Walking down related object's properties using array_reduce:
<?php
$a=new stdClass;
$a->b=new stdClass;
$a->b->c="Hello World!\n";
$reductionPath=array("b","c");
print_r(
array_reduce(
$reductionPath,
function($result, $item){
return $result->$item;
},
$a
)
);
?>