Mailman 3 December 2004 - Cplusplus-sig

Path problems! -
by Nicolas Kowenski Dec. 14, 2004

Dec. 14, 2004

Hello, i am trying to extend c++ class to python.. there are *2 ways to build my module*.. : 1- Run the python bin from my sources folder. *cd /home/dev/WireLessStudio/PythonWsUsrlib/src/ /home/dev/Python/Python-2.4/./python WS.py build* Thats work... at least ther are no compilation errors. but does not work..: >>> import WS usage: [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...] or: --help [cmd1 cmd2 ...] or: --help-commands or: cmd --help error: no commands supplied bash-2.05b$ 2- The problem here, is the WS.cpp include other headers located in /home/dev/WireLessStudio/PythonWsUsrlib/src/ when i try to run these: *cd /home/dev/Python/Python-2.4/ ./python /home/dev/WireLessStudio/PythonWsUsrlib/src/WS.py build* the gcc returned some errors. it cant found the included files in WS.cpp and if I specify the path in WS.cpp like these: #include </home/dev/WireLessStudio/PythonWsUsrlib/src/ WSApp.h> thats dont work, because WSApp.h calls other headers located in .../src/ If i move all (a lot) the files to /home/dev/Python/Python-2.4/ i supouse thats works. but its very derty :'( WS.py : from distutils.core import setup, Extension module3 = Extension('testclases1', sources = ['WS.cpp']) setup (name = 'PackageName', version = '1.0', description = 'probando claes en piton, gross', ext_modules = [module3]) WS.cpp: #include "WSApp.h" #include </home/dev/Python/Python-2.4/Include/Python.h> WSApp app; static PyObject *WStest_BC_AddBarcode(PyObject *self, PyObject *args) { int sts; int nBarcodeType; int bExpand; int nDecode; int nMin; int nMax; if (!PyArg_ParseTuple(args, "ibiii",&nBarcodeType,&bExpand,&nDecode,&nMin,&nMax)) return NULL; sts = app.m_RFBarcode.AddBarcode(nBarcodeType,bExpand,nDecode,nMin,nMax); return Py_BuildValue("b", sts); } static PyMethodDef WStestMeth[] = { {"BC_AddBarcode", WStest_BC_AddBarcode, METH_VARARGS,"BC_AddBarcode"}, {NULL, NULL, 0, NULL} /* Sentinel */ }; PyMODINIT_FUNC initWStest(void) { (void) Py_InitModule("WStest", WStestMeth); } int main(int argc, char *argv[]) { /* Pass argv[0] to the Python interpreter */ Py_SetProgramName(argv[0]); /* Initialize the Python interpreter. Required. */ Py_Initialize(); /* Add a static module */ initWStest(); } i try to invert the include order.. its the same.

2 1

problem with overloaded address operator
by Fred Houben Dec. 14, 2004

Dec. 14, 2004

Hello, I'm using boost.python 1.30.2 with Python 2.3 and msvc6. I want to wrap a struct that has an object as data member. The problem is that the address operator has been overloaded and returns a data member address instead of the object address. Personally I think its' bad practise to overload the address operator (especially in this manner) , but it didn't write the code and removing the operator isn't a option. I've simplified the problem into a Hello world example: #include <boost/python.hpp> using namespace boost::python; class Hello { public: char const* greet(){return "Hello, world";} }; class World { public: char const* greet(){return hello.greet();} Hello* operator&() { return &hello; } Hello hello; }; struct Data { World world; }; BOOST_PYTHON_MODULE(world) { class_<Hello>("Hello") .def("greet", &Hello::greet) ; class_<World>("World") .def("greet", &World::greet) ; class_<Data>("Data") .def_readonly("world", &Data::world) ; } this result in the following error: pointer_holder.hpp(177) : error c2440: 'initializing" : cannot convert from 'class Hello *' to 'class World *' I solved the problem by editing pointer_holder.hpp. Replacing Value* p = &*this->m_p; with boost::addressof(*this->m_p);. This way I avoid using the address operator. This works fine, but maybe there's something I'm missing here, any input is welcome. I'm forced to uses boost.python for now 1.30.2, but is this problem solved in other releases? Thanks, Fred Houben

2 8

RE: [C++-sig] Re: Wrapper for exception translation
by Gottfried.Ganssauge＠HAUFE.DE Dec. 13, 2004

Dec. 13, 2004

> > ... > >> > >> > Currently, in order to wrap user defined exceptions you need to > >> > > >> > - allocate a python exception using PyErr_NewException > >> > >> Well, no. I don't see any call to PyErr_NewException in > >> libs/python/test/exception_translator.cpp > > > > Right, you don't need to if you are content with RuntimeError > > exceptions. > > or any other pre-packaged exception type provided by Python. > > > My objective was another one: I wanted to create module exceptions > > that are derived from the python "Exception" class. > >> > >> > This function needs to be parametrized using a specific naming > >> > convention > >> > >> It's not clear to me what you're referring to. Are you > sure you mean > >> "naming convention"? > > Yes. > > From the documentation to PyErr_NewException: > > > > ... The __module__ attribute of the new class is set to > the first part > > (up to the last dot) of the name argument, and the > class name is set to > > the last part (after the last dot). > > ...yeah, that's a naming convention, but I don't see how that affects > the parameterization of any function. It is enforced by PyErr_NewException, so you must follow this convention. On the hand I don't think that any user of boost.python is aware of that convention, so I wanted to codify it within my facility. ... > > What I wanted to achieve was the following: > > Create an instance of a translated_exception_handler<> t > which will be > > registered with the library by calling > > register_exception_translator<>(). > > Sorry to be difficult, but I'm going to contradict you. You didn't > want any of that. What you wanted was to create a new Python > exception type in the module which would correspond to a particular > C++ exception type and would be raised at the boundary with Python > whenever a wrapped function threw the C++ exception. Right? Right. I actually described the way to do it within the current library design. > > > Normally t would be destructed by the end of exception_<>() thereby > > leaving a registration to a non-existing translator - very bad > > karma. > > I don't understand any of this. All you have to pass to > register_exception_translator is a function pointer, and functions > live forever. So where's the lifetime issue? A pointer to a function which has access to python exception instance e. As I didn't want to create separate entities I chose to supply a functor instead which has e as a member variable. > > > Because I didn't like to have an additional container for all > > translated_exception_handler<> instances, I chose to store t within > > e's class dictionary. At that moment it seemed to be the easiest > > way to create a wrapper class using class_<> instead of making a > > true python class by hand (and it even works!). You are right, it > > is way too complex, I will change it to the mechanism I used in > > opaque_pointer_converter. > > I don't know what that is, but before you consider doing something > which is again too complex, please consider: > > template <class E> > struct translate_exception > { > static char const* msg; This would need to be defined somewhere. > static object python_exception_type; ... and this would need to be defined somewhere as well. > > static void handler(E const&) > { > PyErr_SetString(python_exception_type.ptr(), msg.c_str()); > }; > > translate_exception(char const* python_exception_name, > char const* msg_) > { > // need fancier name manipulation here > python_exception_type > = object( > handle<>(PyErr_NewException(name))); > msg = msg_; > register_exception_translator<E>(handler); > } > }; > > > Simple. Yes. ... > > I'll make a redesign ... At times you don't see the forrest, just trees ... I think this time I have a simple facility which is also easy to use (no macros). It could be even simpler with a completely different design but frankly - I have no clue how to implement that: We would need a way to somehow derive (in the python sense) a class_<> from PyExc_Exception (the type of the python Exception class) or any other python class (PyErr_NewException() has a base parameter, which could be used for that). At the same time an exception_translator should be registered for that class_<> which uses PyErr_SetObject() to raise a copy of the exception caught. This would allow us to have true Python exceptions in a pythonic sense directly wrapped around the corresponding C++ exception. > > Thnx for your feedback. > > Cool! Looking forward to it. > > -- > Dave Abrahams > Boost Consulting > www.boost-consulting.com Cheers, Gottfried

3 7

problem with embbed boost.python in multi-interpreter and multi-thread HELP please
by Donnie Leen Dec. 12, 2004

Dec. 12, 2004

I wrote a program embbed boost.python, each thread running a sub-interpreter, i made a module implement by boost.python, and i wish this module imported in each sub-interpreter, i find that the module could initialize only once, otherwise the boost.python will throw a exception said that something already registered; second conversion method ignored. So I try another way, initialize and import the module in one interpreter such as the main interpreter, and I hope to import the module in any sub-interpreter, because I found the python document said: "Extension modules are shared between (sub-)interpreters as follows: the first time a particular extension is imported, it is initialized normally, and a (shallow) copy of its module's dictionary is squirreled away. When the same extension is imported by another (sub-)interpreter, a new module is initialized and filled with the contents of this copy; the extension's init function is not called. " but when i try this way i found that the program throw an exception:ImportError: No module named mym, (mym is the module name). This happens even i wrote the module in Python/C API without boost.python. Could somebody tell me why this happened or how to deal with it, thanks for any suggestion. Donnie Leen

1 0

Solaris 10 x86 - Compiling libboost_python
by Johan Carlstedt Dec. 11, 2004

Dec. 11, 2004

Hello, I am having problems compiling Boost 1.32 on Solaris 10 X86 with gcc 3.4.1 and Python 2.23. The compilation fails for libboost_python with the error message below. I have tried with and without "-fpermissive". I would be grateful if anyone was able to advice. With friendly regards, Johan Carlstedt bash-2.05b# bjam "-sTOOLS=gcc" "-sGXX=g++ -fpermissive" install ....found 11612 targets... ....updating 32 targets... gcc-C++-action bin/boost/libs/python/build/libboost_python.so/gcc/debug/shared-linkable- true/inheritance.o In file included from /export/home/johan/boost_1_32_0/libs/python/build/../src/object/inherit ance.cpp:11: /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:441: error: expected identifier before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:441: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:441: error: expected `>' before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `VP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `EP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `GP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `EL' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: type/value mismatch at argument 3 in template parameter list for `template<class OutEdgeListS, class VertexListS, class DirectedS, class VertexProperty, class EdgeProperty, class GraphProperty, class EdgeListS> class boost::adjacency_list' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: expected a type, got `3' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 4 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 5 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 6 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 7 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `Tag' has not been declared /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: error: expected `,' or `...' before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: warning: ISO C++ forbids declaration of `g' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: warning: ISO C++ forbids declaration of `Value' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp: In function `void boost::set_property(int&, int, int)': /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: `m_property' has not been declared /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: request for member of non-aggregate type before ',' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: warning: there are no arguments to `Tag' that depend on a template parameter, so a declaration of `Tag' must be available /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: `value' undeclared (first use this function) /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: (Each undeclared identifier is reported only once for each function it appears in.) /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp: At global scope: /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:449: error: expected identifier before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:449: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:449: error: expected `>' before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `VP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `EP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `GP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `EL' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: type/value mismatch at argument 3 in template parameter list for `template<class OutEdgeListS, class VertexListS, class DirectedS, class VertexProperty, class EdgeProperty, class GraphProperty, class EdgeListS> class boost::adjacency_list' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: expected a type, got `3' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 4 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 5 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 6 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 7 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `Tag' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 1 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 2 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: expected init-declarator before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: expected `;' before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:457: error: expected identifier before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:457: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:457: error: expected `>' before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `VP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `EP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `GP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `EL' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: type/value mismatch at argument 3 in template parameter list for `template<class OutEdgeListS, class VertexListS, class DirectedS, class VertexProperty, class EdgeProperty, class GraphProperty, class EdgeListS> class boost::adjacency_list' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: expected a type, got `3' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 4 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 5 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 6 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 7 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `Tag' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 1 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 2 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: expected init-declarator before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: expected `;' before '&' token

2 1

Solaris 10x86 - Problem compiling libboost_python
by Johan Carlstedt Dec. 10, 2004

Dec. 10, 2004

Hello, I am having problems compiling Boost 1.32 on Solaris 10 X86 with gcc 3.4.1 and Python 2.23. The compilation fails for libboost_python with the error message below. I have tried with and without "-fpermissive". I would be grateful if anyone was able to advice. With friendly regards, Johan Carlstedt bash-2.05b# bjam "-sTOOLS=gcc" "-sGXX=g++ -fpermissive" install ...found 11612 targets... ...updating 32 targets... gcc-C++-action bin/boost/libs/python/build/libboost_python.so/gcc/debug/shared-linkable- true/inheritance.o In file included from /export/home/johan/boost_1_32_0/libs/python/build/../src/object/inherit ance.cpp:11: /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:441: error: expected identifier before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:441: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:441: error: expected `>' before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `VP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `EP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `GP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `EL' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: type/value mismatch at argument 3 in template parameter list for `template<class OutEdgeListS, class VertexListS, class DirectedS, class VertexProperty, class EdgeProperty, class GraphProperty, class EdgeListS> class boost::adjacency_list' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: expected a type, got `3' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 4 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 5 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 6 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: template argument 7 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:444: error: `Tag' has not been declared /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: error: expected `,' or `...' before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: warning: ISO C++ forbids declaration of `g' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:445: warning: ISO C++ forbids declaration of `Value' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp: In function `void boost::set_property(int&, int, int)': /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: `m_property' has not been declared /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: request for member of non-aggregate type before ',' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: warning: there are no arguments to `Tag' that depend on a template parameter, so a declaration of `Tag' must be available /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: `value' undeclared (first use this function) /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:446: error: (Each undeclared identifier is reported only once for each function it appears in.) /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp: At global scope: /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:449: error: expected identifier before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:449: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:449: error: expected `>' before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `VP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `EP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `GP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `EL' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: type/value mismatch at argument 3 in template parameter list for `template<class OutEdgeListS, class VertexListS, class DirectedS, class VertexProperty, class EdgeProperty, class GraphProperty, class EdgeListS> class boost::adjacency_list' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: expected a type, got `3' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 4 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 5 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 6 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 7 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: `Tag' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 1 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: template argument 2 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: expected init-declarator before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:452: error: expected `;' before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:457: error: expected identifier before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:457: warning: ISO C++ forbids declaration of `parameter' with no type /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:457: error: expected `>' before numeric constant /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `VP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `EP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `GP' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `EL' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: type/value mismatch at argument 3 in template parameter list for `template<class OutEdgeListS, class VertexListS, class DirectedS, class VertexProperty, class EdgeProperty, class GraphProperty, class EdgeListS> class boost::adjacency_list' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: expected a type, got `3' /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 4 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 5 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 6 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 7 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: `Tag' was not declared in this scope /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 1 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: template argument 2 is invalid /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: expected init-declarator before '&' token /export/home/johan/boost_1_32_0/boost/graph/adjacency_list.hpp:461: error: expected `;' before '&' token

1 0

Overloading + different argument types
by Andreas Beyer Dec. 10, 2004

Dec. 10, 2004

Hi. Hope I didn't miss something in the tutorial. I would like to mix different numbers of arguments with different argument types. Consider the following example: int f(int i, bool flag=true) { return i; } int f(string s, bool flag=true) { return atoi(s.c_str()); } The naive way to transfer this to python fails: BOOST_PYTHON_FUNCTION_OVERLOADS(f_overloads, f, 1, 2); BOOST_PYTHON_MODULE(overload_test) { def("f", &f, f_overloads()); } This fails at compile time with: gcc-C++-action bin\example\overload_test.pyd\mingw\runtime\overload_test.obj overload_test.cpp: In function `void init_module_overload_test()': overload_test.cpp:21: error: no matching function for call to `def(const char[2], <unknown type>, f_overloads)' Using thin wrappers works: int f1(int i, bool flag=true) { return f(i, flag); } int f2(string s, bool flag=true) { return f(s, flag); } BOOST_PYTHON_FUNCTION_OVERLOADS(f1_overloads, f1, 1, 2); BOOST_PYTHON_FUNCTION_OVERLOADS(f2_overloads, f2, 1, 2); BOOST_PYTHON_MODULE(overload_test) { def("f", &f1, f1_overloads()); def("f", &f2, f2_overloads()); } Is there a more elegant variant without thin wrappers? (E.g. I played with function pointers, but so far I had no success.) Is it feasible to improve BOOST_PYTHON_FUNCTION_OVERLOADS() to deal with different argument types in the future? Thanks, Andreas

2 1

How to extract a sublist from a list in C++ ?
by PJ Durai Dec. 8, 2004

Dec. 8, 2004

Greetings, I couldnt figure out the following bit. Say I am passing a list of lists. [ [a, b] , [c,d]] to a method in a C++ object. In the C++ class, void ParseList (list lst) { object o = lst[0]; // how do I conver 'o' to a list again? list l1 = extract<list> (o); <- naive attempt. but doesnt work. } Appreciate your time. thanks pj

3 3

How to expose virtual function with default arguments in boost.python ?
by Baptiste Lepilleur Dec. 8, 2004

Dec. 8, 2004

I'm trying to fix a bug in Pyste regarding exposure of virtual function with default arguments, but I can't figure out what is the correct code to generate (e.g. this is a question regarding boost.python, not pyste). I'm basically trying to expose the virtual member function 'set' of the following code: ---- class VirtualNonCopyable { public: virtual void set( const std::string &name_, int size_ = 10, int width_ = 12 ) { name = name_; size = size_; width = width_; } std::string name; int size; int width; }; inline VirtualNonCopyable &getVirtualNonCopyable() { static VirtualNonCopyable instance; return instance; } ---- Pyste generate the following binding code (full source attached): ---- class_< VirtualNonCopyable, py::VirtualNonCopyable_Wrapper >("VirtualNonCopyable", init< >()) .def("set", &VirtualNonCopyable::set, &py::VirtualNonCopyable_Wrapper::default_set_3) .def("set", &py::VirtualNonCopyable_Wrapper::default_set_1) .def("set", &py::VirtualNonCopyable_Wrapper::default_set_2) .def(init< const VirtualNonCopyable& >()) .def_readwrite("name", &VirtualNonCopyable::name) .def_readwrite("size", &VirtualNonCopyable::size) .def_readwrite("width", &VirtualNonCopyable::width) ; ---- Pyste is still using old-style polymorphism. default_set_1, default_set_2 and default_set_3 are methods forwarding to the base class implementation. The binding for default_set_1 should be the one triggered by the python code below. The bug is demonstrated by the following python code: object = getVirtualNonCopyable() # Get a instance of VirtualNonCopyable from C++ object.set( 'abc' ) # use overloading resolution to apply the default values Which produces the following error: object.set( 'abc' ) Boost.Python.ArgumentError: Python argument types in VirtualNonCopyable.set(VirtualNonCopyable, str) did not match C++ signature: set(struct py::VirtualNonCopyable_Wrapper {lvalue}, class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >, int) set(struct py::VirtualNonCopyable_Wrapper {lvalue}, class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >) set(struct py::VirtualNonCopyable_Wrapper {lvalue}, class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >, int, int) set(class VirtualNonCopyable {lvalue}, class std::basic_string<char,struct std::char_traits<char>,class std::allocat or<char> >, int, int) The issue only occurs when the object is returned from C++ and all the parameters are not specified. The following python code works correctly: object = getVirtualNonCopyable() object.set( 'abc', 1, 2 ) # works with all parameters specified object = VirtualNonCopyable() object.set( 'abc' ) # works on instance created in python I couldn't find any example of combining default argument handling with default virtual method implementation. Does anyone know how to do so ? Baptiste.

2 18

exposing C structures in pyste (modifying copyable attribute?)
by Alexis H. Rivera-Rios Dec. 7, 2004

Dec. 7, 2004

Hi, I have some C data structures that I want to expose in python. For example, struct Point { int a; int b; }; I do the following in pyste to expose the structure: Class("Point","my_header.h") But by default, pyste generates this code: class_< Point, boost::noncopyable>("Point", no_init) .def_readwrite("a", &Point::x) .def_readwrite("b", &Point::y) My questions are: -Is there a way to tell pyste that I want this structure to be copyable? (Without having to modify the generated c++ code) - Out of curiosity, is there a way to modify the read/write attributes from Pyste - Is this an acceptable thing to do? Or should I create a c++ wrapper class to my structures and expose that? Thanks Alexis ===== Programming Tutorial: In Python: To do this, do this In Perl: To do this, do this or this or this or this... In C: To do this, do this, but be careful In C++: To do this, do this, but don't do this, be careful of this, watch out for this, and whatever you do, don't do this __________________________________ Do you Yahoo!? Yahoo! Mail - Easier than ever with enhanced search. Learn more. http://info.mail.yahoo.com/mail_250

2 1