Function called twice

[Niels_Overwijn]

Hello,

does anybody know why the function in this next script is called twice?

Thanks,
Niels

function functie()
{
    trace("function called");
    return(0);
}

var Ar:Array = [0,0];
Ar[functie()]++;
trace(Ar);

/* output:

function called
function called
1,0

*/