No Pass-by-Value or Copy Constructors

Question

After having used AS3 for some months now, I've realized that
there is no pass-by-value option when passing variables into
functions. The only option is pass-by-reference. Similarly, there
are no default copy constructors. So, if I want to create a copy of
an object, I have to write code to create a new instance of the
object and manually copy all of the source variable's properties to
the new target object.
This lack of a pass-by-value mechanism and copy constructors
leads to some confusing behavior and necessitates writing quite a
bit of extra code. A common case involving confusion is when a
function call changes a property of a passed-in object. The caller
might assume that the object will not be modified and then be
surprised when it is. This is especially likely to happen when
different people are working on the caller and the callee. It
shouldn't be necessary for the caller to be concerned about the
internal workings of an object being used but, because there is no
pass-by-value mechanism, the caller often must take this into
account.
Because of the lack of a pass-by-value mechanism the onus is
on the person writing a function to always make a copy of passed-in
objects if they are going to be modified. Unfortunately, the lack
of default copy constructors makes this an onerous task. The only
way to copy an object is to write code to create a new object and
then copy each property of the object. Where the properties are
objects themselves a deep copy is needed and the amount of code can
become large and the task tedious. To do this amounts to writing a
set of copy constructors for each object and sub-object - each time
a variable is accessed for modify.
To make matters worse, it's not even possible to write a copy
constructor for user-created classes. Consider the following
attempt at writing a copy constructor to copy two instance
variables for a custom Form class:
public function Form(f:Form) {
this._textHeight = f._textHeight;
this._actionURL = f._actionURL;
This causes a "Duplicate function definition" compile error
because a default constructor already exists.
Pass-by-value and built-in copy constructors are standard
features in most OOP languages and their lack in AS3 is a glaring
omission. I hope Adobe will seriously consider adding them to the
next version of ActionScript.

Answer 1

Nitin_Mathur wrote:
at one time i had doubted my own conceptsNote that the type of a parameter may be different from the type of the object you created. However, it is still the same value that is passed, as pointed out by this example:
public class Test {
    public Test() {
        //an object of type "MyClass" is created on the heap with the "new" operator:
        MyClass myClass = new MyClass();
        doSomething(myClass);//the reference to the object is passed by value
    private void doSomething(MyInterface myInterface) {
        //the passed value is a reference to a "MyClass" object,
        //but here it is considered to be a "MyInterface" object
        //and we don't have access to the "MyClass"-method "testClass()"
        myInterface.testInterface();
    public static void main(String[] args) {
        new Test();
interface MyInterface {
    public void testInterface();
class MyClass implements MyInterface {
    public void testInterface() {
        System.out.println("testInterface");
    public void testClass(){
        System.out.println("testClass");
}