Structures

struct Point<T> { // structure with generic argument
    var x: T;
    var y: T;
    init(x: T,y: T) {
        this.x = x;
        this.y = y;
    }
}

struct Foo: Display {
    fun format(stream: mut String*) { // `format` is a member of `Display` interface
        stream.write("Foo");
    }
}