From 331aaa3559e17f616aa8ef1d69cf67d1e981c0ca Mon Sep 17 00:00:00 2001
From: bolero-MURAKAMI <bolero.murakami@gmail.com>
Date: Sun, 31 Mar 2013 13:39:26 +0900
Subject: [PATCH] add index_tuple/integer_seq

---
 sprout/index_tuple.hpp                  |  8 ++-
 sprout/index_tuple/index_n.hpp          | 71 +++++------------------
 sprout/index_tuple/index_range.hpp      | 76 +++++--------------------
 sprout/index_tuple/index_tuple.hpp      | 36 ++++++++----
 sprout/index_tuple/integer_n.hpp        | 73 ++++++++++++++++++++++++
 sprout/index_tuple/integer_range.hpp    | 76 +++++++++++++++++++++++++
 sprout/index_tuple/integer_seq.hpp      | 32 +++++++++++
 sprout/index_tuple/make_index_tuple.hpp | 33 +++++++++++
 sprout/index_tuple/make_indexes.hpp     |  6 +-
 sprout/index_tuple/make_integer_seq.hpp | 20 +++++++
 sprout/index_tuple/pack_indexes.hpp     | 20 -------
 sprout/index_tuple/tuple.hpp            | 44 +++++++++++---
 sprout/string/alias.hpp                 | 12 +---
 sprout/utility/string_ref/alias.hpp     | 31 +++++++---
 14 files changed, 358 insertions(+), 180 deletions(-)
 create mode 100644 sprout/index_tuple/integer_n.hpp
 create mode 100644 sprout/index_tuple/integer_range.hpp
 create mode 100644 sprout/index_tuple/integer_seq.hpp
 create mode 100644 sprout/index_tuple/make_index_tuple.hpp
 create mode 100644 sprout/index_tuple/make_integer_seq.hpp
 delete mode 100644 sprout/index_tuple/pack_indexes.hpp

diff --git a/sprout/index_tuple.hpp b/sprout/index_tuple.hpp
index 19bc2b92..f62b3236 100644
--- a/sprout/index_tuple.hpp
+++ b/sprout/index_tuple.hpp
@@ -2,11 +2,15 @@
 #define SPROUT_INDEX_TUPLE_HPP
 
 #include <sprout/config.hpp>
+#include <sprout/index_tuple/integer_seq.hpp>
 #include <sprout/index_tuple/index_tuple.hpp>
 #include <sprout/index_tuple/tuple.hpp>
-#include <sprout/index_tuple/make_indexes.hpp>
+#include <sprout/index_tuple/make_integer_seq.hpp>
+#include <sprout/index_tuple/make_index_tuple.hpp>
+#include <sprout/index_tuple/integer_range.hpp>
 #include <sprout/index_tuple/index_range.hpp>
+#include <sprout/index_tuple/integer_n.hpp>
 #include <sprout/index_tuple/index_n.hpp>
-#include <sprout/index_tuple/pack_indexes.hpp>
+#include <sprout/index_tuple/make_indexes.hpp>
 
 #endif	// #ifndef SPROUT_INDEX_TUPLE_HPP
diff --git a/sprout/index_tuple/index_n.hpp b/sprout/index_tuple/index_n.hpp
index cf284bf8..19eea94d 100644
--- a/sprout/index_tuple/index_n.hpp
+++ b/sprout/index_tuple/index_n.hpp
@@ -2,74 +2,29 @@
 #define SPROUT_INDEX_TUPLE_INDEX_N_HPP
 
 #include <cstddef>
-#include <type_traits>
 #include <sprout/config.hpp>
-#include <sprout/index_tuple/index_tuple.hpp>
+#include <sprout/index_tuple/integer_n.hpp>
 #include <sprout/index_tuple/detail/make_indexes_helper.hpp>
 
 namespace sprout {
 	//
 	// index_n
 	//
-	namespace detail {
-		template<typename IndexTuple>
-		struct index_n_next;
-		template<sprout::index_t... Indexes>
-		struct index_n_next<sprout::index_tuple<Indexes...>> {
-		public:
-			typedef sprout::index_tuple<Indexes..., Indexes...> type;
-		};
-
-		template<typename IndexTuple, sprout::index_t Tail>
-		struct index_n_next2;
-		template<sprout::index_t... Indexes, sprout::index_t Tail>
-		struct index_n_next2<sprout::index_tuple<Indexes...>, Tail> {
-		public:
-			typedef sprout::index_tuple<Indexes..., Indexes..., Tail> type;
-		};
-
-		template<sprout::index_t I, std::size_t N, typename Enable = void>
-		struct index_n_impl;
-		template<sprout::index_t I, std::size_t N>
-		struct index_n_impl<
-			I, N,
-			typename std::enable_if<(N == 0)>::type
-		> {
-		public:
-			typedef sprout::index_tuple<> type;
-		};
-		template<sprout::index_t I, std::size_t N>
-		struct index_n_impl<
-			I, N,
-			typename std::enable_if<(N == 1)>::type
-		> {
-		public:
-			typedef sprout::index_tuple<I> type;
-		};
-		template<sprout::index_t I, std::size_t N>
-		struct index_n_impl<
-			I, N,
-			typename std::enable_if<(N > 1 && N % 2 == 0)>::type
-		>
-			: public sprout::detail::index_n_next<
-				typename sprout::detail::index_n_impl<I, N / 2>::type
-			>
-		{};
-		template<sprout::index_t I, std::size_t N>
-		struct index_n_impl<
-			I, N,
-			typename std::enable_if<(N > 1 && N % 2 == 1)>::type
-		>
-			: public sprout::detail::index_n_next2<
-				typename sprout::detail::index_n_impl<I, N / 2>::type,
-				I
-			>
-		{};
-	}	// namespace detail
 	template<sprout::index_t I, std::size_t N>
 	struct index_n
 		: public sprout::detail::make_indexes_helper<
-			sprout::detail::index_n_impl<I, N>
+			typename sprout::integer_n<sprout::index_t, I, N>::type
+				::template transfer<sprout::index_tuple<> >::type
+		>
+	{};
+	//
+	// uindex_n
+	//
+	template<sprout::uindex_t I, std::size_t N>
+	struct uindex_n
+		: public sprout::detail::make_indexes_helper<
+			typename sprout::integer_n<sprout::uindex_t, I, N>::type
+				::template transfer<sprout::uindex_tuple<> >::type
 		>
 	{};
 }	// namespace sprout
diff --git a/sprout/index_tuple/index_range.hpp b/sprout/index_tuple/index_range.hpp
index 4fb1c63b..723bcd5d 100644
--- a/sprout/index_tuple/index_range.hpp
+++ b/sprout/index_tuple/index_range.hpp
@@ -2,78 +2,30 @@
 #define SPROUT_INDEX_TUPLE_INDEX_RANGE_HPP
 
 #include <cstddef>
-#include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/index_tuple/index_tuple.hpp>
+#include <sprout/index_tuple/integer_range.hpp>
 #include <sprout/index_tuple/detail/make_indexes_helper.hpp>
 
 namespace sprout {
 	//
 	// index_range
 	//
-	namespace detail {
-		template<typename IndexTuple, sprout::index_t Next>
-		struct index_range_next;
-		template<sprout::index_t... Indexes, sprout::index_t Next>
-		struct index_range_next<sprout::index_tuple<Indexes...>, Next> {
-		public:
-			typedef sprout::index_tuple<Indexes..., (Indexes + Next)...> type;
-		};
-
-		template<typename IndexTuple, sprout::index_t Next, sprout::index_t Tail>
-		struct index_range_next2;
-		template<sprout::index_t... Indexes, sprout::index_t Next, sprout::index_t Tail>
-		struct index_range_next2<sprout::index_tuple<Indexes...>, Next, Tail> {
-		public:
-			typedef sprout::index_tuple<Indexes..., (Indexes + Next)..., Tail> type;
-		};
-
-		template<sprout::index_t First, sprout::index_t Step, std::size_t N, typename Enable = void>
-		struct index_range_impl;
-		template<sprout::index_t First, sprout::index_t Step, std::size_t N>
-		struct index_range_impl<
-			First, Step, N,
-			typename std::enable_if<(N == 0)>::type
-		> {
-		public:
-			typedef sprout::index_tuple<> type;
-		};
-		template<sprout::index_t First, sprout::index_t Step, std::size_t N>
-		struct index_range_impl<
-			First, Step, N,
-			typename std::enable_if<(N == 1)>::type
-		> {
-		public:
-			typedef sprout::index_tuple<First> type;
-		};
-		template<sprout::index_t First, sprout::index_t Step, std::size_t N>
-		struct index_range_impl<
-			First, Step, N,
-			typename std::enable_if<(N > 1 && N % 2 == 0)>::type
-		>
-			: public sprout::detail::index_range_next<
-				typename sprout::detail::index_range_impl<First, Step, N / 2>::type,
-				First + N / 2 * Step
-			>
-		{};
-		template<sprout::index_t First, sprout::index_t Step, std::size_t N>
-		struct index_range_impl<
-			First, Step, N,
-			typename std::enable_if<(N > 1 && N % 2 == 1)>::type
-		>
-			: public sprout::detail::index_range_next2<
-				typename sprout::detail::index_range_impl<First, Step, N / 2>::type,
-				First + N / 2 * Step,
-				First + (N - 1) * Step
-			>
-		{};
-	}	// namespace detail
-	template<sprout::index_t First, sprout::index_t Last, sprout::index_t Step = 1>
+	template<sprout::index_t First, sprout::index_t Last, std::ptrdiff_t Step = 1>
 	struct index_range
 		: public sprout::detail::make_indexes_helper<
-			sprout::detail::index_range_impl<
-				First, Step, ((Last - First) + (Step - 1)) / Step
-			>
+			typename sprout::integer_range<sprout::index_t, First, Last, Step>::type
+				::template transfer<sprout::index_tuple<> >::type
+		>
+	{};
+	//
+	// uindex_range
+	//
+	template<sprout::uindex_t First, sprout::uindex_t Last, std::ptrdiff_t Step = 1>
+	struct uindex_range
+		: public sprout::detail::make_indexes_helper<
+			typename sprout::integer_range<sprout::uindex_t, First, Last, Step>::type
+				::template transfer<sprout::uindex_tuple<> >::type
 		>
 	{};
 }	// namespace sprout
diff --git a/sprout/index_tuple/index_tuple.hpp b/sprout/index_tuple/index_tuple.hpp
index 69138ef3..6590f904 100644
--- a/sprout/index_tuple/index_tuple.hpp
+++ b/sprout/index_tuple/index_tuple.hpp
@@ -3,26 +3,42 @@
 
 #include <cstddef>
 #include <sprout/config.hpp>
+#include <sprout/index_tuple/integer_seq.hpp>
 
 namespace sprout {
 	//
 	// index_t
-	//
-	typedef std::ptrdiff_t index_t;
-
-	//
 	// index_tuple
 	//
+	typedef std::ptrdiff_t index_t;
 	template<sprout::index_t... Indexes>
-	struct index_tuple {
+	struct index_tuple
+		: public sprout::integer_seq<sprout::index_t, Indexes...>
+	{
 	public:
 		typedef index_tuple type;
-		typedef sprout::index_t value_type;
-	public:
-		SPROUT_STATIC_CONSTEXPR std::size_t size = sizeof...(Indexes);
+		template<sprout::index_t... J>
+		struct rebind
+			: public index_tuple<J...>
+		{};
+	};
+
+	//
+	// uindex_t
+	// uindex_tuple
+	//
+	typedef std::size_t uindex_t;
+	template<sprout::uindex_t... Indexes>
+	struct uindex_tuple
+		: public sprout::integer_seq<sprout::uindex_t, Indexes...>
+	{
+	public:
+		typedef uindex_tuple type;
+		template<sprout::uindex_t... J>
+		struct rebind
+			: public uindex_tuple<J...>
+		{};
 	};
-	template<sprout::index_t... Indexes>
-	SPROUT_CONSTEXPR_OR_CONST std::size_t sprout::index_tuple<Indexes...>::size;
 }	// namespace sprout
 
 #endif	// #ifndef SPROUT_INDEX_TUPLE_INDEX_TUPLE_HPP
diff --git a/sprout/index_tuple/integer_n.hpp b/sprout/index_tuple/integer_n.hpp
new file mode 100644
index 00000000..43a5a91d
--- /dev/null
+++ b/sprout/index_tuple/integer_n.hpp
@@ -0,0 +1,73 @@
+#ifndef SPROUT_INDEX_TUPLE_INTEGER_N_HPP
+#define SPROUT_INDEX_TUPLE_INTEGER_N_HPP
+
+#include <cstddef>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/index_tuple/integer_seq.hpp>
+#include <sprout/index_tuple/detail/make_indexes_helper.hpp>
+
+namespace sprout {
+	//
+	// integer_n
+	//
+	namespace detail {
+		template<typename T, typename Seq>
+		struct integer_n_next_even;
+		template<typename T, T... Is>
+		struct integer_n_next_even<T, sprout::integer_seq<T, Is...> >
+			: public sprout::integer_seq<T, Is..., Is...>
+		{};
+
+		template<typename T, typename Seq, T Tail>
+		struct integer_n_next_even_odd;
+		template<typename T, T... Is, T Tail>
+		struct integer_n_next_even_odd<T, sprout::integer_seq<T, Is...>, Tail>
+			: public sprout::integer_seq<T, Is..., Is..., Tail>
+		{};
+
+		template<typename T, T I, std::size_t N, typename Enable = void>
+		struct integer_n_impl;
+		template<typename T, T I, std::size_t N>
+		struct integer_n_impl<
+			T, I, N,
+			typename std::enable_if<(N == 0)>::type
+		>
+			: public sprout::integer_seq<T>
+		{};
+		template<typename T, T I, std::size_t N>
+		struct integer_n_impl<
+			T, I, N,
+			typename std::enable_if<(N == 1)>::type
+		>
+			: public sprout::integer_seq<T, I>
+		{};
+		template<typename T, T I, std::size_t N>
+		struct integer_n_impl<
+			T, I, N,
+			typename std::enable_if<(N > 1 && N % 2 == 0)>::type
+		>
+			: public sprout::detail::integer_n_next_even<
+				T, typename sprout::detail::integer_n_impl<T, I, N / 2>::type
+			>
+		{};
+		template<typename T, T I, std::size_t N>
+		struct integer_n_impl<
+			T, I, N,
+			typename std::enable_if<(N > 1 && N % 2 == 1)>::type
+		>
+			: public sprout::detail::integer_n_next_even_odd<
+				T, typename sprout::detail::integer_n_impl<T, I, N / 2>::type,
+				I
+			>
+		{};
+	}	// namespace detail
+	template<typename T, T I, std::size_t N>
+	struct integer_n
+		: public sprout::detail::make_indexes_helper<
+			sprout::detail::integer_n_impl<T, I, N>
+		>
+	{};
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_INDEX_TUPLE_INTEGER_N_HPP
diff --git a/sprout/index_tuple/integer_range.hpp b/sprout/index_tuple/integer_range.hpp
new file mode 100644
index 00000000..44053d1f
--- /dev/null
+++ b/sprout/index_tuple/integer_range.hpp
@@ -0,0 +1,76 @@
+#ifndef SPROUT_INDEX_TUPLE_INTEGER_RANGE_HPP
+#define SPROUT_INDEX_TUPLE_INTEGER_RANGE_HPP
+
+#include <cstddef>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/index_tuple/integer_seq.hpp>
+#include <sprout/index_tuple/detail/make_indexes_helper.hpp>
+
+namespace sprout {
+	//
+	// integer_range
+	//
+	namespace detail {
+		template<typename T, typename Seq, T Next>
+		struct integer_range_next_even;
+		template<typename T, T... Is, T Next>
+		struct integer_range_next_even<T, sprout::integer_seq<T, Is...>, Next>
+			: public sprout::integer_seq<T, Is..., (Is + Next)...>
+		{};
+
+		template<typename T, typename Seq, T Next, T Tail>
+		struct integer_range_next_odd;
+		template<typename T, T... Is, T Next, T Tail>
+		struct integer_range_next_odd<T, sprout::integer_seq<T, Is...>, Next, Tail>
+			 : public sprout::integer_seq<T, Is..., (Is + Next)..., Tail>
+		{};
+
+		template<typename T, T First, std::ptrdiff_t Step, std::size_t N, typename Enable = void>
+		struct integer_range_impl;
+		template<typename T, T First, std::ptrdiff_t Step, std::size_t N>
+		struct integer_range_impl<
+			T, First, Step, N,
+			typename std::enable_if<(N == 0)>::type
+		>
+			: public sprout::integer_seq<T>
+		{};
+		template<typename T, T First, std::ptrdiff_t Step, std::size_t N>
+		struct integer_range_impl<
+			T, First, Step, N,
+			typename std::enable_if<(N == 1)>::type
+		>
+			: public sprout::integer_seq<T, First>
+		{};
+		template<typename T, T First, std::ptrdiff_t Step, std::size_t N>
+		struct integer_range_impl<
+			T, First, Step, N,
+			typename std::enable_if<(N > 1 && N % 2 == 0)>::type
+		>
+			: public sprout::detail::integer_range_next_even<
+				T, typename sprout::detail::integer_range_impl<T, First, Step, N / 2>::type,
+				First + N / 2 * Step
+			>
+		{};
+		template<typename T, T First, std::ptrdiff_t Step, std::size_t N>
+		struct integer_range_impl<
+			T, First, Step, N,
+			typename std::enable_if<(N > 1 && N % 2 == 1)>::type
+		>
+			: public sprout::detail::integer_range_next_odd<
+				T, typename sprout::detail::integer_range_impl<T, First, Step, N / 2>::type,
+				First + N / 2 * Step, First + (N - 1) * Step
+			>
+		{};
+	}	// namespace detail
+	template<typename T, T First, T Last, std::ptrdiff_t Step = 1>
+	struct integer_range
+		: public sprout::detail::make_indexes_helper<
+			sprout::detail::integer_range_impl<
+				T, First, Step, ((Last - First) + (Step - 1)) / Step
+			>
+		>
+	{};
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_INDEX_TUPLE_INTEGER_RANGE_HPP
diff --git a/sprout/index_tuple/integer_seq.hpp b/sprout/index_tuple/integer_seq.hpp
new file mode 100644
index 00000000..002843f8
--- /dev/null
+++ b/sprout/index_tuple/integer_seq.hpp
@@ -0,0 +1,32 @@
+#ifndef SPROUT_INDEX_TUPLE_INTEGER_SEQ_HPP
+#define SPROUT_INDEX_TUPLE_INTEGER_SEQ_HPP
+
+#include <cstddef>
+#include <sprout/config.hpp>
+
+namespace sprout {
+	//
+	// integer_seq
+	//
+	template<typename T, T... Is>
+	struct integer_seq {
+	public:
+		typedef integer_seq type;
+		template<T... J>
+		struct rebind
+			: public integer_seq<T, J...>
+		{};
+	public:
+		typedef T value_type;
+		template<typename Seq>
+		struct transfer
+			: public Seq::template rebind<Is...>
+		{};
+	public:
+		SPROUT_STATIC_CONSTEXPR std::size_t size = sizeof...(Is);
+	};
+	template<typename T, T... Is>
+	SPROUT_CONSTEXPR_OR_CONST std::size_t sprout::integer_seq<T, Is...>::size;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_INDEX_TUPLE_INTEGER_SEQ_HPP
diff --git a/sprout/index_tuple/make_index_tuple.hpp b/sprout/index_tuple/make_index_tuple.hpp
new file mode 100644
index 00000000..056af9c8
--- /dev/null
+++ b/sprout/index_tuple/make_index_tuple.hpp
@@ -0,0 +1,33 @@
+#ifndef SPROUT_INDEX_TUPLE_MAKE_INDEX_TUPLE_HPP
+#define SPROUT_INDEX_TUPLE_MAKE_INDEX_TUPLE_HPP
+
+#include <cstddef>
+#include <sprout/config.hpp>
+#include <sprout/index_tuple/index_tuple.hpp>
+#include <sprout/index_tuple/make_integer_seq.hpp>
+#include <sprout/index_tuple/detail/make_indexes_helper.hpp>
+
+namespace sprout {
+	//
+	// make_index_tuple
+	//
+	template<sprout::index_t N>
+	struct make_index_tuple
+		: public sprout::detail::make_indexes_helper<
+			typename sprout::make_integer_seq<sprout::index_t, N>::type
+				::template transfer<sprout::index_tuple<> >::type
+		>
+	{};
+	//
+	// make_uindex_tuple
+	//
+	template<sprout::uindex_t N>
+	struct make_uindex_tuple
+		: public sprout::detail::make_indexes_helper<
+			typename sprout::make_integer_seq<sprout::uindex_t, N>::type
+				::template transfer<sprout::uindex_tuple<> >::type
+		>
+	{};
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_INDEX_TUPLE_MAKE_INDEX_TUPLE_HPP
diff --git a/sprout/index_tuple/make_indexes.hpp b/sprout/index_tuple/make_indexes.hpp
index 21cd51c5..13069326 100644
--- a/sprout/index_tuple/make_indexes.hpp
+++ b/sprout/index_tuple/make_indexes.hpp
@@ -7,10 +7,10 @@ namespace sprout {
 	//
 	// make_indexes
 	//
-	template<typename IndexTupleType>
-	inline SPROUT_CONSTEXPR typename IndexTupleType::type
+	template<typename Seq>
+	inline SPROUT_CONSTEXPR typename Seq::type
 	make_indexes() {
-		return typename IndexTupleType::type();
+		return typename Seq::type();
 	}
 }	// namespace sprout
 
diff --git a/sprout/index_tuple/make_integer_seq.hpp b/sprout/index_tuple/make_integer_seq.hpp
new file mode 100644
index 00000000..2d3519eb
--- /dev/null
+++ b/sprout/index_tuple/make_integer_seq.hpp
@@ -0,0 +1,20 @@
+#ifndef SPROUT_INDEX_TUPLE_MAKE_INTEGER_SEQ_HPP
+#define SPROUT_INDEX_TUPLE_MAKE_INTEGER_SEQ_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/index_tuple/integer_range.hpp>
+#include <sprout/index_tuple/detail/make_indexes_helper.hpp>
+
+namespace sprout {
+	//
+	// make_integer_seq
+	//
+	template<typename T, T N>
+	struct make_integer_seq
+		: public sprout::detail::make_indexes_helper<
+			sprout::integer_range<T, 0, N>
+		>
+	{};
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_INDEX_TUPLE_MAKE_INTEGER_SEQ_HPP
diff --git a/sprout/index_tuple/pack_indexes.hpp b/sprout/index_tuple/pack_indexes.hpp
deleted file mode 100644
index a6e6bfa1..00000000
--- a/sprout/index_tuple/pack_indexes.hpp
+++ /dev/null
@@ -1,20 +0,0 @@
-#ifndef SPROUT_INDEX_TUPLE_PACK_INDEXES_HPP
-#define SPROUT_INDEX_TUPLE_PACK_INDEXES_HPP
-
-#include <sprout/config.hpp>
-#include <sprout/index_tuple/index_range.hpp>
-#include <sprout/index_tuple/detail/make_indexes_helper.hpp>
-
-namespace sprout {
-	//
-	// pack_indexes
-	//
-	template<typename... Args>
-	struct pack_indexes
-		: public sprout::detail::make_indexes_helper<
-			sprout::index_range<0, sizeof...(Args)>
-		>
-	{};
-}	// namespace sprout
-
-#endif	// #ifndef SPROUT_INDEX_TUPLE_PACK_INDEXES_HPP
diff --git a/sprout/index_tuple/tuple.hpp b/sprout/index_tuple/tuple.hpp
index 99c3456d..ca6c2ae4 100644
--- a/sprout/index_tuple/tuple.hpp
+++ b/sprout/index_tuple/tuple.hpp
@@ -5,6 +5,7 @@
 #include <tuple>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/index_tuple/integer_seq.hpp>
 #include <sprout/index_tuple/index_tuple.hpp>
 
 namespace std {
@@ -12,23 +13,52 @@ namespace std {
 #	pragma clang diagnostic push
 #	pragma clang diagnostic ignored "-Wmismatched-tags"
 #endif
+	//
+	// tuple_size
+	//
+	template<typename T, T... Is>
+	struct tuple_size<sprout::integer_seq<T, Is...> >
+		: public std::integral_constant<std::size_t, sizeof...(Is)>
+	{};
+	//
+	// tuple_element
+	//
+	template<std::size_t I, typename T, T... Is>
+	struct tuple_element<I, sprout::integer_seq<T, Is...> > {
+		static_assert(I < sizeof...(Is), "tuple_element<>: index out of range");
+	public:
+		typedef T type;
+	};
+
 	//
 	// tuple_size
 	//
 	template<sprout::index_t... Indexes>
 	struct tuple_size<sprout::index_tuple<Indexes...> >
-		: public std::integral_constant<std::size_t, sizeof...(Indexes)>
+		: public std::tuple_size<sprout::integer_seq<sprout::index_t, Indexes...> >
 	{};
-
 	//
 	// tuple_element
 	//
 	template<std::size_t I, sprout::index_t... Indexes>
-	struct tuple_element<I, sprout::index_tuple<Indexes...> > {
-		static_assert(I < sizeof...(Indexes), "tuple_element<>: index out of range");
-	public:
-		typedef sprout::index_t type;
-	};
+	struct tuple_element<I, sprout::index_tuple<Indexes...> >
+		: public std::tuple_element<I, sprout::integer_seq<sprout::index_t, Indexes...> >
+	{};
+
+	//
+	// tuple_size
+	//
+	template<sprout::uindex_t... Indexes>
+	struct tuple_size<sprout::uindex_tuple<Indexes...> >
+		: public std::tuple_size<sprout::integer_seq<sprout::uindex_t, Indexes...> >
+	{};
+	//
+	// tuple_element
+	//
+	template<std::size_t I, sprout::uindex_t... Indexes>
+	struct tuple_element<I, sprout::uindex_tuple<Indexes...> >
+		: public std::tuple_element<I, sprout::integer_seq<sprout::uindex_t, Indexes...> >
+	{};
 #if defined(__clang__)
 #	pragma clang diagnostic pop
 #endif
diff --git a/sprout/string/alias.hpp b/sprout/string/alias.hpp
index 9344530d..85005816 100644
--- a/sprout/string/alias.hpp
+++ b/sprout/string/alias.hpp
@@ -11,22 +11,16 @@ namespace sprout {
 #if SPROUT_USE_TEMPLATE_ALIASES
 	//
 	// string
+	// wstring
+	// u16string
+	// u32string
 	//
 	template<std::size_t N>
 	using string = sprout::basic_string<char, N>;
-	//
-	// wstring
-	//
 	template<std::size_t N>
 	using wstring = sprout::basic_string<wchar_t, N>;
-	//
-	// u16string
-	//
 	template<std::size_t N>
 	using u16string = sprout::basic_string<char16_t, N>;
-	//
-	// u32string
-	//
 	template<std::size_t N>
 	using u32string = sprout::basic_string<char32_t, N>;
 #endif	// #if SPROUT_USE_TEMPLATE_ALIASES
diff --git a/sprout/utility/string_ref/alias.hpp b/sprout/utility/string_ref/alias.hpp
index 3fdf1274..dcfe695b 100644
--- a/sprout/utility/string_ref/alias.hpp
+++ b/sprout/utility/string_ref/alias.hpp
@@ -2,25 +2,38 @@
 #define SPROUT_UTILITY_STRING_REF_ALIAS_HPP
 
 #include <sprout/config.hpp>
+#include <sprout/string/char_traits.hpp>
 #include <sprout/utility/string_ref/string_ref.hpp>
 
 namespace sprout {
 	//
 	// string_ref
-	//
-	typedef sprout::basic_string_ref<char> string_ref;
-	//
 	// wstring_ref
-	//
-	typedef sprout::basic_string_ref<wchar_t> wstring_ref;
-	//
 	// u16string_ref
-	//
-	typedef sprout::basic_string_ref<char16_t> u16string_ref;
-	//
 	// u32string_ref
 	//
+	typedef sprout::basic_string_ref<char> string_ref;
+	typedef sprout::basic_string_ref<wchar_t> wstring_ref;
+	typedef sprout::basic_string_ref<char16_t> u16string_ref;
 	typedef sprout::basic_string_ref<char32_t> u32string_ref;
+	//
+	// string_view
+	// wstring_view
+	// u16string_view
+	// u32string_view
+	//
+	typedef sprout::basic_string_ref<char> string_view;
+	typedef sprout::basic_string_ref<wchar_t> wstring_view;
+	typedef sprout::basic_string_ref<char16_t> u16string_view;
+	typedef sprout::basic_string_ref<char32_t> u32string_view;
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	//
+	// basic_string_view
+	//
+	template<typename T, typename Traits = sprout::char_traits<T> >
+	using basic_string_view = sprout::basic_string_ref<T, Traits>;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
 }	// namespace sprout
 
 #endif	// #ifndef SPROUT_UTILITY_STRING_REF_ALIAS_HPP