class :admin:auto extends :x:element {
        attribute
                string brand = "Ferrari" @required,
                enum { "blau", "rot" } color;

        protected function render() {
                foreach ($this->getAttributes() as $key => $val) {
                        $output .= ' ' . $key . '="' . $val . '"';
                }
                return <div> {$output} </div>;
        }
}

echo <admin:auto brand="bmw" color="blau" />;