include/luabind/discard_result_policy.hpp

   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>
  29
  30 namespace luabind { namespace detail
  31 {
  32         struct discard_converter
  33         {
  34                 template<class T>
  35                 void apply(lua_State*, T) {}
  36         };
  37
  38         struct discard_result_policy : conversion_policy<0>
  39         {
  40                 static void precall(lua_State*, const index_map&) {}
  41                 static void postcall(lua_State*, const index_map&) {}
  42
  43                 struct can_only_convert_from_cpp_to_lua {};
  44
  45                 template<class T, class Direction>
  46                 struct apply
  47                 {
  48                         typedef typename boost::mpl::if_<boost::is_same<Direction, cpp_to_lua>
  49                                 , discard_converter
  50                                 , can_only_convert_from_cpp_to_lua
  51                         >::type type;
  52                 };
  53         };
  54
  55 }}
  56
  57 namespace luabind
  58 {
  59   detail::policy_cons<
  60       detail::discard_result_policy, detail::null_type> const discard_result = {};
  61
  62   namespace detail
  63   {
  64     inline void ignore_unused_discard_result()
  65     {
  66         (void)discard_result;
  67     }
  68   }
  69 }
  70
  71 #endif // LUABIND_DISCARD_RESULT_POLICY_HPP_INCLUDED
  72