Tutorial: Programmatically Extending Validator Rules

use Zero\Core\Validator;

// Instantiating validator with custom inputs
$validator = new Validator($_POST, [
    'age' => 'required|integer',
    'serial' => 'required|even_number'
]);

// Register a dynamic custom rule closure on-the-fly!
$validator->addRule('even_number', function($field, $value) {
    return is_numeric($value) && (intval($value) % 2 === 0);
}, 'The {field} field must be an even number.');

if ($validator->validate()) {
    // Form inputs verified successfully!
}