fn greet(name: string) -> result<string> {
    if (name matches "") {
        return failure("empty-name", "name is empty");
    }
    return success("Welcome, " + name + "!");
}
fn start_main() -> i64 {
    let greeting: result<string> = greet("سلمى");
    if (greeting::ok) {
        print(greeting::value + "\n");
    } else {
        print(greeting::error::code + "\n");
    }
    let empty: result<string> = greet("");
    if (empty::ok) {
        print(empty::value + "\n");
    } else {
        print(empty::error::code + "\n");
    }
    return 0;
}