Hi Rich Are you coming from a c background? Logically a object parameter is passed by reference, which means, the address is passed to the method instead of a copy of the object's values. Technically the address itself is passed by value though, so you cannot change it.
Cheers Ralf. On Nov 9, 2007 1:03 PM, quiet.mountain <[EMAIL PROTECTED]> wrote: > > > > > > > Hi, > > I've read through all of the posts here on pointers and also this > page - http://www.mischel.com/diary/2006/07/24.htm, but can someone > clear up something that's been bothering me please? > > Can a function change the value of a non-primitive type that's passed > as a parameter? > > If I pass a reference to an object as a function parameter, the local > function variable then holds the address of the object on the heap. > Fine. > > If I then attempt to make changes to this object within the function, > the address of the local function reference variable changes to > another address on the heap and creates a new object. The original > object is not updated. We end up with two reference variables > pointing to two different objects on the heap. > > I thought the point of "pass by reference" for non-primitives in AS3 > was to be able to manipulate objects directly by passing the hex > address of the object on the heap (as in c++) > > I understand that a solution is to return the local reference to the > temporary object from the function and assign it to the class > instance variable, so this is more an exercise in understanding the > essential workings of AS3. > > Here's some code. > > ----- AS3 Code starts ----- > > private var collectionAC:ArrayCollection = new ArrayCollection(); > // Debug: value of collectionAC is @4deb859 > > private function resultHandler(event:ResultEvent, ac:ArrayCollection) > { > // Debug: value of ac is also @4deb859 > // There are now 2 reference variables pointing to > // one object on the heap > > ac = event.result.products.rug; > > // Debug: value of ac is now @4f839e1 > // ?WHY? does this line create a new object scoped to > // the function and not modify the original object directly? > } > > ------ MXML code starts ---------- > > <mx:HTTPService id="collectionService" > url="data/collection.xml" > result="resultHandler(event, collectionAC);"/> > > ------ Code ends -------- > > Many thanks, Rich > > -- Ralf Bokelberg <[EMAIL PROTECTED]> Flex & Flash Consultant based in Cologne/Germany Phone +49 (0) 221 530 15 35
