choice Result {
    ok: i32,
    err: String,
}

pub fn main(world: World) -> Void raises {
    let result: Result = Result.ok(42)
    match result {
        .ok(value) {
            if value == 42 {
                check world.out.write("payload binding ok\n")
            }
        }
        .err(message) {
            check world.out.write(message)
        }
    }
}