有什么办法从闭包内部从函数返回吗? [英] Is there any way to return from a function from inside a closure?
问题描述
我有以下简化代码:
fn f() -> i32 {
let a = some_result.unwrap_or_else(|_| {
return 1; // want to return this value from f <-------------
});
}
我要返回值 1 $在这种特定的错误情况下,来自整个函数
f
的c $ c>,但我无法从封闭中找出方法。
I want to return the value 1
from the whole function f
in this specific error case but I can't figure out how to do it from within a closure.
如果我改用 match
表达式,它的工作原理如下:
If I instead use a match
expression, it works fine as follows:
fn f() -> i32 {
let a = match some_result {
Ok(result) => result,
Err(_) => { return 1; },
};
}
但是,由于我的琐碎<$ c $,这使代码变得冗长c> OK 匹配臂。
However, this makes the code verbose since I have the trivial Ok
match arm.
推荐答案
不,没有。
闭包是内部的一种方法(一种功能)。您正在要求能够从任意深度嵌套的函数调用中退出父函数。通常,这种非本地流控制对程序员的理智和程序维护极为不利。
A closure is a method (a kind of function) under the hood. You are asking for the ability to exit a parent function from an arbitrarily deeply nested function call. Such non-local flow control has generally proven to be extremely bad for programmer sanity and program maintenance.
解决您的问题:
- How do you unwrap a Result on Ok or return from the function on Err?
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