Default parameters in ActionScript 3.0

I have a function, for example

function test(p1:int=7,p2:Boolean=true,p3:uint=0xffff00,p4:Number=55.5) {

//instructions

}

How to 开发者_C百科change only p4, for example, and parameters p1,p3,p3 was still default?

Next time I want to change for example only p2, and parameters p1,p3,p4 was still default?

etc.

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you could always do something like (but I don't think it's a great idea):

private function test(a1:Object=null, a2:Object=null, a3:Object = null, a4:Object = null):void {
    var p1:int      = (a1 !== null ? int(a1) : 3);
    var p2:Boolean  = (a2 !== null ? Boolean(a2) : true);
    var p3:uint     = (a3 !== null ? uint(a3) : 0xFFFF00);
    var p4:Number   = (a4 !== null ? Number(a4) : 55.5);
}

that way if you want something to be default, you can just pass in null:

with:

test(null,false,null,null);

but again, it's a bad idea. Maybe make the parameter an object -- it sounds like you're passing in a colortransform object -- which already has rgb + alpha + transparency? (just a wild guess)

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You can't. You can leave p3 and p4 out and they will use the default value when you want to only specify p2. But then you'd have to enter a value for p1 too.