ActionScript 3.0 :: Semi-idle Question About For Each Instances?

when you iterate through an array using for / each, assuming the elements in the array are primitive types, the looping var takes on the type and value of each item, but is not a reference to the item.

Code:
var arr:Object = {a:1,b:2,c:3};
for each (var a:int in arr) {
a++;

[code]...

This differs from the behavior of PHP5, for example, where even though most objects are passed by reference automatically, objects within foreach loops are treated as copies unless specifically passed as &references like

PHP Code:

foreach ($arr as $key=>&$b) {}

Is there any way to get AS3 to do the decent thing and give you a choice whether subarrays are passed as references or not, without resorting to making ByteArray copies of your objects for every iteration of a loop?