make_int_range.cpp

namespace detail
{
	template <class...> struct integer_range;

	template <class T, class Ofst, T... Vals>
	struct integer_range<T, Ofst, std::integer_sequence<T, Vals...>>
	{
		using type = std::integer_sequence<T, (Ofst::value + Vals)...>;
	};
}

template <class T, T I1, T I2, class Check = std::enable_if_t<I1 <= I2>>
using make_integer_range = typename detail::integer_range<T,
	std::integral_constant<T, I1>, std::make_integer_sequence<T, I2 - I1>>::type;

template <std::size_t I1, std::size_t I2>
using make_index_range = make_integer_range<std::size_t, I1, I2>;