Anonymous Function/Closure and using self:: or static::

Question

I am working with anonymous functions where I am creating anonymous function outside of the object, and then adding it to an object later in which it will be used with __callStatic magic function. The closures that are being added to contain methods from the parent class. I am wondering if I would be able to call those methods from the closure?

Right now I get this error:

EmptyObject::addMethod('open', function(){
    if (static::_hasAdapter(get_class(), __FUNCTION__))
            return self::_callAdapter(get_class(), __FUNCTION__, $details);

    echo '<p>You have mail!</p>';
});

throws this error:

Fatal error: Cannot access static:: when no class scope is active in

And

//Add the functions
EmptyObject::addMethod('open', function(){
    if (EmptyObject::_hasAdapter('EmptyObject', __FUNCTION__))
            return EmptyObject::_callAdapter('EmptyObject', __FUNCTION__, $details);

    echo '<p>You have mail!</p>';
});

throw this error because the method is protected

Fatal error: Uncaught exception 'BadMethodCallException' with message 'Method '_hasAdapter' was not found in class EmptyObject'

Answer 1

You can achieve this by using Closure::bind() (PHP >= 5.4.0)

abstract class EmptyObject
{
   protected static $methods = array();

   final public static function __callStatic($name, $arguments)
   {
      return call_user_func(self::$methods[$name], $arguments);
   }

   final public static function addMethod($name, $fn)
   {
      self::$methods[$name] = Closure::bind($fn, NULL, __CLASS__);
   }

   final protected static function protectedMethod()
   {
      echo __METHOD__ . " was called" . PHP_EOL;
   }
}

Now any anonymous function passed to EmptyObject::addMethod() will be run in the scope of the EmptyObject class

EmptyObject::addMethod("test", function()
{
   self::protectedMethod();
});


// will output:
// EmptyObject::protectedMethod was called

EmptyObject::test();