Question

The example comes from the book “Professional PHP5” by Edward Lecky-Thompson.

  function __get($propertyName) {
  if(!array_key_exists($propertyName, $this->propertyTable))
     throw new Exception("Błędna własność \"$propertyName\"!");

  if(method_exists($this, 'get' . $propertyName)) {
     return call_user_func(array($this, 'get' . $propertyName));
  } else {
     return $this->data[$this->propertyTable[$propertyName]];
  }
}

Can somebody please explain what happens exactly step-by-step in the call_user_func function?

On php.net I’ve read that the first parameter is a function to be called and the remaining parameters are passed to that function as its parameters.

On php.net there were simple examples and I had no problem understanding them. However I don’t get it why in the above example there is an array, and why $this as the first element of the array?

P.S.
I found a similar question on stackoverflow, and I understand what the code is supposed to do but I don’t understand fully why what’s written works.

Here’s the link to the similar question:
PropertyObject

Answer 1

The two-part array is PHP’s informal formal convention of passing the method of a specific object as a callback/callable. See http://php.net/manual/en/language.types.callable.php for details.

array($this, 'getFoo') simply stands for the getFoo method of the $this object.