The Object-relational Mapping (ORM) tool in the Istarel Workshop Application Framework has a number of switches that affect the way model object classes are constructed. Consider a simple table for categories (used to characterize articles on this blog).
In many environments, session_start() is either meaningless or will generate permission errors for PHP scripts being executed from the command line. Fortunately, the $_SERVER global variable contains data that make it possible to differentiate where a PHP script is being run.
Though not strictly part of the Iterator design pattern (and definitely distinct from the Iterator interface of the SPL Library), implementing the Countable interface is complementary functionality.