I have created a template class which takes two plain template parameters (like int or double) and have derived several other classes from it:
template <typename A, typename B>
class IClassBase {...}
template <typename B>
class Derived1Class : public IClassBase<std::string, B> {...}
template <typename B>
class Derived2Class : public IClassBase<std::string, B> {...}
I need to design a structure which would allow compiler to build a std::tuple based on list of template types and their parameters (B type in code snippet above).
So given the list below
Derived1Class<int>, Derived1Class<double>, Derived2Class<bool>, Derived2Class<std::string>
compiler should infer following tuple:
std::tuple<int, double, bool, std::string>
Is this even possible, and if so, how it can be done in C++?
Thanks in advance)
Is this even possible, and if so, how it can be done in C++?
Anything is possible in C++. Especially the current C++ standard. Tested with gcc 6.2.
#include <tuple>
#include <string>
template<typename template_type> class extract_param;
template<template<typename T> typename template_param, typename template_param_t>
class extract_param<template_param<template_param_t>> {
public:
typedef template_param_t type_t;
};
template<typename ...Args>
using extract_tuple=std::tuple<typename extract_param<Args>::type_t...>;
template<typename T> class sometemplate {};
int main()
{
extract_tuple< sometemplate<int>, sometemplate<std::string>> tuple;
int &intref=std::get<0>(tuple);
std::string &stringref=std::get<1>(tuple);
return 0;
}