CODEWITHSUNDEEP
phpclassscopeoperator-keyword
john81
john81

Reputation: 11

PHP parent scope resolution operator

I was wondering how I should interpret the following code (source: http://www.php.net/manual/en/language.oop5.paamayim-nekudotayim.php)

<?php
class MyClass
{
    protected function myFunc() {
        echo "MyClass::myFunc()\n";
    }
}

class OtherClass extends MyClass
{
    // Override parent's definition
    public function myFunc()
    {
        // But still call the parent function
        parent::myFunc();
        echo "OtherClass::myFunc()\n";
    }
}

$class = new OtherClass();
$class->myFunc();
?>

My question is: why is the scope resolution operator ('::') used to access the parent function:

parent::myFunc();

To me, the double colon suggests a static member / method. When creating the OtherClass object:

$class = new OtherClass();

there will be a new instance (object) of the OtherClass. But will there be an instance of the parent class at the same time? How should I interpretet this?

I understand the idea of creating a new object from the extended OtherClass, but how should I interpret its parent class: like a static class or like an object (copy of class)?

I hope my question makes sense.

Upvotes: 1

Views: 386

Answers (2)

dhinchliff
dhinchliff

Reputation: 1194

parent::myFunc(); is not a static invocation, it is a bit confusing that it used the same operator though. You only need this operator if you have overridden the method and want to call the parent method.

there will be a new instance (object) of the OtherClass. But will there be an instance of the parent class at the same time? How should I interpretet this?

Because OtherClass extends MyClass the single object you constructed is an instance of both these classes at the same time.

Upvotes: 0

axiac
axiac

Reputation: 72346

An object of class OtherClass is also an object of class MyClass because class OtherClass extends class MyClass. It has all the properties and methods of MyClass but some of the methods might be redefined in OtherClass.

The scope resolution operator is used both to access static class members and methods (using class name, self or static) but also to access methods defined in the parent class (using parent).

Upvotes: 1

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