pub type Option(some) {
  Some(some)
  None
}

fn replace(option: Option(a), with: b) -> Option(b) {
  case option {
    Some(_) -> Some(with)
    None -> None
  }
}

fn are_equal(lhs: a, rhs: a) -> Bool {
  lhs == rhs
}

pub fn main() {
  are_equal(1, 2)
  are_equal("hi", "hello")

  replace(Some(10), 20)
  replace(Some("hi"), "hello")
}