Description:
------------
When we invoke a non existent sub-node, SimpleXMLElement returns a SimpleXMLElement object. But when we try to get a non existent sub-node on that object, it returns NULL.
IMO this renderes it inconsistent.

Test script:
---------------
<?php
class XXX {

	public	function test () {
		$sx = new \SimpleXMLElement ('<x></x>');
		$node = $sx->node;
		echo '1: $node = $sx->node => ', $node === $this ? 'this' : gettype ($node) . ':' . get_class ($node), '   node->count: ', $node->count (), "<br />\n";
		$node = $sx->node->node;
		echo '2: $node = $node->node => ', $node === $this ? 'this' : gettype ($node), "<br />\n";
	}
}


$x = new XXX;
$x->test ();


Expected result:
----------------
Or both ($sx and $node) SimpleXMLElement objects should return NULL for a non existent sub-node or both sould return a SimpleXMLElement object. As it is, it's a surprise lurking.

I think the second option is best. It makes things like this possible:

if ($products = $sx->Catalog->Products->Product) {
  // Never gets here if there's no <Catalog>, or if it has no sub-nodes
  // named <Products>, or if it has no sub-nodes named Product.
}
else die ('No products');

Actual result:
--------------
$node it's a SimpleXMLElement, then it is NULL.


1: $node = $sx->node => object:SimpleXMLElement   node->count: 0<br />
2: $node = $node->node => NULL<br />