Apache Mesos
some.hpp
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1 // Licensed under the Apache License, Version 2.0 (the "License");
2 // you may not use this file except in compliance with the License.
3 // You may obtain a copy of the License at
4 //
5 // http://www.apache.org/licenses/LICENSE-2.0
6 //
7 // Unless required by applicable law or agreed to in writing, software
8 // distributed under the License is distributed on an "AS IS" BASIS,
9 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
10 // See the License for the specific language governing permissions and
11 // limitations under the License.
12 
13 #ifndef __STOUT_SOME_HPP__
14 #define __STOUT_SOME_HPP__
15 
16 #include <type_traits>
17 #include <utility>
18 
19 // A useful type that can be used to represent an Option or Result.
20 //
21 // Examples:
22 //
23 // Result<int> result = Some(42);
24 // Option<std::string> = Some("hello world");
25 //
26 // void foo(Option<std::string> o) {}
27 //
28 // foo(Some("hello world"));
29 
30 // NOTE: We use an intermediate type, _Some, so that one doesn't need
31 // to explicitly define the template type when doing 'Some(value)'.
32 template <typename T>
33 struct _Some
34 {
35  _Some(T _t) : t(std::move(_t)) {}
36 
37  T t;
38 };
39 
40 
41 template <typename T>
43 {
44  return _Some<typename std::decay<T>::type>(std::forward<T>(t));
45 }
46 
47 #endif // __STOUT_SOME_HPP__
Definition: type_utils.hpp:510
T t
Definition: some.hpp:37
Definition: some.hpp:33
_Some< typename std::decay< T >::type > Some(T &&t)
Definition: some.hpp:42
_Some(T _t)
Definition: some.hpp:35