by: Ksenia Milkand & Cxx
#include <iostream>
#include <type_traits>
template <class type, class... types>
struct list
{
private:
template <class>
struct identity {
};
template <class... types_>
struct identities : identity <types_>... {
};
public:
template <class element, class... elements>
struct contain
{
constexpr static bool value = std::is_base_of <identity <type> , identities <element, elements...>>::value || (std::is_base_of <identity <types>, identities <element, elements...>>::value || ...);
};
};
template <class element_0, class... element_rest>
struct _restrict_
{
template <class type_0, class... type_rest>
struct _access_to_ {
template <class type_x0, class... type_rest>
constexpr static decltype(auto) process(type_x0 args0, type_rest... arg_rest)
{
return [](auto... args)
{
static_assert(!(list <type_x0, type_rest...>::template contain <element_0, element_rest...>::value &&
list < decltype(args)...>::template contain < type_0, type_rest ...>::value),
"bad_type_access" );
puts("processing elements");
};
};
};
_restrict_() = delete;
};
int main() {
using mode = _restrict_ <int>::_access_to_ <float, double>;
//mode::process(int{})(float{}, double{}); // assert
mode::process(char{})(float{}, double{});
return 0;
}
1: Ksenia Milkand & Cxx - https://godbolt.org/z/IMU6KX