mirror of
https://github.com/darlinghq/darling-WTF.git
synced 2024-11-27 05:40:25 +00:00
98 lines
3.4 KiB
C++
98 lines
3.4 KiB
C++
/*
|
|
* Copyright (C) 2016-2017 Apple Inc. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
|
|
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
|
|
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
|
|
* THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
// Implementation of Library Fundamentals v3's std::expected, as described here: http://wg21.link/p0323r4
|
|
|
|
#pragma once
|
|
|
|
/*
|
|
unexpected synopsis
|
|
|
|
namespace std {
|
|
namespace experimental {
|
|
inline namespace fundamentals_v3 {
|
|
// ?.?.3, Unexpected object type
|
|
template <class E>
|
|
class unexpected;
|
|
|
|
// ?.?.4, Unexpected relational operators
|
|
template <class E>
|
|
constexpr bool
|
|
operator==(const unexpected<E>&, const unexpected<E>&);
|
|
template <class E>
|
|
constexpr bool
|
|
operator!=(const unexpected<E>&, const unexpected<E>&);
|
|
|
|
template <class E>
|
|
class unexpected {
|
|
public:
|
|
unexpected() = delete;
|
|
template <class U = E>
|
|
constexpr explicit unexpected(E&&);
|
|
constexpr const E& value() const &;
|
|
constexpr E& value() &;
|
|
constexpr E&& value() &&;
|
|
constexpr E const&& value() const&&;
|
|
private:
|
|
E val; // exposition only
|
|
};
|
|
|
|
}}}
|
|
|
|
*/
|
|
|
|
#include <cstdlib>
|
|
#include <utility>
|
|
#include <wtf/StdLibExtras.h>
|
|
|
|
namespace std {
|
|
namespace experimental {
|
|
inline namespace fundamentals_v3 {
|
|
|
|
template<class E>
|
|
class unexpected {
|
|
public:
|
|
unexpected() = delete;
|
|
template <class U = E>
|
|
constexpr explicit unexpected(U&& u) : val(std::forward<U>(u)) { }
|
|
constexpr const E& value() const & { return val; }
|
|
constexpr E& value() & { return val; }
|
|
constexpr E&& value() && { return WTFMove(val); }
|
|
constexpr const E&& value() const && { return WTFMove(val); }
|
|
|
|
private:
|
|
E val;
|
|
};
|
|
|
|
template<class E> constexpr bool operator==(const unexpected<E>& lhs, const unexpected<E>& rhs) { return lhs.value() == rhs.value(); }
|
|
template<class E> constexpr bool operator!=(const unexpected<E>& lhs, const unexpected<E>& rhs) { return lhs.value() != rhs.value(); }
|
|
|
|
}}} // namespace std::experimental::fundamentals_v3
|
|
|
|
template<class E> using Unexpected = std::experimental::unexpected<E>;
|
|
|
|
// Not in the std::expected spec, but useful to work around lack of C++17 deduction guides.
|
|
template<class E> constexpr Unexpected<std::decay_t<E>> makeUnexpected(E&& v) { return Unexpected<typename std::decay<E>::type>(std::forward<E>(v)); }
|