apply constexpr if

include/nana/gui/detail/general_events.hpp

@@ -1,7 +1,7 @@
 /**
 *	Definition of General Events
 *	Nana C++ Library(http://www.nanapro.org)
-*	Copyright(C) 2003-2016 Jinhao(cnjinhao@hotmail.com)
+*	Copyright(C) 2003-2017 Jinhao(cnjinhao@hotmail.com)
 *
 *	Distributed under the Boost Software License, Version 1.0.
 *	(See accompanying file LICENSE_1_0.txt or copy at
@@ -134,10 +134,24 @@ namespace nana
 		template<typename Function>
 		event_handle connect_front(Function && fn)
 		{
+#ifdef _nana_cxx_constexpr_if
+			if constexpr(std::is_invocable_v<Function, arg_reference>)
+			{
+				return _m_emplace(new docker{ this, fn, false }, true);
+			}
+			else if constexpr(std::is_invocable_v<Function>)
+			{
+				return _m_emplace(new docker{ this, [fn](arg_reference) {
+					fn();
+				}, false }, true);
+			}
+#else
 			using prototype = typename std::remove_reference<Function>::type;
 			return _m_emplace(new docker(this, factory<prototype, std::is_bind_expression<prototype>::value>::build(std::forward<Function>(fn)), false), true);
+#endif
 		}
 
+#ifndef _nana_cxx_constexpr_if
 		/// It will not get called if stop_propagation() was called.
 		event_handle connect(void (*fn)(arg_reference))
 		{
@@ -145,13 +159,27 @@ namespace nana
 				fn(arg);
 			});
 		}
+#endif
 
 		/// It will not get called if stop_propagation() was called, because it is set at the end of the chain..
 		template<typename Function>
 		event_handle connect(Function && fn)
 		{
+#ifdef _nana_cxx_constexpr_if
+			if constexpr(std::is_invocable_v<Function, arg_reference>)
+			{
+				return _m_emplace(new docker{ this, fn, false }, false);
+			}
+			else if constexpr(std::is_invocable_v<Function>)
+			{
+				return _m_emplace(new docker{ this, [fn](arg_reference){
+					fn();
+				}, false }, false);
+			}
+#else
 			using prototype = typename std::remove_reference<Function>::type;
 			return _m_emplace(new docker(this, factory<prototype, std::is_bind_expression<prototype>::value>::build(std::forward<Function>(fn)), false), false);
+#endif
 		}
 
 		/// It will not get called if stop_propagation() was called.
@@ -165,9 +193,21 @@ namespace nana
         template<typename Function>
 		event_handle connect_unignorable(Function && fn, bool in_front = false)
 		{
+#ifdef _nana_cxx_constexpr_if
+			if constexpr(std::is_invocable_v<Function, arg_reference>)
+			{
+				return _m_emplace(new docker{ this, fn, true }, in_front);
+			}
+			else if constexpr(std::is_invocable_v<Function>)
+			{
+				return _m_emplace(new docker{ this, [fn](arg_reference) {
+					fn();
+				}, true }, in_front);
+			}
+#else
 			using prototype = typename std::remove_reference<Function>::type;
-
 			return _m_emplace(new docker(this, factory<prototype, std::is_bind_expression<prototype>::value>::build(std::forward<Function>(fn)), true), in_front);
+#endif
 		}
 
 		void emit(arg_reference& arg, window window_handle)
@@ -210,6 +250,8 @@ namespace nana
 			}
 		}
 	private:
+
+#ifndef _nana_cxx_constexpr_if
 		template<typename Fn, bool IsBind>
 		struct factory
 		{
@@ -385,6 +427,7 @@ namespace nana
 				};
 			}
 		};
+#endif
 	};
  
 	struct arg_mouse

include/nana/gui/programming_interface.hpp

@@ -245,6 +245,19 @@ namespace API
 		if (nullptr == general_evt)
 			throw std::invalid_argument("API::events(): bad parameter window handle, no events object or invalid window handle.");
 
+#ifdef _nana_cxx_constexpr_if
+		if constexpr(std::is_same_v<event_type, ::nana::general_events>)
+		{
+			return *general_evt;
+		}
+		else
+		{
+			auto * widget_evt = dynamic_cast<event_type*>(general_evt);
+			if (nullptr == widget_evt)
+				throw std::invalid_argument("API::events(): bad template parameter Widget, the widget type and window handle do not match.");
+			return *widget_evt;
+		}
+#else
 		if (std::is_same<::nana::general_events, event_type>::value)
 			return *static_cast<event_type*>(general_evt);
 
@@ -252,6 +265,7 @@ namespace API
 		if (nullptr == widget_evt)
 			throw std::invalid_argument("API::events(): bad template parameter Widget, the widget type and window handle do not match.");
 		return *widget_evt;
+#endif
 	}
 
 	template<typename EventArg, typename std::enable_if<std::is_base_of< ::nana::event_arg, EventArg>::value>::type* = nullptr>
@@ -278,6 +292,19 @@ namespace API
 		if (nullptr == wdg_colors)
 			throw std::invalid_argument("API::scheme(): bad parameter window handle, no events object or invalid window handle.");
 
+#ifdef _nana_cxx_constexpr_if
+		if constexpr(std::is_same<::nana::widget_geometrics, scheme_type>::value)
+		{
+			return *static_cast<scheme_type*>(wdg_colors);
+		}
+		else
+		{
+			auto * comp_wdg_colors = dynamic_cast<scheme_type*>(wdg_colors);
+			if (nullptr == comp_wdg_colors)
+				throw std::invalid_argument("API::scheme(): bad template parameter Widget, the widget type and window handle do not match.");
+			return *comp_wdg_colors;
+		}
+#else
 		if (std::is_same<::nana::widget_geometrics, scheme_type>::value)
 			return *static_cast<scheme_type*>(wdg_colors);
 
@@ -285,6 +312,7 @@ namespace API
 		if (nullptr == comp_wdg_colors)
 			throw std::invalid_argument("API::scheme(): bad template parameter Widget, the widget type and window handle do not match.");
 		return *comp_wdg_colors;
+#endif
 	}
 
 	point window_position(window);

source/gui/widgets/spinbox.cpp

@@ -82,10 +82,39 @@ namespace nana
 
 				bool check_value(const std::string& str) const override
 				{
+#ifdef _nana_cxx_constexpr_if
+					auto i = str.c_str();
+					if ('+' == *i || '-' == *i)
+						++i;
+
+					if constexpr(std::is_same<T, int>::value)
+					{
+						for (; 0 != *i; ++i)
+						{
+							if (*i < '0' || '9' < *i)
+								return false;
+						}
+					}
+					else
+					{
+						bool dot = false;
+						for (; 0 != *i; ++i)
+						{
+							if (('.' == *i) && (!dot))
+							{
+								dot = true;
+								continue;
+							}
+
+							if (*i < '0' || '9' < *i)
+								return false;
+						}
+					}
+#else
 					if (str.empty())
 						return true;
 
-					auto size = str.size();
+					auto const size = str.size();
 					std::size_t pos = 0;
 					if (str[0] == '+' || str[0] == '-')
 						pos = 1;
@@ -115,6 +144,7 @@ namespace nana
 								return false;
 						}
 					}
+#endif
 					return true;
 				}