How to use class methods as callbacks

Question

I have a class with methods that I want to use as callbacks.
How can I pass them as arguments?

Class MyClass {
    
    public function myMethod() {
        // How should these be called?
        $this->processSomething(this->myCallback);
        $this->processSomething(self::myStaticCallback);
    }

    private function processSomething(callable $callback) {
        // Process something...
        $callback();
    }

    private function myCallback() {
        // Do something...
    }

    private static function myStaticCallback() {
        // Do something...
    }   
    
}

Answer 1

Since 5.3 there is a more elegant way you can write it, I'm still trying to find out if it can be reduced more

$this->processSomething(function() {
    $this->myCallback();
});

Answer 2

You can also to use call_user_func() to specify a callback:

public function myMethod() {

    call_user_func(array($this, 'myCallback'));
}

private function myCallback() {
    // do something...
}

Answer 3

As of PHP 8.1, we now have first-class callables. They use the syntax $callable = functionName(...).

You can use the new syntax to create callable class methods.

Class MyClass {
    
    public function myMethod() {
        // first-class callables
        $this->processSomething($this->myCallback(...));
        $this->processSomething(self::myStaticCallback(...));
    }

    private function processSomething(callable $callback) {
        // Process something...
        $callback();
    }

    private function myCallback() {
        // Do something...
    }

    private static function myStaticCallback() {
        // Do something...
    }   
    
}