Re: [boost] Re: newbie: python and reference

From: Thomas Malik (Thomas_Malik%LGBANK_at_[hidden])
Date: 2001-09-13 05:36:39

On Fri, 07 Sep 2001, you wrote:
> --- In boost_at_y..., conversy_at_l... wrote:
> > --- In boost_at_y..., rwgk_at_y... wrote:
> > > --- In boost_at_y..., conversy_at_l... wrote:
> > > > currently this code prints "0", but I want it to print "1"...
> > >
> > > This is known as the "returned reference problem":
> > > http://groups.yahoo.com/group/boost/message/10144
> >
> > is there any plan to include the features describe in this mail,
> such
> > as own_args ?
>
> See:
>
> http://cci.lbl.gov/~rwgk/boost.python/projects.html
>
>
>
> Info: http://www.boost.org  Unsubscribe:
> <mailto:boost-unsubscribe_at_[hidden]>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
I just created a 'reference' type for boost::python, just an object holding
a pointer to the 'real' object type. It's done a template class, built on
the stuff in boost::python::detail, and provides
to_python/from_python/make_ref
template functions.
Use is as follows:
in refmodule.cpp:
BOOST_PYTHON_MODULE_INIT(ref)
{
  try
  {
      python::module_builder this_module("ref");
      this_module.def(make_ref<int>, "make_ref");
      this_module.def(make_ref<const char*>, "make_ref");
     ... other reference types needed
  }
  catch(...)
  {
      python::handle_exception();
  }
}

reftest.py
import ref
>> r=ref.make_ref(1)
>> print r
<reference to int object at b4f40>
>> print type(r)
<type 'reference to int'>
>> print r()
1
>> function_with_intref_parameter(r)
>> print r()
10

The whole module is fairly short. Any interest ?

BTW. did my first mail, concerning unsigned char* conversions did get to
the mailing list ?
I didn't receive any comments on it.

--
Thomas Malik
Landesbank Baden-Wuerttemberg (Stuttgart, Germany)
Abt. 2340 Tel. [phone]
Thomas_Malik%lgbank_at_[hidden]
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