... ShopProduct .php. Using the PEAR convention, on the other hand, you would name the file ShopProduct .php, but the class would be named according to its package address: business_ShopProduct, perhaps. PHP ... function ( http://www .php. net/spl_autoload_register ), which supports that functionality. The Class and Object Functions PHP provides a powerful set of functions for testing classes and objects. Why ... this end, PHP provides the instanceof operator. ■ Note PHP 4 did not support instanceof . Instead, it provided the is_a() function which was deprecated in PHP 5.0 deprecated. As of PHP 5.3 it...