fn precedence(op: u8) -> u8 {
    if op == 42 || op == 47 {
        return 2
    }
    if op == 43 || op == 45 {
        return 1
    }
    return 0
}

pub fn main(world: World) -> Void raises {
    if precedence(42) > precedence(43) {
        check world.out.write("shunting yard ok\n")
    }
}