从 std::tuple 成员中删除引用 [英] Remove reference from std::tuple members

问题描述

我正在 stl 元组的帮助下为某些变量实现保存/恢复功能，如下所示:

I'm implementing save/restore functionality for some variables with the help of stl tuples as follows:

double a = 1, b = 2;
int c = 3;
auto tupleRef = std::make_tuple(std::ref(a), std::ref(b), std::ref(c));

// here I'm saving current state of a, b, c
std::tuple<double, double, int> saved = tupleRef;

//here goes block of code, where a, b, and c get spoiled
......................
//

//now I'm restoring initial state of a, b, c
tupleRef = savedTuple;

此代码运行良好.但不是在

This code works well. But instead of explicit specifying tuple members types in

std::tuple<double, double, int> saved = tupleRef;

我宁愿删除所有 tupleRef 成员的引用，如下所示

I'd like to rather remove references from all tupleRef members, like in the following

auto saved = remove_ref_from_tuple_members(tupleRef);

我相信可以为此编写remove_ref_from_tuple_members"模板.

I believe that it is possible to write "remove_ref_from_tuple_members" template to that end.

感谢您的回答.

推荐答案

一个简单的类型别名可用于将 std::remove_reference 应用于元组中的所有类型.

A simple type alias can be used to apply std::remove_reference to all types in a tuple.

template <typename... T>
using tuple_with_removed_refs = std::tuple<typename std::remove_reference<T>::type...>;

有了这个，您现在可以编写函数模板:

Armed with this you can now write the function template:

template <typename... T>
tuple_with_removed_refs remove_ref_from_tuple_members(std::tuple<T...> const& t) {
    return tuple_with_removed_refs { t };
}

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