1 // Copyright (c) 2003 Daniel Wallin and Arvid Norberg
2 
3 // Permission is hereby granted, free of charge, to any person obtaining a
4 // copy of this software and associated documentation files (the "Software"),
5 // to deal in the Software without restriction, including without limitation
6 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
7 // and/or sell copies of the Software, and to permit persons to whom the
8 // Software is furnished to do so, subject to the following conditions:
9 
10 // The above copyright notice and this permission notice shall be included
11 // in all copies or substantial portions of the Software.
12 
13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
14 // ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
15 // TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
16 // PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
17 // SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
18 // ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
19 // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
21 // OR OTHER DEALINGS IN THE SOFTWARE.
22 
23 
24 #ifndef LUABIND_DISCARD_RESULT_POLICY_HPP_INCLUDED
25 #define LUABIND_DISCARD_RESULT_POLICY_HPP_INCLUDED
26 
27 #include <luabind/config.hpp>
28 #include <luabind/detail/policy.hpp>    // for index_map, etc
29 #include <luabind/detail/primitives.hpp>  // for null_type, etc
30 
31 #include <boost/mpl/if.hpp>             // for if_
32 #include <boost/type_traits/is_same.hpp>  // for is_same
33 
34 #include <luabind/lua_include.hpp>
35 
36 namespace luabind { namespace detail
37 {
38     struct discard_converter
39     {
40         template<class T>
applyluabind::detail::discard_converter41         void apply(lua_State*, T) {}
42     };
43 
44     struct discard_result_policy : conversion_policy<0>
45     {
precallluabind::detail::discard_result_policy46         static void precall(lua_State*, const index_map&) {}
postcallluabind::detail::discard_result_policy47         static void postcall(lua_State*, const index_map&) {}
48 
49         struct can_only_convert_from_cpp_to_lua {};
50 
51         template<class T, class Direction>
52         struct apply
53         {
54             typedef typename boost::mpl::if_<boost::is_same<Direction, cpp_to_lua>
55                 , discard_converter
56                 , can_only_convert_from_cpp_to_lua
57             >::type type;
58         };
59     };
60 
61 }}
62 
63 namespace luabind
64 {
65   detail::policy_cons<
66       detail::discard_result_policy, detail::null_type> const discard_result = {};
67 
68   namespace detail
69   {
ignore_unused_discard_result()70     inline void ignore_unused_discard_result()
71     {
72         (void)discard_result;
73     }
74   }
75 }
76 
77 #endif // LUABIND_DISCARD_RESULT_POLICY_HPP_INCLUDED
78