Re: [pygccxml-development] serialization support?

[Neal B. <ndb...@gm...>]

On Wednesday 13 September 2006 6:52 am, Roman Yakovenko wrote:
> On 9/13/06, Neal Becker <ndb...@gm...> wrote:
> > On Wednesday 13 September 2006 12:58 am, Roman Yakovenko wrote:
> > > On 9/13/06, Neal Becker <ndb...@gm...> wrote:
> > > > Has any work been done on adding boost::serialization support?
> > >
> > > What do you mean?
> >
> > Automatic generation of pickle support.  Probably using
> > boost::serialization.
>
> That what I thought. No we don't work on this functionality. Moreover
> I think, that Py++
> can not implement it. The primary reason is that Py++ deals with class
> interface
> and not with its state. Py++ can provide some convinience API that
> will make the task
> to be easier to implement. Tell me what you need and I will check how
> I can integrate
> your ideas.

The technique I have used is not really elegant, but works.  First serialize 
with boost::serializatoin into a string, then pickle the string:

struct mt_pickle_suite : python::pickle_suite {
    
  static python::object getstate (const rng_t& rng) {
    std::ostringstream os;
    boost::archive::binary_oarchive oa(os);
    oa << rng;
    return python::str (os.str());
  }

  static void
  setstate(rng_t& rng, python::object entries) {
    python::str s = python::extract<python::str> (entries)();
    std::string st = python::extract<std::string> (s)();
    std::istringstream is (st);
    
    boost::archive::binary_iarchive ia (is);
    ia >> rng;
  }
};

[...]
class_<rng_t> ("rng", "Mersenne Twister", python::init<rng_t::result_type>(
									     (python::arg ("seed")=4357),
									     "__init__(seed=4357)\n"
									     "Construct with optional seed\n"
									     "@param seed: initial seed\n"
									     ))
    .def_pickle(mt_pickle_suite())
    .def ("getstate", &mt_pickle_suite::getstate)
    .def ("setstate", &mt_pickle_suite::setstate)
[...]