enum OptionalInt {
  Nothing,
  Int(i32)
}

fn generate_optional(v: i32) -> OptionalInt
{
  if v == 0 {
    OptionalInt::Nothing
  } else {
    OptionalInt::Int(v)
  }
}

fn display(v: OptionalInt)
{
  if let OptionalInt::Int(iv) = v {
    println!("Value: {}", iv)
  } else {
    println!("No value")
  }
}

fn main()
{
  let a = generate_optional(0);
  let b = generate_optional(1);

  display(a);
  display(b)
}