References and Varargs

ref parameters

Use ref to let a function modify a variable in place:

fun increment(ref x: Int) {
    x = x + 1;
}

Swapping values

fun swap(ref x: Int, ref y: Int) {
    var tmp: Int = x;
    x = y;
    y = tmp;
}

Example

fun main() Int {
    var a: Int = 10;
    var b: Int = 20;
    increment(ref a);
    swap(ref a, ref b);
    return a + b;
}

Varargs

Variadic parameters use ...Type:

fun sum(first: Int, rest: ...Int) Int {
    var total: Int = first;
    var i: Int = 0;
    while i < rest.len {
        total = total + rest[i];
        i = i + 1;
    }
    return total;
}

Forwarding varargs

fun forward(rest: ...Int) Int {
    return sum(10, ...rest);
}