在Kotlin的`forEach`中`break`和`continue`

问题描述

Kotlin有很好的迭代函数，比如 forEach 或者 repeat ，但是我不能使 break 和 continue 操作符与它们一起工作（包括本地和非本地）：

  repeat（5）{
 break 
} 
 
（1..5）.forEach {
 continue @ forEach 
} 
  

目标是模仿通常的循环，尽可能靠近。这在Kotlin的一些老版本中是绝对有可能的，但我很难重现这个语法。

这个问题可能是标签（M12）的错误，但我认为第一个例子应该可以工作。

在我看来，我已经读了一些关于特殊技巧/注释的地方，但我找不到任何关于这个主题的参考。可能看起来像下面这样：

  public inline fun repeat（times：Int，@loop body：（Int） - > Unit ）{
 for（index in 0..times -1）{
 body（index）
} 
} 
   
 
 问题这个功能是3岁，所以我想这是不会被固定的。
 
 
 
 
 
 
 原始回答：
 
由于您提供了（Int） - >单元，你不能打破它，因为编译器不知道它在循环中使用。
 
 
 
 ：
 
 
 
 使用常规循环：  
 
 
  // your code here 
} 
  
 如果循环是方法的最后一个代码 
 
，可以使用 return 来退出方法（或返回值，如果它不是 unit 方法）。
 
 
 使用方法 
 
创建一个返回 Boolean 继续的自定义重复方法方法。  
 
 
  public inline fun repeatUntil（times：Int，body：（Int） - > Boolean）{
 for如果（！body（index））break 
} 
} 
   
Kotlin has very nice iterating functions, like forEach or repeat, but I am not able to make the break and continue operators work with them (both local and non-local):
repeat(5) {
    break
}

(1..5).forEach {
    continue@forEach
}
The goal is to mimic usual loops with the functional syntax as close as it might be. It was definitely possible in some older versions of Kotlin, but I struggle to reproduce the syntax. 
The problem might be a bug with labels (M12), but I think that the first example should work anyway.
It seems to me that I've read somewhere about a special trick/annotation, but I could not find any reference on the subject. Might look like the following:
public inline fun repeat(times: Int, @loop body: (Int) -> Unit) {
    for (index in 0..times - 1) {
        body(index)
    }
}
 解决方案 
Edit:
According to Kotlin's old documents, it should be possible using annotations. However, it is not implemented yet.
The issue for this functionality is 3 years old, so I guess it is not going to be fixed.
Original Answer:
Since you supply a (Int) -> Unit, you can't break from it, since the compiler do not know that it is used in a loop.
You have few options:  
Use a regular for loop:
for (index in 0..times - 1) {
    // your code here
}
If the loop is the last code in the method
you can use return to get out of the method (or return value if it is not unit method).
Use a method
Create a custom repeat method method that returns Boolean for continuing.  
public inline fun repeatUntil(times: Int, body: (Int) -> Boolean) {
    for (index in 0..times - 1) {
        if (!body(index)) break
    }
}
                        
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