Hi
being an enthusiastic user of boost python, I often missed the possibility to
use function objects, see
http://www.boost.org/doc/libs/1_55_0/libs/python/todo.html#wrapping-function-objects.
Now I succeeded in a workaround to do so. The code below allows to use function
objects, lambdas and std::function<> with arbitrary signature. It should work
for c++11 compliant compilers (declspec must be implemented), I tested it with
Visual Studio 2012 and gcc4.8.1. For the latter the code must be included prior
to #include <boost/python.hpp>.
Up to now it didn't break my existing code and the definitions with lambdas
work as expected.
Regards
Martin
------------------------------------------------------------------------------------------
#ifndef BOOST_NO_CXX11_DECLTYPE
# include <boost/mpl/erase.hpp>
# include <boost/mpl/next.hpp>
# include <boost/utility.hpp>
# include <boost/function_types/is_callable_builtin.hpp>
# include <boost/mpl/size.hpp>
# include <boost/mpl/greater.hpp>
# include <boost/mpl/size_t.hpp>
namespace boost { namespace python { namespace detail {
template<typename T, typename Enable = void>
struct fun_sign
{
typedef T type;
};
template<typename T>
struct fun_sign<
T,
typename enable_if<
mpl::greater<
mpl::size<T>,
mpl::size_t<1>
>
>::type
>
{
typedef typename mpl::erase<
T,
typename mpl::next<
typename mpl::begin<
T
>::type
>::type
>::type type;
};
template<typename T>
typename disable_if<typename function_types::is_callable_builtin<T>, typename
fun_sign<typename
function_types::components<decltype(&T::operator())>::types>::type>::type
get_signature(T, void* = 0)
{
return typename fun_sign<typename
function_types::components<decltype(&T::operator())>::types>::type();
}
}}}
//#endif
#ifndef BOOST_NO_CXX11_DECLTYPE
# include <boost/mpl/erase.hpp>
# include <boost/mpl/next.hpp>
# include <boost/utility.hpp>
# include <boost/function_types/is_callable_builtin.hpp>
# include <boost/mpl/size.hpp>
# include <boost/mpl/greater.hpp>
# include <boost/mpl/size_t.hpp>
namespace boost { namespace python { namespace detail {
template<typename T, typename Enable = void>
struct fun_sign
{
typedef T type;
};
template<typename T>
struct fun_sign<
T,
typename enable_if<
mpl::greater<
mpl::size<T>,
mpl::size_t<1>
>
>::type
>
{
typedef typename mpl::erase<
T,
typename mpl::next<
typename mpl::begin<
T
>::type
>::type
>::type type;
};
template<typename T>
typename disable_if<typename function_types::is_callable_builtin<T>, typename
fun_sign<typename
function_types::components<decltype(&T::operator())>::types>::type>::type
get_signature(T, void* = 0)
{
return typename fun_sign<typename
function_types::components<decltype(&T::operator())>::types>::type();
}
}}}
//#endif
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