add various overlodings for widget::caption()

source/gui/widgets/label.cpp

@@ -52,8 +52,8 @@ namespace nana
 				struct traceable
 				{
 					nana::rectangle r;
-					nana::string target;
-					nana::string url;
+					std::wstring target;
+					std::wstring url;
 				};
 
 			public:
@@ -148,7 +148,7 @@ namespace nana
 					graph.typeface(ft);
 				}
 
-				bool find(int x, int y, nana::string& target, nana::string& url) const
+				bool find(int x, int y, std::wstring& target, std::wstring& url) const
 				{
 					for (auto & t : traceable_)
 					{

source/gui/widgets/listbox.cpp

@@ -4324,7 +4324,7 @@ namespace nana
 			ess.update();
 		}
 
-		auto listbox::insert(cat_proxy cat, nana::string str) -> cat_proxy
+		auto listbox::insert(cat_proxy cat, std::wstring str) -> cat_proxy
 		{
 			internal_scope_guard lock;
 			auto & ess = _m_ess();
@@ -4358,7 +4358,12 @@ namespace nana
 			return at(pos_abs.cat).at(pos_abs.item);
 		}
 
-		void listbox::insert(const index_pair& pos, nana::string text)
+		void listbox::insert(const index_pair& pos, std::string text)
+		{
+			insert(pos, utf8_cast(text));
+		}
+
+		void listbox::insert(const index_pair& pos, std::wstring text)
 		{
 			internal_scope_guard lock;
 			auto & ess = _m_ess();

source/gui/widgets/widget.cpp

@@ -59,10 +59,31 @@ namespace nana
 			return this->_m_caption();
 		}
 
-		void widget::caption(std::string utf8)
+		std::wstring widget::caption_wstring() const throw()
+		{
+			return utf8_cast(_m_caption());
+		}
+
+		auto widget::caption_native() const throw() -> native_string_type
+		{
+#if defined(NANA_WINDOWS)
+			return caption_wstring();
+#else
+			return caption();
+#endif
+		}
+
+		widget& widget::caption(std::string utf8)
 		{
 			::nana::throw_not_utf8(utf8);
 			_m_caption(std::move(utf8));
+			return *this;
+		}
+
+		widget& widget::caption(std::wstring text)
+		{
+			_m_caption(utf8_cast(text));
+			return *this;
 		}
 
 		void widget::i18n(i18n_eval eval)