let i = 0;

loop {
    i = i + 1;
    print("i", i);
    if (i > 5) break;
}

fn for(array, op) {
    let index = 0;
    loop {
        let item = array[index];
        if (item == none) break;
        op(item, index);
        index = index + 1;
    }
}

for([1, 2, 3], (item, index) => {
    print("at index", index, "item", item);
});