CODEWITHSUNDEEP
php
Beachhouse
Beachhouse

Reputation: 5052

Accessing a static variablefrom a class instance

I would like to use this line of code:

$this->ClassInstance::$StaticVariable;

Where this is the basic setup:

Class foo{
   public static $StaticVariable;
}

$this->ClassInstance = new foo();

What is the reasoning behind this being a parse error?

When this:

$ClassInstance = $this->ClassInstance;
$ClassInstance::$StaticVariable;

Is perfectly valid.

Upvotes: 1

Views: 48

Answers (3)

Gordon
Gordon

Reputation: 316969

Assuming you meant

Class Foo{
    public static $StaticVariable = 42;
}

class Bar {
    private $ClassInstance;

    public function fn() {
        $this->ClassInstance = new Foo();
        return $this->ClassInstance::$StaticVariable;
    }
}

$bar = new Bar;
echo $bar->fn();

Then this works as of PHP7. Prior to that, the parser could simply not dereference this. See the wiki page linked in the comments to your question for details.

You could use get_class($this->ClassInstance)::$StaticVariable; though.

Upvotes: 3

bxN5
bxN5

Reputation: 1430

In PHP docs

Declaring class properties or methods as static makes them accessible without needing an instantiation of the class. A property declared as static can not be accessed with an instantiated class object (though a static method can).

source http://php.net/manual/en/language.oop5.static.php

Upvotes: 2

fragmentedreality
fragmentedreality

Reputation: 1317

You can access it with self::$staticVariable or foo::$staticVariable. No need to make use of the instance.

Upvotes: 2

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