我怎样才能像经典元组那样解压缩元组结构？

Question

我可以解压这样的经典元组:

let pair = (1, true);
let (one, two) = pair;

如果我有一个元组结构,如果我struct Matrix(f32, f32, f32, f32)尝试解压缩它,我得到一个关于"意外类型"的错误:

struct Matrix(f32, f32, f32, f32);
let mat = Matrix(1.1, 1.2, 2.1, 2.2);
let (one, two, three, four) = mat;

结果出现此错误:

error[E0308]: mismatched types
  --> src/main.rs:47:9
   |
47 |     let (one, two, three, four) = mat;
   |
   = note: expected type `Matrix`
              found type `(_, _, _, _)`

如何解压缩元组结构？我是否需要将其显式转换为元组类型？或者我需要硬编码吗？

Answer 1

这很简单:只需添加类型名称!

struct Matrix(f32, f32, f32, f32);

let mat = Matrix(1.1, 1.2, 2.1, 2.2);
let Matrix(one, two, three, four) = mat;
//  ^^^^^^

这按预期工作.

它与普通结构完全相同.在这里,您可以绑定到字段名称或自定义名称(如height):

struct Point {
    x: f64,
    y: f64,
}

let p = Point { x: 0.0, y: 5.0 };
let Point { x, y: height } = p;