On the Stubbles blog today Frank Kleine looks at a cool trick that the features of PHP 5.3 now make possible - extending objects at runtime by adding in new methods and functionality.

With the advent of PHP 5.3 adding new methods to an instance of a class at runtime becomes possible with PHP as well, using anonymous functions and a little bit of __call() magic.

He illustrates with a bit of code - defining the base class and using a __call method to catch any undefined method calls. Using this in conjunction with closures makes it possible to call the method internally, avoiding the usual error that could result from setting it like you would a class property.