to_string adjustments

[SVN r44192]

include/boost/exception/detail/is_output_streamable.hpp

@@ -12,7 +12,7 @@ namespace
 boost
     {
 	namespace
-	exception_detail
+	to_string_detail
 		{
 		template <bool>
 		struct
@@ -43,7 +43,7 @@ boost
     struct
 	is_output_streamable
 		{
-		enum e { value=exception_detail::is_output_streamable_impl<T,CharT,Traits>::value };
+		enum e { value=to_string_detail::is_output_streamable_impl<T,CharT,Traits>::value };
 		};
     }
 

include/boost/exception/to_string.hpp

@@ -14,55 +14,44 @@ namespace
 boost
     {
 	namespace
-	exception_detail
+	to_string_detail
 		{
-		template <bool>
-		struct
-		has_to_string_dispatch
+        template <class T>
+        typename disable_if<is_output_streamable<T>,char>::type to_string( T const & );
+
+		template <class,bool IsOutputStreamable>
+        struct has_to_string_impl;
+
+		template <class T>
+        struct
+		has_to_string_impl<T,true>
 			{
 			enum e { value=1 };
 			};
 
-		template <>
-		struct
-		has_to_string_dispatch<false>
-			{
-			enum e { value=0 };
-			};
-
-		template <class T>
-		std::string
-		to_string( T const & x, typename enable_if< is_output_streamable<T> >::type * = 0 )
-			{
-			std::ostringstream out;
-			out << x;
-			return out.str();
-			}
-
-        template <class T>
-        char to_string( T const &, typename disable_if< is_output_streamable<T> >::type * = 0 );
-
 		template <class T>
         struct
-		has_to_string_impl
+		has_to_string_impl<T,false>
 			{
-			enum e { value=has_to_string_dispatch<1!=sizeof(to_string(*(T*)0))>::value };
+			enum e { value=1!=sizeof(to_string(*(T*)0)) };
 			};
 		}
 
 	template <class T>
+	typename enable_if<is_output_streamable<T>,std::string>::type
+	to_string( T const & x )
+		{
+		std::ostringstream out;
+		out << x;
+		return out.str();
+		}
+
+	template <class T>
     struct
 	has_to_string
 		{
-		enum e { value=exception_detail::has_to_string_impl<T>::value };
+		enum e { value=to_string_detail::has_to_string_impl<T,is_output_streamable<T>::value>::value };
 		};
-
-	template <class T>
-    std::string
-	to_string( T const & x, typename enable_if< is_output_streamable<T> >::type * = 0 )
-        {
-		return exception_detail::to_string(x);
-        }
     }
 
 #endif

test/Jamfile.v2

@@ -9,6 +9,7 @@ import testing ;
 
 #to_string
 run is_output_streamable_test.cpp ;
+run has_to_string_test.cpp ;
 run to_string_test.cpp ;
 run to_string_stub_test.cpp ;
 compile-fail to_string_fail.cpp ;

test/has_to_string_test.cpp

@@ -0,0 +1,57 @@
+//Copyright (c) 2006-2008 Emil Dotchevski and Reverge Studios, Inc.
+
+//Distributed under the Boost Software License, Version 1.0. (See accompanying
+//file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/exception/to_string.hpp>
+#include <boost/detail/lightweight_test.hpp>
+
+namespace
+n1
+    {
+    struct
+    c1
+        {
+        };
+    }
+
+namespace
+n2
+    {
+    struct
+    c2
+        {
+        };
+
+	std::string
+    to_string( c2 const & )
+        {
+        return "c2";
+        }           
+    }
+
+namespace
+n3
+    {
+    struct
+    c3
+        {
+        };
+
+	std::ostream &
+	operator<<( std::ostream & s, c3 const & )
+        {
+        return s << "c3";
+        }           
+    }
+
+int
+main()
+    {
+	using namespace boost;
+	BOOST_TEST( !has_to_string<n1::c1>::value );
+	BOOST_TEST( has_to_string<n2::c2>::value );
+	BOOST_TEST( has_to_string<n3::c3>::value );
+	BOOST_TEST( has_to_string<int>::value );
+    return boost::report_errors();
+    }

test/to_string_test.cpp

@@ -49,10 +49,6 @@ int
 main()
     {
 	using namespace boost;
-	BOOST_TEST( !has_to_string<n1::c1>::value );
-	BOOST_TEST( has_to_string<n2::c2>::value );
-	BOOST_TEST( has_to_string<n3::c3>::value );
-	BOOST_TEST( has_to_string<int>::value );
 	BOOST_TEST( "c2"==to_string(n2::c2()) );
 	BOOST_TEST( "c3"==to_string(n3::c3()) );
 	BOOST_TEST( "42"==to_string(42) );