Extend form container via neon

Hey, is it possible replace this by “clear neon way” without PHP code? Ofcourse I can do it via Compiler extension, but is another possibility?

	\Code\Component\Form::extensionMethod(
	'addCurrency',
	    function(\Nette\Forms\Container $container, $name, $title = 'currencyInput') {
	    return $container[$name] = new \Scania\Extension\CurrencyInput($title);
	    }
	);

Something like:

form:
	extension:
		addCurrency: ClassPath