Modify to override operator= to set values as datatype

Currently, set_value() can be specified only as string data. However, if
use STL, it can to specify various types of data more easily using
std::to_string (or to_wstring).
This commit modifies to override the assignment operator to make it more
usefully to set values when using STL.

Signed-off-by: Jihun Ahn <jhun.ahnn@gmail.com>

src/pugixml.cpp

@@ -5691,6 +5691,16 @@ namespace pugi
 		return impl::strcpy_insitu(_root->value, _root->header, impl::xml_memory_page_value_allocated_mask, rhs, impl::strlength(rhs));
 	}
 
+	PUGI__FN bool xml_node::set_value(const bool rhs)
+	{
+	#ifdef PUGIXML_WCHAR_MODE
+		const char_t* text = rhs ? L"true" : L"false";
+	#else
+		const char_t* text = rhs ? "true" : "false";
+	#endif
+		return set_value(text);
+	}
+
 	PUGI__FN xml_attribute xml_node::append_attribute(const char_t* name_)
 	{
 		if (!impl::allow_insert_attribute(type())) return xml_attribute();

src/pugixml.hpp

@@ -38,6 +38,8 @@
 #	include <string>
 #endif
 
+#include <type_traits>
+
 // Macro for deprecated features
 #ifndef PUGIXML_DEPRECATED
 #	if defined(__GNUC__)
@@ -491,6 +493,21 @@ namespace pugi
 		xml_node operator[](const char_t* name_);
 		xml_node& operator=(const char_t* rhs);
 
+	#ifndef PUGIXML_NO_STL
+		template <typename T> xml_node& operator=(const T& rhs)
+		{
+			if (std::is_arithmetic<T>::value)
+			{
+				xml_node node = append_child(node_pcdata);
+
+				node.set_value(rhs);
+			}
+
+			return *this;
+		}
+
+	#endif
+
 		// Check if node is empty.
 		bool empty() const;
 
@@ -543,6 +560,22 @@ namespace pugi
 		// Set node name/value (returns false if node is empty, there is not enough memory, or node can not have name/value)
 		bool set_name(const char_t* rhs);
 		bool set_value(const char_t* rhs);
+		bool set_value(const bool rhs);
+
+	#ifndef PUGIXML_NO_STL
+		template <typename T> bool set_value(const T& rhs)
+		{
+			if (!std::is_arithmetic<T>::value)
+				return false;
+
+#	ifdef PUGIXML_WCHAR_MODE
+			const string_t& _str = std::to_wstring(rhs);
+#	else
+			const string_t& _str = std::to_string(rhs);
+#	endif
+			return set_value(_str.c_str());
+		}
+	#endif
 
 		// Add attribute with specified name. Returns added attribute, or empty attribute on errors.
 		xml_attribute append_attribute(const char_t* name);