速记回报

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本文介绍了速记回报的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

以下代码在Go 1.6或1.7中生成语法错误(语句末尾意外的++ ):

The following code generates a syntax error (unexpected ++ at end of statement) in Go 1.6 or 1.7:

package main

import "fmt"

var x int

func increment() int {
        return x++   // not allowed
}

func main() {
  fmt.Println( increment() )
}

这是不允许的吗?

推荐答案

这是一个错误,因为Go中的 ++ -是语句,而不是表达式:规范:IncDec语句(并且该语句没有将返回的结果).

It's an error, because the ++ and -- in Go are statements, not expressions: Spec: IncDec Statements (and statements have no results that would be returned).

有关推理的信息,请参阅Go常见问题解答:为什么++和-语句而不是表达式?为何使用后缀而不是前缀?

For reasoning, see Go FAQ: Why are ++ and -- statements and not expressions? And why postfix, not prefix?

所以您编写的代码只能写为:

So the code you wrote can only be written as:

func increment() int {
    x++
    return x
}

而且您必须在不传递任何内容的情况下调用它:

And you have to call it without passing anything:

fmt.Println(increment())

请注意,我们仍然会尝试使用赋值将其写在一行中,例如:

Note that we would be tempted to still try to write it in one line using an assignment, e.g.:

func increment() int {
    return x += 1 // Compile-time error!
}

但这在Go中也不起作用,因为分配也是一个声明,因此您会得到一个编译时错误:

But this also doesn't work in Go, because the assignment is also a statement, and thus you get a compile-time error:

这篇关于速记回报的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

05-28 00:16
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