Optionals and Error Unions

Optionals (?T)

let some: ?i32 = 10
let empty: ?i32 = none

if some != none {
    println(some)
}

Error Unions (E!T)

type Io error {
    denied
}

fn load(ok: bool) -> Io!i32 {
    if ok {
        return 41
    }
    return Io::denied
}

fn fallback(ok: bool) -> i32 {
    return load(ok) catch -1
}