00001 // This file is a part of Catsfoot. 00002 // Copyright (C) 2011 Uni Research 00003 // 00004 // This program is free software: you can redistribute it and/or modify 00005 // it under the terms of the GNU Lesser Public License as published by 00006 // the Free Software Foundation, either version 3 of the License, or 00007 // (at your option) any later version. 00008 // 00009 // This program is distributed in the hope that it will be useful, 00010 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00012 // GNU Lesser Public License for more details. 00013 // 00014 // You should have received a copy of the GNU Lesser Public License 00015 // along with this program. If not, see <http://www.gnu.org/licenses/>. 00016 00017 #ifndef __TYPE_MEMBER_HH 00018 # define __TYPE_MEMBER_HH 00019 00020 namespace catsfoot { 00022 struct undefined_member_type {}; 00023 } 00024 00032 # define DEF_TYPE_MEMBER_PREDICATE(X...) \ 00033 namespace details { \ 00034 template <typename T> \ 00035 std::false_type has_member_##X##_helper \ 00036 (catsfoot::details::try_second, const T&) { \ 00037 static_assert(catsfoot::details::always_false<T>::value, \ 00038 "Cannot use this function"); \ 00039 return 0; \ 00040 } \ 00041 template <typename T, \ 00042 typename = typename T::X> \ 00043 std::true_type has_member_##X##_helper \ 00044 (catsfoot::details::try_first, const T&) { \ 00045 static_assert(catsfoot::details::always_false<T>::value, \ 00046 "Cannot use this function"); \ 00047 return 0; \ 00048 } \ 00049 template <typename T> \ 00050 struct has_member_##X##_real_map { \ 00051 typedef typename T::X member_type; \ 00052 }; \ 00053 template <typename> \ 00054 struct has_member_##X##_bad_map { \ 00055 typedef catsfoot::undefined_member_type member_type; \ 00056 }; \ 00057 } \ 00058 template <typename T> \ 00059 struct has_member_##X: \ 00060 public catsfoot::identity \ 00061 <decltype(details:: \ 00062 has_member_##X##_helper \ 00063 (catsfoot::details::try_first(), std::declval<T>()))> \ 00064 ::type { \ 00065 typedef typename catsfoot::identity \ 00066 <decltype(details:: \ 00067 has_member_##X##_helper \ 00068 (catsfoot::details::try_first(), std::declval<T>()))> \ 00069 ::type \ 00070 super; \ 00071 typedef typename \ 00072 std::conditional<super::value, \ 00073 details::has_member_##X##_real_map<T>, \ 00074 details::has_member_##X##_bad_map<T> > \ 00075 ::type::member_type member_type; \ 00076 }; \ 00077 template <> \ 00078 struct has_member_##X<void>: \ 00079 public std::false_type { \ 00080 typedef ::catsfoot::undefined_member_type member_type; \ 00081 }; 00082 00083 #endif