| 1 | use std::ops::{Add, AddAssign}; |
| 2 | |
| 3 | macro_rules! point { |
| 4 | ( $x:expr, $y:expr ) => { Point2D { x:$x, y:$y } }; |
| 5 | } |
| 6 | |
| 7 | #[derive(Debug, Copy, Clone, PartialEq)] |
| 8 | pub struct Point2D<T> { |
| 9 | pub x: T, |
| 10 | pub y: T, |
| 11 | } |
| 12 | |
| 13 | impl Point2D<f64> { |
| 14 | pub fn length(self) -> f64 { |
| 15 | ((self.x * self.x) + (self.y * self.y)).sqrt() |
| 16 | } |
| 17 | } |
| 18 | |
| 19 | impl<T: Add<Output=T>> Add for Point2D<T> { |
| 20 | type Output = Point2D<T>; |
| 21 | |
| 22 | fn add(self, rhs: Point2D<T>) -> Self::Output { |
| 23 | Point2D { x: self.x + rhs.x, y: self.y + rhs.y } |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | impl<T: AddAssign> AddAssign for Point2D<T> { |
| 28 | fn add_assign(&mut self, rhs: Point2D<T>) { |
| 29 | self.x += rhs.x; |
| 30 | self.y += rhs.y; |
| 31 | } |
| 32 | } |
| 33 | |
| 34 | #[cfg(test)] |
| 35 | mod tests { |
| 36 | use super::*; |
| 37 | |
| 38 | #[test] |
| 39 | fn immutable_copy_of_point() { |
| 40 | let a = point!(0, 0); |
| 41 | let mut b = a; // Copy |
| 42 | assert_eq!(a, b); // PartialEq |
| 43 | b.x = 1; |
| 44 | assert_ne!(a, b); // PartialEq |
| 45 | } |
| 46 | |
| 47 | #[test] |
| 48 | fn add_points() { |
| 49 | let mut a = point!(1, 0); |
| 50 | assert_eq!(a + point!(2, 2), point!(3, 2)); // Add |
| 51 | a += point!(2, 2); // AddAssign |
| 52 | assert_eq!(a, point!(3, 2)); |
| 53 | } |
| 54 | } |