Mailman 3 October 2005 - Cplusplus-sig

c++ bool to python bool
by Nicolas P. Rougier Nov. 1, 2005

Nov. 1, 2005

Hello, This is certainly a newbie question but how do I get boost python to wrap a c++ bool type to a python bool type ? Here is what I tried: #include <boost/python.hpp> class Boolean { public: Boolean (bool v) : value(v) {} bool value; }; BOOST_PYTHON_MODULE(boolean) { using namespace boost::python; class_<Boolean>("Boolean", init <bool>() ) .def_readwrite ("value", &Boolean::value); } But the value property is considered as being an 'int' in python (and it's important for me to get the right type). I saw that boost python changelog indicates support for python's bool type but I found no further documentation. Did I miss something ? Nicolas Rougier.

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void* questions\thoughts
by Roman Yakovenko Nov. 1, 2005

Nov. 1, 2005

Hi. There is nice explanation in boost.python FAQs how to export function that takes\returns void*. I have 2 questions: 1. Why void_ should be defined in each translation unit? If I understand right "translation unit" is cpp file? If there is no special reason to define void_ in every translation unit, then next question: 2. Why boost.python does not define void_ class and does not registrate it? BOOST_PYTHON_OPAQUE_SPECIALIZED_TYPE_ID( void_ ) Thanks Roman Yakovenko

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Few questions about Pyste and pyplusplus
by Roman Yakovenko Oct. 29, 2005

Oct. 29, 2005

Hi. I hope you saw my announcement about new version of pyplusplus. I would like to create some table that compares Pyste and pyplusplus. I think I need your agreement for this. I created pyplusplus after I studied Pyste and used it for few middle size projects. I think that I treat all weaknesses Pyste has. In this table pyplusplus will look much better, then Pyste. What do you think? Roman Yakovenko

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[Announce] pyplusplus 0.5.0
by Roman Yakovenko Oct. 29, 2005

Oct. 29, 2005

Hi. I would like announce of new version of pyplusplus (0.5). What is this? The pyplusplus is a framework of components for creating C++ code generator for boost.python library Code generation with the pyplusplus framework is a very flexible and highly configurable process. You can find an introduction to pyplusplus at: 1. http://tinyurl.com/dbbrj 2. http://sue.mydnsbox9.net/~admin191/pyplusplus/pyplusplus.html Status: First of all, this project is under active development. Second I think from now this project could be used in production. Third: list of implemented features: * classes * class wrappers * two modes of code generation: * using scope - better error messages location from compiler * no scope * automatic detection of held type * nested classes * implicit conversion * functions * virtual methods * protected method, even non virtual ones can be accessed from `Python`_. * overloading * two modes of code generation: * with function type - good for exporting template instantiated functions and overloaded ones. * without function type * static methods * code generated for wrapped methods takes into account types of arguments * operators, both free and member ones * call policies resolver * enumerations * variables * namespace aliasing and using * writing multiple files * user code could be inserted almost any where * write code into file if there were changes * user licence is written at the top of every file * ... 4'th - examples. Now it has real world example. I created Python binding for boost.date_time library almost all functionality has been exported. Next functionality was not exported: facet, parsing and iterators. See this page for more information: 1. http://tinyurl.com/8zk8r 2. http://sue.mydnsbox9.net/~admin191/pyplusplus/examples/py_date_time/py_date… 5'th - demo mode. In order to evaluate pyplusplus you don't have to learn new API. pyplusplus has nice and simple gui. For convenience this gui is packed as standalone executable for Windows and Linux. In order to use pyplusplus you have to have CVS version of boost.python. Ideas, comments, suggestions or help are welcomed. Roman Yakovenko

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extracting data from a tuple
by cramissor＠aim.com Oct. 29, 2005

Oct. 29, 2005

Hi all. Probably a newbie question here but how do you extract data from a tuple using boost::python? I've done some digging in the docs as well as the mailing list but have been unable to figure it out. For example, I have the following declared in my code: std::map<int, tuple> widgets; I would like to extract the third item of the tuple associated with a particular widget. I have had no luck so far so any pointers would be much appreciated. TIA Marc ________________________________________________________________________ Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection.

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Problem with extracting a C++ object from python
by Matt Oct. 29, 2005

Oct. 29, 2005

Hi all, Here's some sample code of what I'm trying to do: class Base { public: Base() {} virtual ~Base() {} }; class Derived : public Base { public: Derived() {} virtual ~Derived() {} virtual void DoSomething() {} }; Elsewhere: class MyUtility { static object ms_oDerived; static Derived * ms_pDerived; public: static Derived * GetDerived() {return ms_pDerived;} static void SetDerived(handle <>hDerived) { try { ms_oDerived = object(hDerived); ms_pDerived = extract<Base*>(ms_oDerived); ms_pDerived->DoSomething(); } catch(...) { PyErr_Print(); } } }; BOOST_PYTHON_MODULE(MyModule) { class_<Derived, boost::noncopyable>("PyDerived"); def("PySetDerived", &MyUtility::SetDerived); } In Python: import MyModule def Foo(): MyModule.PySetDerived(MyModule.PyDerived()) When I run my code (which mimics the above), I get an error on the extract<Base*>... line: "TypeError: No registered converter was able to extract a C++ pointer to type class Base from this Python object of type PyDerived" Any advice on this? Thanks!

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Regression in Boost.Python v1.33
by Niall Douglas Oct. 27, 2005

Oct. 27, 2005

The TnFOX Python bindings are failing to compile on MSVC7.1 in BPL v1.33 when they worked in v1.32: D:\Tornado\Tn\TClient\boost\boost\python\converter\registered.hpp(88) : error C2784: 'const boost::python::converter::registration &boost::python::converter::detail::registry_lookup(T &(__cdecl *)(void))' : could not deduce template argument for 'T1 &(__cdecl *)(void)' from 'volatile const boost::add_reference<T>::type (__cdecl *)(void)' I see some changes have been made in converter/registered.hpp, namely: template <class T> registration const& registered_base<T>::converters = registry::lookup(type_id<T>()); ... has become: template <class T> registration const& registered_base<T>::converters = detail::registry_lookup((T(*)())0); Is this known about, and why was it done when the old code seems perfectly fine? Cheers, Niall

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One more question about method with argc, argv like arguments
by Emmanuel Taurel Oct. 25, 2005

Oct. 25, 2005

Hello everybody, Certainly this question has already been posted on this list but I don't really find example of how it could be solved. I want to wrap a class which has constructor taking arguments like the famous "int argc, char *argv[]" and build instance of this class in python using my_class(len(sys.argv),argv) It is a quite common problem. As the second parameter is a pointer to pointer I guess that there is a special trick to be used here. Can anyone send me brief example of how this could be wrapped ? Thank's in advance Emmanuel Taurel (etaurel(a)cells.es)

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wrapping typedef equivalent types
by Neal Becker Oct. 23, 2005

Oct. 23, 2005

What happens if, using boost::python, I try to wrap 2 type equivalent classes? For example (this is a trivial example): class_<int>... class_<int32_t>... where int == int32_t My real objective is to wrap classes template<int_t> class X {}; where int_t is int (natural int size) int32_t (force 32-bit) int64_t (force 64-bit) Can wrapped X<int>, X<int32_t>, X<int64_t> co-exist in the same python module?

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wrapper & HeldType
by Roman Yakovenko Oct. 22, 2005

Oct. 22, 2005

Hi. I think I found bug in treatment of held type. Consider next code: struct data{ virtual

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