Actionscript Constructor Overloading

[EatJason]

Is it not possible to overload constructors in actionscript? I just want two different ways to construct a class. Meaning I want two different parameter lists, not simply omiting certain variables. Do I have to just make a single constructor with all parameters, and run a function based on which ones are filled in?

[panel]

No overload is possible in AS3

[Nomad2000]

You can have default parameters in the constructor, which let you call it with different numbers of parameters:

class Foo
{
    function Foo(x:int = 0, y:int = 0):void
    {
        // Do something with x and y
    }
}

Or you could take the approach of using initialize() methods:

class Foo
{
    function Foo():void
    {
    }

    function initialize(x:int = 0, y:int = 0):void
    {
        // Initialize the object using x and y
    }

    function initializeString(s:String):void
    {
        // Initialize object by parsing the string
    }
}

// To use it
var foo1:Foo = new Foo();
foo1.initialize(1, 2);
var foo2:Foo = new Foo();
foo2.initialize("1,2");

[creynders]

Or if the parameterlist is substantially different you can use the rest parameter

package{
    class Foo{
        public function Foo( ...args ){
            if( args[ 0 ] is Date ){
                _init( args[ 0 ] );
            }else if( args[ 0 ] is String ){
                var d : Date = new Date( args[ 2 ], args[ 1 ], args[ 0 ] );
                _init( d );
            }
        }
        
        private function _init( date : Date ) : void{
            //do something
        }
    }
}

you can use it like this:

var bar : Foo = new Foo( new Date() );
//OR
var bar : Foo = new Foo( "07", "12", "2007" );

[Nomad2000]

Yes, that makes for a nice clean looking syntax for the caller, but just remember that you lose all compile-time type safety if that is important to you. The compiler cannot tell you that the following code won't work:

var bar : Foo = new Foo( 7, 12, 2007 );

In this case, the code will fail silently with no error. In other cases if you are not careful, it will crash.

Also, you won't get any syntax completion help with that either.

Check your needs and pick your poison!