note 33772 deleted from language.oop by didou

Note Submitter: barend@maximedia.nl ---- PHP doesn't know abstract classes, it'll always let you instantiate any defined class. Not a critical problem if you (and your staff) are disciplined, but if you want to enforce it, here's a simple way to do so from the constructor: class AbstractClass { ....function AbstractClass() { ........assert( is_subclass_of($this, 'AbstractClass') ); ........// remainder of constructor code ....} } Any subclass of AbstractClass can be instantiated, but trying to instantiate AbstractClass itself results in an assertion failure.