will introduce OvenToBoost
emit IR for multi return values

    func div(a, b)
        if b == 0
            return 0, false
        else
            return a / b, true
        end
    end

    func print_if_no_error(e)
        println(e[0]) if e[1]
    end

    func main
        ret := div(4, 2)
        print_if_no_error(ret)
        ret2 := div(4, 0)
        print_if_no_error(ret2)
    end