Function get

include/boost/parser/tuple.hpp:322–336

    template<typename T, typename U, U I>
    constexpr decltype(auto) get(T && x, integral_constant<U, I> i)
    {
        using just_t = std::decay_t<T>;
        if constexpr (detail::is_tuple<just_t>::value) {
            return detail::tuple_get((T &&) x, i);
        } else if constexpr (std::is_aggregate_v<just_t>) {
            auto tup = detail::tie_aggregate(x);
            return detail::tuple_get(tup, i);
        } else {
            static_assert(
                sizeof(T) != sizeof(T),
                "boost::parser::get() is only defined for boost::parser::tuple "
                "and aggregate structs.");
        }
    }

}}