// -*- rust -*-

tag color {
  rgb(int, int, int);
  rgba(int, int, int, int);
  hsl(int, int, int);
}

fn process(color c) -> int {
  let int x;
  alt (c) {
    case (rgb(?r, _, _)) {
      log "rgb";
      log r;
      x = r;
    }
    case (rgba(_, _, _, ?a)) {
      log "rgba";
      log a;
      x = a;
    }
    case (hsl(_, ?s, _)) {
      log "hsl";
      log s;
      x = s;
    }
  }
  ret x;
}

fn main() {
  let color gray = rgb(127, 127, 127);
  let color clear = rgba(50, 150, 250, 0);
  let color red = hsl(0, 255, 255);
  assert (process(gray) == 127);
  assert (process(clear) == 0);
  assert (process(red) == 255);
}