Calling closure assigned to object property directly

Question

I would like to be able to call a closure that I assign to an object\'s property directly without reassigning the closure to a variable and then calling it. Is this possible

Answer 1

Since PHP 7 a closure can be called using the call() method:

$obj->callback->call($obj);

Since PHP 7 is possible to execute operations on arbitrary (...) expressions too (as explained by Korikulum):

($obj->callback)();

Other common PHP 5 approaches are:

• using the magic method __invoke() (as explained by Brilliand)

  $obj->callback->__invoke();
  

• using the call_user_func() function

  call_user_func($obj->callback);
  

• using an intermediate variable in an expression

  ($_ = $obj->callback) && $_();
  

Each way has its own pros and cons, but the most radical and definitive solution still remains the one presented by Gordon.

class stdKlass
{
    public function __call($method, $arguments)
    {
        // is_callable([$this, $method])
        //   returns always true when __call() is defined.

        // is_callable($this->$method)
        //   triggers a "PHP Notice: Undefined property" in case of missing property.

        if (isset($this->$method) && is_callable($this->$method)) {
            return call_user_func($this->$method, ...$arguments);
        }

        // throw exception
    }
}

$obj = new stdKlass();
$obj->callback = function() { print "HelloWorld!"; };
$obj->callback();