record Question { prompt: string, answer: i64 }
fn start_main() -> i64 {
    let questions: list<Question> = [
        Question { prompt: "2 + 3?", answer: 5 },
        Question { prompt: "9 - 4?", answer: 5 },
        Question { prompt: "3 * 4?", answer: 12 },
        Question { prompt: "12 / 3?", answer: 4 },
        Question { prompt: "7 + 8?", answer: 15 }
    ];
        print(questions[0]::prompt + " ");
        let line: string = read_line();
        if (line matches "q") {
            print("Stopped early. Correct: 0; answered: 0; total: " + format_i64(length(questions)) + ".\n");
            return 0;
        }
        let parsed: result<i64> = parse_i64(line);
        if (parsed::ok) {
            print("Parsed: " + format_i64(parsed::value) + "\n");
        } else {
            print("Invalid: " + parsed::error::code + "\n");
        }
    return 0;
}