import "../../std/iter.zc"
import "../../std/option.zc"

struct RangeIter {
    current: int;
    stop: int;
}

impl RangeIter {
    fn next(self) -> Option<int> {
        if (self.current < self.stop) {
            let v = self.current;
            self.current += 1;
            return Option<int>::Some(v);
        }
        return Option<int>::None();
    }
}

struct MyRange {
    start: int;
    end: int;
}

impl MyRange {
    fn iterator(self) -> RangeIter {
        return RangeIter {
            current: self.start,
            stop: self.end
        };
    }
}

test "iterator_desugaring" {
    let range = MyRange { start: 0, end: 5 };
    let sum = 0;

    // This loop should be desugared by the compiler
    for i in range {
        println "Got: {i}"; // Verification print
        sum += i;
    }

    assert(sum == 10); // 0+1+2+3+4 = 10
}