PHP - What could the Object structure be, when we use two object operator tokens like this -> -> ?

Question

I've seen something like this:

echo ($hello->somethingA->somethingB);

What does this mean?

I will try to make my question more clear:

When we have $domain->something; (we are accessing something PROPERTY of $domain OBJECT. precise?

When we have $domain->something->run(); we are telling our something PROPERTY of $DOMAIN OBJECT to access run() METHOD. precise?

So what are we telling with: echo ($hello->somethingA->somethingB); ? Accessing some properties property? Does this makes sense?

Thanks in advance, MEM

Answer 1

Yes, you are accessing a property's property. Apparently, $hello is an object with a property named $somethingA. That property is an object that has a property named $somethingB. $somethingB is apparently a string or some other type that can be echoed out.

Answer 2

+1 to Scott Saunders, here's an example to illustrate it:

class Hello 
{
  /**
   * @var SomethingA
   */
  public $somethingA;
}

class SomethingA
{
  /**
   * @var, don't know what type
   */
  public $somethingB;
}

$hello = new Hello();
$hello->somethingA = new SomethingA();
$hello->somethingA->somethingB = new stdClass();

var_dump($hello);

Answer 3

There is another facet to this that hasn't been explored in the other answers. The other answers you are accessing properties, not methods. But PHP5's objects can be made to chain methods, and perhaps that's what you're referring to.

Instead of this:

$obj = new Object();
$obj->setId('1');
$obj->setName('name');
$obj->setAge('24');

You can do this:

$obj = new Object();
$obj->setId('1')->setName('name')->setAge('24');

In each method, return $this and you're golden. See this article for more details and inspiration:

http://www.talkphp.com/advanced-php-programming/1163-php5-method-chaining.html