C ++：通过对象的所有成员的迭代？ [英] C++: Iterating through all of an object's members?

问题描述

假设我有许多成员的对象：

Suppose I have an object with many members:

class Example {
    AnotherClass member1;
    AnotherClass member2;
    YetAnotherClass member3;
    ...
};

有一个短/简洁的方式做这样的事情：

Is there a short/concise way to do something like:

foreach(member m: myExample)
    m.sharedMethod();

而不是单独访问每个人的？

Instead of accessing each one individually?

我想我可以把它们放在一个载体，并使用的shared_ptr 对于同样的效果，我只是说，如果想知道，升压或其他一些流行的库不有事要自动执行此操作。

I think I could put them in a vector and use a shared_ptr for the same effect, I was just wondering if say, Boost or some other popular library doesn't have something to do this automatically.

推荐答案

C ++并不支持类的反省，所以你不能遍历所有成员在这样的类 - 不是没有具有（手写）函数迭代反正多为你的所有成员。

C++ does not support class introspection, so you cannot iterate over all of the members in a class like that - not without having a (manually written) function that iterates over all members for you anyway.

您可以在原则上，增加一个模板成员像这样：

You could, in principle, add a template member like so:

template<typename Functor>
void doAllMembers(Functor &f) {
  f(member1);
  f(member2);
  f(member3);
}

这是说，我认为这是一个破碎的设计;你走了，暴露所有的内部成员的公开。如果你添加了以后会发生什么？或改变一个的语义？做一个缓存值，有时过时了？等。此外，如果您有来自同一类型的成员，其中并不都继承了该怎么办？

That said, I would regard this as a broken design; you've gone and exposed all of your internal members publicly. What happens if you add one later? Or change the semantics of one? Make one a cached value that's sometimes out of date? etc. Moreover, what happens if you have members which don't all inherit from the same types?

退一步重新考虑你的设计。

Step back and reconsider your design.

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