template dispatching to pointer to member function

gistfile1.cpp

template<class T, int Arity, v8::Handle<v8::Value> (T::*InvocationCallbackMember)(v8::Arguments const&)>
static v8::Handle<v8::Value> InvocationCallbackDispatcher(v8::Arguments const& args) {
  if (args.Length() < Arity)
    return ThrowArgCount();
  T* object = T::FromV8Object(args.Holder());
  if (!object)
    return ThrowObjectDisposed();
  try {
    return ((*object).*(InvocationCallbackMember))(args);
  } catch (...) {
    return v8::ThrowException(v8::String::New("Caught unknown native exception."));
  }
}

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InvocationCallbackDispatcher<Canvas, 2, &Canvas::Callback_getContext>(args);