如何读取与Rust中的自定义类型相关联的枚举的值? [英] How to read a value of an enum which associates with a custom type in Rust?

问题描述

我在Rust中有一个实现，如下所示.在主要功能中，我正在读取 SalaryRange 枚举中的一个值，它将显示 High("So High").

I have an implementation in Rust as follows. In the main function, I am reading a value in SalaryRange enum and this will display High("So High").

// This can be a complex type, just using string for the question 
type SRange = String;
type SalEnu = SalaryRange<SRange>;

struct User<SRange> {
    username: String,
    email: String,
    sign_in_count: u64,
    active: bool,
    income: Income<SRange>,
}

struct Income<SRange> {
    salary_range: SalaryRange<SRange>
}

#[derive(Debug)]
enum SalaryRange<SRange> {
    Low(SRange),
    Mid(SRange),
    High(SRange),
}

fn main() {
    let user1 = User {
        email: String::from("[e-mail]"),
        username: String::from("test_name"),
        active: true,
        sign_in_count: 1,
        income: Income {
            salary_range: (
                SalaryRange::High("So High")
            )
        },
    };
    let mut srange: SalaryRange<&str> = user1.income.salary_range;
    println!("{:?}", srange);
}

此a>可以在这里找到.

Link for this example can be found here.

只想知道是否有可能以 println！("{:?}"，srange :: High); 的形式读取和打印该枚举中的值字符串值?我只想打印值 So High .

Just wanted to know if there is a possibility to read and print the value in that enum as println!("{:?}", srange::High);, just to print out the string value? I only want to print the value So High.

如果我使用 srange :: High ，这将引发错误

If I use srange::High This will throw an error saying

      println!("{:?}", srange::High);
|                      ^^^^^^ use of undeclared type or module `srange`
error: aborting due to previous error

推荐答案

您可以在枚举上实现一种方法来提取值:

You can implement a method on your enum to extract the value:

#[derive(Debug)]
enum SalaryRange<S> {
    Low(S),
    Mid(S),
    High(S),
}

impl<S> SalaryRange<S> {
    fn value(&self) -> &S {
        match self {
            SalaryRange::Low(value) => value,
            SalaryRange::Mid(value) => value,
            SalaryRange::High(value) => value,
        }
    }
}

println!("{:?}", srange.value());

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