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Late static binding

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In PHP 5.3+ and above you can utilize late static binding to control which class a static property or method is called from. It was added to overcome the problem inherent with the self:: scope resolutor. Take the following code 

class Horse {
    public static function whatToSay() {
         echo 'Neigh!';
    }

    public static function speak() {
         self::whatToSay();
    }
}

class MrEd extends Horse {
    public static function whatToSay() {
         echo 'Hello Wilbur!';
    }
}

You would expect that the MrEd class will override the parent whatToSay() function. But when we run this we get something unexpected 

Horse::speak(); // Neigh!
MrEd::speak(); // Neigh!

The problem is that self::whatToSay(); can only refer to the Horse class, meaning it doesn’t obey MrEd. If we switch to the static:: scope resolutor, we don’t have this problem. This newer method tells the class to obey the instance calling it. Thus we get the inheritance we’re expecting 

class Horse {
    public static function whatToSay() {
         echo 'Neigh!';
    }

    public static function speak() {
         static::whatToSay(); // Late Static Binding
    }
}

Horse::speak(); // Neigh!
MrEd::speak(); // Hello Wilbur!
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Classes and objects:
* Classes and Objects
* Method Chaining in PHP
* Class Constants
* Abstract Classes
* Late static binding
* Namespacing and Autoloading
* Interfaces
* Final Keyword
* Method and Property Visibility
* Autoloading
* Calling a parent constructor when instantiating a child
* Dynamic Binding
* this self and static plus the singleton
* Defining a Basic Class
* Anonymous Classes
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