gistfile1.txt

trait Positioned {
    fn get_x(&self) -> int;
    fn get_y(&self) -> int;
    fn set_x(&self, x: int);
    fn set_y(&self, y: int);
}

trait Movable: Positioned {
    fn translate(&self, dx: int, dy: int) {
        self.set_x(self.get_x() + dx);
        self.set_y(self.get_y() + dy);
    }
}

trait Renderable: Positioned {
    fn render(&self) {
        io::println(fmt!("%?, %?", self.get_x(), self.get_y());
    }
}

struct Point {
    mut x: int,
    mut y: int
}

struct Entity {
    mut pos: Point,
}

impl Point: Positioned { ... }

impl Entity: Moveable;

impl Entity: Renderable;

impl Entity: Positioned {

    // How to get rid of this boilerplate? Not sure yet
    // The compiler can probably auto-derive it eventually.
    fn get_x(&self) -> int { self.pos.get_x() }

    ...
}

fn main() {

    let mut e: Entity = Entity {
        pos: Point{x: 0, y: 0},
    };

    e.translate(5, 10);
    e.render();

}