Object-Oriented PHP

__get and __set

To set the context for this discussion, remember that we spent some time discussing accessor, or set and get methods, in Chapter 6. There I argued that instance variables should be made private and only retrieved or changed through accessor methods. Doing otherwise violates the object-oriented (OO) principle of data hiding (or encapsulation if you prefer) and leaves instance variables exposed to inadvertent changes.

PHP 5 introduces magic set and get methods for undefined instance variables. Let's see what this means by looking at an example. Suppose you have a class, Person, devoid of any data members or methods, defined as follows:

class Person{
}

PHP allows you to do the following:

 $p = new Person(); $p->name = "Fred"; ...