improve class_::extend()

Removed `class` suffix since the function extende is in the `v8pp::class_` name scope already.
Added `class_::extend()` usage example to the documentation and test case.

See pull-request #136

docs/wrapping.md

@@ -97,7 +97,8 @@ read-write property to `v8pp::class_`:
 struct X
 {
 	bool b;
-	X(bool b) : b(b) {}
+	int c;
+	X(bool b) : b(b), c(0) {}
 };
 
 struct Y : X
@@ -149,6 +150,9 @@ Y_class
 	.set("ext_fun", &ext_fun)
 	;
 
+// Extend existing X bindings
+v8pp::class_<X>::extend(isolate).set("c", &X::c);
+
 // set class into the module template
 module.set("X", X_class);
 module.set("Y", Y_class);

test/test_class.cpp

@@ -167,14 +167,14 @@ void test_class_()
 		.template ctor<int>()
 		.set("useX", &Y::useX)
 		.set("useX_ptr", &Y::useX_ptr<Traits>)
-		.set("toJSON", [](const v8::FunctionCallbackInfo<v8::Value>& args)
+		;
+
+	auto Y_class_find = v8pp::class_<Y, Traits>::extend(isolate);
+	Y_class_find.set("toJSON", [](const v8::FunctionCallbackInfo<v8::Value>& args)
 			{
 				bool const with_functions = true;
 				args.GetReturnValue().Set(v8pp::json_object(args.GetIsolate(), args.This(), with_functions));
-			})
-		;
-
-	auto Y_class_find  = v8pp::class_<Y, Traits>::extend_class(isolate);
+			});
 
 	check_ex<std::runtime_error>("already wrapped class X", [isolate]()
 	{

v8pp/class.hpp

@@ -181,6 +181,11 @@ class class_
 	using ctor_function = std::function<object_pointer_type (v8::FunctionCallbackInfo<v8::Value> const& args)>;
 	using dtor_function = std::function<void (v8::Isolate* isolate, object_pointer_type const& obj)>;
 
+	explicit class_(v8::Isolate* isolate, detail::type_info const& existing)
+		: class_info_(detail::classes::find<Traits>(isolate, existing))
+	{
+	}
+
 public:
 	explicit class_(v8::Isolate* isolate, dtor_function destroy = &factory<T, Traits>::destroy)
 		: class_info_(detail::classes::add<Traits>(isolate, detail::type_id<T>(),
@@ -191,7 +196,11 @@ class class_
 	{
 	}
 
-	static class_ extend_class(v8::Isolate* isolate) { return class_(isolate, detail::type_id<T>());}
+	/// Find existing class_ to extend bindings
+	static class_ extend(v8::Isolate* isolate)
+	{
+		return class_(isolate, detail::type_id<T>());
+	}
 
 	/// Set class constructor signature
 	template<typename ...Args, typename Create = factory_create<Args...>>
@@ -441,9 +450,6 @@ class class_
 	}
 
 private:
-	explicit class_(v8::Isolate *isolate, detail::type_info const &ty) :
-		class_info_(detail::classes::find<Traits>(isolate, ty)) { }
-
 	template<typename Attribute>
 	static void member_get(v8::Local<v8::String>,
 		v8::PropertyCallbackInfo<v8::Value> const& info)