            return $string; // Empty.
        }
        if (!$will_force_match_all) {
            $string = preg_replace('/[*?[\]!{},\^$]/u', '[${0}]', $string);
        } else { // `^` and `$` are not special characters.
            $string = preg_replace('/[*?[\]!{},]/u', '[${0}]', $string);
        }
        return $string;
    }