C++ 成员变量别名? [英] C++ member variable aliases?

问题描述

我很确定这是可能的，因为我很确定我已经看到它完成了.我认为这很棒，但我很乐意接受这是一个糟糕的主意，因为 ____"这样的答案.

I'm pretty sure this is possible, because I'm pretty sure I've seen it done. I think it is awesome, but I will gladly accept answers along the lines of "this is a terrible idea because ____".

假设我们有一个基本结构.

Say we have a basic struct.

struct vertex
{
    float x, y, z;
};

现在，我想在这些变量上实现别名.

Now, I want to implement aliases on these variables.

vertex pos;
vertex col;
vertex arr;

pos.x = 0.0f; pos.y = 0.5f; pos.z = 1.0f;
col.r = 0.0f; col.g = 0.5f; col.b = 1.0f;
arr[0] = 0.0f; arr[1] = 0.5f; arr[2] = 1.0f;

理想情况下，第三种语法与数组无法区分.也就是说，如果我将 arr 作为一个引用参数发送给一个函数，该函数需要一个浮点数组来存储数据(例如，许多 OpenGL glGet 函数)，它会工作得很好.

Ideally the third syntax would be indistinguishable from an array. That is, if I sent arr as a reference parameter to a function expecting an array of floats into which it will store data (eg many of the OpenGL glGet functions), it would work fine.

你怎么看?可能的?可能但愚蠢?

What do you think? Possible? Possible but stupid?

推荐答案

我要做的是制作访问器:

What I would do is make accessors:

struct Vertex {
    float& r() { return values[0]; }
    float& g() { return values[1]; }
    float& b() { return values[2]; }

    float& x() { return values[0]; }
    float& y() { return values[1]; }
    float& z() { return values[2]; }

    float  operator [] (unsigned i) const { return this->values_[i]; }
    float& operator [] (unsigned i)       { return this->values_[i]; }
    operator float*() const { return this->values_; }

private:
    float[3] values_;
}

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