Fibonacci numbers in Ceylon

Example for versions Ceylon M1

This example calculates Fibonacci numbers iteratively. 

void run() {
    variable String output := "";
    variable Integer fib1 := 0;
    variable Integer fib2 := 1;
    variable Integer fib3;
    for (i in 1..16) {
        output := "" output "" fib2 ", ";
        fib3 := fib1 + fib2;
        fib1 := fib2;
        fib2 := fib3;
    }
    print("" output "...");
}