関連型(associated types)(@Rust)

fn main() {
    // associated types
    //
    let point = Point(x, y);

    println!("Point X:{}, Y:{}", &x, &y);
    println!("Exist?:{}", point.exist(&x, &y));

    println!("Point-X:{}", point.v_axis());
    println!("Point-X:{}", point.h_axis());

    new_point(&point);
}

struct Point(i32, i32);

trait Position {
    type X;         // to use associated types
    type Y;

    fn exist(&self, _: &Self::X, _: &Self::Y) -> bool;
    fn h_axis(&self) -> i32;
    fn v_axis(&self) -> i32;
}

impl Position for Point {
    type X = i32;
    type Y = i32;

    fn exist(&self, x: &Self::X, y: &Self::Y) -> bool {
        (&self.0 == x) && (&self.1 == y)
    }

    fn h_axis(&self) -> Self::X {
        self.0
    }

    fn v_axis(&self) -> Self::Y {
        self.1
    }
}

fn new_point<Z: Position>(point: &Z) {                          // you don't need specify X and Y anymore
    println!("POINT:({},{})", point.v_axis(), point.h_axis())   // like "fn new_point<X, Y, Z>(point: &Z) where Z: Position<X, Y>"
}