struct Vector2 {
	x: int,
	y: int
}

impl Vector2 {
	pub fn new(xs: int, ys: int) -> Vector2 {
		Vector2 {
			x: xs,
			y: ys
		}
	}

	fn add(&self, otr: Vector2) -> &Vector2 {
		self.x += otr.x; // cannot assign to immutable field
		self.y += otr.y; // cannot assign to immutable field
		return self; // lifetime mismatch
	}
}

fn main() {
	let mut vec1 = Vector2::new(42, 12);
	println(fmt!("vec1 = [x: %?, y: %?]", vec1.x, vec1.y));

	let vec2 = Vector2::new(13, 34);
	println(fmt!("vec2 = [x: %?, y: %?]", vec2.x, vec2.y));

	let vec3 = vec1.add(vec2);
	println(fmt!("vec1 + vec2 = [x: %?, y: %?]", vec3.x, vec3.y))
}