Mailman 3 July 2002 - Cplusplus-sig

RE: Cygwin Boost.Python Build
by Raoul Gough Aug. 3, 2002

Aug. 3, 2002

If it's any help, here's my set-up script for building Boost with the Cygwin Python: export PYTHON='f:\cygwin\bin\python.exe' export PYTHON_ROOT='f:\cygwin\lib\python2.1' export PYTHON_VERSION='2.1' export PYTHON_INCLUDES='f:\cygwin\usr\include\python2.1' export PYTHON_LIB_PATH='f:\cygwin\lib\python2.1\config' export PYTHON_STDLIB_PATH='f:\cygwin\lib\python2.1' export GCC_PYTHON_ROOT='f:\cygwin\usr' I remember it taking some time to arrive at this - maybe it will help Scott get his set-up working (with appropriate replacements). Regards, Raoul Gough. _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

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bpl_utils explained
by Ralf W. Grosse-Kunstleve July 29, 2002

July 29, 2002

I beat some more on the convertible() function of the register_container_from_python_sequence class in bpl_utils.h (everything else pretty much unchanged). The goal was to make this "more robust" rather than "more magical." This is how it works now: - Only Python lists, tuples, iterators and xrange objects are convertible. The limitation to these types is essential for avoiding surprises without much loss of generality: the Python list() or iter() command can be used to easily convert custom sequence types before passing them to a wrapped C++ function. - Conversion policies are defined by a "registration_adaptor" struct (see bpl_utils.h). - There are two fundamentally different conversion policies. Which one is used is determined by a static member function in the registration adaptors, e.g.: static bool check_convertibility_per_element() { return true; } true: The native Python object must be a list, tuple or xrange object. Any other object is not convertible. PyObject_Length() is used to determine the size of the sequence and passed to the check_size() function of the registration adaptor. If this returns true, lists and tuples are traversed. extract<> is called for each element. The input object is deemed convertible only if the size check returns true and if all elements are convertible. As an optimization, if the input sequence is a xrange object, only the first element is tested for convertibility. If overload resolution finally calls the construct() function, the input object is traversed a second time. false: convertible() returns true if the input object is a list, tuple, iterator or xrange object. No other checks are performed. The input sequence or iterator is not traversed. If overload resolution finally calls the construct() function the input object is traversed. An exception is thrown if any of the elements is not convertible. David, I feel that this is now at a point where it could be moved to the library. When doing this, we should rename virtually everything. E.g. registration_adaptor -> registration_policy, register_container_from_python_sequence -> register_container_from_native or maybe extract_container_from_native. Feel free to make unilateral decisions on the naming. Ralf To get the files: cvs -z3 -d:pserver:anonymous@cvs.cctbx.sourceforge.net:/cvsroot/cctbx co -r boost_python_v2_transition cctbx cctbx/include/cctbx/bpl_utils.h cctbx/misc __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com

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my final question , really i swear :)
by Srivatsan Raghavan July 27, 2002

July 27, 2002

i'd like to thank you all for your help, and the work you've done with boost::python it's a great library, and i've *LOVED* using it .. i've only got one *LAST* question :) from my limited understanding bpl is used for extending c++ types in python not for embedding python into a C++ application, am i wrong? and if so i can use bpl to embed python, how can i call a function in a python script using one of my bpl wrapped types ? these will actually be 2 seperate dll's (if possible) .. i have one dll called Logging.dll (the python interface to my C++ api) that i've copy'd to %PYTHON_ROOT%\libs\site-packages\ now i can write scripts such as the following: #in script.py import Logging def run( e ): print "this is a function run" # e is an object of type LogEvent now, in another program , i've got a function call such as this // in c++ bool OutputEvent ( LogEvent &le ) {} now here in the OutputEvent() function , i want to call the function run() in script.py and pass it a pointer or reference to le (and can i pass a ref to the original object that can be modified in the python script) or do i have to pass a copy? that's my question right now? --vat

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(no subject)
by Ralf W. Grosse-Kunstleve July 26, 2002

July 26, 2002

David, are you aware of this problem (8am build from today)? http://cci.lbl.gov/boost/results/1027695600/dailylog_unix_gcc_test Is it fixed? If not, you still have 29 minutes before the next auto-build starts. Ralf __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com

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Implicit constructors?
by Ralf W. Grosse-Kunstleve July 26, 2002

July 26, 2002

The register_container_from_python_sequence in the bpl_utils enables implicit conversion from Python sequences to container types such as std::vector<> when function signatures are matched. Now say I've actually exposed std::vector<double> with class_<> as std_vector in Python. Now I'd like this to work: from arrays import std_vector_double v=std_vector_double((1,2,3)) Given that the corresponding register_container_from_python_sequence is in the registry, could this be made to work (or will this work) without explicitly def()'ing a constructor that takes a tuple? Thanks, Ralf __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com

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A first glance at what could be the boost::python exception system
by Berthold Höllmann July 26, 2002

July 26, 2002

Hello all, David asked if I coud implement the C++ wrapper system for the Python exception system. Now, it is friday afternoon again and I won't have time to work on this over the weekend. The only test I did was sending this through the compiler (g++ 3.1). How do I enable "str(exception)" doing someting meaningfull? Another facility that is missing is a routine checking for a set Python exception and returning/raising the apropriate C++ counterpart. Is there any idea how this could be accomplished without a huge set of if/else if's and in a way easy extensible for user defined exceptions? I tried to map the class hierarchy found with >python Python 2.2.1 (#3, Jun 4 2002, 09:47:49) [GCC 3.1] on sunos5 Type "help", "copyright", "credits" or "license" for more information. >>> import exceptions >>> help(exceptions) I left out the warnings, because I don't think they should be mapped to C++ Exceptions, but they could be added. I hope it's OK to attach "exceptions.hpp" and "exceptions.cpp". Greetings Berthold This email contains confidential information for the exclusive attention of the intended addressee. Any access of third parties to this email is unauthorized. Any use of this email by not intended recipients like copying, distribution, disclosure etc. is prohibited and may be unlawful. When addressed to our clients the content of this email is subject to the General Terms and Conditions of GL's Group of Companies applicable at the date of this email. GL's Group of Companies does not warrant and/or guarantee that this message at the moment of receipt is authentic, correct and its communication free of errors, interruption etc.

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bpl_utils update
by Ralf W. Grosse-Kunstleve July 25, 2002

July 25, 2002

I have just updated the bpl_utils: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/cctbx/cctbx/include/cctbx/bp… http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/cctbx/cctbx/misc/?only_with_… This should work with the latest boost code from cvs. However, I've only tested with Compaq cxx 6.5. Ralf P.S.: The bpl_utils include code for the automatic conversion of Python lists or tuples (and other "measurable" sequences) to STL containers. __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com

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Silly naming question
by David Abrahams July 25, 2002

July 25, 2002

As I revise the class_<> interface to use object instead of handle<>, I came across .setattr("name", obj) and I'm just wondering if the name "bind" wouldn't be more appropriate here than a tweaky abbreviation like setattr: .bind("name", value) I'm mildly +1 on this change before we release the library. Other votes? --------------------------------- David Abrahams * Boost Consulting dave(a)boost-consulting.com * http://www.boost-consulting.com

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boost/python/detail/module_init.hpp gone?
by Ralf W. Grosse-Kunstleve July 25, 2002

July 25, 2002

As of last night we are having a problem with the Boost.Python V1 autobuild: cxx: Error: /net/ringneck/scratch1/sauter/daily_build/1027587601/boost/boost/python/module_builder.hpp, line 16: #5 could not open source file "boost/python/detail/module_init.hpp" # include <boost/python/detail/module_init.hpp> -----------------------------------------------^ Is V1 being cleaned out already? Thanks, Ralf __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com

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Re: Hnadling Python exceptions in C++
by David Abrahams July 25, 2002

July 25, 2002

Non-type template parameters must be compile-time constants, and those pointers are not. Try using: template <PyObject** E> with &PyExc_Exception, et al. We could use a reference non-type parameter to make things prettier, but I think VC6 will choke on that. -Dave ----- Original Message ----- From: "Berthold Höllmann" <hoel(a)germanlloyd.org> If you are willing and able (from the time avaible) to help me I could try. I tried something like the following #include <Python.h> #define BOOST_PYTHON_V2 1 #include <boost/python/object_core.hpp> namespace boost { namespace python { template <PyObject* E> class python_exception { public: python_exception() { }; protected: static object PyExc; }; template <PyTypeObject* E> object python_exception<E>::PyExc(E); class exception : public python_exception<PyExc_Exception> { }; class standard_error : exception, public python_exception<PyExc_StandardError> { }; class keyboard_interrupt : public standard_error, public python_exception<PyExc_KeyboardInterrupt> { }; } } I thought of this as a nice way to get the python exception information into the C++ exception classes. But trying to compile this (gcc 3.1) I get g++ -g -Wall -isystem /usr/local/gltools/python/Python-2.2.1/include/python2.2 -isystem /usr/local/gltools/python/Python-2.2.1/sol2/include/python2.2 -I/usr/local/fitools/sol2/boost -I. -c exceptions.cxx -o sol2/exceptions.o In file included from exceptions.cxx:32: aa.h:17: `PyExc_Exception' is not a valid template argument aa.h:17: it must be the address of an object with external linkage aa.h:20: `PyExc_StandardError' is not a valid template argument aa.h:20: it must be the address of an object with external linkage aa.h:23: `PyExc_KeyboardInterrupt' is not a valid template argument aa.h:23: it must be the address of an object with external linkage aa.h:17: `PyExc_Exception' is not a valid template argument aa.h:17: it must be the address of an object with external linkage but isn't "extern PyObject *PyExc_Exception" the address of an object with extenal linkage. Or is my idea totay dumb? Shall I give each derived class its own static pointer to the Python exception? Still learning C++ Berthold -- Dipl.-Ing. Berthold HÃ¶llmann __ Address: hoel(a)germanlloyd.org G / \ L Germanischer Lloyd phone: +49-40-36149-7374 -+----+- Vorsetzen 32/35 P.O.Box 111606 fax : +49-40-36149-7320 \__/ D-20459 Hamburg D-20416 Hamburg This email contains confidential information for the exclusive attention of the intended addressee. Any access of third parties to this email is unauthorized. Any use of this email by not intended recipients like copying, distribution, disclosure etc. is prohibited and may be unlawful. When addressed to our clients the content of this email is subject to the General Terms and Conditions of GL's Group of Companies applicable at the date of this email. GL's Group of Companies does not warrant and/or guarantee that this message at the moment of receipt is authentic, correct and its communication free of errors, interruption etc.

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