import class Range from range;
import fn { iterator, next, is_consumed } from range;

fn sum(r: Range) -> Int {
    let res: Int = 0;

    for i in *<Range>r {
        res = res + i;
    }

    return *<Int>res;
}

let r: Range = Range(0, 0, 10);

iterator(*<Range>r);
next(r);
is_consumed(r);

if sum(Range(0, 0, 101)) != 5050 {
    panic("Invalid result");
}