tt-5-php-6001/vendor/workerman/validation/library/Rules/PhpLabel.php

<?php

/*
 * Copyright (c) Alexandre Gomes Gaigalas <alganet@gmail.com>
 * SPDX-License-Identifier: MIT
 */

declare(strict_types=1);

namespace Respect\Validation\Rules;

use function is_string;
use function preg_match;

/**
 * Validates if a value is considered a valid PHP Label, so that it can be used as a variable, function or class name.
 *
 * @author Danilo Correa <danilosilva87@gmail.com>
 * @author Emmerson Siqueira <emmersonsiqueira@gmail.com>
 * @author Henrique Moody <henriquemoody@gmail.com>
 */
final class PhpLabel extends AbstractRule
{
    /**
     * {@inheritDoc}
     */
    public function validate($input): bool
    {
        return is_string($input) && preg_match('/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$/', $input);
    }
}