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djarek/index_template_parameter_pack.hpp

Created September 29, 2016 22:37
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index_template_parameter_pack.hpp
template <typename T, typename U=void, typename... Types>
constexpr size_t index() {
return std::is_same<T, U>::value ? 0 : 1 + index<T, Types...>();
}
template<size_t index, typename... T>
struct TypeAtIndex
{
using type = typename std::tuple_element<index, std::tuple<T...>>::type;
};
template <typename... T>
struct TestPackIndex {
static constexpr auto value = index<bool ,T...>();
using type = typename TypeAtIndex<value, T...>::type;
};
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