运算符

运算符

运算符重载是通过 std::ops 中的特征实现的：

#[derive(Debug, Copy, Clone)]
struct Point {
    x: i32,
    y: i32,
}
impl std::ops::Add for Point {
    type Output = Self;
    fn add(self, other: Self) -> Self {
        Self { x: self.x + other.x, y: self.y + other.y }
    }
}
fn main() {
    let p1 = Point { x: 10, y: 20 };
    let p2 = Point { x: 100, y: 200 };
    println!("{:?} + {:?} = {:?}", p1, p2, p1 + p2);
}

This slide should take about 10 minutes.

讨论点：

You could implement Add for &Point. In which situations is that useful?
- 回答：Add:add 会耗用 self。如果您的运算符重载对象（即类型 T）不是 Copy，建议您也为 &T 重载运算符。这可避免调用点上存在不必要的克隆任务。
为什么 Output 是关联类型？可将它用作该方法的类型形参吗？
- Short answer: Function type parameters are controlled by the caller, but associated types (like Output) are controlled by the implementer of a trait.
您可以针对两种不同类型实现 Add，例如， impl Add<(i32, i32)> for Point 会向 Point 中添加元组。

17.2. 运算符

运算符