pub trait Add<Rhs = Self> {
type Output;
// Required method
fn add(self, rhs: Rhs) -> Self::Output;
}Expand description
The addition operator +.
Note that Rhs is Self by default, but this is not mandatory. For
example, std::time::SystemTime implements Add<Duration>, which permits
operations of the form SystemTime = SystemTime + Duration.
Examples
Addable points
use std::ops::Add;
#[derive(Debug, Copy, Clone, PartialEq)]
struct Point {
x: i32,
y: i32,
}
impl Add for Point {
type Output = Self;
fn add(self, other: Self) -> Self {
Self {
x: self.x + other.x,
y: self.y + other.y,
}
}
}
assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
Point { x: 3, y: 3 });Implementing Add with generics
Here is an example of the same Point struct implementing the Add trait
using generics.
use std::ops::Add;
#[derive(Debug, Copy, Clone, PartialEq)]
struct Point<T> {
x: T,
y: T,
}
// Notice that the implementation uses the associated type `Output`.
impl<T: Add<Output = T>> Add for Point<T> {
type Output = Self;
fn add(self, other: Self) -> Self::Output {
Self {
x: self.x + other.x,
y: self.y + other.y,
}
}
}
assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
Point { x: 3, y: 3 });