[vsipl++] patch: python bindings prototype

[Jules Bergmann]

Stefan,

How does this behave when python isn't present on the system?  It looks 
like configure will run python even if scripting isn't enabled.

Can you gate the python bindings with --enable-scripting?  If the user 
doesn't explicitly '--enable-scripting', then configure shouldn't try to 
run python.

Also, what is the story with shared libraries?  That is only for the 
scripting, right?

				-- Jules



Stefan Seefeld wrote:
> I just checked in the attached patch, which provides a prototype
> for python bindings for VSIPL++, using boost.python.
> This is really more a proof-of-concept than a complete binding,
> since most functions are still missing.
> However, I'm able to use it to create vectors and run simple
> functions, as well as ffts and convolutions on them.
> 
> Regards,
> 		Stefan
> 
> 
> 
> ------------------------------------------------------------------------
> 

> +}
> Index: configure.ac
> ===================================================================
> --- configure.ac	(revision 150667)
> +++ configure.ac	(working copy)
> @@ -333,6 +333,28 @@
>  
>  AC_SUBST(QMTEST, $with_qmtest)
>   
> +AC_ARG_ENABLE(scripting,
> +  [  --enable-scripting         Specify whether or not to build the python bindings.],,
> +  [enable_scripting="no"])
> +
> +AC_ARG_WITH(python, 
> +  [  --with-python=PATH      Specify the Python interpreter.],
> +  PYTHON="$with_python",
> +  PYTHON="python"
> +)
> +
> +AC_ARG_WITH(boost-prefix,
> +  [  --with-boost-prefix=PATH      Specify the boost installation prefix.],
> +  BOOST_PREFIX="$with_boost_prefix",
> +  BOOST_PREFIX="/usr"
> +)
> +
> +AC_ARG_WITH(boost-version,
> +  [  --with-boost-version=VERSION      Specify the boost version.],
> +  BOOST_VERSION="$with_boost_version",
> +  BOOST_VERSION="1.33"
> +)
> +
>  #
>  # Put libs directory int INT_LDFLAGS:
>  #
> @@ -1329,7 +1351,6 @@
>  # Copy libg2c into libdir, if requested.
>  #
>  if test "x$with_g2c_copy" != "x"; then
> -  mkdir -p lib
>    cp $with_g2c_copy lib
>    curdir=`pwd`
>    G2C_LDFLAGS="-L$curdir/lib"
> @@ -2009,6 +2030,76 @@
>  AC_SUBST(INT_CPPFLAGS)
>  
>  #
> +# Python frontend
> +#
> +echo "PYTHON $PYTHON"
> +if test -n "$PYTHON" -a "$PYTHON" != yes; then

Why is this code comment out?  Either explain why it is commented out, 
our delete it.

> +dnl  AC_CHECK_FILE($PYTHON,,AC_MSG_ERROR([Cannot find Python interpreter]))
> +dnl else


> +  AC_PATH_PROG(PYTHON, python2 python, python)
> +fi
> +PYTHON_INCLUDE=`$PYTHON -c "from distutils import sysconfig; print sysconfig.get_python_inc()"`
> +PYTHON_EXT=`$PYTHON -c "from distutils import sysconfig; print sysconfig.get_config_var('SO')"`
> +
> +case $build in
> +CYGWIN*)
> +  if test `$PYTHON -c "import os; print os.name"` = posix; then
> +    PYTHON_PREFIX=`$PYTHON -c "import sys; print sys.prefix"`
> +    PYTHON_VERSION=`$PYTHON -c "import sys; print '%d.%d'%(sys.version_info[[0]],sys.version_info[[1]])"`
> +    PYTHON_LIBS="-L $PYTHON_PREFIX/lib/python$PYTHON_VERSION/config -lpython$PYTHON_VERSION"

This sounds like a FIXME.

Let's just document what we do:

"Cygwin doesn't have a -lutil, but some version of distutils tell us to 
use it anyway.  This has been tested for cygwin versions UMPTY-UMP."

and add an issue for the check each library thing if it is important to 
fix later.

> +dnl Cygwin doesn't have an -lutil, but some versions of distutils tell us to use it anyway.
> +dnl It would be better to check for each library it tells us to use with AC_CHECK_LIB, but
> +dnl to do that, we need the name of a function in each one, so we'll just hack -lutil out 
> +dnl of the list.
> +    PYTHON_DEP_LIBS=`$PYTHON -c "from distutils import sysconfig; import re; print re.sub(r'\\s*-lutil', '', sysconfig.get_config_var('LIBS') or '')"`
> +  else dnl this is 'nt'
> +    if test "$CXX" = "g++"; then
> +      CFLAGS="-mno-cygwin $CFLAGS"
> +      CXXFLAGS="-mno-cygwin $CXXFLAGS"
> +      LDFLAGS="-mno-cygwin $LDFLAGS"
> +      PYTHON_PREFIX=`$PYTHON -c "import sys; print sys.prefix"`
> +      PYTHON_VERSION=`$PYTHON -c "import sys; print '%d%d'%(sys.version_info[[0]],sys.version_info[[1]])"`
> +      PYTHON_LIBS="-L `cygpath -a $PYTHON_PREFIX`/Libs -lpython$PYTHON_VERSION"
> +    fi
> +    PYTHON_INCLUDE=`cygpath -a $PYTHON_INCLUDE`
> +    PYTHON_DEP_LIBS=`$PYTHON -c "from distutils import sysconfig; print sysconfig.get_config_var('LIBS') or ''"`
> +  fi
> +  LDSHARED="$CXX -shared"
> +  PYTHON_LIBS="$PYTHON_LIBS $PYTHON_DEP_LIBS"
> +  ;;
> +*)
> +  LDSHARED="$CXX -shared"
> +  ;;
> +esac
> +
> +PYTHON_LIBS="$PYTHON_LIBS $PYTHON_DEP_LIBS"
> +
> +AC_SUBST(PYTHON)
> +AC_SUBST(PYTHON_CPP, "-I $PYTHON_INCLUDE")
> +AC_SUBST(PYTHON_LIBS)
> +AC_SUBST(PYTHON_EXT)
> +
> +AC_SUBST(LDSHARED)
> +


Whats the AC_LANG(C++) for?  We should have set it to C++ at the top of 
configure.

> +AC_LANG(C++)
> +if test "$enable_scripting" == "yes"; then
> +  AC_SUBST(enable_scripting, 1)
> +  if test -n "$with_boost_prefix"; then
> +    BOOST_CPPFLAGS="-I$with_boost_prefix/include"
> +    BOOST_LDFLAGS="-L$with_boost_prefix/lib"
> +  fi
> +  save_CPPFLAGS=$CPPFLAGS
> +  CPPFLAGS="$CPPFLAGS $BOOST_CPPFLAGS $PYTHON_CPP"
> +  AC_CHECK_HEADER([boost/python.hpp], [], 
> +    [AC_MSG_ERROR([boost.python could not be found])])
> +  CPPFLAGS="$save_CPPFLAGS"

Likewise, why is this dnl?

> +dnl save_LIBS=$LIBS
> +dnl LIBS="$LIBS $BOOST_LDFLAGS -lboost_wave"
> +dnl AC_CHECK_LIB(boost_wave, boost::wave::wave_init)

> +  AC_SUBST(BOOST_CPPFLAGS)
> +  AC_SUBST(BOOST_LDFLAGS)
> +fi
> +#
>  # Print summary.
>  #
>  AC_MSG_NOTICE(Summary)
> @@ -2032,10 +2123,14 @@
>    AC_MSG_RESULT([Complex storage format:                  interleaved])
>  fi
>  AC_MSG_RESULT([Timer:                                   ${enable_timer}])
> +AC_MSG_RESULT([With Python bindings:                    ${enable_scripting}])
>  
>  #
>  # Done.
>  #
> +mkdir -p bin
> +mkdir -p lib
> +mkdir -p lib/python/site-packages/vsip
>  mkdir -p src/vsip/impl/sal
>  mkdir -p src/vsip/impl/ipp
>  mkdir -p src/vsip/impl/fftw3


-- 
Jules Bergmann
CodeSourcery
jules at codesourcery.com
(650) 331-3385 x705