<?php defined('SYSPATH') or die('No direct access allowed.'); /** * This interface ensures that all cart processing objects have the right methods * * @package Cart * @category Interface * @author Deon George * @copyright (c) 2009-2013 Open Source Billing * @license http://dev.osbill.net/license.html */ interface Cartable { // Render a cart line item. public function cart_item(); // Return if this invoice is already in the cart public function cart_exists(); } ?>