some.hpp

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// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef __STOUT_SOME_HPP__
#define __STOUT_SOME_HPP__

#include <type_traits>
#include <utility>

// A useful type that can be used to represent an Option or Result.
//
// Examples:
//
//   Result<int> result = Some(42);
//   Option<std::string> = Some("hello world");
//
//   void foo(Option<std::string> o) {}
//
//   foo(Some("hello world"));

// NOTE: We use an intermediate type, _Some, so that one doesn't need
// to explicitly define the template type when doing 'Some(value)'.
template <typename T>
struct _Some
{
  _Some(T _t) : t(std::move(_t)) {}

  T t;
};


template <typename T>
_Some<typename std::decay<T>::type> Some(T&& t)
{
  return _Some<typename std::decay<T>::type>(std::forward<T>(t));
}

#endif // __STOUT_SOME_HPP__