I'm not even sure how to articulate this, so I'm going to just include test code. Maybe someone else will someday wonder the same thing.
<?
error_reporting(E_ALL);
class testParent
{
var $child;
function testParent()
{
$this->child = new testChild();
}
}
class testChild
{
function testChild()
{
}
}
$parent = new testParent();
$parent2 = 'foobar';
print join(',', Array(
is_object($parent) ? 'yes' : 'no',
is_object($parent->child) ? 'yes' : 'no',
is_object($parent2) ? 'yes' : 'no',
is_object($parent2->child) ? 'yes' : 'no'
));
?>
This prints "yes,yes,no,no". Basically this shows that you can use is_object to test if the child object is an object without worrying about an error if the parent object isn't an object either.