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ActionScript 2.0 to 3.0

Constants

You can use the 

const

 keyword to define constants in ActionScript 3.0. First, you determine 

which class and instance variables qualify as constants, and then declare them with 

const

 

instead of 

var

; for example:

static const NONMODAL:Number = Alert.NONMODAL;
const backgroundColorName:String = "buttonColor";

In general, constants should be class constants rather than instance constants.

The initial value for a constant must be an expression that can be evaluated at compile time. 
Also, you cannot create constants of type Array or Object.

Method signatures

This section describes changes to method signatures in ActionScript 3.0.

No arguments

If a function takes no arguments, be sure to specify its argument list as 

()

 and not as 

(void)

. 

The latter specifies a single argument of type Object named “void”. Consider which, if any, of 
the arguments should be optional, and assign default values for them; for example:

override public function createClassObject(type:Class, name:String=null, 

depth:int=0, initObj:Object=null):UIObject

Variable number of arguments

If the function takes a variable number of arguments, use the new “...” syntax:

function function_name([ arguments ], ... arrayOfArgs)

For example:

function foo(n:Number, ... arrayOfArgs):void

The “

...

” and its array must be the last argument in the method. You cannot specify a type 

because it is always an Array containing the other arguments.

The following example shows how to use a method with a variable number of arguments. If 
you define the following:

function myfunc(arg1, ... arrayOfArgs)

you can call it as:

myfunc(a, b, c, d);

and the Array arrayOfArgs will have the value 

[ b, c, d ]

.