fix weed type_traits

sprout/weed/traits/expr/expr_of.hpp

@@ -3,6 +3,7 @@
 
 #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>
@@ -14,15 +15,16 @@ namespace sprout {
 			// expr_of
 			//
 			template<typename Tag, typename... Args>
-			struct expr_of {
-			public:
-				typedef sprout::weed::expr<
-					Tag,
-					typename sprout::weed::traits::terminal_or_expr_of<
-						typename sprout::remove_shallow_cvref<Args>::type
-					>::type...
-				> type;
-			};
+			struct expr_of
+				: public sprout::identity<
+					sprout::weed::expr<
+						Tag,
+						typename sprout::weed::traits::terminal_or_expr_of<
+							typename sprout::remove_shallow_cvref<Args>::type
+						>::type...
+					>
+				>
+			{};
 		}	// namespace traits
 	}	// namespace weed
 }	// namespace sprout

sprout/weed/traits/expr/tag_of.hpp

@@ -3,6 +3,7 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/type_traits/identity.hpp>
 #include <sprout/weed/traits/expr/is_expr.hpp>
 
 namespace sprout {
@@ -23,10 +24,9 @@ namespace sprout {
 				typename std::enable_if<
 					sprout::weed::traits::is_expr<Expr>::value
 				>::type
-			> {
-			public:
-				typedef typename Expr::expr_tag type;
-			};
+			>
+				: public sprout::identity<typename Expr::expr_tag>
+			{};
 		}	// namespace traits
 	}	// namespace weed
 }	// namespace sprout

sprout/weed/traits/expr/terminal_of.hpp

@@ -3,6 +3,7 @@
 
 #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/expr/tag.hpp>
@@ -25,13 +26,14 @@ namespace sprout {
 						typename sprout::remove_shallow_cvref<Arg>::type
 					>::value
 				>::type
-			> {
-			public:
-				typedef sprout::weed::expr<
-					sprout::weed::tag::terminal,
-					typename sprout::remove_shallow_cvref<Arg>::type
-				> type;
-			};
+			>
+				: public sprout::identity<
+					sprout::weed::expr<
+						sprout::weed::tag::terminal,
+						typename sprout::remove_shallow_cvref<Arg>::type
+					>
+				>
+			{};
 			template<typename Arg>
 			struct terminal_of<
 				Arg,
@@ -40,15 +42,16 @@ namespace sprout {
 						typename sprout::remove_shallow_cvref<Arg>::type
 					>::value
 				>::type
-			> {
-			public:
-				typedef sprout::weed::expr<
-					sprout::weed::tag::terminal,
-					typename sprout::weed::detail::c_str_as_string<
-						typename sprout::remove_shallow_cvref<Arg>::type
-					>::type
-				> type;
-			};
+			>
+				: public sprout::identity<
+					sprout::weed::expr<
+						sprout::weed::tag::terminal,
+						typename sprout::weed::detail::c_str_as_string<
+							typename sprout::remove_shallow_cvref<Arg>::type
+						>::type
+					>
+				>
+			{};
 		}	// namespace traits
 	}	// namespace weed
 }	// namespace sprout

sprout/weed/traits/expr/terminal_or_expr_of.hpp

@@ -14,16 +14,15 @@ namespace sprout {
 			// terminal_or_expr_of
 			//
 			template<typename Arg>
-			struct terminal_or_expr_of {
-			public:
-				typedef typename std::conditional<
+			struct terminal_or_expr_of
+				: public std::conditional<
 					sprout::weed::traits::is_expr<
 						typename sprout::remove_shallow_cvref<Arg>::type
 					>::value,
-					typename sprout::remove_shallow_cvref<Arg>::type,
-					typename sprout::weed::traits::terminal_of<Arg>::type
-				>::type type;
-			};
+					sprout::remove_shallow_cvref<Arg>,
+					sprout::weed::traits::terminal_of<Arg>
+				>::type
+			{};
 		}	// namespace traits
 	}	// namespace weed
 }	// namespace sprout

sprout/weed/traits/parser/attribute_of.hpp

@@ -3,6 +3,7 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/weed/traits/expr/is_expr.hpp>
 #include <sprout/weed/unused.hpp>
 #include <sprout/weed/expr/expr.hpp>
 #include <sprout/weed/expr/tag.hpp>
@@ -37,10 +38,9 @@ namespace sprout {
 					&& !sprout::weed::traits::is_c_str<T>::value
 					&& !sprout::weed::traits::is_string<T>::value
 				>::type
-			> {
-			public:
-				typedef typename T::template attribute<Context, Iterator>::type type;
-			};
+			>
+				: public T::template attribute<Context, Iterator>
+			{};
 			template<typename T, typename Iterator, typename Context>
 			struct attribute_of<
 				T,
@@ -49,10 +49,9 @@ namespace sprout {
 				typename std::enable_if<
 					sprout::weed::traits::is_expr<T>::value
 				>::type
-			> {
-			public:
-				typedef typename Context::template eval<T>::attribute_type type;
-			};
+			>
+				: public sprout::identity<typename Context::template eval<T>::attribute_type>
+			{};
 			template<typename T, typename Iterator, typename Context>
 			struct attribute_of<
 				T,

sprout/weed/traits/parser/is_parser.hpp

@@ -52,6 +52,7 @@ namespace sprout {
 				T,
 				typename std::enable_if<
 					sprout::weed::traits::is_c_str<T>::value
+					&& !std::is_const<T>::value
 				>::type
 			>
 				: public std::true_type
@@ -61,7 +62,6 @@ namespace sprout {
 				T,
 				typename std::enable_if<
 					std::is_const<T>::value
-					&& !std::is_array<T>::value
 				>::type
 			>
 				: public sprout::weed::traits::is_parser<