你如何在 Ok 上解包 Result 或从 Err 上的函数返回? [英] How do you unwrap a Result on Ok or return from the function on Err?

问题描述

我有一个函数调用另一个返回 Result 的函数.我需要检查 Result 是 Ok 还是 Err，如果它是 Err，我需要 return 从我的函数中提早开始.这就是我现在正在做的:

I have a function that calls another function which returns a Result. I need to check if the Result is Ok or Err and if it is an Err, I need to return early from my function. This is what I'm doing now:

match callable(&mut param) {
    Ok(_v) => (),
    Err(_e) => return,
};

有没有更惯用的 Rust 方法来做到这一点?

Is there a more idiomatic Rust way to do this?

推荐答案

您可以创建一个宏:

macro_rules! unwrap_or_return {
    ( $e:expr ) => {
        match $e {
            Ok(x) => x,
            Err(_) => return,
        }
    }
}

fn callable(param: &mut i32) -> Result<i32, ()> {
    Ok(*param)
}

fn main() {
    let mut param = 0;
    let res = unwrap_or_return!(callable(&mut param));

    println!("{:?}", res);
}

请注意，我不建议丢弃错误.Rust 的错误处理非常符合人体工程学，所以我会返回错误，即使只是记录它:

Note that I wouldn't recommend discarding the errors. Rust's error handling is pretty ergonomic, so I would return the error, even if it is only to log it:

fn callable(param: &mut i32) -> Result<i32, ()> {
    Ok(*param)
}

fn run() -> Result<(), ()> {
    let mut param = 0;
    let res = callable(&mut param)?;

    println!("{:?}", res);

    Ok(())
}

fn main() {
    if let Err(()) = run() {
        println!("Oops, something went wrong!");
    }
}

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