Ticket #6818: tuple_subscript.h

#ifndef TUPLE_SUBSCRIPT_H
#define TUPLE_SUBSCRIPT_H

#include <tuple>

template< std::size_t > struct Number2Type { };

template< class... Ts >
class tupless: public std::tuple<Ts...>
{
public:
        template< class... ARGS >
        tupless(ARGS... args): std::tuple<Ts...>(args...)
        {
        }
        template< std::size_t N >
        auto operator[](Number2Type<N>) const ->
                decltype(std::get<N>(std::tuple<Ts...>())) const&
        {
                return std::get<N>(*this);
        }
        template< std::size_t N >
        auto operator[](Number2Type<N>) ->
                decltype(std::get<N>(std::tuple<Ts...>())) &
        {
                return std::get<N>(*this);
        }
};

template< int N >
constexpr std::size_t chars_to_int(const char (&array)[N], int current = 0, std::size_t acc = 0)
{
        return (current >= N || array[current] == 0) ?
                        acc
                  : chars_to_int(array, current + 1, 10 * acc + array[current] - '0');
};

template<char... Cs>
constexpr auto operator "" _t() -> Number2Type<chars_to_int((const char[1 + sizeof...(Cs)]){Cs..., '\0'})>
{
        return {};
};


#endif //TUPLE_SUBSCRIPT_H