为什么严格模式不限制标识符“eval"和“arguments"?从作为标签名称出现?

因此，如您所知，JavaScript 的严格模式对标识符 eval 和 arguments 增加了限制，有效地使它们成为保留字，但有两个例外:

So, as you may know, the strict mode of JavaScript adds restrictions on the identifiers eval, and arguments, effectively making them reserved words, with two exceptions:

• 它们仍然可以用作表达式，即在需要表达式的地方(但有几个例外)，
• 它们仍然可以用作标签名称，并在 break/continue 语句中引用标签.

• they can still be uses as expressions, i.e. in places where an expression is expected (with a couple of exceptions, though),
• they can still be used as label names, and in break/continue statements to reference labels.

现在，我明白了第一点.例如，如果标识符 eval 不允许作为表达式(而真正的保留字不允许)，我们将无法调用 eval 函数根本没有(因为 eval(str) 是一个表达式).arguments 也是如此——我们需要能够将其用作表达式以便能够访问其元素(例如 arguments[0]).

Now, I understand the first bullet. If, for instance, the identifier eval wasn't allowed as an expression (and true reserved words aren't), we wouldn't be able to invoke the eval function at all (since eval(str) is an expression). Same goes for arguments - we need to be able to use it as an expression in order to be able to access its elements (e.g. arguments[0]).

不过，这条规则有三个例外.eval/arguments 可能不会出现 (1) 作为赋值中的左侧表达式(例如 eval = true;)，(2)作为++/-- 的操作数(例如 eval++)，(3)作为 delete 的操作数(例如 删除评估).不过，这些是唯一的例外，并且在所有其他表达式上下文中，它们都是有效的.

This rule has a three exceptions, though. eval/arguments may not appear (1) as left-hand side expressions in assignments (e.g. eval = true;), (2) as operands of ++/-- (e.g. eval++), (3) as operands of delete (e.g. delete eval). Those are the only exceptions though, and in all other expression-contexts, they are valid.

我不明白的是第二个子弹.为什么它们仍然可以用作标签名称?例如，即使在严格模式下，这段代码也是有效的:

What I don't understand is the second bullet. Why can they be still used as label names? For instance, this code is valid even in strict mode:

eval: for ( var i = 0; i < 10; i++ ) {
    arguments: for ( var j = 0; j < 10; j++ ) {
        if ( i < j ) continue eval;
        console.log( i - j );    
    }        
}

注意 continue eval; 是如何引用 eval 标签的，与实际的 eval 函数无关.

Notice how continue eval; references the eval label, and has nothing to do with the actual eval function.

另外，请注意如何将真正的保留字不能用作标签名称.根据我的理解，严格模式的目的是使名称 eval 和 arguments 尽可能类似于保留字.那么为什么要将它们保留为有效的标签名称呢?

Also, notice how true reserved words cannot be used as label names. From my understanding, the intend of strict mode was to make the names eval, and arguments as reserved-word-like as possible. Then why keep them as valid label names?