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- /* Says how to convert value, error and exception types
- (C) 2017-2019 Niall Douglas <http://www.nedproductions.biz/> (12 commits)
- File Created: Nov 2017
- Boost Software License - Version 1.0 - August 17th, 2003
- Permission is hereby granted, free of charge, to any person or organization
- obtaining a copy of the software and accompanying documentation covered by
- this license (the "Software") to use, reproduce, display, distribute,
- execute, and transmit the Software, and to prepare derivative works of the
- Software, and to permit third-parties to whom the Software is furnished to
- do so, all subject to the following:
- The copyright notices in the Software and this entire statement, including
- the above license grant, this restriction and the following disclaimer,
- must be included in all copies of the Software, in whole or in part, and
- all derivative works of the Software, unless such copies or derivative
- works are solely in the form of machine-executable object code generated by
- a source language processor.
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
- SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
- FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
- ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- DEALINGS IN THE SOFTWARE.
- */
- #ifndef BOOST_OUTCOME_CONVERT_HPP
- #define BOOST_OUTCOME_CONVERT_HPP
- #include "detail/basic_result_storage.hpp"
- BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN
- namespace convert
- {
- #if defined(__cpp_concepts)
- #if !defined(_MSC_VER) && !defined(__clang__) && __GNUC__ < 9
- #define BOOST_OUTCOME_GCC6_CONCEPT_BOOL bool
- #else
- #define BOOST_OUTCOME_GCC6_CONCEPT_BOOL
- #endif
- namespace detail
- {
- template <class T, class U> concept BOOST_OUTCOME_GCC6_CONCEPT_BOOL SameHelper = std::is_same<T, U>::value;
- template <class T, class U> concept BOOST_OUTCOME_GCC6_CONCEPT_BOOL same_as = detail::SameHelper<T, U> &&detail::SameHelper<U, T>;
- } // namespace detail
- /* The `ValueOrNone` concept.
- \requires That `U::value_type` exists and that `std::declval<U>().has_value()` returns a `bool` and `std::declval<U>().value()` exists.
- */
- template <class U> concept BOOST_OUTCOME_GCC6_CONCEPT_BOOL ValueOrNone = requires(U a)
- {
- {
- a.has_value()
- }
- ->detail::same_as<bool>;
- {a.value()};
- };
- /* The `ValueOrError` concept.
- \requires That `U::value_type` and `U::error_type` exist;
- that `std::declval<U>().has_value()` returns a `bool`, `std::declval<U>().value()` and `std::declval<U>().error()` exists.
- */
- template <class U> concept BOOST_OUTCOME_GCC6_CONCEPT_BOOL ValueOrError = requires(U a)
- {
- {
- a.has_value()
- }
- ->detail::same_as<bool>;
- {a.value()};
- {a.error()};
- };
- #else
- namespace detail
- {
- struct no_match
- {
- };
- inline no_match match_value_or_none(...);
- inline no_match match_value_or_error(...);
- BOOST_OUTCOME_TEMPLATE(class U)
- BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TEXPR(std::declval<U>().has_value()), BOOST_OUTCOME_TEXPR(std::declval<U>().value()))
- inline U match_value_or_none(U &&);
- BOOST_OUTCOME_TEMPLATE(class U)
- BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TEXPR(std::declval<U>().has_value()), BOOST_OUTCOME_TEXPR(std::declval<U>().value()), BOOST_OUTCOME_TEXPR(std::declval<U>().error()))
- inline U match_value_or_error(U &&);
- template <class U> static constexpr bool ValueOrNone = !std::is_same<no_match, decltype(match_value_or_none(std::declval<BOOST_OUTCOME_V2_NAMESPACE::detail::devoid<U>>()))>::value;
- template <class U> static constexpr bool ValueOrError = !std::is_same<no_match, decltype(match_value_or_error(std::declval<BOOST_OUTCOME_V2_NAMESPACE::detail::devoid<U>>()))>::value;
- } // namespace detail
- /* The `ValueOrNone` concept.
- \requires That `U::value_type` exists and that `std::declval<U>().has_value()` returns a `bool` and `std::declval<U>().value()` exists.
- */
- template <class U> static constexpr bool ValueOrNone = detail::ValueOrNone<U>;
- /* The `ValueOrError` concept.
- \requires That `U::value_type` and `U::error_type` exist;
- that `std::declval<U>().has_value()` returns a `bool`, `std::declval<U>().value()` and `std::declval<U>().error()` exists.
- */
- template <class U> static constexpr bool ValueOrError = detail::ValueOrError<U>;
- #endif
- namespace detail
- {
- template <class T, class X> struct make_type
- {
- template <class U> static constexpr T value(U &&v) { return T{in_place_type<typename T::value_type>, static_cast<U &&>(v).value()}; }
- template <class U> static constexpr T error(U &&v) { return T{in_place_type<typename T::error_type>, static_cast<U &&>(v).error()}; }
- static constexpr T error() { return T{in_place_type<typename T::error_type>}; }
- };
- template <class T> struct make_type<T, void>
- {
- template <class U> static constexpr T value(U && /*unused*/) { return T{in_place_type<typename T::value_type>}; }
- template <class U> static constexpr T error(U && /*unused*/) { return T{in_place_type<typename T::error_type>}; }
- static constexpr T error() { return T{in_place_type<typename T::error_type>}; }
- };
- } // namespace detail
- /*! AWAITING HUGO JSON CONVERSION TOOL
- type definition value_or_error. Potential doc page: NOT FOUND
- */
- template <class T, class U> struct value_or_error
- {
- static constexpr bool enable_result_inputs = false;
- static constexpr bool enable_outcome_inputs = false;
- BOOST_OUTCOME_TEMPLATE(class X)
- BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(std::is_same<U, std::decay_t<X>>::value //
- &&ValueOrError<U> //
- && (std::is_void<typename std::decay_t<X>::value_type>::value || BOOST_OUTCOME_V2_NAMESPACE::detail::is_explicitly_constructible<typename T::value_type, typename std::decay_t<X>::value_type>) //
- &&(std::is_void<typename std::decay_t<X>::error_type>::value || BOOST_OUTCOME_V2_NAMESPACE::detail::is_explicitly_constructible<typename T::error_type, typename std::decay_t<X>::error_type>) ))
- constexpr T operator()(X &&v) { return v.has_value() ? detail::make_type<T, typename T::value_type>::value(static_cast<X &&>(v)) : detail::make_type<T, typename U::error_type>::error(static_cast<X &&>(v)); }
- };
- } // namespace convert
- BOOST_OUTCOME_V2_NAMESPACE_END
- #endif
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