I actually tested that code I posted beforehand so I'm pretty sure that's the case. Everything else would be insane, as it would mean objects are passed by value, meaning a new copy would be created, which makes no sense.
[Objects in Haxe are passed as call by reference](http://haxe.org/forum/thread/3395#nabble-td3378098).

Not sure what would happen to a String, not really relevant here.