tupleのヘルパーメタ関数

AsTuple.hpp

#pragma once
#include<tuple>

///<summary>
//タプル型の結合
///<summary>
template<class Type1, class Type2>
struct TupleCombine
{
	using type = std::tuple<Type1, Type2>;
};
template<class Type, class... Args>
struct TupleCombine<Type, std::tuple<Args...>>
{
	using type = std::tuple<Type, Args...>;
};
template<class Type, class... Args>
struct TupleCombine<std::tuple<Args...>, Type>
{
	using type = std::tuple<Args..., Type>;
};
template<class ...Args1, class... Args2>
struct TupleCombine<std::tuple<Args1...>, std::tuple<Args2...>>
{
	using type = std::tuple<Args1..., Args2...>;
};


///<summary>
///ある型をtuple型として取得する
///<summary>
template<class Type, size_t N = 1>
struct AsTuple
{
	using type = typename TupleCombine<
		Type,
		typename AsTuple<Type, N - 1>::type
	>::type;
};
template<class Type>
struct AsTuple<Type, 1>
{
	using type = std::tuple<Type>;
};

template<class Type>
struct AsTuple<Type, 0>
{};


template<class Type, size_t N = 1>
using AsTuple_t = typename AsTuple<Type, N>::type;

/*
int main()
{
//std::tuple<int>
AsTuple_t<int> a(1);

//std::tuple<int,int,int>
AsTuple_t<int, 3> b(1,2,3);

return 0;
}

*/