Created attachment 2911 [details]
C++11 version of the patch

Variadic templates allow to pass an arbitrary number of arguments to ObjectFactory::Set, so that helper functions (and CreateObjectWithAttributes<T>()) can be greatly simplified and allow arbitrary number of arguments. For instance:

template<typename T>
Ptr<T>
CreateObjectWithAttributes (std::string n1, const AttributeValue & v1,
                            std::string n2, const AttributeValue & v2,
                            std::string n3, const AttributeValue & v3,
                            std::string n4, const AttributeValue & v4,
                            std::string n5, const AttributeValue & v5,
                            std::string n6, const AttributeValue & v6,
                            std::string n7, const AttributeValue & v7,
                            std::string n8, const AttributeValue & v8,
                            std::string n9, const AttributeValue & v9)
{
  ObjectFactory factory;
  factory.SetTypeId (T::GetTypeId ());
  factory.Set (n1, v1);
  factory.Set (n2, v2);
  factory.Set (n3, v3);
  factory.Set (n4, v4);
  factory.Set (n5, v5);
  factory.Set (n6, v6);
  factory.Set (n7, v7);
  factory.Set (n8, v8);
  factory.Set (n9, v9);
  return factory.Create<T> ();
}

becomes


template<typename T, typename... Args>
Ptr<T>
CreateObjectWithAttributes (Args... args)
{
  ObjectFactory factory;
  factory.SetTypeId (T::GetTypeId ());
  factory.Set (args...);
  return factory.Create<T> ();
}

I did not implement the "recursive" approach (Set consumes two arguments and calls itself), but an approach where all the name-value pairs are used to initialize a map and then set by calling the DoSet member function (which is exactly the current Set member function).

I used this approach to simplify the traffic-control helper and verified that the python bindings can be scanned (with castxml, 64-bit only) and ns-3 builds on Linux (g++-4.9 and g++-7.1) and Mac OSX (clang 8.1).

I also prepared a C++14 version of the patch, where I could avoid defining index_sequence and make_index_sequence and reuse std::index_sequence and std::make_index_sequence.

I switched ns-3 to using C++14 and:

- ns-3 builds on Mac OSX (clang 8.1) and Linux (g++ 7.1)
- ns-3 does not build on Linux with g++ 4.9, not because of this patch but because of the pattern below used in the emulation devices:

char control[CMSG_SPACE (msg_size)];
...
msg.msg_controllen = sizeof (control);

"error: taking sizeof array of runtime bound"

I think it is anyway safe to replace 

msg.msg_controllen = sizeof (control);

with

msg.msg_controllen = CMSG_SPACE (msg_size) * sizeof (char);

After that, everything builds and runs just fine.