[C++-sig] [GSoC] Boost.Python py3k support project final report

[Renato Araujo]

Congratulations, I will wait for get this merged in mainline for start
some work in PySide.


Renato Araujo Oliveira Filho




On Tue, Sep 1, 2009 at 1:19 AM, Haoyu Bai<divinekid at gmail.com> wrote:
> Hi,
>
> As GSoC is officially finished, this is the final report of the
> Boost.Python py3k(Python 3) support project. The goal of this project
> is to provide seamless support for Python 2 and 3 in Boost.Python. So
> extension modules using Boost.Python can be easily migrated to Python
> 3.
>
> The SVN branch is located at:
> https://svn.boost.org/svn/boost/sandbox-branches/bhy/py3k/
>
> Status
> =====
>
> Currently, all the BPL test cases passed when running under Python 3,
> and there are almost no change for most of the test cases. To support
> the Python 3 unicode string, some of the default converts between
> PyString and C/C++ strings are changed to convert between PyUnicode
> and C/C++ strings. Support for py3k in Boost.Build is done. Also, a
> piece of document is written in the "News" part of BPL document.
>
>
> API Changes
> ==========
>
> There are some minor API changes:
>
> 1) Introduced object.contains where x.contains(y)  is equivalent to
> Python code y in x. Now dict.has_key is just a wrapper of
> object.contains.
>
> 2) When building against Python 3, str.decode will be removed.
>
> 3) When building against Python 3, the original signature of
> list.sort, which is:
>
>    void sort(object_cref cmpfunc);
>
> will change to:
>
>    void sort(args_proxy const &args, kwds_proxy const &kwds);
>
> This is because in Python 3 list.sort requires all its arguments be
> keyword argument. So you should call it like this:
>
>    x.sort(*tuple(), **dict(make_tuple(make_tuple("reverse", true))));
> // This is equivalent to the Python call x.sort(reverse=true)
>
> 4) When building Boost.Python against Python older than 2.6, the
> following macros will be defined in Boost.Python header:
>
>  # define Py_TYPE(o)    (((PyObject*)(o))->ob_type)
>  # define Py_REFCNT(o)  (((PyObject*)(o))->ob_refcnt)
>  # define Py_SIZE(o)    (((PyVarObject*)(o))->ob_size)
>
> These are macros defined in Python >=2.6 header. We defined for Python
> < 2.6 so when you are using Boost.Python, these macros will be always
> available. Please refer to PEP 3123
> (http://www.python.org/dev/peps/pep-3123/) for details about these
> macro.
>
>
> Building and Testing
> ===============
>
> To build Boost.Python with Python 3, first write your user-config.jam
> contains these line:
>
> using python : 2.6 ;
> using python : 3.2 ;
>
> where the "2.6" and "3.2" should be replaced by the actual version of
> Python 2 and Python 3 on your system, respectively.
>
> Then call "bjam", it will build out a "libboost_python.so" and a
> "libboost_python3.so". The latter one is the Boost.Python library
> built against Python 3.
>
> To run test cases against Python 3, what you need to do is to switch
> into the libs/python/test, then run:
>
> bjam python=3.2
>
> It will automatically call the "2to3" tool to convert the Python
> source code in test case to Python 3 syntax. So we only need to
> maintain the test cases in Python 2.
>
>
> Further Works
> ===========
>
> I'm going to merge the py3k branch back to trunk. After the merge,
> more tests can be done to check is there any regression, also some
> people may want to start to use it to make your projects run on Python
> 3. Then I can get some bug report and feedback, thus more improvement
> is expected.
>
>
> Thanks!
> --
> Haoyu BAI
> School of Computing,
> National University of Singapore.
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