fn increment(value: i64) -> i64 { return value + 4; }
fn choose() -> fn(i64) -> i64 { return increment; }
record Carrier { callback: fn(i64) -> i64 }
fn apply(action: fn(i64) -> i64, value: i64) -> i64 { return action(value); }
fn start_main() -> i64 {
    let saved: list<fn(i64) -> i64> = [choose()];
    let wrapped: result<fn(i64) -> i64> = success(saved[0]);
    let carrier = Carrier { callback: wrapped::value };
    if carrier::callback not matches increment { return 1; }
    print(format_i64(apply(carrier::callback, 38)) + "\n");
    return 0;
}