Dynamic Var names

I’ve created a class which simulates an action for example a ball bouncing about a screen thus I’d create it like so:

var Ball1:ball = new ball(x,y);

How would I go about adding this to a loop, in a sense of every frame add another ball till you reach the maximum balls
currently after looking in help, google and forums this is all I could find

var ["Ball"+currentball]:ball = new ball(x,y);

but this doesn’t seem to work and just causes

Error Scene=Scene 1, layer=balls, frame=1:Line 15: Identifier expected”