为什么在一个被认为是糟糕风格的函数中使用 return 作为最后一个语句? [英] Why is using return as the last statement in a function considered bad style?

问题描述

我在阅读 Rust 文档时遇到了以下示例和语句

I was reading through the Rust documentation and came across the following example and statement

使用 return 作为函数的最后一行有效，但被认为是糟糕的风格:

Using a return as the last line of a function works, but is considered poor style:

fn foo(x: i32) -> i32 {
    if x < 5 { return x; }

    return x + 1;
}

我知道我可以把上面写成

I know I could have written the above as

fn foo(x: i32) -> i32 {
    if x < 5 { return x; }

    x + 1
}

但我更倾向于写前者，因为它更直观.我确实理解函数返回值应该用作表达式，以便后者工作，但为什么不鼓励前者?

but I am more tempted to write the former, as that is more intuitive. I do understand that the function return value should be used as an expression so the later works but then why wouldn't the former be encouraged?

推荐答案

It just is.

约定不需要特别好的理由，他们只需要被普遍接受的约定.碰巧，这个确实有一个比较好的理由——它更短，因为你没有 return 和 ;.你可能认为 return x + 1; 更直观，但我强烈反对——它真的很令人讨厌，我觉得有必要修复它.我这样说的人，在开始使用 Rust 之前，从来没有使用过面向表达式的语言.写Python的时候，在那个地方return x + 1看起来是对的，而写Rust的时候就错了.

Conventions don’t need to have particularly good reasons, they just need to be generally accepted conventions. As it happens, this one does have a comparatively good reason—it’s shorter as you don’t have the return and ;. You may think that return x + 1; is more intuitive, but I disagree strongly—it really grates and I feel a compelling need to fix it. I say this as one who, before starting using Rust, had never used an expression-oriented language before. While writing Python, return x + 1 in that place looks right, while writing Rust it looks wrong.

现在碰巧，该代码可能应该这样编写:

Now as it happens, that code should probably be written thus instead:

fn foo(x: i32) -> i32 {
    if x < 5 {
        x
    } else {
        x + 1
    }
}

这强调了语言的表达取向.

This emphasises the expression orientation of the language.

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