如何写一个C ++转换操作符来返回数组引用？ [英] How to write a C++ conversion operator returning reference to array?
问题描述
在C ++中可以在类或结构中添加隐式转换操作符。例如，3D向量类型通常包括这样的：
In C++ one can add implicit-conversion operators in a class or struct. For instance, 3D vector types usually include something like:
struct Vector {
float x, y, z;
operator float * () { return reinterpret_cast<float *>(this); }
};
允许访问向量与标元素，传递给那些需要一个指针，等我突然想知道的功能：我们可以改为编写返回到浮动的数组引用的转换操作符，而不是一个指针浮？
to allow accessing the vector's elements with subscripts, passing to functions that want a pointer, etc. It occurred to me to wonder: can we instead write a conversion operator that returns a reference to array of float, instead of a pointer to float?
（这是纯粹的学术兴趣。我不知道有什么好处的引用到阵列会的，如果有的话，过一个简单的指针。）
(This is of purely academic interest. I don't know what benefits a reference-to-array would have, if any, over a simple pointer.)
作为一个自由的功能，我们可以做到这一点，如：
As a free function we can do this like:
float (&convert(Vector & v))[3]
{
return reinterpret_cast<float(&)[3]>(v);
}
Vector v;
convert(v);
不过，我一直没能找到合适的语法来做到这一点作为一个转换操作符。我试过喜欢的东西：
However, I haven't been able to find the right syntax to do this as a conversion operator. I've tried things like:
operator float(&)[3] ()
operator float(&())[3]
float (&operator())[3]
和其他各种排列，但我只是得到了各种各样的语法错误（G ++ 4.8.1）。
and various other permutations, but I just get various syntax errors (g++ 4.8.1).
是否可以写一个转换操作符返回数组的引用，如果是这样，什么是语法，这样做呢？
Is it possible to write a conversion operator returning a reference to array, and if so, what is the syntax to do so?
推荐答案
在事实上，你可以，你几乎是最后一个了吧：
In fact you can, you almost had it with the last one:
(&operator float())[3];
而对于一个typedef是否必要过这个问题，我认为这是从阅读 HTTP的评论：// stackoverflow.com/a/6755760/2925619 （这答案是什么帮助我得到的语法以上为好）。
As for the question of whether or not a typedef is ever necessary, I think it is from reading the comments on http://stackoverflow.com/a/6755760/2925619 (which answer is what helped me get the syntax for the above as well).
修改
显然，这语法不正确，返回数组的引用是被禁止的克里斯发现了我们。我猜你只需要解决一个的typedef 。
Apparently, this syntax is incorrect and returning a reference to an array is forbidden as chris discovered for us. I guess you'll just have to settle for a typedef.
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