1 use std::ops::{Add, AddAssign, Mul};
5 ( $x:expr, $y:expr ) => { Point2D { x:$x, y:$y } };
8 #[derive(Debug, Copy, Clone, PartialEq)]
9 pub struct Point2D<T> {
15 pub fn length(self) -> f64 {
16 ((self.x * self.x) + (self.y * self.y)).sqrt()
20 impl<T: Add<Output=T>> Add for Point2D<T> {
21 type Output = Point2D<T>;
23 fn add(self, rhs: Point2D<T>) -> Self::Output {
24 Point2D { x: self.x + rhs.x, y: self.y + rhs.y }
28 impl<T: AddAssign> AddAssign for Point2D<T> {
29 fn add_assign(&mut self, rhs: Point2D<T>) {
41 impl<T: Mul<Output=T> + Copy> Rect<T> {
43 pub fn area(&self) -> T {
44 self.width * self.height
48 impl<T> From<(T, T)> for Rect<T> {
49 fn from(item: (T, T)) -> Self {
50 Rect { width: item.0, height: item.1 }
59 fn immutable_copy_of_point() {
61 let mut b = a; // Copy
62 assert_eq!(a, b); // PartialEq
64 assert_ne!(a, b); // PartialEq
69 let mut a = point!(1, 0);
70 assert_eq!(a + point!(2, 2), point!(3, 2)); // Add
71 a += point!(2, 2); // AddAssign
72 assert_eq!(a, point!(3, 2));
76 fn area_for_rect_of_multipliable_type() {
77 let r: Rect<_> = (30, 20).into(); // the Into trait uses the From trait
78 assert_eq!(r.area(), 30 * 20);
79 // let a = Rect::from(("a".to_string(), "b".to_string())).area(); // this doesn't work, because area() is not implemented for String