title: Access child property from parent scope
body: <p>I need a parent class to access its child properties:</p>
  
  <pre><code>class Parent {
    private $_fields = null;
  
    public function do_something() {
      // Access $_fields and $child_var here
    }
  }
  
  class Child extends Parent {
    private $child_var = 'hello';
  }
  
  $child = new Child();
  $child-&gt;do_something();
  </code></pre>
  
  <p>When <code>$_fields</code> is modified from the child scope, it's still <code>null</code> in the parent scope. When trying to access $child_var from parent scope using <code>$this-&gt;child_var</code>, it's of course undefined.</p>
  
  <p>I didn't find anything like a "function set" that would just be copied in the child class...</p>