What is the PHP `::class` Syntax and How Does it Improve Code?

Understanding ::class in PHP

The ::class syntax in PHP refers to a relatively recent addition introduced in version 5.5. It serves as a shorthand notation to represent the fully qualified name of a class, including its namespace.

Functionality and Advantages

SomeClass::class will return the string representation of SomeClass's fully qualified name. This feature offers several advantages:

• Improved Code Refactoring: By using ::class, you can eliminate the need to hard-code class names as strings. This allows IDEs to easily identify and update class names during code refactoring.
• Use Keyword Compatibility: The use keyword can be combined with ::class to simplify class resolution, reducing the need to type out the complete class name. For instance:

use \App\Console\Commands\Inspire;

//...

protected $commands = [
    Inspire::class, // Equivalent to "App\Console\Commands\Inspire"
];

Additional Benefit: Late Static Binding

In addition to the aforementioned advantages, ::class is also useful for implementing Late Static Binding, where the name of the derived class can be obtained within the parent class. This is achieved by using static::class instead of the CLASS magic constant, as seen in the following example:

class A {

    public function getClassName(){
        return __CLASS__;
    }

    public function getRealClassName() {
        return static::class;
    }
}

class B extends A {}

$a = new A;
$b = new B;

echo $a->getClassName();      // A
echo $a->getRealClassName();  // A
echo $b->getClassName();      // A
echo $b->getRealClassName();  // B

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