1 /*************************************************************************
3 * Copyright 2017 Realm Inc.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
17 **************************************************************************/
19 #ifndef REALM_UTIL_OVERLOAD_HPP
20 #define REALM_UTIL_OVERLOAD_HPP
28 template<typename Fn, typename... Fns>
36 // Declare an overload set using lambdas or other function objects.
37 // A minimal version of C++ Library Evolution Working Group proposal P0051R2.
39 template<typename... Fns>
40 _impl::Overloaded<Fns...> overload(Fns&&... f)
42 return _impl::Overloaded<Fns...>(std::forward<Fns>(f)...);
50 template<typename Fn, typename... Fns>
51 struct Overloaded : Fn, Overloaded<Fns...> {
52 template<typename U, typename... Rest>
53 Overloaded(U&& fn, Rest&&... rest) : Fn(std::forward<U>(fn)), Overloaded<Fns...>(std::forward<Rest>(rest)...) { }
56 using Overloaded<Fns...>::operator();
60 struct Overloaded<Fn> : Fn {
62 Overloaded(U&& fn) : Fn(std::forward<U>(fn)) { }
70 #endif // REALM_UTIL_OVERLOAD_HPP