Description:
------------
PHP version 5.3.0-a3.
I think $f_source in the anonymous function passed to myForeach isn't passed by reference, even though the syntax is correct.
The problem appears when an anonymous function is passed to a global function in a method of a class. Within that anonymous (nameless) function the source of the myForeach can't be retrieved (only local and global can be retrieved), so I pass $list to the anonymous function as well. When I change a key or unset the member, it's not recorded back to the original $list.
Which makes me conclude $f_source is NOT passed by reference.

Reproduce code:
---------------
function myForeach( $f_source, $f_handler ) {
	foreach ( $f_source AS $k => $v ) {
		$f_handler($v, $k, $f_source);
	}
}

class SecondClass {
	public function __construct() {
		$list = range('A', 'J');
		myForeach($list, function($v, $k, &$f_source) {
			if ( 'F' == $v ) {
				$f_source[$k] = 'X';
				unset($f_source[$k]);
				$f_source[$k] = 'X';
			}
		});
		print_r($list);
	}
}

new SecondClass;

Expected result:
----------------
Array
(
    [0] => A
    [1] => B
    [2] => C
    [3] => D
    [4] => E
    [6] => G
    [7] => H
    [8] => I
    [9] => J
)
Notice the [5] => F missing.
-OR-
Array
(
    [0] => A
    [1] => B
    [2] => C
    [3] => D
    [4] => E
    [5] => X
    [6] => G
    [7] => H
    [8] => I
    [9] => J
)

Actual result:
--------------
Array
(
    [0] => A
    [1] => B
    [2] => C
    [3] => D
    [4] => E
    [5] => F
    [6] => G
    [7] => H
    [8] => I
    [9] => J
)