Re: [Boost-users] Exposing std::pair to Python

Subject: Re: [Boost-users] Exposing std::pair to Python
From: A B (python6009_at_[hidden])
Date: 2009-04-17 20:20:28

Michal,
Thanks for the response. I was able to locate the following post
(http://www.nabble.com/Exposing-members-of-members-td21545250.html)
and following sample code mentioned in the post
(http://cci.lbl.gov/cctbx_sources/boost_adaptbx/) that were very
helpful. In fact, exactly what I was looking for. Good luck.

2009/4/16 Micha³ Nowotka <mmmnow_at_[hidden]>:
> I think I can partially answer your question. Although I don't know
> how to expose std::pair using indexing suite, thanks to Roman
> Yakovenko and his Py++ package, I can show you working example of
> exporting pair using different approach:
>
> This is *.h file with class containing variable of type std::pair<int,
> int> to be exposed (this file is also available here:
> http://pygccxml.svn.sourceforge.net/viewvc/pygccxml?view=rev):
>
> // Copyright 2004-2008 Roman Yakovenko.
> // Distributed under the Boost Software License, Version 1.0. (See
> // accompanying file LICENSE_1_0.txt or copy at
> // http://www.boost.org/LICENSE_1_0.txt)
>
> #ifndef __std_pair_to_be_exported_hpp__
> #define __std_pair_to_be_exported_hpp__
>
> #include <utility>
>
> struct tester_t{
>    tester_t(int a, int b){
>       pair_.first = a;
>       pair_.second = b;
>    }
>
>    int compute(){return pair_.first + pair_.second;}
>
>    std::pair<int, int> pair_;
> };
> #endif//__std_pair_to_be_exported_hpp__
>
>
>
>
> And here is wrapper code generated by Py++:
>
>
>
> // This file has been generated by Py++.
>
> // Copyright 2004-2008 Roman Yakovenko.
> // Distributed under the Boost Software License, Version 1.0. (See
> // accompanying file LICENSE_1_0.txt or copy at
> // http://www.boost.org/LICENSE_1_0.txt)
>
> #include "boost/python.hpp"
>
> #include "std_pair_to_be_exported.hpp"
>
> namespace bp = boost::python;
>
> BOOST_PYTHON_MODULE(std_pair){
>    bp::class_< std::pair< int, int > >(
> "pair_less__int_comma__int__greater_", "documentation", bp::init<
>>("documentation") )
>        .def( bp::init< int const &, int const & >(( bp::arg("__a"),
> bp::arg("__b") ), "documentation") )
>        .def_readwrite( "first", &std::pair< int, int >::first,
> "documentation" )
>        .def_readwrite( "second", &std::pair< int, int >::second,
> "documentation" );
>
>    bp::class_< tester_t >( "tester_t", "documentation", bp::init<
> int, int >(( bp::arg("a"), bp::arg("b") ), "documentation") )
>        .def(
>            "compute"
>            , (int ( ::tester_t::* )(  ) )( &::tester_t::compute )
>            , "documentation" )
>        .def_readwrite( "pair_", &tester_t::pair_, "documentation" );
> }
>
>
>
> You should notice that in python:
> pairA = module.pair_less__int_comma__int__greater_(2,3)
> pairB = module.pair_less__int_comma__int__greater_(2,3)
> pairA.first == pairB.first
>
>>True
>
> pairA.second == pairB.second
>
>>True
>
> BUT:
>
> pairA == pairB
>
>>False
>
> I'm also interested in exposing std::pair using indexing suite because
> it perhaps make statement pairA == pairB become true.
> Especially if that code would be auto-generated by Py++ just like
> other STL containers it could be very useful. Roman Yakovenko wrote
> there is a chance this functionality would be added in next release of
> Py++.
>
> Also you can ask this question on Cplusplus-sig mailing list:
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>
> If you find accurate answer to your question, please let me know.
>
> --
> Regards
>
> Micha³ Nowotka
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