Mailman 3 March 2005 - Cplusplus-sig

RE: Wrapper for exception translation
by Gottfried.Ganssauge＠HAUFE.DE April 4, 2006

April 4, 2006

> -----Original Message----- > From: David Abrahams [mailto:dave@boost-consulting.com] > Sent: Monday, December 13, 2004 1:04 PM > To: c++-sig(a)python.org; Gottfried Ganßauge > Subject: Re: Wrapper for exception translation > > > Gottfried Ganßauge wrote: > > Hi Dave, > > > > I digged through the class_<> implementation and I think I > know what I > > must do to implement it. Like you suggested I would add another > > argument to the class_base constructor which is used as > another base > > class for the newly created class. > > Hi Gottfried, Hi Dave, > > I don't know if you're still listening, but today I offered to > implement this patch on the C++-sig (see my other post). > Are you still interested? I am still listening but was buried deeply with work so I even had to abandon the work already invested into this. Nonetheless: Yes - I'm still interested. Cheers, Gottfried P.S.: What second Post? I got 2 Copies of this one. > > > > -- > Dave Abrahams > Boost Consulting > http://www.boost-consulting.com >

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Re: exporting __stdcall methods
by David Abrahams Feb. 11, 2006

Feb. 11, 2006

"John Maddock" <john(a)johnmaddock.co.uk> writes: >> Files like boost/type_traits/detail/is_mem_fun_pointer_tester.hpp >> which are outside the Boost.Python library would need to be enhanced >> to deal with __stdcall, etc. > > Should now be fixed in cvs: provided the changes don't break anything else > of course! Fantastic! Thanks, John! -- Dave Abrahams Boost Consulting www.boost-consulting.com

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Pyste bug? Using Wrapper with member functions and --pyste-ns
by Dan Haffey April 25, 2005

April 25, 2005

Hello, I just noticed that when using the Pyste Wrapper call to create a member function wrapper, it places the wrapper definition code outside of the specified (--pyste-ns=) namespace, but the generated module code looks for it in the namespace. This doesn't seem to happen with normal functions, just members. -- Dan Haffey

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what happened with this std::string parameter in boost.python
by Donnie Leen April 4, 2005

April 4, 2005

I made a program embedding boost.python, writting a module as following: void write( std::string s ) { // do nothing } BOOST_PYTHON_MODULE(mym) { def( "write", &write ); } I run the python code: import mym s = 'hello' mym.write(s) it runs ok, but if i run the python code as following: import mym s = int.__doc__ mym.write(s) it crashed, and it seems to crashed while boost.python try to delete the parameter s. Can someone tell me what happened to it? Thanks first. Donnie Leen

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newbie questions...
by Marco Correia March 30, 2005

March 30, 2005

Hi, I just started using boost.python, so please excuse if this is trivial. I have two questions, the first one is related to registering a converter for the std::pair<T1,T2> to a python tuple. I've learned that I cannot have bindings for c++ templates, so lets say that T1=T2=int. I'm a little bit lost on how to do this. I thought I had to do something like this: namespace boost { namespace python { template <class T1,class T2> struct to_python_value<std::pair<T1,T2> > { typedef typename add_reference< typename add_const<std::pair<T1,T2> >::type >::type argument_type; static bool convertible() {return true;} PyObject* operator()(argument_type x) const { PyObject* aux1 = to_python_value<T1>()(x.first); PyObject* aux2 = to_python_value<T2>()(x.second); return Py_BuildValue("(O,O)",aux1,aux2); } }; }; }; and then register this with the 'to_python_converter': to_python_converter<std::pair<int,int>, to_python_value<std::pair<int,int> > >(); but since the second parameter is supposed to have a convert() method, I guess this is not the way to do it. I could wrap the to_python_value struct in another struct with a convert method, but I have the feeling that I'm complicating things. How do I do this? ---- The next question is about std::set::iterator. I'm trying to come up with a front end in python to a library I've been working on focused on constraint logic programming. A central object in the library is derived from std::set and I would be very happy if my python users could also handle std::set::iterators, for efficiency reasons. I had no problems in converting std::set using pyste, but set::iterator seems more complicated. My first attempt was to try to export only the "std::_Rb_tree_const_iterator". I had to comment a ".def( *self )" line but it compiled and linked with no errors. However, when I import the module in python I get an undefined symbol. Next stop was to try to export all std::_Rb_tree_const_iterator class hierarchy (actually only the std::_Rb_tree_node base class), but still get the undefined symbol. I guess that the .def(*self) is a wrapper for the set::operator*, but this shouldn't be the cause for undefined symbol, or am I wrong? --- I've have read and re-read the tutorial and reference manual of boost.python, and searched the mailing list. I found the boost.python tutorial too basic for these questions and I'm having trouble in learning from the reference manual. Pointers to documentation somewhere between these two are very welcome. Thanks! ps: Please reply me directly since I'm not subscribed. -- Marco Correia <mvc(a)di.fct.unl.pt>

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Re: [C++-sig] Re: newbie questions...
by Ralf W. Grosse-Kunstleve March 30, 2005

March 30, 2005

--- David Abrahams <dave(a)boost-consulting.com> wrote: > wouldn't > > template <typename T1, typename T2> > void std_pair_to_python_converter() > { > boost::python::to_python_converter< > std::pair<T1, T2>, > std_pair_to_tuple<T1, T2> >(); > } > > be so much simpler? This is not supported by some older compilers, e.g. gcc 2.96 and possibly older EDG's. __________________________________ Do you Yahoo!? Yahoo! Small Business - Try our new resources site! http://smallbusiness.yahoo.com/resources/

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Re: [C++-sig] newbie questions...
by Ralf W. Grosse-Kunstleve March 29, 2005

March 29, 2005

I just checked in a slightly modified version of the code in my previous message; boost/libs/python/example/std_pair.cpp. It would be nice if someone more familiar with bjam could help with the Jamfile. A possible test_std_pair.py: import std_pair_ext assert std_pair_ext.foo() == (3,5) print "OK" --- "Ralf W. Grosse-Kunstleve" <rwgk(a)yahoo.com> wrote: > --- Marco Correia <mvc(a)di.fct.unl.pt> wrote: > > the std::pair<T1,T2> to a python tuple. I've learned that I cannot have > > bindings for c++ templates, so lets say that T1=T2=int. > > Here you go (tested with g++ 3.2.3): > > #include <boost/python/module.hpp> ... __________________________________ Do you Yahoo!? Yahoo! Small Business - Try our new resources site! http://smallbusiness.yahoo.com/resources/

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Re: [C++-sig] newbie questions...
by Ralf W. Grosse-Kunstleve March 29, 2005

March 29, 2005

--- Marco Correia <mvc(a)di.fct.unl.pt> wrote: > the std::pair<T1,T2> to a python tuple. I've learned that I cannot have > bindings for c++ templates, so lets say that T1=T2=int. Here you go (tested with g++ 3.2.3): #include <boost/python/module.hpp> #include <boost/python/def.hpp> #include <boost/python/tuple.hpp> #include <boost/python/to_python_converter.hpp> namespace { template <typename T1, typename T2> struct std_pair_to_tuple { static PyObject* convert(std::pair<T1,T2> const& p) { return boost::python::incref( boost::python::make_tuple(p.first, p.second).ptr()); } }; template <typename T1, typename T2> struct std_pair_to_python_converter { std_pair_to_python_converter() { boost::python::to_python_converter< std::pair<T1, T2>, std_pair_to_tuple<T1, T2> >(); } }; std::pair<int, int> foo() { std::pair<int, int> result; result.first = 3; result.second = 5; return result; } } // namespace anonymous BOOST_PYTHON_MODULE(std_pair_example) { using namespace boost::python; std_pair_to_python_converter<int, int>(); def("foo", foo); } __________________________________ Do you Yahoo!? Yahoo! Small Business - Try our new resources site! http://smallbusiness.yahoo.com/resources/

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Constructors (and destrucrtors) wrappers
by Eric Jardim March 29, 2005

March 29, 2005

Hi, again... There is a case where I have an object constructor that recieves the (int argc, char** argv) parameter from the main function: class QApplication { public: QApplication(int argc, char** argv) {...} ... }; int main(int argc, char** argv) { obj = new QApplication(argc, argv); ... } Is it possible to change the way it is constructed, just passing a list of args (the way of python does) >>> import sys >>> import Qt >>> app = Qt.QApplication(sys.argv) >>> ... I thinked some possibilities: * Creating a free function (or static method) with a factory role. But it could confuse the API... * Extending the class and reimplementing the constructor. I am afraid of this, because I do not know how extended objects will behave in python. Especially if some of them are constructed internally (in c++). The same question is applied to destructors. Any help and insights are welcome :) thanks, [Eric Jardim]

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Problem after building Boost.Python from source (get_override)
by Clay Culver March 28, 2005

March 28, 2005

I downloaded the boost source from the sourceforge page and followed these instructions: http://www.boost.org/libs/python/doc/building.html#VisualStudio I'm using Python2.3, Visual Studio 7.1. I opened up the solution (and converted to 7.1) the solution in libs\python\build\VisualStudio. I added the python2.3 include/lib directories and told it to link against python23.lib. Everything built flawlessly. However, when I try to compile my pyste generated wrapper I get an unresolved external symbol to "get_override". The really strange thing though, is that this isn't the only use of get_override. In several of the generated cpp files, get_override is called without any problems, but in some of them it results in these errors: http://www.idleengineer.net/misc/errors.txt Here is one of the files that generates errors: http://www.idleengineer.net/misc/Camera.cpp This is one of the files that does not generate errors, which I can't see anything different: http://www.idleengineer.net/misc/TextureManager.cpp Any ideas what I can do to fix this? Thanks, Clay

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