Returning by-refernce it is useful when you want to use function
to find variable which should be bound to. When returning
references, use this syntax:
In this example, property of the object returned by the
find_var function would be set, not of the
copy, as it would be without using reference syntax.
Note:
Unlike parameter passing, here you have to use
& in both places - to indicate that you
return by-reference, not a copy as usual, and to indicate than
reference binding and not usual assignment should be done for
$foo.
