Let an object loop as array with a foreach() by extending ArrayObject

Question

So I have an object which contains a set of objects in a private data member. I can now loop it with a for loop by overriding the count() function of an ArrayObject and offsetGet($index), but I also want to loop it within a foreach loop.

What functions do I need to minimally extend to add this functionality?

Answer 1

Use the SPL Iterator Interface see http://uk.php.net/manual/en/class.iterator.php for details

Answer 2

AFAIK You can use directly foreach on ArrayObject:

$ao = new ArrayObject(array(1, 2, 3, 4));
$res = 0;
foreach($ao as $el) {
    $res += $el;
}
echo 'ArrayObject elements sum: '.$res;

SAMPLE: http://codepad.org/uQDGQ03A