diff --git a/include/ext/util/expected-lite.hpp b/include/ext/util/expected-lite.hpp new file mode 100644 index 0000000..e613a4b --- /dev/null +++ b/include/ext/util/expected-lite.hpp @@ -0,0 +1,2178 @@ +// This version targets C++11 and later. +// +// Copyright (C) 2016-2018 Martin Moene. +// +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// +// expected lite is based on: +// A proposal to add a utility class to represent expected monad +// by Vicente J. Botet Escriba and Pierre Talbot. http:://wg21.link/p0323 + +#ifndef NONSTD_EXPECTED_LITE_HPP +#define NONSTD_EXPECTED_LITE_HPP + +#define expected_lite_MAJOR 0 +#define expected_lite_MINOR 3 +#define expected_lite_PATCH 0 + +#define expected_lite_VERSION expected_STRINGIFY(expected_lite_MAJOR) "." expected_STRINGIFY(expected_lite_MINOR) "." expected_STRINGIFY(expected_lite_PATCH) + +#define expected_STRINGIFY( x ) expected_STRINGIFY_( x ) +#define expected_STRINGIFY_( x ) #x + +// expected-lite configuration: + +#define nsel_EXPECTED_DEFAULT 0 +#define nsel_EXPECTED_NONSTD 1 +#define nsel_EXPECTED_STD 2 + +#if !defined( nsel_CONFIG_SELECT_EXPECTED ) +# define nsel_CONFIG_SELECT_EXPECTED ( nsel_HAVE_STD_EXPECTED ? nsel_EXPECTED_STD : nsel_EXPECTED_NONSTD ) +#endif + +// Proposal revisions: +// +// DXXXXR0: -- +// N4015 : -2 (2014-05-26) +// N4109 : -1 (2014-06-29) +// P0323R0: 0 (2016-05-28) +// P0323R1: 1 (2016-10-12) +// -------: +// P0323R2: 2 (2017-06-15) +// P0323R3: 3 (2017-10-15) +// P0323R4: 4 (2017-11-26) +// P0323R5: 5 (2018-02-08) +// P0323R6: 6 (2018-04-02) +// P0323R7: 7 (2018-06-22) * +// +// expected-lite uses 2 and higher + +#ifndef nsel_P0323R +# define nsel_P0323R 7 +#endif +// Control presence of exception handling (try and auto discover): + +#ifndef nsel_CONFIG_NO_EXCEPTIONS +# if defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND) +# define nsel_CONFIG_NO_EXCEPTIONS 0 +# else +# define nsel_CONFIG_NO_EXCEPTIONS 1 +# endif +#endif + + +// C++ language version detection (C++20 is speculative): +// Note: VC14.0/1900 (VS2015) lacks too much from C++14. + +#ifndef nsel_CPLUSPLUS +# if defined(_MSVC_LANG ) && !defined(__clang__) +# define nsel_CPLUSPLUS (_MSC_VER == 1900 ? 201103L : _MSVC_LANG ) +# else +# define nsel_CPLUSPLUS __cplusplus +# endif +#endif + +#define nsel_CPP98_OR_GREATER ( nsel_CPLUSPLUS >= 199711L ) +#define nsel_CPP11_OR_GREATER ( nsel_CPLUSPLUS >= 201103L ) +#define nsel_CPP14_OR_GREATER ( nsel_CPLUSPLUS >= 201402L ) +#define nsel_CPP17_OR_GREATER ( nsel_CPLUSPLUS >= 201703L ) +#define nsel_CPP20_OR_GREATER ( nsel_CPLUSPLUS >= 202000L ) + +// Use C++20 std::expected if available and requested: + +#if nsel_CPP20_OR_GREATER && defined(__has_include ) +# if __has_include( ) +# define nsel_HAVE_STD_EXPECTED 1 +static_assert(false); +# else +static_assert(false); +# define nsel_HAVE_STD_EXPECTED 0 +# endif +#else +# define nsel_HAVE_STD_EXPECTED 0 +#endif + +#define nsel_USES_STD_EXPECTED ( (nsel_CONFIG_SELECT_EXPECTED == nsel_EXPECTED_STD) || ((nsel_CONFIG_SELECT_EXPECTED == nsel_EXPECTED_DEFAULT) && nsel_HAVE_STD_EXPECTED) ) + +// +// in_place: code duplicated in any-lite, expected-lite, optional-lite, value-ptr-lite, variant-lite: +// + +#ifndef nonstd_lite_HAVE_IN_PLACE_TYPES +#define nonstd_lite_HAVE_IN_PLACE_TYPES 1 + +// C++17 std::in_place in : + +#include + +namespace nonstd { + +using std::in_place; +using std::in_place_type; +using std::in_place_index; +using std::in_place_t; +using std::in_place_type_t; +using std::in_place_index_t; + +#define nonstd_lite_in_place_t( T) std::in_place_t +#define nonstd_lite_in_place_type_t( T) std::in_place_type_t +#define nonstd_lite_in_place_index_t(K) std::in_place_index_t + +#define nonstd_lite_in_place( T) std::in_place_t{} +#define nonstd_lite_in_place_type( T) std::in_place_type_t{} +#define nonstd_lite_in_place_index(K) std::in_place_index_t{} + +} // namespace nonstd + +#endif // nonstd_lite_HAVE_IN_PLACE_TYPES + + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +// additional includes: + +#if nsel_CONFIG_NO_EXCEPTIONS +// already included: +#else +# include +#endif + +// C++ feature usage: + +# define nsel_constexpr constexpr +# define nsel_constexpr14 constexpr +# define nsel_inline17 inline + +// Method enabling + +#define nsel_REQUIRES_0(...) \ + template< bool B = (__VA_ARGS__), typename std::enable_if::type = 0 > + +#define nsel_REQUIRES_T(...) \ + , typename = typename std::enable_if< (__VA_ARGS__), nonstd::expected_lite::detail::enabler >::type + +#define nsel_REQUIRES_R(R, ...) \ + typename std::enable_if< (__VA_ARGS__), R>::type + +#define nsel_REQUIRES_A(...) \ + , typename std::enable_if< (__VA_ARGS__), void*>::type = nullptr + +// Compiler versions: +// +// MSVC++ 6.0 _MSC_VER == 1200 (Visual Studio 6.0) +// MSVC++ 7.0 _MSC_VER == 1300 (Visual Studio .NET 2002) +// MSVC++ 7.1 _MSC_VER == 1310 (Visual Studio .NET 2003) +// MSVC++ 8.0 _MSC_VER == 1400 (Visual Studio 2005) +// MSVC++ 9.0 _MSC_VER == 1500 (Visual Studio 2008) +// MSVC++ 10.0 _MSC_VER == 1600 (Visual Studio 2010) +// MSVC++ 11.0 _MSC_VER == 1700 (Visual Studio 2012) +// MSVC++ 12.0 _MSC_VER == 1800 (Visual Studio 2013) +// MSVC++ 14.0 _MSC_VER == 1900 (Visual Studio 2015) +// MSVC++ 14.1 _MSC_VER >= 1910 (Visual Studio 2017) + +#if defined(_MSC_VER) && !defined(__clang__) +# define nsel_COMPILER_MSVC_VER (_MSC_VER ) +# define nsel_COMPILER_MSVC_VERSION (_MSC_VER / 10 - 10 * ( 5 + (_MSC_VER < 1900)) ) +#else +# define nsel_COMPILER_MSVC_VER 0 +# define nsel_COMPILER_MSVC_VERSION 0 +#endif + +#define nsel_COMPILER_VERSION( major, minor, patch ) ( 10 * ( 10 * (major) + (minor) ) + (patch) ) + +#if defined(__clang__) +# define nsel_COMPILER_CLANG_VERSION nsel_COMPILER_VERSION(__clang_major__, __clang_minor__, __clang_patchlevel__) +#else +# define nsel_COMPILER_CLANG_VERSION 0 +#endif + +#if defined(__GNUC__) && !defined(__clang__) +# define nsel_COMPILER_GNUC_VERSION nsel_COMPILER_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__) +#else +# define nsel_COMPILER_GNUC_VERSION 0 +#endif + +// half-open range [lo..hi): +//#define nsel_BETWEEN( v, lo, hi ) ( (lo) <= (v) && (v) < (hi) ) + +// Presence of language and library features: + +#ifdef _HAS_CPP0X +# define nsel_HAS_CPP0X _HAS_CPP0X +#else +# define nsel_HAS_CPP0X 0 +#endif + +//#define nsel_CPP11_140 (nsel_CPP11_OR_GREATER || nsel_COMPILER_MSVC_VER >= 1900) + +// Clang, GNUC, MSVC warning suppression macros: + +#ifdef __clang__ +# pragma clang diagnostic push +#elif defined __GNUC__ +# pragma GCC diagnostic push +#endif // __clang__ + +#if nsel_COMPILER_MSVC_VERSION >= 140 +# pragma warning( push ) +# define nsel_DISABLE_MSVC_WARNINGS(codes) __pragma( warning(disable: codes) ) +#else +# define nsel_DISABLE_MSVC_WARNINGS(codes) +#endif + +#ifdef __clang__ +# define nsel_RESTORE_WARNINGS() _Pragma("clang diagnostic pop") +#elif defined __GNUC__ +# define nsel_RESTORE_WARNINGS() _Pragma("GCC diagnostic pop") +#elif nsel_COMPILER_MSVC_VERSION >= 140 +# define nsel_RESTORE_WARNINGS() __pragma( warning( pop ) ) +#else +# define nsel_RESTORE_WARNINGS() +#endif + +// Suppress the following MSVC (GSL) warnings: +// - C26409: Avoid calling new and delete explicitly, use std::make_unique instead (r.11) + +nsel_DISABLE_MSVC_WARNINGS( 26409 ) + +// +// expected: +// + +namespace nonstd { namespace expected_lite { + +// type traits C++17: + +namespace std17 { +using std::conjunction; +using std::is_swappable; +using std::is_nothrow_swappable; +} // namespace std17 + +// type traits C++20: + +namespace std20 { + + +template< typename T > +struct remove_cvref +{ + typedef typename std::remove_cv< typename std::remove_reference::type >::type type; +}; + + +} // namespace std20 + +// forward declaration: + +template< typename T, typename E > +class expected; + +namespace detail { + +/// for nsel_REQUIRES_T + +enum class enabler{}; + +/// discriminated union to hold value or 'error'. + +template< typename T, typename E > +class storage_t_impl +{ + template< typename, typename > friend class nonstd::expected_lite::expected; + +public: + using value_type = T; + using error_type = E; + + // no-op construction + storage_t_impl() {} + ~storage_t_impl() {} + + explicit storage_t_impl( bool has_value ) + : m_has_value( has_value ) + {} + + void construct_value( value_type const & e ) + { + new( &m_value ) value_type( e ); + } + + void construct_value( value_type && e ) + { + new( &m_value ) value_type( std::move( e ) ); + } + + template< class... Args > + void emplace_value( Args&&... args ) + { + new( &m_value ) value_type( std::forward(args)...); + } + + template< class U, class... Args > + void emplace_value( std::initializer_list il, Args&&... args ) + { + new( &m_value ) value_type( il, std::forward(args)... ); + } + + void destruct_value() + { + m_value.~value_type(); + } + + void construct_error( error_type const & e ) + { + new( &m_error ) error_type( e ); + } + + void construct_error( error_type && e ) + { + new( &m_error ) error_type( std::move( e ) ); + } + + template< class... Args > + void emplace_error( Args&&... args ) + { + new( &m_error ) error_type( std::forward(args)...); + } + + template< class U, class... Args > + void emplace_error( std::initializer_list il, Args&&... args ) + { + new( &m_error ) error_type( il, std::forward(args)... ); + } + + void destruct_error() + { + m_error.~error_type(); + } + + constexpr value_type const & value() const & + { + return m_value; + } + + value_type & value() & + { + return m_value; + } + + constexpr value_type const && value() const && + { + return std::move( m_value ); + } + + nsel_constexpr14 value_type && value() && + { + return std::move( m_value ); + } + + value_type const * value_ptr() const + { + return &m_value; + } + + value_type * value_ptr() + { + return &m_value; + } + + error_type const & error() const & + { + return m_error; + } + + error_type & error() & + { + return m_error; + } + + constexpr error_type const && error() const && + { + return std::move( m_error ); + } + + nsel_constexpr14 error_type && error() && + { + return std::move( m_error ); + } + + bool has_value() const + { + return m_has_value; + } + + void set_has_value( bool v ) + { + m_has_value = v; + } + +private: + union + { + value_type m_value; + error_type m_error; + }; + + bool m_has_value = false; +}; + +/// discriminated union to hold only 'error'. + +template< typename E > +struct storage_t_impl +{ + template< typename, typename > friend class nonstd::expected_lite::expected; + +public: + using value_type = void; + using error_type = E; + + // no-op construction + storage_t_impl() {} + ~storage_t_impl() {} + + explicit storage_t_impl( bool has_value ) + : m_has_value( has_value ) + {} + + void construct_error( error_type const & e ) + { + new( &m_error ) error_type( e ); + } + + void construct_error( error_type && e ) + { + new( &m_error ) error_type( std::move( e ) ); + } + + template< class... Args > + void emplace_error( Args&&... args ) + { + new( &m_error ) error_type( std::forward(args)...); + } + + template< class U, class... Args > + void emplace_error( std::initializer_list il, Args&&... args ) + { + new( &m_error ) error_type( il, std::forward(args)... ); + } + + void destruct_error() + { + m_error.~error_type(); + } + + error_type const & error() const & + { + return m_error; + } + + error_type & error() & + { + return m_error; + } + + constexpr error_type const && error() const && + { + return std::move( m_error ); + } + + nsel_constexpr14 error_type && error() && + { + return std::move( m_error ); + } + + bool has_value() const + { + return m_has_value; + } + + void set_has_value( bool v ) + { + m_has_value = v; + } + +private: + union + { + char m_dummy; + error_type m_error; + }; + + bool m_has_value = false; +}; + +template< typename T, typename E, bool isConstructable, bool isMoveable > +class storage_t +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) = delete; + storage_t( storage_t && other ) = delete; +}; + +template< typename T, typename E > +class storage_t : public storage_t_impl +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) + : storage_t_impl( other.has_value() ) + { + if ( this->has_value() ) this->construct_value( other.value() ); + else this->construct_error( other.error() ); + } + + storage_t(storage_t && other ) + : storage_t_impl( other.has_value() ) + { + if ( this->has_value() ) this->construct_value( std::move( other.value() ) ); + else this->construct_error( std::move( other.error() ) ); + } +}; + +template< typename E > +class storage_t : public storage_t_impl +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) + : storage_t_impl( other.has_value() ) + { + if ( this->has_value() ) ; + else this->construct_error( other.error() ); + } + + storage_t(storage_t && other ) + : storage_t_impl( other.has_value() ) + { + if ( this->has_value() ) ; + else this->construct_error( std::move( other.error() ) ); + } +}; + +template< typename T, typename E > +class storage_t : public storage_t_impl +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) + : storage_t_impl(other.has_value()) + { + if ( this->has_value() ) this->construct_value( other.value() ); + else this->construct_error( other.error() ); + } + + storage_t( storage_t && other ) = delete; +}; + +template< typename E > +class storage_t : public storage_t_impl +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) + : storage_t_impl(other.has_value()) + { + if ( this->has_value() ) ; + else this->construct_error( other.error() ); + } + + storage_t( storage_t && other ) = delete; +}; + +template< typename T, typename E > +class storage_t : public storage_t_impl +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) = delete; + + storage_t( storage_t && other ) + : storage_t_impl( other.has_value() ) + { + if ( this->has_value() ) this->construct_value( std::move( other.value() ) ); + else this->construct_error( std::move( other.error() ) ); + } +}; + +template< typename E > +class storage_t : public storage_t_impl +{ +public: + storage_t() = default; + ~storage_t() = default; + + explicit storage_t( bool has_value ) + : storage_t_impl( has_value ) + {} + + storage_t( storage_t const & other ) = delete; + + storage_t( storage_t && other ) + : storage_t_impl( other.has_value() ) + { + if ( this->has_value() ) ; + else this->construct_error( std::move( other.error() ) ); + } +}; + +} // namespace detail + +/// x.x.5 Unexpected object type; unexpected_type; C++17 and later can also use aliased type unexpected. + +template< typename E > +class unexpected_type +{ +public: + using error_type = E; + + // x.x.5.2.1 Constructors + +// unexpected_type() = delete; + + constexpr unexpected_type( unexpected_type const & ) = default; + constexpr unexpected_type( unexpected_type && ) = default; + + template< typename... Args + nsel_REQUIRES_T( + std::is_constructible::value + ) + > + constexpr explicit unexpected_type( nonstd_lite_in_place_t(E), Args &&... args ) + : m_error( std::forward( args )...) + {} + + template< typename U, typename... Args + nsel_REQUIRES_T( + std::is_constructible, Args&&...>::value + ) + > + constexpr explicit unexpected_type( nonstd_lite_in_place_t(E), std::initializer_list il, Args &&... args ) + : m_error( il, std::forward( args )...) + {} + + template< typename E2 + nsel_REQUIRES_T( + std::is_constructible::value + && !std::is_same< typename std20::remove_cvref::type, nonstd_lite_in_place_t(E2) >::value + && !std::is_same< typename std20::remove_cvref::type, unexpected_type >::value + ) + > + constexpr explicit unexpected_type( E2 && error ) + : m_error( std::forward( error ) ) + {} + + template< typename E2 > + constexpr explicit unexpected_type( unexpected_type const & error + nsel_REQUIRES_A( + std::is_constructible< E, E2>::value + && !std::is_constructible & >::value + && !std::is_constructible >::value + && !std::is_constructible const & >::value + && !std::is_constructible const >::value + && !std::is_convertible< unexpected_type &, E>::value + && !std::is_convertible< unexpected_type , E>::value + && !std::is_convertible< unexpected_type const &, E>::value + && !std::is_convertible< unexpected_type const , E>::value + && !std::is_convertible< E2 const &, E>::value /*=> explicit */ ) + ) + : m_error( E{ error.value() } ) + {} + + template< typename E2 > + constexpr /*non-explicit*/ unexpected_type( unexpected_type const & error + nsel_REQUIRES_A( + std::is_constructible< E, E2>::value + && !std::is_constructible & >::value + && !std::is_constructible >::value + && !std::is_constructible const & >::value + && !std::is_constructible const >::value + && !std::is_convertible< unexpected_type &, E>::value + && !std::is_convertible< unexpected_type , E>::value + && !std::is_convertible< unexpected_type const &, E>::value + && !std::is_convertible< unexpected_type const , E>::value + && std::is_convertible< E2 const &, E>::value /*=> explicit */ ) + ) + : m_error( error.value() ) + {} + + template< typename E2 > + constexpr explicit unexpected_type( unexpected_type && error + nsel_REQUIRES_A( + std::is_constructible< E, E2>::value + && !std::is_constructible & >::value + && !std::is_constructible >::value + && !std::is_constructible const & >::value + && !std::is_constructible const >::value + && !std::is_convertible< unexpected_type &, E>::value + && !std::is_convertible< unexpected_type , E>::value + && !std::is_convertible< unexpected_type const &, E>::value + && !std::is_convertible< unexpected_type const , E>::value + && !std::is_convertible< E2 const &, E>::value /*=> explicit */ ) + ) + : m_error( E{ std::move( error.value() ) } ) + {} + + template< typename E2 > + constexpr /*non-explicit*/ unexpected_type( unexpected_type && error + nsel_REQUIRES_A( + std::is_constructible< E, E2>::value + && !std::is_constructible & >::value + && !std::is_constructible >::value + && !std::is_constructible const & >::value + && !std::is_constructible const >::value + && !std::is_convertible< unexpected_type &, E>::value + && !std::is_convertible< unexpected_type , E>::value + && !std::is_convertible< unexpected_type const &, E>::value + && !std::is_convertible< unexpected_type const , E>::value + && std::is_convertible< E2 const &, E>::value /*=> non-explicit */ ) + ) + : m_error( std::move( error.value() ) ) + {} + + // x.x.5.2.2 Assignment + + nsel_constexpr14 unexpected_type& operator=( unexpected_type const & ) = default; + nsel_constexpr14 unexpected_type& operator=( unexpected_type && ) = default; + + template< typename E2 = E > + nsel_constexpr14 unexpected_type & operator=( unexpected_type const & other ) + { + unexpected_type{ other.value() }.swap( *this ); + return *this; + } + + template< typename E2 = E > + nsel_constexpr14 unexpected_type & operator=( unexpected_type && other ) + { + unexpected_type{ std::move( other.value() ) }.swap( *this ); + return *this; + } + + // x.x.5.2.3 Observers + + nsel_constexpr14 E & value() & noexcept + { + return m_error; + } + + constexpr E const & value() const & noexcept + { + return m_error; + } + +#if !nsel_COMPILER_GNUC_VERSION || nsel_COMPILER_GNUC_VERSION >= 490 + + nsel_constexpr14 E && value() && noexcept + { + return std::move( m_error ); + } + + constexpr E const && value() const && noexcept + { + return std::move( m_error ); + } + +#endif + + // x.x.5.2.4 Swap + + nsel_REQUIRES_R( void, + std17::is_swappable::value + ) + swap( unexpected_type & other ) noexcept ( + std17::is_nothrow_swappable::value + ) + { + using std::swap; + swap( m_error, other.m_error ); + } + + // TODO: ??? unexpected_type: in-class friend operator==, != + +private: + error_type m_error; +}; + +/// template deduction guide: + +template< typename E > +unexpected_type( E ) -> unexpected_type< E >; + + +/// class unexpected_type, std::exception_ptr specialization (P0323R2) + + +/// x.x.4, Unexpected equality operators + +template< typename E1, typename E2 > +constexpr bool operator==( unexpected_type const & x, unexpected_type const & y ) +{ + return x.value() == y.value(); +} + +template< typename E1, typename E2 > +constexpr bool operator!=( unexpected_type const & x, unexpected_type const & y ) +{ + return ! ( x == y ); +} + + + +/// x.x.5 Specialized algorithms + +template< typename E + nsel_REQUIRES_T( + std17::is_swappable::value + ) +> +void swap( unexpected_type & x, unexpected_type & y) noexcept ( noexcept ( x.swap(y) ) ) +{ + x.swap( y ); +} + + + +// unexpected: factory + +// keep make_unexpected() removed in p0323r2 for pre-C++17: + +template< typename E> +nsel_constexpr14 auto +make_unexpected( E && value ) -> unexpected_type< typename std::decay::type > +{ + return unexpected_type< typename std::decay::type >( std::forward(value) ); +} + + +template< typename E > +class bad_expected_access; + +/// x.x.7 bad_expected_access: expected access error + +template <> +class bad_expected_access< void > : public std::exception +{ +public: + explicit bad_expected_access() + : std::exception() + {} +}; + +/// x.x.6 bad_expected_access: expected access error + +#if !nsel_CONFIG_NO_EXCEPTIONS + +template< typename E > +class bad_expected_access : public bad_expected_access< void > +{ +public: + using error_type = E; + + explicit bad_expected_access( error_type error ) + : m_error( error ) + {} + + virtual char const * what() const noexcept override + { + return "bad_expected_access"; + } + + nsel_constexpr14 error_type & error() & + { + return m_error; + } + + constexpr error_type const & error() const & + { + return m_error; + } + + + nsel_constexpr14 error_type && error() && + { + return std::move( m_error ); + } + + constexpr error_type const && error() const && + { + return std::move( m_error ); + } + + +private: + error_type m_error; +}; + +#endif // nsel_CONFIG_NO_EXCEPTIONS + +/// x.x.8 unexpect tag, in_place_unexpected tag: construct an error + +struct unexpect_t{}; +using in_place_unexpected_t = unexpect_t; + +nsel_inline17 constexpr unexpect_t unexpect{}; +nsel_inline17 constexpr unexpect_t in_place_unexpected{}; + +/// class error_traits + +#if nsel_CONFIG_NO_EXCEPTIONS + +namespace detail { + bool text( char const * /*text*/ ) { return true; } +} +template< typename Error > +struct error_traits +{ + static void rethrow( Error const & /*e*/ ) + { + assert( false && detail::text("throw bad_expected_access{ e };") ); + } +}; + +template<> +struct error_traits< std::exception_ptr > +{ + static void rethrow( std::exception_ptr const & /*e*/ ) + { + assert( false && detail::text("throw bad_expected_access{ e };") ); + } +}; + +template<> +struct error_traits< std::error_code > +{ + static void rethrow( std::error_code const & /*e*/ ) + { + assert( false && detail::text("throw std::system_error( e );") ); + } +}; + +#else // nsel_CONFIG_NO_EXCEPTIONS + +template< typename Error > +struct error_traits +{ + static void rethrow( Error const & e ) + { + throw bad_expected_access{ e }; + } +}; + +template<> +struct error_traits< std::exception_ptr > +{ + static void rethrow( std::exception_ptr const & e ) + { + std::rethrow_exception( e ); + } +}; + +template<> +struct error_traits< std::error_code > +{ + static void rethrow( std::error_code const & e ) + { + throw std::system_error( e ); + } +}; + +#endif // nsel_CONFIG_NO_EXCEPTIONS + +} // namespace expected_lite + +// provide nonstd::unexpected_type: + +using expected_lite::unexpected_type; + +namespace expected_lite { + +/// class expected + +template< typename T, typename E > +class expected +{ +private: + template< typename, typename > friend class expected; + +public: + using value_type = T; + using error_type = E; + using unexpected_type = nonstd::unexpected_type; + + template< typename U > + struct rebind + { + using type = expected; + }; + + // x.x.4.1 constructors + + nsel_REQUIRES_0( + std::is_default_constructible::value + ) + nsel_constexpr14 expected() + : contained( true ) + { + contained.construct_value( value_type() ); + } + + nsel_constexpr14 expected( expected const & ) = default; + nsel_constexpr14 expected( expected && ) = default; + + template< typename U, typename G > + nsel_constexpr14 explicit expected( expected const & other + nsel_REQUIRES_A( + std::is_constructible< T, U const &>::value + && std::is_constructible::value + && !std::is_constructible & >::value + && !std::is_constructible && >::value + && !std::is_constructible const & >::value + && !std::is_constructible const && >::value + && !std::is_convertible< expected & , T>::value + && !std::is_convertible< expected &&, T>::value + && !std::is_convertible< expected const & , T>::value + && !std::is_convertible< expected const &&, T>::value + && (!std::is_convertible::value || !std::is_convertible::value ) /*=> explicit */ ) + ) + : contained( other.has_value() ) + { + if ( has_value() ) contained.construct_value( T{ other.contained.value() } ); + else contained.construct_error( E{ other.contained.error() } ); + } + + template< typename U, typename G > + nsel_constexpr14 /*non-explicit*/ expected( expected const & other + nsel_REQUIRES_A( + std::is_constructible< T, U const &>::value + && std::is_constructible::value + && !std::is_constructible & >::value + && !std::is_constructible && >::value + && !std::is_constructible const & >::value + && !std::is_constructible const && >::value + && !std::is_convertible< expected & , T>::value + && !std::is_convertible< expected &&, T>::value + && !std::is_convertible< expected const &, T>::value + && !std::is_convertible< expected const &&, T>::value + && !(!std::is_convertible::value || !std::is_convertible::value ) /*=> non-explicit */ ) + ) + : contained( other.has_value() ) + { + if ( has_value() ) contained.construct_value( other.contained.value() ); + else contained.construct_error( other.contained.error() ); + } + + template< typename U, typename G > + nsel_constexpr14 explicit expected( expected && other + nsel_REQUIRES_A( + std::is_constructible< T, U>::value + && std::is_constructible::value + && !std::is_constructible & >::value + && !std::is_constructible && >::value + && !std::is_constructible const & >::value + && !std::is_constructible const && >::value + && !std::is_convertible< expected & , T>::value + && !std::is_convertible< expected &&, T>::value + && !std::is_convertible< expected const & , T>::value + && !std::is_convertible< expected const &&, T>::value + && (!std::is_convertible::value || !std::is_convertible::value ) /*=> explicit */ ) + ) + : contained( other.has_value() ) + { + if ( has_value() ) contained.construct_value( T{ std::move( other.contained.value() ) } ); + else contained.construct_error( E{ std::move( other.contained.error() ) } ); + } + + template< typename U, typename G > + nsel_constexpr14 /*non-explicit*/ expected( expected && other + nsel_REQUIRES_A( + std::is_constructible< T, U>::value + && std::is_constructible::value + && !std::is_constructible & >::value + && !std::is_constructible && >::value + && !std::is_constructible const & >::value + && !std::is_constructible const && >::value + && !std::is_convertible< expected & , T>::value + && !std::is_convertible< expected &&, T>::value + && !std::is_convertible< expected const & , T>::value + && !std::is_convertible< expected const &&, T>::value + && !(!std::is_convertible::value || !std::is_convertible::value ) /*=> non-explicit */ ) + ) + : contained( other.has_value() ) + { + if ( has_value() ) contained.construct_value( std::move( other.contained.value() ) ); + else contained.construct_error( std::move( other.contained.error() ) ); + } + + template< typename U = T > + nsel_constexpr14 expected( value_type const & value + nsel_REQUIRES_A( + std::is_copy_constructible::value ) + ) + : contained( true ) + { + contained.construct_value( value ); + } + + template< typename U = T > + nsel_constexpr14 explicit expected( U && value + nsel_REQUIRES_A( + std::is_constructible::value + && !std::is_same::type, nonstd_lite_in_place_t(U)>::value + && !std::is_same< expected , typename std20::remove_cvref::type>::value + && !std::is_same, typename std20::remove_cvref::type>::value + && !std::is_convertible::value /*=> explicit */ + ) + ) noexcept + ( + std::is_nothrow_move_constructible::value && + std::is_nothrow_move_constructible::value + ) + : contained( true ) + { + contained.construct_value( T{ std::forward( value ) } ); + } + + template< typename U = T > + nsel_constexpr14 /*non-explicit*/ expected( U && value + nsel_REQUIRES_A( + std::is_constructible::value + && !std::is_same::type, nonstd_lite_in_place_t(U)>::value + && !std::is_same< expected , typename std20::remove_cvref::type>::value + && !std::is_same, typename std20::remove_cvref::type>::value + && std::is_convertible::value /*=> non-explicit */ + ) + ) noexcept + ( + std::is_nothrow_move_constructible::value && + std::is_nothrow_move_constructible::value + ) + : contained( true ) + { + contained.construct_value( std::forward( value ) ); + } + + // construct error: + + template< typename G = E > + nsel_constexpr14 explicit expected( nonstd::unexpected_type const & error + nsel_REQUIRES_A( + std::is_constructible::value + && !std::is_convertible< G const &, E>::value /*=> explicit */ ) + ) + : contained( false ) + { + contained.construct_error( E{ error.value() } ); + } + + template< typename G = E > + nsel_constexpr14 /*non-explicit*/ expected( nonstd::unexpected_type const & error + nsel_REQUIRES_A( + std::is_constructible::value + && std::is_convertible< G const &, E>::value /*=> non-explicit */ ) + ) + : contained( false ) + { + contained.construct_error( error.value() ); + } + + template< typename G = E > + nsel_constexpr14 explicit expected( nonstd::unexpected_type && error + nsel_REQUIRES_A( + std::is_constructible::value + && !std::is_convertible< G&&, E>::value /*=> explicit */ ) + ) + : contained( false ) + { + contained.construct_error( E{ std::move( error.value() ) } ); + } + + template< typename G = E > + nsel_constexpr14 /*non-explicit*/ expected( nonstd::unexpected_type && error + nsel_REQUIRES_A( + std::is_constructible::value + && std::is_convertible< G&&, E>::value /*=> non-explicit */ ) + ) + : contained( false ) + { + contained.construct_error( std::move( error.value() ) ); + } + + // in-place construction, value + + template< typename... Args + nsel_REQUIRES_T( + std::is_constructible::value + ) + > + nsel_constexpr14 explicit expected( nonstd_lite_in_place_t(T), Args&&... args ) + : contained( true ) + { + contained.emplace_value( std::forward( args )... ); + } + + template< typename U, typename... Args + nsel_REQUIRES_T( + std::is_constructible, Args&&...>::value + ) + > + nsel_constexpr14 explicit expected( nonstd_lite_in_place_t(T), std::initializer_list il, Args&&... args ) + : contained( true ) + { + contained.emplace_value( il, std::forward( args )... ); + } + + // in-place construction, error + + template< typename... Args + nsel_REQUIRES_T( + std::is_constructible::value + ) + > + nsel_constexpr14 explicit expected( unexpect_t, Args&&... args ) + : contained( false ) + { + contained.emplace_error( std::forward( args )... ); + } + + template< typename U, typename... Args + nsel_REQUIRES_T( + std::is_constructible, Args&&...>::value + ) + > + nsel_constexpr14 explicit expected( unexpect_t, std::initializer_list il, Args&&... args ) + : contained( false ) + { + contained.emplace_error( il, std::forward( args )... ); + } + + // x.x.4.2 destructor + + // TODO: ~expected: triviality + // Effects: If T is not cv void and is_trivially_destructible_v is false and bool(*this), calls val.~T(). If is_trivially_destructible_v is false and !bool(*this), calls unexpect.~unexpected(). + // Remarks: If either T is cv void or is_trivially_destructible_v is true, and is_trivially_destructible_v is true, then this destructor shall be a trivial destructor. + + ~expected() + { + if ( has_value() ) contained.destruct_value(); + else contained.destruct_error(); + } + + // x.x.4.3 assignment + + expected & operator=( expected const & other ) + { + expected( other ).swap( *this ); + return *this; + } + + expected & operator=( expected && other ) noexcept + ( + std::is_nothrow_move_constructible< T>::value + && std::is_nothrow_move_assignable< T>::value + && std::is_nothrow_move_constructible::value // added for missing + && std::is_nothrow_move_assignable< E>::value ) // nothrow above + { + expected( std::move( other ) ).swap( *this ); + return *this; + } + + template< typename U + nsel_REQUIRES_T( + !std::is_same, typename std20::remove_cvref::type>::value + && std17::conjunction, std::is_same> >::value + && std::is_constructible::value + && std::is_assignable< T&,U>::value + && std::is_nothrow_move_constructible::value ) + > + expected & operator=( U && value ) + { + expected( std::forward( value ) ).swap( *this ); + return *this; + } + + template< typename G + nsel_REQUIRES_T( + std::is_copy_constructible::value // TODO: std::is_nothrow_copy_constructible + && std::is_copy_assignable::value + ) + > + expected & operator=( nonstd::unexpected_type const & error ) + { + expected( unexpect, error.value() ).swap( *this ); + return *this; + } + + template< typename G + nsel_REQUIRES_T( + std::is_move_constructible::value // TODO: std::is_nothrow_move_constructible + && std::is_move_assignable::value + ) + > + expected & operator=( nonstd::unexpected_type && error ) + { + expected( unexpect, std::move( error.value() ) ).swap( *this ); + return *this; + } + + template< typename... Args + nsel_REQUIRES_T( + std::is_nothrow_constructible::value + ) + > + value_type & emplace( Args &&... args ) + { + expected( nonstd_lite_in_place(T), std::forward(args)... ).swap( *this ); + return value(); + } + + template< typename U, typename... Args + nsel_REQUIRES_T( + std::is_nothrow_constructible&, Args&&...>::value + ) + > + value_type & emplace( std::initializer_list il, Args &&... args ) + { + expected( nonstd_lite_in_place(T), il, std::forward(args)... ).swap( *this ); + return value(); + } + + // x.x.4.4 swap + + template< typename U=T, typename G=E > + nsel_REQUIRES_R( void, + std17::is_swappable< U>::value + && std17::is_swappable::value + && ( std::is_move_constructible::value || std::is_move_constructible::value ) + ) + swap( expected & other ) noexcept + ( + std::is_nothrow_move_constructible::value && std17::is_nothrow_swappable::value && + std::is_nothrow_move_constructible::value && std17::is_nothrow_swappable::value + ) + { + using std::swap; + + if ( bool(*this) && bool(other) ) { swap( contained.value(), other.contained.value() ); } + else if ( ! bool(*this) && ! bool(other) ) { swap( contained.error(), other.contained.error() ); } + else if ( bool(*this) && ! bool(other) ) { error_type t( std::move( other.error() ) ); + other.contained.destruct_error(); + other.contained.construct_value( std::move( contained.value() ) ); + contained.destruct_value(); + contained.construct_error( std::move( t ) ); + bool has_value = contained.has_value(); + bool other_has_value = other.has_value(); + other.contained.set_has_value(has_value); + contained.set_has_value(other_has_value); + } + else if ( ! bool(*this) && bool(other) ) { other.swap( *this ); } + } + + // x.x.4.5 observers + + constexpr value_type const * operator ->() const + { + return assert( has_value() ), contained.value_ptr(); + } + + value_type * operator ->() + { + return assert( has_value() ), contained.value_ptr(); + } + + constexpr value_type const & operator *() const & + { + return assert( has_value() ), contained.value(); + } + + value_type & operator *() & + { + return assert( has_value() ), contained.value(); + } + + constexpr value_type const && operator *() const && + { + return assert( has_value() ), std::move( contained.value() ); + } + + nsel_constexpr14 value_type && operator *() && + { + return assert( has_value() ), std::move( contained.value() ); + } + + constexpr explicit operator bool() const noexcept + { + return has_value(); + } + + constexpr bool has_value() const noexcept + { + return contained.has_value(); + } + + constexpr value_type const & value() const & + { + return has_value() + ? ( contained.value() ) + : ( error_traits::rethrow( contained.error() ), contained.value() ); + } + + value_type & value() & + { + return has_value() + ? ( contained.value() ) + : ( error_traits::rethrow( contained.error() ), contained.value() ); + } + + constexpr value_type const && value() const && + { + return std::move( has_value() + ? ( contained.value() ) + : ( error_traits::rethrow( contained.error() ), contained.value() ) ); + } + + nsel_constexpr14 value_type && value() && + { + return std::move( has_value() + ? ( contained.value() ) + : ( error_traits::rethrow( contained.error() ), contained.value() ) ); + } + + constexpr error_type const & error() const & + { + return assert( ! has_value() ), contained.error(); + } + + error_type & error() & + { + return assert( ! has_value() ), contained.error(); + } + + constexpr error_type const && error() const && + { + return assert( ! has_value() ), std::move( contained.error() ); + } + + error_type && error() && + { + return assert( ! has_value() ), std::move( contained.error() ); + } + + constexpr unexpected_type get_unexpected() const + { + return make_unexpected( contained.error() ); + } + + template< typename Ex > + bool has_exception() const + { + using ContainedEx = typename std::remove_reference< decltype( get_unexpected().value() ) >::type; + return ! has_value() && std::is_base_of< Ex, ContainedEx>::value; + } + + template< typename U + nsel_REQUIRES_T( + std::is_copy_constructible< T>::value + && std::is_convertible::value + ) + > + value_type value_or( U && v ) const & + { + return has_value() + ? contained.value() + : static_cast( std::forward( v ) ); + } + + template< typename U + nsel_REQUIRES_T( + std::is_move_constructible< T>::value + && std::is_convertible::value + ) + > + value_type value_or( U && v ) && + { + return has_value() + ? std::move( contained.value() ) + : static_cast( std::forward( v ) ); + } + + // unwrap() + +// template +// constexpr expected expected,E>::unwrap() const&; + +// template +// constexpr expected expected::unwrap() const&; + +// template +// expected expected, E>::unwrap() &&; + +// template +// template expected expected::unwrap() &&; + + // factories + +// template< typename Ex, typename F> +// expected catch_exception(F&& f); + +// template< typename F> +// expected())),E> map(F&& func) ; + +// template< typename F> +// 'see below' bind(F&& func); + +// template< typename F> +// expected catch_error(F&& f); + +// template< typename F> +// 'see below' then(F&& func); + +private: + detail::storage_t + < + T + ,E + , std::is_copy_constructible::value && std::is_copy_constructible::value + , std::is_move_constructible::value && std::is_move_constructible::value + > + contained; +}; + +/// class expected, void specialization + +template< typename E > +class expected +{ +private: + template< typename, typename > friend class expected; + +public: + using value_type = void; + using error_type = E; + using unexpected_type = nonstd::unexpected_type; + + // x.x.4.1 constructors + + constexpr expected() noexcept + : contained( true ) + {} + + nsel_constexpr14 expected( expected const & other ) = default; + nsel_constexpr14 expected( expected && other ) = default; + + constexpr explicit expected( nonstd_lite_in_place_t(void) ) + : contained( true ) + {} + + template< typename G = E > + nsel_constexpr14 explicit expected( nonstd::unexpected_type const & error + nsel_REQUIRES_A( + !std::is_convertible::value /*=> explicit */ + ) + ) + : contained( false ) + { + contained.construct_error( E{ error.value() } ); + } + + template< typename G = E > + nsel_constexpr14 /*non-explicit*/ expected( nonstd::unexpected_type const & error + nsel_REQUIRES_A( + std::is_convertible::value /*=> non-explicit */ + ) + ) + : contained( false ) + { + contained.construct_error( error.value() ); + } + + template< typename G = E > + nsel_constexpr14 explicit expected( nonstd::unexpected_type && error + nsel_REQUIRES_A( + !std::is_convertible::value /*=> explicit */ + ) + ) + : contained( false ) + { + contained.construct_error( E{ std::move( error.value() ) } ); + } + + template< typename G = E > + nsel_constexpr14 /*non-explicit*/ expected( nonstd::unexpected_type && error + nsel_REQUIRES_A( + std::is_convertible::value /*=> non-explicit */ + ) + ) + : contained( false ) + { + contained.construct_error( std::move( error.value() ) ); + } + + template< typename... Args + nsel_REQUIRES_T( + std::is_constructible::value + ) + > + nsel_constexpr14 explicit expected( unexpect_t, Args&&... args ) + : contained( false ) + { + contained.emplace_error( std::forward( args )... ); + } + + template< typename U, typename... Args + nsel_REQUIRES_T( + std::is_constructible, Args&&...>::value + ) + > + nsel_constexpr14 explicit expected( unexpect_t, std::initializer_list il, Args&&... args ) + : contained( false ) + { + contained.emplace_error( il, std::forward( args )... ); + } + + // destructor + + ~expected() + { + if ( ! has_value() ) + { + contained.destruct_error(); + } + } + + // x.x.4.3 assignment + + expected & operator=( expected const & other ) + { + expected( other ).swap( *this ); + return *this; + } + + expected & operator=( expected && other ) noexcept + ( + std::is_nothrow_move_assignable::value && + std::is_nothrow_move_constructible::value ) + { + expected( std::move( other ) ).swap( *this ); + return *this; + } + + void emplace() + { + expected().swap( *this ); + } + + // x.x.4.4 swap + + template< typename G = E > + nsel_REQUIRES_R( void, + std17::is_swappable::value + && std::is_move_constructible::value + ) + swap( expected & other ) noexcept + ( + std::is_nothrow_move_constructible::value && std17::is_nothrow_swappable::value + ) + { + using std::swap; + + if ( ! bool(*this) && ! bool(other) ) { swap( contained.error(), other.contained.error() ); } + else if ( bool(*this) && ! bool(other) ) { contained.construct_error( std::move( other.error() ) ); + bool has_value = contained.has_value(); + bool other_has_value = other.has_value(); + other.contained.set_has_value(has_value); + contained.set_has_value(other_has_value); + } + else if ( ! bool(*this) && bool(other) ) { other.swap( *this ); } + } + + // x.x.4.5 observers + + constexpr explicit operator bool() const noexcept + { + return has_value(); + } + + constexpr bool has_value() const noexcept + { + return contained.has_value(); + } + + void value() const + { + if ( ! has_value() ) + { + error_traits::rethrow( contained.error() ); + } + } + + constexpr error_type const & error() const & + { + return assert( ! has_value() ), contained.error(); + } + + error_type & error() & + { + return assert( ! has_value() ), contained.error(); + } + +#if !nsel_COMPILER_GNUC_VERSION || nsel_COMPILER_GNUC_VERSION >= 490 + + constexpr error_type const && error() const && + { + return assert( ! has_value() ), std::move( contained.error() ); + } + + error_type && error() && + { + return assert( ! has_value() ), std::move( contained.error() ); + } + +#endif + + constexpr unexpected_type get_unexpected() const + { + return make_unexpected( contained.error() ); + } + + template< typename Ex > + bool has_exception() const + { + using ContainedEx = typename std::remove_reference< decltype( get_unexpected().value() ) >::type; + return ! has_value() && std::is_base_of< Ex, ContainedEx>::value; + } + +// template constexpr 'see below' unwrap() const&; +// +// template 'see below' unwrap() &&; + + // factories + +// template< typename Ex, typename F> +// expected catch_exception(F&& f); +// +// template< typename F> +// expected map(F&& func) ; +// +// template< typename F> +// 'see below' bind(F&& func) ; +// +// template< typename F> +// expected catch_error(F&& f); +// +// template< typename F> +// 'see below' then(F&& func); + +private: + detail::storage_t + < + void + , E + , std::is_copy_constructible::value + , std::is_move_constructible::value + > + contained; +}; + +// x.x.4.6 expected<>: comparison operators + +template< typename T1, typename E1, typename T2, typename E2 > +constexpr bool operator==( expected const & x, expected const & y ) +{ + return bool(x) != bool(y) ? false : bool(x) == false ? x.error() == y.error() : *x == *y; +} + +template< typename T1, typename E1, typename T2, typename E2 > +constexpr bool operator!=( expected const & x, expected const & y ) +{ + return !(x == y); +} + +template< typename E1, typename E2 > +constexpr bool operator==( expected const & x, expected const & y ) +{ + return bool(x) != bool(y) ? false : bool(x) == false ? x.error() == y.error() : true; +} + +#if nsel_P0323R <= 2 + +template< typename T, typename E > +constexpr bool operator<( expected const & x, expected const & y ) +{ + return (!y) ? false : (!x) ? true : *x < *y; +} + +template< typename T, typename E > +constexpr bool operator>( expected const & x, expected const & y ) +{ + return (y < x); +} + +template< typename T, typename E > +constexpr bool operator<=( expected const & x, expected const & y ) +{ + return !(y < x); +} + +template< typename T, typename E > +constexpr bool operator>=( expected const & x, expected const & y ) +{ + return !(x < y); +} + +#endif + +// x.x.4.7 expected: comparison with T + +template< typename T1, typename E1, typename T2 > +constexpr bool operator==( expected const & x, T2 const & v ) +{ + return bool(x) ? *x == v : false; +} + +template< typename T1, typename E1, typename T2 > +constexpr bool operator==(T2 const & v, expected const & x ) +{ + return bool(x) ? v == *x : false; +} + +template< typename T1, typename E1, typename T2 > +constexpr bool operator!=( expected const & x, T2 const & v ) +{ + return bool(x) ? *x != v : true; +} + +template< typename T1, typename E1, typename T2 > +constexpr bool operator!=( T2 const & v, expected const & x ) +{ + return bool(x) ? v != *x : true; +} + +#if nsel_P0323R <= 2 + +template< typename T, typename E > +constexpr bool operator<( expected const & x, T const & v ) +{ + return bool(x) ? *x < v : true; +} + +template< typename T, typename E > +constexpr bool operator<( T const & v, expected const & x ) +{ + return bool(x) ? v < *x : false; +} + +template< typename T, typename E > +constexpr bool operator>( T const & v, expected const & x ) +{ + return bool(x) ? *x < v : false; +} + +template< typename T, typename E > +constexpr bool operator>( expected const & x, T const & v ) +{ + return bool(x) ? v < *x : false; +} + +template< typename T, typename E > +constexpr bool operator<=( T const & v, expected const & x ) +{ + return bool(x) ? ! ( *x < v ) : false; +} + +template< typename T, typename E > +constexpr bool operator<=( expected const & x, T const & v ) +{ + return bool(x) ? ! ( v < *x ) : true; +} + +template< typename T, typename E > +constexpr bool operator>=( expected const & x, T const & v ) +{ + return bool(x) ? ! ( *x < v ) : false; +} + +template< typename T, typename E > +constexpr bool operator>=( T const & v, expected const & x ) +{ + return bool(x) ? ! ( v < *x ) : true; +} + +#endif // nsel_P0323R + +// x.x.4.8 expected: comparison with unexpected_type + +template< typename T1, typename E1 , typename E2 > +constexpr bool operator==( expected const & x, unexpected_type const & u ) +{ + return (!x) ? x.get_unexpected() == u : false; +} + +template< typename T1, typename E1 , typename E2 > +constexpr bool operator==( unexpected_type const & u, expected const & x ) +{ + return ( x == u ); +} + +template< typename T1, typename E1 , typename E2 > +constexpr bool operator!=( expected const & x, unexpected_type const & u ) +{ + return ! ( x == u ); +} + +template< typename T1, typename E1 , typename E2 > +constexpr bool operator!=( unexpected_type const & u, expected const & x ) +{ + return ! ( x == u ); +} + +#if nsel_P0323R <= 2 + +template< typename T, typename E > +constexpr bool operator<( expected const & x, unexpected_type const & u ) +{ + return (!x) ? ( x.get_unexpected() < u ) : false; +} + +template< typename T, typename E > +constexpr bool operator<( unexpected_type const & u, expected const & x ) +{ + return (!x) ? ( u < x.get_unexpected() ) : true ; +} + +template< typename T, typename E > +constexpr bool operator>( expected const & x, unexpected_type const & u ) +{ + return ( u < x ); +} + +template< typename T, typename E > +constexpr bool operator>( unexpected_type const & u, expected const & x ) +{ + return ( x < u ); +} + +template< typename T, typename E > +constexpr bool operator<=( expected const & x, unexpected_type const & u ) +{ + return ! ( u < x ); +} + +template< typename T, typename E > +constexpr bool operator<=( unexpected_type const & u, expected const & x) +{ + return ! ( x < u ); +} + +template< typename T, typename E > +constexpr bool operator>=( expected const & x, unexpected_type const & u ) +{ + return ! ( u > x ); +} + +template< typename T, typename E > +constexpr bool operator>=( unexpected_type const & u, expected const & x ) +{ + return ! ( x > u ); +} + +#endif // nsel_P0323R + +/// x.x.x Specialized algorithms + +template< typename T, typename E + nsel_REQUIRES_T( + ( std::is_void::value || std::is_move_constructible::value ) + && std::is_move_constructible::value + && std17::is_swappable::value + && std17::is_swappable::value ) +> +void swap( expected & x, expected & y ) noexcept ( noexcept ( x.swap(y) ) ) +{ + x.swap( y ); +} + +#if nsel_P0323R <= 3 + +template< typename T > +constexpr auto make_expected( T && v ) -> expected< typename std::decay::type > +{ + return expected< typename std::decay::type >( std::forward( v ) ); +} + +// expected specialization: + +auto inline make_expected() -> expected +{ + return expected( in_place ); +} + +template< typename T > +constexpr auto make_expected_from_current_exception() -> expected +{ + return expected( make_unexpected_from_current_exception() ); +} + +template< typename T > +auto make_expected_from_exception( std::exception_ptr v ) -> expected +{ + return expected( unexpected_type( std::forward( v ) ) ); +} + +template< typename T, typename E > +constexpr auto make_expected_from_error( E e ) -> expected::type> +{ + return expected::type>( make_unexpected( e ) ); +} + +template< typename F > +/*nsel_constexpr14*/ +auto make_expected_from_call( F f, + nsel_REQUIRES_A( ! std::is_same::type, void>::value ) +) -> expected< typename std::result_of::type > +{ + try + { + return make_expected( f() ); + } + catch (...) + { + return make_unexpected_from_current_exception(); + } +} + +template< typename F > +/*nsel_constexpr14*/ +auto make_expected_from_call( F f, + nsel_REQUIRES_A( std::is_same::type, void>::value ) +) -> expected +{ + try + { + f(); + return make_expected(); + } + catch (...) + { + return make_unexpected_from_current_exception(); + } +} + +#endif // nsel_P0323R + +} // namespace expected_lite + +using namespace expected_lite; + +// using expected_lite::expected; +// using ... + +} // namespace nonstd + +namespace std { + +// expected: hash support + +template< typename T, typename E > +struct hash< nonstd::expected > +{ + using result_type = std::size_t; + using argument_type = nonstd::expected; + + constexpr result_type operator()(argument_type const & arg) const + { + return arg ? std::hash{}(*arg) : result_type{}; + } +}; + +// TBD - ?? remove? see spec. +template< typename T, typename E > +struct hash< nonstd::expected > +{ + using result_type = std::size_t; + using argument_type = nonstd::expected; + + constexpr result_type operator()(argument_type const & arg) const + { + return arg ? std::hash{}(*arg) : result_type{}; + } +}; + +// TBD - implement +// bool(e), hash>()(e) shall evaluate to the hashing true; +// otherwise it evaluates to an unspecified value if E is exception_ptr or +// a combination of hashing false and hash()(e.error()). + +template< typename E > +struct hash< nonstd::expected > +{ +}; + +} // namespace std + +namespace nonstd { + +// void unexpected() is deprecated && removed in C++17 + +#if nsel_CPP17_OR_GREATER || nsel_COMPILER_MSVC_VERSION > 141 +template< typename E > +using unexpected = unexpected_type; +#endif + +} // namespace nonstd + +#undef nsel_REQUIRES +#undef nsel_REQUIRES_0 +#undef nsel_REQUIRES_T + +nsel_RESTORE_WARNINGS() + + +#endif // NONSTD_EXPECTED_LITE_HPP