diff --git a/README b/README
index 9f9748ca..55ec6e98 100644
--- a/README
+++ b/README
@@ -167,6 +167,8 @@ https://github.com/sscrisk/CEL---ConstExpr-Library
 * 作者 (Author)
 
 Bolero MURAKAMI
+
+Website: http://www.boleros.x0.com/
 Twitter: https://twitter.com/bolero_murakami
 Facebook: http://www.facebook.com/genya.murakami
 Blog: http://d.hatena.ne.jp/boleros/
diff --git a/sprout/logic.hpp b/sprout/logic.hpp
new file mode 100644
index 00000000..6224a4cc
--- /dev/null
+++ b/sprout/logic.hpp
@@ -0,0 +1,7 @@
+#ifndef SPROUT_LOGIC_HPP
+#define SPROUT_LOGIC_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/logic/tribool.hpp>
+
+#endif	// #ifndef SPROUT_LOGIC_HPP
diff --git a/sprout/logic/tribool.hpp b/sprout/logic/tribool.hpp
new file mode 100644
index 00000000..56894b26
--- /dev/null
+++ b/sprout/logic/tribool.hpp
@@ -0,0 +1,9 @@
+#ifndef SPROUT_LOGIC_TRIBOOL_HPP
+#define SPROUT_LOGIC_TRIBOOL_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/logic/tribool/tribool_fwd.hpp>
+#include <sprout/logic/tribool/tribool.hpp>
+#include <sprout/logic/tribool/io.hpp>
+
+#endif	// #ifndef SPROUT_LOGIC_TRIBOOL_HPP
diff --git a/sprout/logic/tribool/io.hpp b/sprout/logic/tribool/io.hpp
new file mode 100644
index 00000000..f249e39b
--- /dev/null
+++ b/sprout/logic/tribool/io.hpp
@@ -0,0 +1,207 @@
+#ifndef SPROUT_LOGIC_TRIBOOL_TRIBOOL_IO_HPP
+#define SPROUT_LOGIC_TRIBOOL_TRIBOOL_IO_HPP
+
+#include <locale>
+#include <string>
+#include <iosfwd>
+#include <ios>
+#include <sprout/config.hpp>
+#include <sprout/utility/noncopyable.hpp>
+#include <sprout/logic/tribool/tribool.hpp>
+
+namespace sprout {
+	namespace logic {
+		//
+		// get_default_indeterminate_name
+		//
+		template<typename Char>
+		inline std::basic_string<Char>
+		get_default_indeterminate_name();
+		template<>
+		inline std::basic_string<char>
+		get_default_indeterminate_name<char>() {
+			return "indeterminate";
+		}
+		template<>
+		inline std::basic_string<wchar_t>
+		get_default_indeterminate_name<wchar_t>() {
+			return L"indeterminate";
+		}
+		template<>
+		inline std::basic_string<char16_t>
+		get_default_indeterminate_name<char16_t>() {
+			return u"indeterminate";
+		}
+		template<>
+		inline std::basic_string<char32_t>
+		get_default_indeterminate_name<char32_t>() {
+			return U"indeterminate";
+		}
+
+		//
+		// indeterminate_name
+		//
+		template<typename Char>
+		class indeterminate_name
+			: public std::locale::facet
+			, private sprout::noncopyable
+		{
+		public:
+			typedef Char char_type;
+			typedef std::basic_string<char_type> string_type;
+		public:
+			static std::locale::id id;
+		private:
+			string_type name_;
+		public:
+			indeterminate_name()
+				: name_(sprout::logic::get_default_indeterminate_name<char_type>())
+			{}
+			explicit indeterminate_name(string_type const& initial_name)
+				: name_(initial_name)
+			{}
+			string_type name() const {
+				return name_;
+			}
+		};
+		template<typename Char>
+		std::locale::id sprout::logic::indeterminate_name<Char>::id;
+
+		//
+		// operator<<
+		//
+		template<typename Char, typename Traits>
+		inline std::basic_ostream<Char, Traits>&
+		operator<<(std::basic_ostream<Char, Traits>& lhs, sprout::logic::tribool rhs) {
+			if (!sprout::logic::indeterminate(rhs)) {
+				lhs << static_cast<bool>(rhs);
+			} else {
+				typename std::basic_ostream<Char, Traits>::sentry cerberus(lhs);
+				if (cerberus) {
+					if (lhs.flags() & std::ios_base::boolalpha) {
+						if (std::has_facet<sprout::logic::indeterminate_name<Char> >(lhs.getloc())) {
+							indeterminate_name<Char> const& facet
+								= std::use_facet<sprout::logic::indeterminate_name<Char> >(lhs.getloc())
+								;
+							lhs << facet.name();
+						} else {
+							lhs << sprout::logic::get_default_indeterminate_name<Char>();
+						}
+					} else {
+						lhs << 2;
+					}
+				}
+			}
+			return lhs;
+		}
+		template<typename Char, typename Traits>
+		inline std::basic_ostream<Char, Traits>&
+		operator<<(std::basic_ostream<Char, Traits>& lhs, sprout::logic::indeterminate_keyword_t) {
+			return lhs << sprout::logic::tribool(indeterminate);
+		}
+
+		//
+		// operator>>
+		//
+		template<typename Char, typename Traits>
+		inline std::basic_istream<Char, Traits>&
+		operator>>(std::basic_istream<Char, Traits>& lhs, sprout::logic::tribool& rhs) {
+			if (lhs.flags() & std::ios_base::boolalpha) {
+				typename std::basic_istream<Char, Traits>::sentry cerberus(lhs);
+				if (cerberus) {
+					typedef std::basic_string<Char> string_type;
+					const std::numpunct<Char>& numpunct_facet =
+						std::use_facet<std::numpunct<Char> >(lhs.getloc())
+						;
+					string_type falsename = numpunct_facet.falsename();
+					string_type truename = numpunct_facet.truename();
+					string_type othername = std::has_facet<sprout::logic::indeterminate_name<Char> >(lhs.getloc())
+						? std::use_facet<indeterminate_name<Char> >(lhs.getloc()).name()
+						: sprout::logic::get_default_indeterminate_name<Char>()
+						;
+					typename string_type::size_type pos = 0;
+					bool falsename_ok = true;
+					bool truename_ok = true;
+					bool othername_ok = true;
+					while (falsename_ok && pos < falsename.size()
+						|| truename_ok && pos < truename.size()
+						|| othername_ok && pos < othername.size()
+						)
+					{
+						typename Traits::int_type c = lhs.get();
+						if (c == Traits::eof()) {
+							return lhs;
+						}
+						bool matched = false;
+						if (falsename_ok && pos < falsename.size()) {
+							if (Traits::eq(Traits::to_char_type(c), falsename[pos])) {
+								matched = true;
+							} else {
+								falsename_ok = false;
+							}
+						}
+						if (truename_ok && pos < truename.size()) {
+							if (Traits::eq(Traits::to_char_type(c), truename[pos])) {
+								matched = true;
+							} else {
+								truename_ok = false;
+							}
+						}
+						if (othername_ok && pos < othername.size()) {
+							if (Traits::eq(Traits::to_char_type(c), othername[pos])) {
+								matched = true;
+							} else {
+								othername_ok = false;
+							}
+						}
+						if (matched) {
+							++pos;
+						}
+						if (pos > falsename.size()) {
+							falsename_ok = false;
+						}
+						if (pos > truename.size()) {
+							truename_ok = false;
+						}
+						if (pos > othername.size()) {
+							othername_ok = false;
+						}
+					}
+					if (pos == 0) {
+						lhs.setstate(std::ios_base::failbit);
+					} else {
+						if (falsename_ok) {
+							rhs = false;
+						} else if (truename_ok)	{ 
+							rhs = true;
+						} else if (othername_ok) {
+							rhs = indeterminate;
+						} else {
+							lhs.setstate(std::ios_base::failbit);
+						}
+					}
+				}
+			} else {
+				long value;
+				if (lhs >> value) {
+					switch (value) {
+					case 0:
+						rhs = false;
+						break;
+					case 1:
+						rhs = true;
+						break;
+					case 2:
+						rhs = indeterminate;
+						break;
+					default:
+						lhs.setstate(std::ios_base::failbit);
+					}
+				}
+			}
+			return lhs;
+		}
+	}	// namespace logic
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_LOGIC_TRIBOOL_TRIBOOL_IO_HPP
diff --git a/sprout/logic/tribool/tribool.hpp b/sprout/logic/tribool/tribool.hpp
new file mode 100644
index 00000000..48830a7c
--- /dev/null
+++ b/sprout/logic/tribool/tribool.hpp
@@ -0,0 +1,191 @@
+#ifndef SPROUT_LOGIC_TRIBOOL_TRIBOOL_HPP
+#define SPROUT_LOGIC_TRIBOOL_TRIBOOL_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/logic/tribool/tribool_fwd.hpp>
+
+namespace sprout {
+	namespace logic {
+		namespace detail {
+			struct indeterminate_t {};
+		}	// namespace detail
+
+		//
+		// indeterminate_keyword_t
+		//
+		typedef bool (*indeterminate_keyword_t)(sprout::logic::tribool, sprout::logic::detail::indeterminate_t);
+
+		//
+		// tribool
+		//
+		class tribool {
+		private:
+			struct dummy {
+			public:
+				void nonnull() {}
+			};
+			typedef void (dummy::*safe_bool)();
+		public:
+			enum value_t {
+				false_value,
+				true_value,
+				indeterminate_value
+			};
+		public:
+			value_t value;
+		public:
+			SPROUT_CONSTEXPR tribool()
+				: value(false_value)
+			{}
+			SPROUT_CONSTEXPR tribool(bool initial_value)
+				: value(initial_value? true_value : false_value)
+			{}
+			SPROUT_CONSTEXPR tribool(sprout::logic::indeterminate_keyword_t)
+				: value(indeterminate_value)
+			{}
+			SPROUT_CONSTEXPR operator safe_bool() const {
+				return value == true_value ? &dummy::nonnull : 0;
+			}
+		};
+
+		//
+		// indeterminate
+		//
+		inline SPROUT_CONSTEXPR bool
+		indeterminate(sprout::logic::tribool x, sprout::logic::detail::indeterminate_t = sprout::logic::detail::indeterminate_t()) {
+			return x.value == sprout::logic::tribool::indeterminate_value;
+		}
+
+		//
+		// operator!
+		//
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator!(sprout::logic::tribool x) {
+			return x.value == sprout::logic::tribool::false_value ? sprout::logic::tribool(true)
+				: x.value == sprout::logic::tribool::true_value ? sprout::logic::tribool(false)
+				: sprout::logic::tribool(sprout::logic::indeterminate)
+				;
+		}
+
+		//
+		// operator&&
+		//
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator&&(sprout::logic::tribool lhs, sprout::logic::tribool rhs) {
+			return static_cast<bool>(!lhs) || static_cast<bool>(!rhs) ? sprout::logic::tribool(false)
+				: static_cast<bool>(lhs) && static_cast<bool>(rhs) ? sprout::logic::tribool(true)
+				: sprout::logic::tribool(sprout::logic::indeterminate)
+				;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator&&(tribool lhs, bool rhs) {
+			return rhs ? lhs : sprout::logic::tribool(false);
+		}
+
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator&&(bool lhs, sprout::logic::tribool rhs) {
+			return lhs ? rhs : sprout::logic::tribool(false);
+		}
+
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator&&(sprout::logic::indeterminate_keyword_t, sprout::logic::tribool lhs) {
+			return !lhs ? sprout::logic::tribool(false) : sprout::logic::tribool(sprout::logic::indeterminate);
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator&&(sprout::logic::tribool lhs, sprout::logic::indeterminate_keyword_t) {
+			return !lhs ? sprout::logic::tribool(false) : sprout::logic::tribool(indeterminate);
+		}
+
+		//
+		// operator||
+		//
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator||(sprout::logic::tribool lhs, sprout::logic::tribool rhs) {
+			return static_cast<bool>(!lhs) && static_cast<bool>(!rhs) ? sprout::logic::tribool(false)
+				: static_cast<bool>(lhs) || static_cast<bool>(rhs) ? sprout::logic::tribool(true)
+				: sprout::logic::tribool(sprout::logic::indeterminate)
+				;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator||(sprout::logic::tribool lhs, bool rhs) {
+			return rhs ? sprout::logic::tribool(true) : lhs;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator||(bool lhs, sprout::logic::tribool rhs) {
+			return lhs ? sprout::logic::tribool(true) : rhs;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator||(sprout::logic::indeterminate_keyword_t, sprout::logic::tribool lhs) {
+			return lhs ? sprout::logic::tribool(true) : sprout::logic::tribool(sprout::logic::indeterminate);
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator||(sprout::logic::tribool lhs, sprout::logic::indeterminate_keyword_t) {
+			return lhs ? sprout::logic::tribool(true) : sprout::logic::tribool(sprout::logic::indeterminate);
+		}
+
+		//
+		// operator==
+		//
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator==(sprout::logic::tribool lhs, sprout::logic::tribool rhs) {
+			return sprout::logic::indeterminate(lhs) || sprout::logic::indeterminate(rhs)
+				? sprout::logic::tribool(sprout::logic::indeterminate)
+				: (lhs && rhs) || (!lhs && !rhs)
+				;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator==(sprout::logic::tribool lhs, bool rhs) {
+			return lhs == sprout::logic::tribool(rhs);
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator==(bool lhs, sprout::logic::tribool rhs) {
+			return sprout::logic::tribool(lhs) == rhs;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator==(sprout::logic::indeterminate_keyword_t, sprout::logic::tribool lhs) {
+			return sprout::logic::tribool(sprout::logic::indeterminate) == lhs;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator==(sprout::logic::tribool lhs, sprout::logic::indeterminate_keyword_t) {
+			return sprout::logic::tribool(sprout::logic::indeterminate) == lhs;
+		}
+
+		//
+		// operator!=
+		//
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator!=(sprout::logic::tribool lhs, sprout::logic::tribool rhs) {
+			return sprout::logic::indeterminate(lhs) || sprout::logic::indeterminate(rhs)
+				? sprout::logic::tribool(sprout::logic::indeterminate)
+				: !((lhs && rhs) || (!lhs && !rhs))
+				;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator!=(sprout::logic::tribool lhs, bool rhs) {
+			return lhs != sprout::logic::tribool(rhs);
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator!=(bool lhs, sprout::logic::tribool rhs) {
+			return sprout::logic::tribool(lhs) != rhs;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator!=(sprout::logic::indeterminate_keyword_t, sprout::logic::tribool lhs) {
+			return sprout::logic::tribool(sprout::logic::indeterminate) != lhs;
+		}
+		inline SPROUT_CONSTEXPR sprout::logic::tribool
+		operator!=(sprout::logic::tribool lhs, sprout::logic::indeterminate_keyword_t) {
+			return sprout::logic::tribool(sprout::logic::indeterminate) != lhs;
+		}
+	}	// namespace logic
+
+	using sprout::logic::tribool;
+	using sprout::logic::indeterminate;
+}	// namespace sprout
+
+#define SPROUT_TRIBOOL_THIRD_STATE(NAME) \
+	inline SPROUT_CONSTEXPR bool \
+	NAME(sprout::logic::tribool lhs, sprout::logic::detail::indeterminate_t = sprout::logic::detail::indeterminate_t()) { \
+		return lhs.value == sprout::logic::tribool::indeterminate_value; \
+	}
+
+#endif	// #ifndef SPROUT_LOGIC_TRIBOOL_TRIBOOL_HPP
diff --git a/sprout/logic/tribool/tribool_fwd.hpp b/sprout/logic/tribool/tribool_fwd.hpp
new file mode 100644
index 00000000..6f518e3e
--- /dev/null
+++ b/sprout/logic/tribool/tribool_fwd.hpp
@@ -0,0 +1,15 @@
+#ifndef SPROUT_LOGIC_TRIBOOL_TRIBOOL_FWD_HPP
+#define SPROUT_LOGIC_TRIBOOL_TRIBOOL_FWD_HPP
+
+#include <sprout/config.hpp>
+
+namespace sprout {
+	namespace logic {
+		//
+		// tribool
+		//
+		class tribool;
+	}	// namespace logic
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_LOGIC_TRIBOOL_TRIBOOL_FWD_HPP
diff --git a/sprout/logic/tribool_fwd.hpp b/sprout/logic/tribool_fwd.hpp
new file mode 100644
index 00000000..e6bc719c
--- /dev/null
+++ b/sprout/logic/tribool_fwd.hpp
@@ -0,0 +1,7 @@
+#ifndef SPROUT_LOGIC_TRIBOOL_FWD_HPP
+#define SPROUT_LOGIC_TRIBOOL_FWD_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/logic/tribool/tribool_fwd.hpp>
+
+#endif	// #ifndef SPROUT_LOGIC_TRIBOOL_FWD_HPP
diff --git a/sprout/utility.hpp b/sprout/utility.hpp
index 3734ae6f..65a69355 100644
--- a/sprout/utility.hpp
+++ b/sprout/utility.hpp
@@ -7,6 +7,7 @@
 #include <sprout/utility/operation.hpp>
 #include <sprout/utility/operation_ext.hpp>
 #include <sprout/utility/enabler_if.hpp>
+#include <sprout/utility/noncopyable.hpp>
 #include <sprout/utility/pack.hpp>
 #include <sprout/utility/value_holder.hpp>
 
diff --git a/sprout/utility/noncopyable.hpp b/sprout/utility/noncopyable.hpp
new file mode 100644
index 00000000..7c039870
--- /dev/null
+++ b/sprout/utility/noncopyable.hpp
@@ -0,0 +1,21 @@
+#ifndef SPROUT_UTILITY_NONCOPYABLE_HPP
+#define SPROUT_UTILITY_NONCOPYABLE_HPP
+
+#include <sprout/config.hpp>
+
+namespace sprout {
+	namespace noncopyable_ {
+		class noncopyable {
+		public:
+			SPROUT_CONSTEXPR noncopyable() = default;
+			noncopyable(noncopyable const&) = delete;
+			noncopyable& operator=(noncopyable const&) = delete;
+		};
+	}	// namespace noncopyable_
+	//
+	// noncopyable
+	//
+	typedef sprout::noncopyable_::noncopyable noncopyable;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_UTILITY_NONCOPYABLE_HPP
diff --git a/sprout/uuid/io.hpp b/sprout/uuid/io.hpp
index b743765a..9077a772 100644
--- a/sprout/uuid/io.hpp
+++ b/sprout/uuid/io.hpp
@@ -113,7 +113,8 @@ namespace sprout {
 		// to_string_of
 		//
 		template<typename Elem, typename Traits = sprout::char_traits<Elem> >
-		inline SPROUT_CONSTEXPR sprout::basic_string<Elem, 36, Traits> to_string_of(sprout::uuids::uuid const& u) {
+		inline SPROUT_CONSTEXPR sprout::basic_string<Elem, 36, Traits>
+		to_string_of(sprout::uuids::uuid const& u) {
 			return sprout::basic_string<Elem, 36, Traits>{
 				{
 					sprout::uuids::detail::digits<Elem>::table[(u[0] >> 4) & 0x0F],
@@ -158,26 +159,24 @@ namespace sprout {
 		}
 		//
 		// to_string
-		//
-		inline SPROUT_CONSTEXPR sprout::basic_string<char, 36> to_string(sprout::uuids::uuid const& u) {
-			return sprout::uuids::to_string_of<char>(u);
-		}
-		//
 		// to_wstring
-		//
-		inline SPROUT_CONSTEXPR sprout::basic_string<wchar_t, 36> to_wstring(sprout::uuids::uuid const& u) {
-			return sprout::uuids::to_string_of<wchar_t>(u);
-		}
-		//
 		// to_u16string
-		//
-		inline SPROUT_CONSTEXPR sprout::basic_string<char16_t, 36> to_u16string(sprout::uuids::uuid const& u) {
-			return sprout::uuids::to_string_of<char16_t>(u);
-		}
-		//
 		// to_u32string
 		//
-		inline SPROUT_CONSTEXPR sprout::basic_string<char32_t, 36> to_u32string(sprout::uuids::uuid const& u) {
+		inline SPROUT_CONSTEXPR sprout::basic_string<char, 36>
+		to_string(sprout::uuids::uuid const& u) {
+			return sprout::uuids::to_string_of<char>(u);
+		}
+		inline SPROUT_CONSTEXPR sprout::basic_string<wchar_t, 36>
+		to_wstring(sprout::uuids::uuid const& u) {
+			return sprout::uuids::to_string_of<wchar_t>(u);
+		}
+		inline SPROUT_CONSTEXPR sprout::basic_string<char16_t, 36>
+		to_u16string(sprout::uuids::uuid const& u) {
+			return sprout::uuids::to_string_of<char16_t>(u);
+		}
+		inline SPROUT_CONSTEXPR sprout::basic_string<char32_t, 36>
+		to_u32string(sprout::uuids::uuid const& u) {
 			return sprout::uuids::to_string_of<char32_t>(u);
 		}
 	}	// namespace uuids
diff --git a/testspr/tools.hpp b/testspr/tools.hpp
index 60056458..98a960cd 100644
--- a/testspr/tools.hpp
+++ b/testspr/tools.hpp
@@ -265,7 +265,8 @@ namespace testspr {
 			)
 		{
 			return first1_ == last1 && first2_ == last2 ? true
-				: testspr::count(first1, last1, *first1_) != testspr::count(first2, first2 + testspr::distance(first1, last1), *first1_) ? false
+				: testspr::count(first1, last1, *first1_) != testspr::count(first2, first2 + testspr::distance(first1, last1), *first1_)
+					? false
 				: testspr::detail::is_permutation_impl(first1, last1, first2, last2, first1_ + 1, first2_ + 1)
 				;
 		}