“悬挂” scala中的本地块 [英] "dangling" local blocks in scala

问题描述

在scala中，可以在函数中定义一个局部块。本地块评估为最后一个语句，例如

In scala it is possible to define a local block in a function. The local block evaluates to the last statements, for example,

val x = {val x =1;x+1}

这里 x == 2 code> val x 是该块的本地。

Here x==2, the inner val x is local to that block.

但是，当编写匿名类时，这些本地块会导致鬼祟的错误。例如（来自scala的引用）

However those local blocks can cause sneaky bugs when writing anonymous classes. For example (from scala's reference)

new Iterator[Int]
{...} // new anonymous class inheriting from Iterator[Int]

new Iterator[Int]

{...} //new Iterator[Int] followed by a "dangling" local block

这两种情况之间的区分令人沮丧。
有时这两个代码片段可以编译，例如，而不是 Iterator [Int] ， Range（0,1,1）被使用。

Differntiating between the two cases is frustrating. Sometimes those two code snippets can compile, for instance if instead of Iterator[Int], Range(0,1,1) is used.

我想到了，并且找不到一个dangling局部块（即，值为n （或使代码更优雅）。

I thought about it and couldn't find a case where "dangling" local block (ie, a local block whose value isn't use) is needed (or makes the code more elegant).

有一种情况，我们想要一个局部块，而不使用它的值在不同的函数并调用这个函数）？我会很高兴的例子。

Is there a case where we want a local block, without using its value (and without putting it in a different function and calling this function)? I'll be glad for an example.

如果没有，我认为发布警告（甚至禁止别人）每当 scalac 遇到dangling本地块。我错过了什么？

If not, I think it would be nice to issue a warning (or even forbid altogther) whenever scalac encounter "dangling" local block. Am I missing something?

推荐答案

  {
    import my.crazy.implicit.functions._

    // use them...
  }

  // code I know isn't touched by them.

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