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- // Copyright David Abrahams and Nikolay Mladenov 2003.
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- #ifndef RETURN_ARG_DWA2003719_HPP
- # define RETURN_ARG_DWA2003719_HPP
- # include <boost/python/default_call_policies.hpp>
- # include <boost/python/detail/none.hpp>
- # include <boost/python/detail/value_arg.hpp>
- #ifndef BOOST_PYTHON_NO_PY_SIGNATURES
- # include <boost/python/converter/pytype_function.hpp>
- #endif
- # include <boost/python/detail/type_traits.hpp>
- # include <boost/mpl/int.hpp>
- # include <boost/mpl/at.hpp>
- # include <boost/static_assert.hpp>
- # include <boost/python/refcount.hpp>
- # include <cstddef>
- namespace boost { namespace python {
- namespace detail
- {
- template <std::size_t>
- struct return_arg_pos_argument_must_be_positive
- # if defined(__GNUC__) || defined(__EDG__)
- {}
- # endif
- ;
- struct return_none
- {
- template <class T> struct apply
- {
- struct type
- {
- static bool convertible()
- {
- return true;
- }
-
- PyObject *operator()( typename value_arg<T>::type ) const
- {
- return none();
- }
- #ifndef BOOST_PYTHON_NO_PY_SIGNATURES
- PyTypeObject const *get_pytype() const { return converter::expected_pytype_for_arg<T>::get_pytype() ; }
- #endif
- };
- };
- };
- }
-
- template <
- std::size_t arg_pos=1
- , class Base = default_call_policies
- >
- struct return_arg : Base
- {
- private:
- BOOST_STATIC_CONSTANT(bool, legal = arg_pos > 0);
- public:
- typedef typename mpl::if_c<
- legal
- , detail::return_none
- , detail::return_arg_pos_argument_must_be_positive<arg_pos>
- // we could default to the base result_converter in case or
- // arg_pos==0 since return arg 0 means return result, but I
- // think it is better to issue an error instead, cause it can
- // lead to confusions
- >::type result_converter;
- template <class ArgumentPackage>
- static PyObject* postcall(ArgumentPackage const& args, PyObject* result)
- {
- // In case of arg_pos == 0 we could simply return Base::postcall,
- // but this is redundant
- BOOST_STATIC_ASSERT(arg_pos > 0);
- result = Base::postcall(args,result);
- if (!result)
- return 0;
- Py_DECREF(result);
- return incref( detail::get(mpl::int_<arg_pos-1>(),args) );
- }
- template <class Sig>
- struct extract_return_type : mpl::at_c<Sig, arg_pos>
- {
- };
- };
- template <
- class Base = default_call_policies
- >
- struct return_self
- : return_arg<1,Base>
- {};
- }} // namespace boost::python
- #endif // RETURN_ARG_DWA2003719_HPP
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