Try operator

The try operator (?) is a control flow operator which causes a function to return early in case the value being tried over has a certain value.

For Option, this causes the function to return if it has the Option::None variant.

fn checked_div_mod(a, b) {
    let div = a.checked_div(b)?;
    Some((div, a % b))
}

pub fn main() {
    if let Some((div, m)) = checked_div_mod(5, 2) {
        println!("Result: {}, {}", div, m);
    }

    if let Some((div, m)) = checked_div_mod(5, 0) {
        println!("Result: {}, {}", div, m);
    }
}

$> cargo run --bin rune -- run scripts/book/try_operator/basic_try.rn
Result: 2, 1