为类型别名元组 (f64, f64) 添加 Impl [英] Impl Add for type alias tuple (f64, f64)

问题描述

我有一个自定义类型 Point

I have a custom type Point

type Point = (f64, f64);

我想将两个 Point 加在一起，但出现此错误

And I want to add two Points together but I get this error

error[E0368]: binary assignment operation `+=` cannot be applied to type `(f64, f64)`
   --> src/main.rs:119:21
    |
119 |                     force_map[&body.name] += force;
    |                     ---------------------^^^^^^^^^
    |                     |
    |                     cannot use `+=` on type `(f64, f64)`

当我尝试实现 Add 时，出现此错误:

And when I try implementing Add, I get this error:

39 | / impl Add for (f64, f64) {
40 | |     #[inline(always)]
41 | |     fn add(self, other: (f64, f64)) -> (f64, f64)  {
42 | |         // Probably it will be optimized to not actually copy self and rhs for each call !
43 | |         (self.0 + other.0, self.1 + other.1);
44 | |     }
45 | | }
   | |_^ impl doesn't use types inside crate
   |
   = note: the impl does not reference any types defined in this crate
   = note: define and implement a trait or new type instead

是否可以为 type 实现 Add?我应该使用 struct 代替吗?

Is it possible to implement Add for a type? Should I use a struct instead?

推荐答案

不，您没有 Point 类型.不幸的是，type 关键字不会创建新类型，而只会为现有类型创建新名称(别名).

No, you don't have a Point type. The type keyword unfortunately does not create a new type, but only a new name (alias) for an existing type.

要创建类型，请使用:

struct Point(f64, f64);

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