struct Vector2 {
    x: float;
    y: float;
}

// Unnamed use (Mixin)
// Transform "is a" Vector2 (inherits x and y)
struct Transform {
    use Vector2; 
    rotation: float;
}

// Named use (Composition)
// Rigidbody "has a" velocity and position
struct Rigidbody {
    use position: Vector2;
    use velocity: Vector2;
    mass: float;
}

fn main() {
    // Mixin usage - flattened fields
    let t = Transform{ x: 10.0, y: 5.0, rotation: 90.0 };
    println "Transform pos: ({t.x}, {t.y})";

    // Named usage - nested fields
    let rb = Rigidbody{
        position: Vector2{x: 0.0, y: 10.0},
        velocity: Vector2{x: 1.0, y: 0.0},
        mass: 50.0
    };
    
    // Access using dot notation
    rb.position.x += rb.velocity.x;
    
    println "Rigidbody pos: ({rb.position.x}, {rb.position.y})";
}