diff --git a/libs/tuple/test/tuple.cpp b/libs/tuple/test/tuple.cpp
index 49b5feee..82c414b2 100644
--- a/libs/tuple/test/tuple.cpp
+++ b/libs/tuple/test/tuple.cpp
@@ -29,34 +29,44 @@ namespace testspr {
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
 			}
 
-			{
-				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(1l);
-				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
-				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 0.0);
-			}
 			{
 				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(1l, 1.0f);
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
 			}
 			{
-				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(1l, 1.0f, '-');
+				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::flexibly_construct, 1l);
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 0.0);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::flexibly_construct, 1l, 1.0f);
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::flexibly_construct, 1l, 1.0f, '-');
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
 			}
 
-			{
-				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::tuple<long>(1l));
-				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
-				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 0.0);
-			}
 			{
 				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::tuple<long, float>(1l, 1.0f));
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
 			}
 			{
-				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::tuple<long, float, char>(1l, 1.0f, '-'));
+				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::flexibly_construct, sprout::tuples::tuple<long>(1l));
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 0.0);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::flexibly_construct, sprout::tuples::tuple<long, float>(1l, 1.0f));
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
+				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
+			}
+			{
+				SPROUT_STATIC_CONSTEXPR auto tup3 = sprout::tuples::tuple<int, double>(sprout::tuples::flexibly_construct, sprout::tuples::tuple<long, float, char>(1l, 1.0f, '-'));
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<0>(tup3) == 1);
 				TESTSPR_BOTH_ASSERT(sprout::tuples::get<1>(tup3) == 1.0);
 			}
diff --git a/sprout/algorithm/string/join.hpp b/sprout/algorithm/string/join.hpp
index 370a66fa..c41fb5d3 100644
--- a/sprout/algorithm/string/join.hpp
+++ b/sprout/algorithm/string/join.hpp
@@ -62,9 +62,8 @@ namespace sprout {
 			// join
 			//
 			template<typename ContainerContainer, typename Separator = void>
-			struct join {
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct join
+				: public sprout::container_transform_traits<
 					typename sprout::container_traits<ContainerContainer>::value_type
 				>::template rebind_size<
 					sprout::container_traits<
@@ -78,20 +77,19 @@ namespace sprout {
 							* sprout::container_traits<ContainerContainer>::static_size
 							- sprout::algorithm::detail::string_size<Separator>::value
 						: 0
-				>::type type;
-			};
+				>
+			{};
 			template<typename ContainerContainer>
-			struct join<ContainerContainer, void> {
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct join<ContainerContainer, void>
+				: public sprout::container_transform_traits<
 					typename sprout::container_traits<ContainerContainer>::value_type
 				>::template rebind_size<
 					sprout::container_traits<
 						typename sprout::container_traits<ContainerContainer>::value_type
 					>::static_size
 					* sprout::container_traits<ContainerContainer>::static_size
-				>::type type;
-			};
+				>
+			{};
 		}	// namespace result_of
 
 		namespace detail {
diff --git a/sprout/container/internal.hpp b/sprout/container/internal.hpp
index d2594b2e..f0294f6a 100644
--- a/sprout/container/internal.hpp
+++ b/sprout/container/internal.hpp
@@ -11,14 +11,11 @@ namespace sprout {
 		// internal
 		//
 		template<typename Container>
-		struct internal {
-		public:
-			typedef typename sprout::sub_container_traits<
+		struct internal
+			: public sprout::sub_container_traits<
 				typename std::remove_reference<Container>::type
-			>::template internal<
-				Container
-			>::type type;
-		};
+			>::template internal<Container>
+		{};
 	}	// namespace containers
 }	// namespace sprout
 
diff --git a/sprout/darkroom/colors/rgb.hpp b/sprout/darkroom/colors/rgb.hpp
index 989d9cca..80f41c51 100644
--- a/sprout/darkroom/colors/rgb.hpp
+++ b/sprout/darkroom/colors/rgb.hpp
@@ -52,11 +52,26 @@ namespace sprout {
 			}
 
 			//
+			// rgb_t
 			// rgb
+			//
+			typedef sprout::tuples::tuple<std::uint8_t, std::uint8_t, std::uint8_t> rgb_t;
+
+			inline SPROUT_CONSTEXPR sprout::darkroom::colors::rgb_t
+			rgb(std::uint8_t r = 0, std::uint8_t g = 0, std::uint8_t b = 0) {
+				return sprout::darkroom::colors::rgb_t(r, g, b);
+			}
+
+			//
+			// rgb_f_t
 			// rgb_f
 			//
-			typedef sprout::tuples::tuple<std::uint8_t, std::uint8_t, std::uint8_t> rgb;
-			typedef sprout::tuples::tuple<double, double, double> rgb_f;
+			typedef sprout::tuples::tuple<double, double, double> rgb_f_t;
+
+			inline SPROUT_CONSTEXPR sprout::darkroom::colors::rgb_f_t
+			rgb_f(double r = 0, double g = 0, double b = 0) {
+				return sprout::darkroom::colors::rgb_f_t(r, g, b);
+			}
 
 			//
 			// mul
diff --git a/sprout/darkroom/coords/vector.hpp b/sprout/darkroom/coords/vector.hpp
index ccd55f01..7b4b1251 100644
--- a/sprout/darkroom/coords/vector.hpp
+++ b/sprout/darkroom/coords/vector.hpp
@@ -42,9 +42,15 @@ namespace sprout {
 			}
 
 			//
+			// vector3d_t
 			// vector3d
 			//
-			typedef sprout::tuples::tuple<double, double, double> vector3d;
+			typedef sprout::tuples::tuple<double, double, double> vector3d_t;
+
+			inline SPROUT_CONSTEXPR sprout::darkroom::coords::vector3d_t
+			vector3d(double x = 0, double y = 0, double z = 0) {
+				return sprout::darkroom::coords::vector3d_t(x, y, z);
+			}
 
 			//
 			// length_sq
diff --git a/sprout/darkroom/intersects/intersection.hpp b/sprout/darkroom/intersects/intersection.hpp
index 66087f2e..71b0b00e 100644
--- a/sprout/darkroom/intersects/intersection.hpp
+++ b/sprout/darkroom/intersects/intersection.hpp
@@ -74,8 +74,8 @@ namespace sprout {
 			typedef sprout::tuples::tuple<
 				bool,
 				double,
-				sprout::darkroom::coords::vector3d,
-				sprout::darkroom::coords::vector3d,
+				sprout::darkroom::coords::vector3d_t,
+				sprout::darkroom::coords::vector3d_t,
 				sprout::darkroom::materials::material
 			> intersection;
 		}	// namespace intersects
diff --git a/sprout/darkroom/lights/ambient_light.hpp b/sprout/darkroom/lights/ambient_light.hpp
index d0722db6..3d4472ab 100644
--- a/sprout/darkroom/lights/ambient_light.hpp
+++ b/sprout/darkroom/lights/ambient_light.hpp
@@ -15,7 +15,7 @@ namespace sprout {
 			//
 			// basic_ambient_light
 			//
-			template<typename Color = sprout::darkroom::colors::rgb_f>
+			template<typename Color = sprout::darkroom::colors::rgb_f_t>
 			class basic_ambient_light {
 			public:
 				typedef Color color_type;
diff --git a/sprout/darkroom/lights/parallel_light.hpp b/sprout/darkroom/lights/parallel_light.hpp
index db3ff5eb..04b5145d 100644
--- a/sprout/darkroom/lights/parallel_light.hpp
+++ b/sprout/darkroom/lights/parallel_light.hpp
@@ -19,8 +19,8 @@ namespace sprout {
 			// basic_parallel_light
 			//
 			template<
-				typename Position = sprout::darkroom::coords::vector3d,
-				typename Color = sprout::darkroom::colors::rgb_f
+				typename Position = sprout::darkroom::coords::vector3d_t,
+				typename Color = sprout::darkroom::colors::rgb_f_t
 			>
 			class basic_parallel_light {
 			public:
diff --git a/sprout/darkroom/lights/point_light.hpp b/sprout/darkroom/lights/point_light.hpp
index 551c9364..6b6b1279 100644
--- a/sprout/darkroom/lights/point_light.hpp
+++ b/sprout/darkroom/lights/point_light.hpp
@@ -19,8 +19,8 @@ namespace sprout {
 			// basic_point_light
 			//
 			template<
-				typename Position = sprout::darkroom::coords::vector3d,
-				typename Color = sprout::darkroom::colors::rgb_f
+				typename Position = sprout::darkroom::coords::vector3d_t,
+				typename Color = sprout::darkroom::colors::rgb_f_t
 			>
 			class basic_point_light {
 			public:
diff --git a/sprout/darkroom/materials/material.hpp b/sprout/darkroom/materials/material.hpp
index fc3f0b14..3534bdab 100644
--- a/sprout/darkroom/materials/material.hpp
+++ b/sprout/darkroom/materials/material.hpp
@@ -81,7 +81,7 @@ namespace sprout {
 			//
 			// material
 			//
-			typedef sprout::tuples::tuple<sprout::darkroom::colors::rgb_f, double> material;
+			typedef sprout::tuples::tuple<sprout::darkroom::colors::rgb_f_t, double> material;
 		}	// namespace materials
 	}	// namespace darkroom
 }	// namespace sprout
diff --git a/sprout/darkroom/objects/aa_plane.hpp b/sprout/darkroom/objects/aa_plane.hpp
index d2d7dbb5..2d615fd5 100644
--- a/sprout/darkroom/objects/aa_plane.hpp
+++ b/sprout/darkroom/objects/aa_plane.hpp
@@ -27,7 +27,7 @@ namespace sprout {
 			//
 			// basic_aa_plane
 			//
-			template<typename Material, typename Position = sprout::darkroom::coords::vector3d>
+			template<typename Material, typename Position = sprout::darkroom::coords::vector3d_t>
 			class basic_aa_plane {
 			public:
 				typedef Material material_type;
diff --git a/sprout/darkroom/objects/polygon/triangle.hpp b/sprout/darkroom/objects/polygon/triangle.hpp
index dc6a32ca..2f6835cb 100644
--- a/sprout/darkroom/objects/polygon/triangle.hpp
+++ b/sprout/darkroom/objects/polygon/triangle.hpp
@@ -17,7 +17,7 @@ namespace sprout {
 			//
 			// basic_triangle
 			//
-			template<typename Material, typename Vertex = sprout::darkroom::coords::vector3d>
+			template<typename Material, typename Vertex = sprout::darkroom::coords::vector3d_t>
 			class basic_triangle {
 			public:
 				typedef Material material_type;
diff --git a/sprout/darkroom/objects/sphere.hpp b/sprout/darkroom/objects/sphere.hpp
index c1c38d6b..049702f2 100644
--- a/sprout/darkroom/objects/sphere.hpp
+++ b/sprout/darkroom/objects/sphere.hpp
@@ -20,7 +20,7 @@ namespace sprout {
 			//
 			// basic_sphere
 			//
-			template<typename Material, typename Position = sprout::darkroom::coords::vector3d>
+			template<typename Material, typename Position = sprout::darkroom::coords::vector3d_t>
 			class basic_sphere {
 			public:
 				typedef Material material_type;
diff --git a/sprout/darkroom/pixels/generate.hpp b/sprout/darkroom/pixels/generate.hpp
index a191770b..f6ebe141 100644
--- a/sprout/darkroom/pixels/generate.hpp
+++ b/sprout/darkroom/pixels/generate.hpp
@@ -125,7 +125,7 @@ namespace sprout {
 			//
 			// color_pixels
 			//
-			template<std::size_t Width, std::size_t Height, typename Color = sprout::darkroom::colors::rgb>
+			template<std::size_t Width, std::size_t Height, typename Color = sprout::darkroom::colors::rgb_t>
 			struct color_pixels {
 			public:
 				typedef sprout::array<sprout::array<Color, Width>, Height> type;
diff --git a/sprout/darkroom/rays/ray.hpp b/sprout/darkroom/rays/ray.hpp
index a48c803a..937acbac 100644
--- a/sprout/darkroom/rays/ray.hpp
+++ b/sprout/darkroom/rays/ray.hpp
@@ -43,7 +43,7 @@ namespace sprout {
 			//
 			// ray
 			//
-			typedef sprout::tuples::tuple<sprout::darkroom::coords::vector3d, sprout::darkroom::coords::vector3d> ray;
+			typedef sprout::tuples::tuple<sprout::darkroom::coords::vector3d_t, sprout::darkroom::coords::vector3d_t> ray;
 
 			//
 			// point_of_intersection
diff --git a/sprout/darkroom/renderers/infinity.hpp b/sprout/darkroom/renderers/infinity.hpp
index 4ae087e6..07f82400 100644
--- a/sprout/darkroom/renderers/infinity.hpp
+++ b/sprout/darkroom/renderers/infinity.hpp
@@ -44,7 +44,7 @@ namespace sprout {
 			//
 			// uniform_color
 			//
-			template<typename Color = sprout::darkroom::colors::rgb_f>
+			template<typename Color = sprout::darkroom::colors::rgb_f_t>
 			class uniform_color {
 			public:
 				typedef Color color_type;
diff --git a/sprout/darkroom/textures/texture.hpp b/sprout/darkroom/textures/texture.hpp
index 240d094c..390c8539 100644
--- a/sprout/darkroom/textures/texture.hpp
+++ b/sprout/darkroom/textures/texture.hpp
@@ -47,7 +47,7 @@ namespace sprout {
 			//
 			// image_type
 			//
-			template<std::size_t Width, std::size_t Height, typename Color = sprout::darkroom::colors::rgb_f>
+			template<std::size_t Width, std::size_t Height, typename Color = sprout::darkroom::colors::rgb_f_t>
 			struct image_type {
 			public:
 				typedef Color color_type;
diff --git a/sprout/darkroom/tracers/raytracer.hpp b/sprout/darkroom/tracers/raytracer.hpp
index 5afafe80..09e2daa5 100644
--- a/sprout/darkroom/tracers/raytracer.hpp
+++ b/sprout/darkroom/tracers/raytracer.hpp
@@ -11,7 +11,7 @@ namespace sprout {
 			//
 			// raytracer
 			//
-			template<typename Color = sprout::darkroom::colors::rgb_f>
+			template<typename Color = sprout::darkroom::colors::rgb_f_t>
 			class raytracer {
 			public:
 				typedef Color color_type;
diff --git a/sprout/operation/fixed/append.hpp b/sprout/operation/fixed/append.hpp
index 8bf313db..d49fc84a 100644
--- a/sprout/operation/fixed/append.hpp
+++ b/sprout/operation/fixed/append.hpp
@@ -14,14 +14,13 @@ namespace sprout {
 			// append
 			//
 			template<typename Container, typename Input>
-			struct append {
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct append
+				: public sprout::container_transform_traits<
 					Container
 				>::template rebind_size<
 					sprout::container_traits<Container>::static_size + sprout::container_traits<Input>::static_size
-				>::type type;
-			};
+				>
+			{};
 		}	// namespace result_of
 
 		namespace detail {
diff --git a/sprout/operation/fixed/erase.hpp b/sprout/operation/fixed/erase.hpp
index cf2509cb..e07fb8c2 100644
--- a/sprout/operation/fixed/erase.hpp
+++ b/sprout/operation/fixed/erase.hpp
@@ -14,14 +14,14 @@ namespace sprout {
 			// erase
 			//
 			template<typename Container>
-			struct erase {
-				static_assert(sprout::container_traits<Container>::static_size >= 1, "static_size >= 1");
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct erase
+				: public sprout::container_transform_traits<
 					Container
 				>::template rebind_size<
 					sprout::container_traits<Container>::static_size - 1
-				>::type type;
+				>
+			{
+				static_assert(sprout::container_traits<Container>::static_size >= 1, "static_size >= 1");
 			};
 		}	// namespace result_of
 
diff --git a/sprout/operation/fixed/erase_n.hpp b/sprout/operation/fixed/erase_n.hpp
index 7125f146..3ea50e59 100644
--- a/sprout/operation/fixed/erase_n.hpp
+++ b/sprout/operation/fixed/erase_n.hpp
@@ -15,14 +15,14 @@ namespace sprout {
 			// erase_n
 			//
 			template<std::size_t N, typename Container>
-			struct erase_n {
-				static_assert(sprout::container_traits<Container>::static_size >= N, "static_size >= N");
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct erase_n
+				: public sprout::container_transform_traits<
 					Container
 				>::template rebind_size<
 					sprout::container_traits<Container>::static_size - N
-				>::type type;
+				>
+			{
+				static_assert(sprout::container_traits<Container>::static_size >= N, "static_size >= N");
 			};
 		}	// namespace result_of
 
diff --git a/sprout/operation/fixed/insert.hpp b/sprout/operation/fixed/insert.hpp
index 71e82134..5bf9f851 100644
--- a/sprout/operation/fixed/insert.hpp
+++ b/sprout/operation/fixed/insert.hpp
@@ -16,14 +16,13 @@ namespace sprout {
 			// insert
 			//
 			template<typename Container, typename T, typename... Values>
-			struct insert {
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct insert
+				: public sprout::container_transform_traits<
 					Container
 				>::template rebind_size<
 					sprout::container_traits<Container>::static_size + 1 + sizeof...(Values)
-				>::type type;
-			};
+				>
+			{};
 		}	// namespace result_of
 
 		namespace detail {
diff --git a/sprout/operation/fixed/insert_n.hpp b/sprout/operation/fixed/insert_n.hpp
index 3abf7c05..2115e835 100644
--- a/sprout/operation/fixed/insert_n.hpp
+++ b/sprout/operation/fixed/insert_n.hpp
@@ -18,14 +18,13 @@ namespace sprout {
 			// insert_n
 			//
 			template<std::size_t N, typename Container, typename T, typename... Values>
-			struct insert_n {
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct insert_n
+				: public sprout::container_transform_traits<
 					Container
 				>::template rebind_size<
 					sprout::container_traits<Container>::static_size + (1 + sizeof...(Values)) * N
-				>::type type;
-			};
+				>
+			{};
 		}	// namespace result_of
 
 		namespace detail {
diff --git a/sprout/operation/fixed/resize.hpp b/sprout/operation/fixed/resize.hpp
index ab069419..c5ae5bbd 100644
--- a/sprout/operation/fixed/resize.hpp
+++ b/sprout/operation/fixed/resize.hpp
@@ -15,14 +15,13 @@ namespace sprout {
 			// resize
 			//
 			template<std::size_t N, typename Container>
-			struct resize {
-			public:
-				typedef typename sprout::container_transform_traits<
+			struct resize
+				: public sprout::container_transform_traits<
 					Container
 				>::template rebind_size<
 					N
-				>::type type;
-			};
+				>
+			{};
 		}	// namespace result_of
 
 		namespace detail {
diff --git a/sprout/range/adaptor/detail/jointed_range_default.hpp b/sprout/range/adaptor/detail/jointed_range_default.hpp
index 319dfb35..696909f5 100644
--- a/sprout/range/adaptor/detail/jointed_range_default.hpp
+++ b/sprout/range/adaptor/detail/jointed_range_default.hpp
@@ -132,40 +132,35 @@ namespace sprout {
 			};
 
 			template<typename LRange, typename RRange, typename = void>
-			class jointed_range_copied_type;
-
+			struct jointed_range_copied_type;
 			template<typename LRange, typename RRange>
-			class jointed_range_copied_type<
+			struct jointed_range_copied_type<
 				LRange, RRange,
 				typename std::enable_if<
 					sprout::containers::is_rebindable_size<LRange>::value
 				>::type
-			> {
-			public:
-				typedef typename sprout::container_construct_traits<
+			>
+				: public sprout::container_construct_traits<
 					typename sprout::containers::weak_rebind_size<
 						typename sprout::container_construct_traits<LRange>::copied_type,
 						sprout::adaptors::detail::jointed_range_size<LRange, RRange>::static_size
 					>::type
-				>::type copied_type;
-			};
-
+				>
+			{};
 			template<typename LRange, typename RRange>
-			class jointed_range_copied_type<
+			struct jointed_range_copied_type<
 				LRange, RRange,
 				typename std::enable_if<
 					!sprout::containers::is_rebindable_size<LRange>::value && sprout::containers::is_rebindable_size<RRange>::value
 				>::type
-			> {
-			public:
-				typedef typename sprout::containers::weak_rebind_size<
+			>
+				: public sprout::containers::weak_rebind_size<
 					typename sprout::container_construct_traits<RRange>::copied_type,
 					sprout::adaptors::detail::jointed_range_size<LRange, RRange>::static_size
-				>::type type;
-			};
-
+				>
+			{};
 			template<typename LRange, typename RRange>
-			class jointed_range_copied_type<
+			struct jointed_range_copied_type<
 				LRange, RRange,
 				typename std::enable_if<
 					!sprout::containers::is_rebindable_size<LRange>::value && !sprout::containers::is_rebindable_size<RRange>::value
diff --git a/sprout/tuple/traits.hpp b/sprout/tuple/traits.hpp
index 7861e1d4..9488c6ac 100644
--- a/sprout/tuple/traits.hpp
+++ b/sprout/tuple/traits.hpp
@@ -46,14 +46,13 @@ namespace sprout {
 			template<typename Tuple, typename IndexTuple>
 			struct default_copied;
 			template<typename Tuple, sprout::index_t... Indexes>
-			struct default_copied<Tuple, sprout::index_tuple<Indexes...> > {
-			public:
-				typedef typename sprout::tuples::rebind_types<Tuple>::template apply<
+			struct default_copied<Tuple, sprout::index_tuple<Indexes...> >
+				: public sprout::tuples::rebind_types<Tuple>::template apply<
 					typename std::decay<
 						typename sprout::tuples::tuple_element<Indexes, Tuple>::type
 					>::type...
-				>::type type;
-			};
+				>
+			{};
 
 			template<typename Tuple, typename... Args>
 			SPROUT_CONSTEXPR typename sprout::tuples::tuple_construct_traits<Tuple>::copied_type
diff --git a/sprout/tuple/tuple.hpp b/sprout/tuple/tuple.hpp
index da2b0ec5..e59f8fa2 100644
--- a/sprout/tuple/tuple.hpp
+++ b/sprout/tuple/tuple.hpp
@@ -10,5 +10,6 @@
 #include <sprout/tuple/tuple/ignore.hpp>
 #include <sprout/tuple/tuple/make_tuple.hpp>
 #include <sprout/tuple/tuple/type_traits.hpp>
+#include <sprout/tuple/tuple/flexibly_construct.hpp>
 
 #endif	// #ifndef SPROUT_TUPLE_TUPLE_HPP
diff --git a/sprout/tuple/tuple/flexibly_construct.hpp b/sprout/tuple/tuple/flexibly_construct.hpp
new file mode 100644
index 00000000..7ebffbf4
--- /dev/null
+++ b/sprout/tuple/tuple/flexibly_construct.hpp
@@ -0,0 +1,20 @@
+#ifndef SPROUT_TUPLE_TUPLE_FREXIBLY_CONSTRUCT_HPP
+#define SPROUT_TUPLE_TUPLE_FREXIBLY_CONSTRUCT_HPP
+
+#include <sprout/config.hpp>
+
+namespace sprout {
+	namespace tuples {
+		//
+		// flexibly_construct_t
+		// flexibly_construct
+		//
+		struct flexibly_construct_t {};
+		SPROUT_STATIC_CONSTEXPR sprout::tuples::flexibly_construct_t flexibly_construct = {};
+	}	// namespace tuples
+
+	using sprout::tuples::flexibly_construct_t;
+	using sprout::tuples::flexibly_construct;
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TUPLE_TUPLE_FREXIBLY_CONSTRUCT_HPP
diff --git a/sprout/tuple/tuple/get.hpp b/sprout/tuple/tuple/get.hpp
index a66743e7..144d9b2b 100644
--- a/sprout/tuple/tuple/get.hpp
+++ b/sprout/tuple/tuple/get.hpp
@@ -40,26 +40,23 @@ namespace sprout {
 			: public std::tuple_element<I, T>
 		{};
 		template<std::size_t I, typename T>
-		struct tuple_element<I, T const> {
-		public:
-			typedef typename std::add_const<
+		struct tuple_element<I, T const>
+			: public std::add_const<
 				typename sprout::tuples::tuple_element<I, T>::type
-			>::type type;
-		};
+			>
+		{};
 		template<std::size_t I, typename T>
-		struct tuple_element<I, T volatile> {
-		public:
-			typedef typename std::add_volatile<
+		struct tuple_element<I, T volatile>
+			: public std::add_volatile<
 				typename sprout::tuples::tuple_element<I, T>::type
-			>::type type;
-		};
+			>
+		{};
 		template<std::size_t I, typename T>
-		struct tuple_element<I, T const volatile> {
-		public:
-			typedef typename std::add_cv<
+		struct tuple_element<I, T const volatile>
+			: public std::add_cv<
 				typename sprout::tuples::tuple_element<I, T>::type
-			>::type type;
-		};
+			>
+		{};
 
 		namespace detail {
 			template<std::size_t I, typename Head, typename... Tail>
diff --git a/sprout/tuple/tuple/make_tuple.hpp b/sprout/tuple/tuple/make_tuple.hpp
index 7dd9b1dd..4de14393 100644
--- a/sprout/tuple/tuple/make_tuple.hpp
+++ b/sprout/tuple/tuple/make_tuple.hpp
@@ -103,12 +103,11 @@ namespace sprout {
 				typedef sprout::index_tuple<> type;
 			};
 			template<typename Head, typename... Tail>
-			struct tuple_cat_1st_indexes<Head, Tail...> {
-			public:
-				typedef typename sprout::index_range<
+			struct tuple_cat_1st_indexes<Head, Tail...>
+				: public sprout::index_range<
 					0, sprout::tuples::tuple_size<typename std::remove_reference<Head>::type>::value
-				>::type type;
-			};
+				>
+			{};
 
 			template<typename Result, typename IndexTuple, typename... Tuples>
 			struct tuple_cat_impl;
diff --git a/sprout/tuple/tuple/tuple.hpp b/sprout/tuple/tuple/tuple.hpp
index 5017295c..ddc90233 100644
--- a/sprout/tuple/tuple/tuple.hpp
+++ b/sprout/tuple/tuple/tuple.hpp
@@ -9,8 +9,10 @@
 #include <sprout/utility/forward.hpp>
 #include <sprout/utility/move.hpp>
 #include <sprout/utility/swap.hpp>
+#include <sprout/type_traits/is_convert_constructible.hpp>
+#include <sprout/tpp/algorithm/all_of.hpp>
 #include <sprout/tuple/tuple/tuple_fwd.hpp>
-#include <sprout/tuple/tuple/type_traits.hpp>
+#include <sprout/tuple/tuple/flexibly_construct.hpp>
 
 namespace sprout {
 	namespace tuples {
@@ -247,32 +249,46 @@ namespace sprout {
 				: inherited_type(elements...)
 			{}
 			template<
-				typename U,
+				typename... UTypes,
 				typename = typename std::enable_if<
-					!sprout::tuples::is_tuple<typename std::remove_reference<U>::type>::value
+					sizeof...(Types) == sizeof...(UTypes) && sprout::tpp::all_of<sprout::is_convert_constructible<Types, UTypes&&>...>::value
 				>::type
 			>
-			explicit SPROUT_CONSTEXPR tuple(U&& elem)
-				: inherited_type(sprout::forward<U>(elem))
+			explicit SPROUT_CONSTEXPR tuple(UTypes&&... elements)
+				: inherited_type(sprout::forward<UTypes>(elements)...)
 			{}
-			template<
-				typename U1,
-				typename U2,
-				typename... UTypes
-			>
-			explicit SPROUT_CONSTEXPR tuple(U1&& elem1, U2&& elem2, UTypes&&... elements)
-				: inherited_type(sprout::forward<U1>(elem1), sprout::forward<U2>(elem2), sprout::forward<UTypes>(elements)...)
+			template<typename... UTypes>
+			explicit SPROUT_CONSTEXPR tuple(sprout::tuples::flexibly_construct_t, UTypes&&... elements)
+				: inherited_type(sprout::forward<UTypes>(elements)...)
 			{}
 			SPROUT_CONSTEXPR tuple(tuple const&) = default;
 			SPROUT_CONSTEXPR tuple(tuple&&) = default;
-			template<typename... UTypes>
+			template<
+				typename... UTypes,
+				typename = typename std::enable_if<
+					sizeof...(Types) == sizeof...(UTypes) && sprout::tpp::all_of<sprout::is_convert_constructible<Types, UTypes const&>...>::value
+				>::type
+			>
 			SPROUT_CONSTEXPR tuple(sprout::tuples::tuple<UTypes...> const& t)
 				: inherited_type(static_cast<sprout::tuples::detail::tuple_impl<0, UTypes...> const&>(t))
 			{}
-			template<typename... UTypes>
+			template<
+				typename... UTypes,
+				typename = typename std::enable_if<
+					sizeof...(Types) == sizeof...(UTypes) && sprout::tpp::all_of<sprout::is_convert_constructible<Types, UTypes&&>...>::value
+				>::type
+			>
 			SPROUT_CONSTEXPR tuple(sprout::tuples::tuple<UTypes...>&& t)
 				: inherited_type(static_cast<sprout::tuples::detail::tuple_impl<0, UTypes...>&&>(t))
 			{}
+			template<typename... UTypes>
+			SPROUT_CONSTEXPR tuple(sprout::tuples::flexibly_construct_t, sprout::tuples::tuple<UTypes...> const& t)
+				: inherited_type(static_cast<sprout::tuples::detail::tuple_impl<0, UTypes...> const&>(t))
+			{}
+			template<typename... UTypes>
+			SPROUT_CONSTEXPR tuple(sprout::tuples::flexibly_construct_t, sprout::tuples::tuple<UTypes...>&& t)
+				: inherited_type(static_cast<sprout::tuples::detail::tuple_impl<0, UTypes...>&&>(t))
+			{}
 			// tuple assignment
 			tuple& operator=(tuple const& rhs) {
 				static_cast<inherited_type&>(*this) = rhs;
diff --git a/sprout/type/iterator/advance.hpp b/sprout/type/iterator/advance.hpp
index 95a887a0..50bc50cc 100644
--- a/sprout/type/iterator/advance.hpp
+++ b/sprout/type/iterator/advance.hpp
@@ -9,10 +9,9 @@ namespace sprout {
 		// advance
 		//
 		template<typename Iterator, std::ptrdiff_t Disatnce, typename Enable = void>
-		struct advance {
-		public:
-			typedef typename Iterator::template advance<Disatnce>::type type;
-		};
+		struct advance
+			: public Iterator::template advance<Disatnce>
+		{};
 
 		template<typename Iterator, std::ptrdiff_t Disatnce>
 		struct advance<Iterator const, Disatnce>
diff --git a/sprout/type/iterator/deref.hpp b/sprout/type/iterator/deref.hpp
index 7c1f139b..3b284ee4 100644
--- a/sprout/type/iterator/deref.hpp
+++ b/sprout/type/iterator/deref.hpp
@@ -9,10 +9,9 @@ namespace sprout {
 		// deref
 		//
 		template<typename Iterator>
-		struct deref {
-		public:
-			typedef typename Iterator::type type;
-		};
+		struct deref
+			: public Iterator
+		{};
 	}	// namespace types
 }	// namespace sprout
 
diff --git a/sprout/type_traits.hpp b/sprout/type_traits.hpp
index 29b3867d..a39e134e 100644
--- a/sprout/type_traits.hpp
+++ b/sprout/type_traits.hpp
@@ -2,6 +2,7 @@
 #define SPROUT_TYPE_TRAITS_HPP
 
 #include <sprout/config.hpp>
+#include <sprout/type_traits/is_convert_constructible.hpp>
 #include <sprout/type_traits/is_int.hpp>
 #include <sprout/type_traits/is_uint.hpp>
 #include <sprout/type_traits/is_char_type.hpp>
diff --git a/sprout/type_traits/is_convert_constructible.hpp b/sprout/type_traits/is_convert_constructible.hpp
new file mode 100644
index 00000000..80fe50ca
--- /dev/null
+++ b/sprout/type_traits/is_convert_constructible.hpp
@@ -0,0 +1,32 @@
+#ifndef SPROUT_TYPE_TRAITS_IS_CONVERT_CONSTRUCTIBLE_HPP
+#define SPROUT_TYPE_TRAITS_IS_CONVERT_CONSTRUCTIBLE_HPP
+
+#include <utility>
+#include <type_traits>
+#include <sprout/config.hpp>
+
+namespace sprout {
+	//
+	// is_convert_constructible
+	//
+	namespace detail {
+		template<typename T>
+		struct is_convert_constructible_test {
+		public:
+			template<typename To = T>
+			static std::true_type test(To);
+			static std::false_type test(...);
+		};
+	}	// namespace detail
+	template<typename T, typename Arg>
+	struct is_convert_constructible
+		: public decltype(sprout::detail::is_convert_constructible_test<T>::test(std::declval<Arg>()))
+	{};
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	template<typename T, typename Arg>
+	using is_convert_constructible_ = typename sprout::is_convert_constructible<T, Arg>::type;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_IS_CONVERT_CONSTRUCTIBLE_HPP
diff --git a/sprout/utility/pack.hpp b/sprout/utility/pack.hpp
index 7f259265..76aac868 100644
--- a/sprout/utility/pack.hpp
+++ b/sprout/utility/pack.hpp
@@ -13,10 +13,9 @@ namespace sprout {
 	//
 	namespace detail {
 		template<std::size_t N, typename Head, typename... Tail>
-		struct tppack_at_impl_1 {
-		public:
-			typedef typename sprout::detail::tppack_at_impl_1<N - 1, Tail...>::type type;
-		};
+		struct tppack_at_impl_1
+			: public sprout::detail::tppack_at_impl_1<N - 1, Tail...>
+		{};
 		template<typename Head, typename... Tail>
 		struct tppack_at_impl_1<0, Head, Tail...> {
 		public:
diff --git a/sprout/variant/variant.hpp b/sprout/variant/variant.hpp
index 2b2a9291..9d8cff48 100644
--- a/sprout/variant/variant.hpp
+++ b/sprout/variant/variant.hpp
@@ -29,11 +29,12 @@ namespace sprout {
 			friend class variant;
 		protected:
 			typedef sprout::tuples::tuple<Types...> tuple_type;
-			typedef sprout::types::type_tuple<typename std::decay<Types>::type...> uncvref_tuple_type;
+			typedef sprout::types::type_tuple<typename std::decay<Types>::type...> decayed_tuple_type;
 		private:
 			template<typename T, sprout::index_t... Indexes>
 			static SPROUT_CONSTEXPR tuple_type init(T&& operand, sprout::index_tuple<Indexes...>) {
 				return sprout::tuples::make<tuple_type>(
+					sprout::tuples::flexibly_construct,
 					typename sprout::tuples::tuple_element<Indexes, tuple_type>::type()...,
 					sprout::forward<T>(operand)
 					);
@@ -72,28 +73,26 @@ namespace sprout {
 	{
 	private:
 		typedef sprout::detail::variant_impl<Types...> impl_type;
-		typedef typename impl_type::uncvref_tuple_type uncvref_tuple_type;
+		typedef typename impl_type::decayed_tuple_type decayed_tuple_type;
 	public:
 		typedef typename impl_type::tuple_type tuple_type;
 	private:
 		template<typename Visitor, typename Tuple, typename IndexTuple>
 		struct visitor_result_impl_2;
 		template<typename Visitor, typename Tuple, sprout::index_t... Indexes>
-		struct visitor_result_impl_2<Visitor, Tuple, sprout::index_tuple<Indexes...> > {
-		public:
-			typedef typename Visitor::template visitor_result<
+		struct visitor_result_impl_2<Visitor, Tuple, sprout::index_tuple<Indexes...> >
+			: public Visitor::template visitor_result<
 				decltype((std::declval<Visitor>())(sprout::tuples::get<Indexes>(std::declval<Tuple>())))...
-			>::type type;
-		};
+			>
+		{};
 		template<typename Visitor, typename Tuple, typename IndexTuple>
 		struct visitor_result_impl_1;
 		template<typename Visitor, typename Tuple, sprout::index_t... Indexes>
-		struct visitor_result_impl_1<Visitor, Tuple, sprout::index_tuple<Indexes...> > {
-		public:
-			typedef typename sprout::common_decay<
+		struct visitor_result_impl_1<Visitor, Tuple, sprout::index_tuple<Indexes...> >
+			: public sprout::common_decay<
 				decltype((std::declval<Visitor>())(sprout::tuples::get<Indexes>(std::declval<Tuple>())))...
-			>::type type;
-		};
+			>
+		{};
 		template<typename Visitor, typename Tuple, typename = void>
 		struct visitor_result_impl;
 		template<typename Visitor, typename Tuple>
@@ -227,7 +226,7 @@ namespace sprout {
 		SPROUT_CONSTEXPR variant(T&& operand)
 			: impl_type(
 				sprout::forward<T>(operand),
-				sprout::types::find_index<uncvref_tuple_type, typename std::decay<T>::type>()
+				sprout::types::find_index<decayed_tuple_type, typename std::decay<T>::type>()
 				)
 		{}
 		// modifiers
diff --git a/sprout/weed/expr/make_terminal.hpp b/sprout/weed/expr/make_terminal.hpp
index 21107357..c3cdc05d 100644
--- a/sprout/weed/expr/make_terminal.hpp
+++ b/sprout/weed/expr/make_terminal.hpp
@@ -5,7 +5,6 @@
 #include <sprout/config.hpp>
 #include <sprout/string.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/traits/type/is_c_str.hpp>
 #include <sprout/weed/traits/expr/terminal_of.hpp>
 
@@ -17,7 +16,7 @@ namespace sprout {
 		template<typename Arg>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			!sprout::weed::traits::is_c_str<
-				typename sprout::remove_shallow_cvref<Arg>::type
+				typename std::remove_reference<Arg>::type
 			>::value,
 			typename sprout::weed::traits::terminal_of<Arg>::type
 		>::type make_terminal(Arg&& arg) {
@@ -28,7 +27,7 @@ namespace sprout {
 		template<typename Arg>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			sprout::weed::traits::is_c_str<
-				typename sprout::remove_shallow_cvref<Arg>::type
+				typename std::remove_reference<Arg>::type
 			>::value,
 			typename sprout::weed::traits::terminal_of<Arg>::type
 		>::type make_terminal(Arg&& arg) {
diff --git a/sprout/weed/expr/make_terminal_or_expr.hpp b/sprout/weed/expr/make_terminal_or_expr.hpp
index 4070d753..cf340fe6 100644
--- a/sprout/weed/expr/make_terminal_or_expr.hpp
+++ b/sprout/weed/expr/make_terminal_or_expr.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/make_terminal.hpp>
 #include <sprout/weed/traits/expr/is_expr.hpp>
 #include <sprout/weed/traits/expr/terminal_or_expr_of.hpp>
@@ -17,7 +16,7 @@ namespace sprout {
 		template<typename Arg>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			sprout::weed::traits::is_expr<
-				typename sprout::remove_shallow_cvref<Arg>::type
+				typename std::remove_reference<Arg>::type
 			>::value,
 			typename sprout::weed::traits::terminal_or_expr_of<Arg>::type
 		>::type make_terminal_or_expr(Arg&& arg) {
@@ -26,7 +25,7 @@ namespace sprout {
 		template<typename Arg>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			!sprout::weed::traits::is_expr<
-				typename sprout::remove_shallow_cvref<Arg>::type
+				typename std::remove_reference<Arg>::type
 			>::value,
 			typename sprout::weed::traits::terminal_or_expr_of<Arg>::type
 		>::type make_terminal_or_expr(Arg&& arg) {
diff --git a/sprout/weed/operator/address_of.hpp b/sprout/weed/operator/address_of.hpp
index 2bdb56c4..0c36d1e3 100644
--- a/sprout/weed/operator/address_of.hpp
+++ b/sprout/weed/operator/address_of.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -19,7 +18,7 @@ namespace sprout {
 			typename Arg,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg>::type
+					typename std::remove_reference<Arg>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/bitwise_or.hpp b/sprout/weed/operator/bitwise_or.hpp
index 84a0ea2b..176d1924 100644
--- a/sprout/weed/operator/bitwise_or.hpp
+++ b/sprout/weed/operator/bitwise_or.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -20,10 +19,10 @@ namespace sprout {
 			typename Arg2,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg1>::type
+					typename std::remove_reference<Arg1>::type
 				>::value
 				&& sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg2>::type
+					typename std::remove_reference<Arg2>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/dereference.hpp b/sprout/weed/operator/dereference.hpp
index 53e32a8b..0c3dd8a0 100644
--- a/sprout/weed/operator/dereference.hpp
+++ b/sprout/weed/operator/dereference.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -19,7 +18,7 @@ namespace sprout {
 			typename Arg,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg>::type
+					typename std::remove_reference<Arg>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/logical_not.hpp b/sprout/weed/operator/logical_not.hpp
index eba98198..354d838b 100644
--- a/sprout/weed/operator/logical_not.hpp
+++ b/sprout/weed/operator/logical_not.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -19,7 +18,7 @@ namespace sprout {
 			typename Arg,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg>::type
+					typename std::remove_reference<Arg>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/mem_ptr.hpp b/sprout/weed/operator/mem_ptr.hpp
index 7fe8f147..cf0d93b5 100644
--- a/sprout/weed/operator/mem_ptr.hpp
+++ b/sprout/weed/operator/mem_ptr.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -20,7 +19,7 @@ namespace sprout {
 			typename Arg2,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg1>::type
+					typename std::remove_reference<Arg1>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/minus.hpp b/sprout/weed/operator/minus.hpp
index 9edfff43..defe576f 100644
--- a/sprout/weed/operator/minus.hpp
+++ b/sprout/weed/operator/minus.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -20,10 +19,10 @@ namespace sprout {
 			typename Arg2,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg1>::type
+					typename std::remove_reference<Arg1>::type
 				>::value
 				&& sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg2>::type
+					typename std::remove_reference<Arg2>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/modulus.hpp b/sprout/weed/operator/modulus.hpp
index e0b380fa..0882fc81 100644
--- a/sprout/weed/operator/modulus.hpp
+++ b/sprout/weed/operator/modulus.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -20,10 +19,10 @@ namespace sprout {
 			typename Arg2,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg1>::type
+					typename std::remove_reference<Arg1>::type
 				>::value
 				&& sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg2>::type
+					typename std::remove_reference<Arg2>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/negate.hpp b/sprout/weed/operator/negate.hpp
index a866961a..72bcd1cd 100644
--- a/sprout/weed/operator/negate.hpp
+++ b/sprout/weed/operator/negate.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -19,7 +18,7 @@ namespace sprout {
 			typename Arg,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg>::type
+					typename std::remove_reference<Arg>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/shift_left.hpp b/sprout/weed/operator/shift_left.hpp
index 3124378f..05f3dac7 100644
--- a/sprout/weed/operator/shift_left.hpp
+++ b/sprout/weed/operator/shift_left.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -20,10 +19,10 @@ namespace sprout {
 			typename Arg2,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg1>::type
+					typename std::remove_reference<Arg1>::type
 				>::value
 				&& sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg2>::type
+					typename std::remove_reference<Arg2>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/operator/unary_plus.hpp b/sprout/weed/operator/unary_plus.hpp
index c0646831..ce1a4939 100644
--- a/sprout/weed/operator/unary_plus.hpp
+++ b/sprout/weed/operator/unary_plus.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/utility/forward.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/tag.hpp>
 #include <sprout/weed/expr/make_expr.hpp>
 #include <sprout/weed/traits/expr/expr_of.hpp>
@@ -19,7 +18,7 @@ namespace sprout {
 			typename Arg,
 			typename = typename std::enable_if<
 				sprout::weed::traits::is_parser<
-					typename sprout::remove_shallow_cvref<Arg>::type
+					typename std::remove_reference<Arg>::type
 				>::value
 			>::type
 		>
diff --git a/sprout/weed/parser/lit.hpp b/sprout/weed/parser/lit.hpp
index 6f96e2ab..7599291e 100644
--- a/sprout/weed/parser/lit.hpp
+++ b/sprout/weed/parser/lit.hpp
@@ -18,7 +18,8 @@ namespace sprout {
 			template<typename T>
 			SPROUT_CONSTEXPR typename eval<
 				typename sprout::remove_shallow_cvref<T>::type
-			>::result_type operator()(T&& t) const {
+			>::result_type
+			operator()(T&& t) const {
 				typedef eval<typename sprout::remove_shallow_cvref<T>::type> eval_type;
 				return eval_type()(sprout::forward<T>(t));
 			}
diff --git a/sprout/weed/traits/expr/expr_of.hpp b/sprout/weed/traits/expr/expr_of.hpp
index bad3daa9..68d62cf6 100644
--- a/sprout/weed/traits/expr/expr_of.hpp
+++ b/sprout/weed/traits/expr/expr_of.hpp
@@ -4,7 +4,6 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/type_traits/identity.hpp>
-#include <sprout/type_traits/remove_shallow_cvref.hpp>
 #include <sprout/weed/expr/expr_fwd.hpp>
 #include <sprout/weed/traits/expr/terminal_or_expr_of.hpp>
 
@@ -20,7 +19,7 @@ namespace sprout {
 					sprout::weed::expr<
 						Tag,
 						typename sprout::weed::traits::terminal_or_expr_of<
-							typename sprout::remove_shallow_cvref<Args>::type
+							typename std::remove_reference<Args>::type
 						>::type...
 					>
 				>
diff --git a/sprout/weed/traits/expr/terminal_of.hpp b/sprout/weed/traits/expr/terminal_of.hpp
index a4a630d7..aab7506e 100644
--- a/sprout/weed/traits/expr/terminal_of.hpp
+++ b/sprout/weed/traits/expr/terminal_of.hpp
@@ -23,7 +23,7 @@ namespace sprout {
 				Arg,
 				typename std::enable_if<
 					!sprout::weed::traits::is_c_str<
-						typename sprout::remove_shallow_cvref<Arg>::type
+						typename std::remove_reference<Arg>::type
 					>::value
 				>::type
 			>
@@ -39,7 +39,7 @@ namespace sprout {
 				Arg,
 				typename std::enable_if<
 					sprout::weed::traits::is_c_str<
-						typename sprout::remove_shallow_cvref<Arg>::type
+						typename std::remove_reference<Arg>::type
 					>::value
 				>::type
 			>
@@ -47,7 +47,7 @@ namespace sprout {
 					sprout::weed::expr<
 						sprout::weed::tag::terminal,
 						typename sprout::weed::detail::c_str_as_string<
-							typename sprout::remove_shallow_cvref<Arg>::type
+							typename std::remove_reference<Arg>::type
 						>::type
 					>
 				>
diff --git a/sprout/weed/traits/expr/terminal_or_expr_of.hpp b/sprout/weed/traits/expr/terminal_or_expr_of.hpp
index 9470c998..c2fe8f76 100644
--- a/sprout/weed/traits/expr/terminal_or_expr_of.hpp
+++ b/sprout/weed/traits/expr/terminal_or_expr_of.hpp
@@ -17,7 +17,7 @@ namespace sprout {
 			struct terminal_or_expr_of
 				: public std::conditional<
 					sprout::weed::traits::is_expr<
-						typename sprout::remove_shallow_cvref<Arg>::type
+						typename std::remove_reference<Arg>::type
 					>::value,
 					sprout::remove_shallow_cvref<Arg>,
 					sprout::weed::traits::terminal_of<Arg>