[C++-sig] vector<foo*> -> list, preserving identity

[Jacek Generowicz]

Imagine I have wrapped (using Boost.Python)

1. a C++ class

2. a function (or method) which returns vector of pointers to said class.

I would like to receive the vector as a Python list of instances of
the class, but would like the identity of the objects to
preserved. IOW, I want the original C++ object at the end of the
pointer to be referenced by the Python object which holds it, rather
than a new C++ object being instantiated.

Here's a minimalized sample of source to demonstrate the situation:

#include <Python.h>
#include <boost/python.hpp>
#include <iostream>
#include <vector>
using namespace boost::python;

struct foo {
  foo () { std::cout << "Creating foo at " << this << std::endl; }
  void pointer() { std::cout << this << std::endl; }
};

std::vector<const foo*> makefoos(int n) {
  std::vector<const foo*> fv;
  for (int i=0; i<n; ++i) {
    fv.push_back(new foo);
  }
  return fv;
}

BOOST_PYTHON_MODULE( nocopy ) {

  class_<foo >("foo", no_init)
    .def("pointer", &foo::pointer);

  def ("makefoos", makefoos);
}


How should I write a converter for the std::vector<foo*>, in order to
preserve the identity of the foos ?

(In the library I am wrapping, the return type of makefoos is actually
const std::vector<const foo*>&)

Thanks,