Neos\Flow\Validation\Validator\AlphanumericValidator::isValid PHP Метод

    protected function isValid($value)
    {
        if (!is_string($value) || preg_match('/^[[:alnum:]]*$/u', $value) !== 1) {
            $this->addError('Only regular characters (a to z, umlauts, ...) and numbers are allowed.', 1221551320);
        }
    }