On 10/19/06, Noah Schwartz <noah.schwartz1 at gmail.com> wrote:
> Hi,
>
> I am having another issue with the indexing suite. I have an std::map from
> int to boost::shared_ptr<MyClass>. However, in python, I can't seem to look
> at the data element of an iterator into that map. I get a TypeError
> complaining that there is no class registered for C++ class
> boost::shared_ptr<MyClass>. However, I did tell python about shared_ptrs of
> MyClass and no_proxy is set to true.
>
> Binding code:
> #include <boost/python.hpp>
> #include <boost/python/suite/indexing/map_indexing_suite.hpp>
> #include <boost/python/register_ptr_to_python.hpp>
> using namespace boost::python;
>
> #include <map>
>
> class MyClass {
> public:
> int e;
> };
>
> class MyClassMaker {
> public:
> std::map<int, boost::shared_ptr<MyClass> > & func() {return myMap;};
> void add(int x, int y) {boost::shared_ptr<MyClass> instance(new MyClass);
> instance->e = y; myMap[x] = instance;};
>
> std::map<int, boost::shared_ptr<MyClass> > myMap;
> };
>
> BOOST_PYTHON_MODULE(testlib)
> {
> class_<MyClass, boost::shared_ptr<MyClass> >("MyClass")
> ;
> class_<MyClassMaker>("MyClassMaker")
> .def("func", &MyClassMaker::func,
> return_value_policy<copy_non_const_reference>())
> .def("add", &MyClassMaker::add)
> ;
>
> class_<std::map<int, boost::shared_ptr<MyClass> > >("MapIntMyClass")
> .def(map_indexing_suite<std::map<int, boost::shared_ptr<MyClass> >, true>())
> ;
> }
>
>
> Python code:
> >>> import testlib
> >>>
> >>> a = testlib.MyClassMaker()
> >>>
> >>> a.add(1, 2)
> >>> a.add(3, 4)
> >>> a.add(5, 6)
> >>>
> >>> map = a.func()
> >>>
> >>> for i in map:
> ... print i.key()
> ... print i.data()
> ...
> 1
> Traceback (most recent call last):
> File "<stdin>", line 3, in ?
> TypeError: No Python class registered for C++ class boost::shared_ptr<MyClass>
>
> If you look at the binding code I have specified shared_ptr as a held type.
>
> I should mention that if I use a simpler container such as a vector container
> of shared_ptr's and do not specify no_proxy to true then I get the same
> error. Maybe the no_proxy code isnt being properly applied to the second
> template type in the map container.
Google is your friend:
http://mail.python.org/pipermail/c++-sig/2005-November/009849.html
http://mail.python.org/pipermail/c++-sig/2005-November/009854.html
--
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/