Merge branch 'develop'

include/boost/variant2/outcome.hpp

@@ -0,0 +1,259 @@
+#ifndef BOOST_VARIANT2_OUTCOME_HPP_INCLUDED
+#define BOOST_VARIANT2_OUTCOME_HPP_INCLUDED
+
+//  Copyright 2017 Peter Dimov.
+//
+//  Distributed under the Boost Software License, Version 1.0.
+//
+//  See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt
+
+#ifndef BOOST_VARIANT2_VARIANT_HPP_INCLUDED
+#include <boost/variant2/variant.hpp>
+#endif
+#include <system_error>
+#include <exception>
+#include <type_traits>
+#include <cassert>
+
+//
+
+namespace boost
+{
+namespace variant2
+{
+
+enum class outcome_errc
+{
+    not_initialized
+};
+
+class outcome_error_category: public std::error_category
+{
+public:
+
+    virtual const char * name() const noexcept
+    {
+        return "boost::variant2::outcome";
+    }
+
+    virtual std::string message( int e ) const
+    {
+        switch( e )
+        {
+        case (int)outcome_errc::not_initialized:
+
+            return "outcome<> not initialized";
+
+        default:
+
+            return "unknown outcome<> error";
+        }
+    }
+
+    static outcome_error_category const & instance()
+    {
+        static outcome_error_category cat;
+        return cat;
+    }
+};
+
+std::error_code make_error_code( outcome_errc e )
+{
+    return std::error_code( static_cast<int>( e ), outcome_error_category::instance() );
+}
+
+template<class T> class outcome
+{
+private:
+
+    variant<T, std::error_code, std::exception_ptr> v_;
+
+public:
+
+    // constructors
+
+    constexpr outcome() noexcept: v_( make_error_code( outcome_errc::not_initialized ) )
+    {
+    }
+
+    constexpr outcome( T const& t ): v_( t )
+    {
+    }
+
+    constexpr outcome( T&& t ): v_( std::move(t) )
+    {
+    }
+
+    constexpr outcome( std::error_code const & ec ) noexcept: v_( ec )
+    {
+    }
+
+    constexpr outcome( std::exception_ptr const & ep ) noexcept: v_( ep )
+    {
+    }
+
+    // queries
+
+    constexpr bool has_value() const noexcept
+    {
+        return v_.index() == 0;
+    }
+
+    constexpr bool has_error() const noexcept
+    {
+        return v_.index() == 1;
+    }
+
+    constexpr bool has_exception() const noexcept
+    {
+        return v_.index() == 2;
+    }
+
+    constexpr explicit operator bool() const noexcept
+    {
+        return v_.index() == 0;
+    }
+
+    // checked value access
+
+    constexpr T& value() &
+    {
+        if( has_value() )
+        {
+            return *get_if<0>(&v_);
+        }
+        else
+        {
+            throw std::system_error( *get_if<1>(&v_) );
+        }
+    }
+
+    constexpr T const& value() const&
+    {
+        if( has_value() )
+        {
+            return *get_if<0>(&v_);
+        }
+        else
+        {
+            throw std::system_error( *get_if<1>(&v_) );
+        }
+    }
+
+    constexpr T&& value() &&
+    {
+        return std::move( value() );
+    }
+
+    constexpr T const&& value() const&&
+    {
+        return std::move( value() );
+    }
+
+    // unchecked value access
+
+    T* operator->() noexcept
+    {
+        return get_if<0>(&v_);
+    }
+
+    T const* operator->() const noexcept
+    {
+        return get_if<0>(&v_);
+    }
+
+    T& operator*() & noexcept
+    {
+        T* p = get_if<0>(&v_);
+
+        assert( p != 0 );
+
+        return *p;
+    }
+
+    T const& operator*() const & noexcept
+    {
+        T const* p = get_if<0>(&v_);
+
+        assert( p != 0 );
+
+        return *p;
+    }
+
+    T&& operator*() && noexcept
+    {
+        return std::move(**this);
+    }
+
+    T const&& operator*() const && noexcept
+    {
+        return std::move(**this);
+    }
+
+    // error access
+
+    /*constexpr*/ std::error_code error() const noexcept
+    {
+        if( has_error() )
+        {
+            return *get_if<1>(&v_);
+        }
+        else
+        {
+            return std::error_code();
+        }
+    }
+
+    // exception access
+
+    std::exception_ptr exception() const noexcept
+    {
+        if( has_exception() )
+        {
+            return *get_if<2>(&v_);
+        }
+        else if( has_value() )
+        {
+            return std::exception_ptr();
+        }
+        else
+        {
+            return std::make_exception_ptr( std::system_error( *get_if<1>(&v_) ) );
+        }
+    }
+
+    // setters
+
+    void set_value( T const& t ) noexcept( std::is_nothrow_copy_constructible<T>::value )
+    {
+        v_.emplace<0>( t );
+    }
+
+    void set_value( T&& t ) noexcept( std::is_nothrow_move_constructible<T>::value )
+    {
+        v_.emplace<0>( std::move( t ) );
+    }
+
+    void set_error( std::error_code const & e ) noexcept
+    {
+        v_.emplace<1>( e );
+    }
+
+    void set_exception( std::exception_ptr const & x ) noexcept
+    {
+        v_.emplace<2>( x );
+    }
+
+    // swap
+
+    void swap( outcome& r ) noexcept( noexcept( v_.swap( r.v_ ) ) )
+    {
+        v_.swap( r.v_ );
+    }
+};
+
+} // namespace variant2
+} // namespace boost
+
+#endif // #ifndef BOOST_VARIANT2_OUTCOME_HPP_INCLUDED

include/boost/variant2/result.hpp

@@ -0,0 +1,226 @@
+#ifndef BOOST_VARIANT2_RESULT_HPP_INCLUDED
+#define BOOST_VARIANT2_RESULT_HPP_INCLUDED
+
+//  Copyright 2017 Peter Dimov.
+//
+//  Distributed under the Boost Software License, Version 1.0.
+//
+//  See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt
+
+#ifndef BOOST_VARIANT2_VARIANT_HPP_INCLUDED
+#include <boost/variant2/variant.hpp>
+#endif
+#include <system_error>
+#include <type_traits>
+#include <cassert>
+
+//
+
+namespace boost
+{
+namespace variant2
+{
+
+enum class result_errc
+{
+    not_initialized
+};
+
+class result_error_category: public std::error_category
+{
+public:
+
+    virtual const char * name() const noexcept
+    {
+        return "boost::variant2::result";
+    }
+
+    virtual std::string message( int e ) const
+    {
+        switch( e )
+        {
+        case (int)result_errc::not_initialized:
+
+            return "result<> not initialized";
+
+        default:
+
+            return "unknown result<> error";
+        }
+    }
+
+    static result_error_category const & instance()
+    {
+        static result_error_category cat;
+        return cat;
+    }
+};
+
+std::error_code make_error_code( result_errc e )
+{
+    return std::error_code( static_cast<int>( e ), result_error_category::instance() );
+}
+
+template<class T> class result
+{
+private:
+
+    variant<T, std::error_code> v_;
+
+public:
+
+    // constructors
+
+    constexpr result() noexcept: v_( make_error_code( result_errc::not_initialized ) )
+    {
+    }
+
+    constexpr result( T const& t ): v_( t )
+    {
+    }
+
+    constexpr result( T&& t ): v_( std::move(t) )
+    {
+    }
+
+    constexpr result( std::error_code const & ec ) noexcept: v_( ec )
+    {
+    }
+
+    // queries
+
+    constexpr bool has_value() const noexcept
+    {
+        return v_.index() == 0;
+    }
+
+    constexpr bool has_error() const noexcept
+    {
+        return v_.index() == 1;
+    }
+
+    constexpr explicit operator bool() const noexcept
+    {
+        return v_.index() == 0;
+    }
+
+    // checked value access
+
+    constexpr T& value() &
+    {
+        if( has_value() )
+        {
+            return *get_if<0>(&v_);
+        }
+        else
+        {
+            throw std::system_error( *get_if<1>(&v_) );
+        }
+    }
+
+    constexpr T const& value() const&
+    {
+        if( has_value() )
+        {
+            return *get_if<0>(&v_);
+        }
+        else
+        {
+            throw std::system_error( *get_if<1>(&v_) );
+        }
+    }
+
+    constexpr T&& value() &&
+    {
+        return std::move( value() );
+    }
+
+    constexpr T const&& value() const&&
+    {
+        return std::move( value() );
+    }
+
+    // unchecked value access
+
+    T* operator->() noexcept
+    {
+        return get_if<0>(&v_);
+    }
+
+    T const* operator->() const noexcept
+    {
+        return get_if<0>(&v_);
+    }
+
+    T& operator*() & noexcept
+    {
+        T* p = get_if<0>(&v_);
+
+        assert( p != 0 );
+
+        return *p;
+    }
+
+    T const& operator*() const & noexcept
+    {
+        T const* p = get_if<0>(&v_);
+
+        assert( p != 0 );
+
+        return *p;
+    }
+
+    T&& operator*() && noexcept
+    {
+        return std::move(**this);
+    }
+
+    T const&& operator*() const && noexcept
+    {
+        return std::move(**this);
+    }
+
+    // error access
+
+    /*constexpr*/ std::error_code error() const noexcept
+    {
+        if( has_error() )
+        {
+            return *get_if<1>(&v_);
+        }
+        else
+        {
+            return std::error_code();
+        }
+    }
+
+    // setters
+
+    void set_value( T const& t ) noexcept( std::is_nothrow_copy_constructible<T>::value )
+    {
+        v_.emplace<0>( t );
+    }
+
+    void set_value( T&& t ) noexcept( std::is_nothrow_move_constructible<T>::value )
+    {
+        v_.emplace<0>( std::move( t ) );
+    }
+
+    void set_error( std::error_code const & e ) noexcept
+    {
+        v_.emplace<1>( e );
+    }
+
+    // swap
+
+    void swap( result& r ) noexcept( noexcept( v_.swap( r.v_ ) ) )
+    {
+        v_.swap( r.v_ );
+    }
+};
+
+} // namespace variant2
+} // namespace boost
+
+#endif // #ifndef BOOST_VARIANT2_RESULT_HPP_INCLUDED

include/boost/variant2/variant.hpp

@@ -1,14 +1,16 @@
 #ifndef BOOST_VARIANT2_VARIANT_HPP_INCLUDED
 #define BOOST_VARIANT2_VARIANT_HPP_INCLUDED
 
-//  Copyright 2015-2017 Peter Dimov.
+//  Copyright 2017 Peter Dimov.
 //
 //  Distributed under the Boost Software License, Version 1.0.
 //
 //  See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt
 
+#ifndef BOOST_MP11_HPP_INCLUDED
 #include <boost/mp11.hpp>
+#endif
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
 #include <cstddef>
@@ -79,22 +81,22 @@ template<std::size_t I, class T> using variant_alternative_t = typename variant_
 
 namespace detail
 {
-    template<class I, class T, class Q> using var_alt_t = mp_invoke<Q, variant_alternative_t<I::value, T>>;
+    template<class I, class T, class Q> using var_alt_impl = mp_invoke<Q, variant_alternative_t<I::value, T>>;
 } // namespace detail
 
 template<std::size_t I, class T> struct variant_alternative
 {
 };
 
-template<std::size_t I, class T> struct variant_alternative<I, T const>: mp_defer< variant2::detail::var_alt_t, mp_size_t<I>, T, mp_quote<std::add_const_t>>
+template<std::size_t I, class T> struct variant_alternative<I, T const>: mp_defer< variant2::detail::var_alt_impl, mp_size_t<I>, T, mp_quote<std::add_const_t>>
 {
 };
 
-template<std::size_t I, class T> struct variant_alternative<I, T volatile>: mp_defer< variant2::detail::var_alt_t, mp_size_t<I>, T, mp_quote<std::add_volatile_t>>
+template<std::size_t I, class T> struct variant_alternative<I, T volatile>: mp_defer< variant2::detail::var_alt_impl, mp_size_t<I>, T, mp_quote<std::add_volatile_t>>
 {
 };
 
-template<std::size_t I, class T> struct variant_alternative<I, T const volatile>: mp_defer< variant2::detail::var_alt_t, mp_size_t<I>, T, mp_quote<std::add_cv_t>>
+template<std::size_t I, class T> struct variant_alternative<I, T const volatile>: mp_defer< variant2::detail::var_alt_impl, mp_size_t<I>, T, mp_quote<std::add_cv_t>>
 {
 };
 
@@ -1063,16 +1065,9 @@ template<class... T> constexpr bool operator>=( variant<T...> const & v, variant
 }
 
 // visitation
-template<class F> constexpr auto visit( F&& f ) -> decltype(std::forward<F>(f)())
-{
-    return std::forward<F>(f)();
-}
-
 namespace detail
 {
 
-template<class T> using remove_cv_ref = std::remove_cv_t<std::remove_reference_t<T>>;
-
 template<class F> struct Qret
 {
     template<class... T> using fn = decltype( std::declval<F>()( std::declval<T>()... ) );
@@ -1080,13 +1075,41 @@ template<class F> struct Qret
 
 template<class L> using front_if_same = mp_if<mp_apply<mp_same, L>, mp_front<L>>;
 
-template<class F, class... V> using Vret = front_if_same<mp_product_q<Qret<F>, remove_cv_ref<V>...>>;
+template<class V> using var_size = variant_size<std::remove_reference_t<V>>;
+
+template<class V, class N, class T = variant_alternative_t<N::value, std::remove_reference_t<V>>> using apply_cv_ref_ = mp_if<std::is_reference<V>, T&, T>;
+
+#if BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
+
+template<class V> struct apply_cv_ref_impl
+{
+    template<class T> using _f = apply_cv_ref_<V, T>;
+
+    using L = mp_iota<var_size<V>>;
+
+    using type = mp_transform<_f, L>;
+};
+
+template<class V> using apply_cv_ref = typename apply_cv_ref_impl<V>::type;
+
+#else
+
+template<class V> using apply_cv_ref = mp_transform_q<mp_bind_front<apply_cv_ref_, V>, mp_iota<var_size<V>>>;
+
+#endif
+
+template<class F, class... V> using Vret = front_if_same<mp_product_q<Qret<F>, apply_cv_ref<V>...>>;
 
 } // namespace detail
 
+template<class F> constexpr auto visit( F&& f ) -> decltype(std::forward<F>(f)())
+{
+    return std::forward<F>(f)();
+}
+
 template<class F, class V1> constexpr auto visit( F&& f, V1&& v1 ) -> variant2::detail::Vret<F, V1>
 {
-    return mp_for_index<mp_size<variant2::detail::remove_cv_ref<V1>>>( v1.index(), [&]( auto I ){
+    return mp_for_index<variant2::detail::var_size<V1>>( v1.index(), [&]( auto I ){
 
         return std::forward<F>(f)( get<I>( std::forward<V1>(v1) ) );
 
@@ -1097,7 +1120,7 @@ template<class F, class V1> constexpr auto visit( F&& f, V1&& v1 ) -> variant2::
 
 template<class F, class V1, class V2> constexpr auto visit( F&& f, V1&& v1, V2&& v2 ) -> variant2::detail::Vret<F, V1, V2>
 {
-    return mp_for_index<mp_size<variant2::detail::remove_cv_ref<V1>>>( v1.index(), [&]( auto I ){
+    return mp_for_index<variant2::detail::var_size<V1>>( v1.index(), [&]( auto I ){
 
         auto f2 = [&]( auto&&... a ){ return std::forward<F>(f)( get<I.value>( std::forward<V1>(v1) ), std::forward<decltype(a)>(a)... ); };
         return visit( f2, std::forward<V2>(v2) );
@@ -1107,7 +1130,7 @@ template<class F, class V1, class V2> constexpr auto visit( F&& f, V1&& v1, V2&&
 
 template<class F, class V1, class V2, class V3> constexpr auto visit( F&& f, V1&& v1, V2&& v2, V3&& v3 ) -> variant2::detail::Vret<F, V1, V2, V3>
 {
-    return mp_for_index<mp_size<variant2::detail::remove_cv_ref<V1>>>( v1.index(), [&]( auto I ){
+    return mp_for_index<variant2::detail::var_size<V1>>( v1.index(), [&]( auto I ){
 
         auto f2 = [&]( auto&&... a ){ return std::forward<F>(f)( get<I.value>( std::forward<V1>(v1) ), std::forward<decltype(a)>(a)... ); };
         return visit( f2, std::forward<V2>(v2), std::forward<V3>(v3) );
@@ -1117,7 +1140,7 @@ template<class F, class V1, class V2, class V3> constexpr auto visit( F&& f, V1&
 
 template<class F, class V1, class V2, class V3, class V4> constexpr auto visit( F&& f, V1&& v1, V2&& v2, V3&& v3, V4&& v4 ) -> variant2::detail::Vret<F, V1, V2, V3, V4>
 {
-    return mp_for_index<mp_size<variant2::detail::remove_cv_ref<V1>>>( v1.index(), [&]( auto I ){
+    return mp_for_index<variant2::detail::var_size<V1>>( v1.index(), [&]( auto I ){
 
         auto f2 = [&]( auto&&... a ){ return std::forward<F>(f)( get<I.value>( std::forward<V1>(v1) ), std::forward<decltype(a)>(a)... ); };
         return visit( f2, std::forward<V2>(v2), std::forward<V3>(v3), std::forward<V4>(v4) );
@@ -1129,7 +1152,7 @@ template<class F, class V1, class V2, class V3, class V4> constexpr auto visit(
 
 template<class F, class V1, class V2, class... V> constexpr auto visit( F&& f, V1&& v1, V2&& v2, V&&... v ) -> variant2::detail::Vret<F, V1, V2, V...>
 {
-    return mp_for_index<mp_size<variant2::detail::remove_cv_ref<V1>>>( v1.index(), [&]( auto I ){
+    return mp_for_index<variant2::detail::var_size<V1>>( v1.index(), [&]( auto I ){
 
         auto f2 = [&]( auto&&... a ){ return std::forward<F>(f)( get<I.value>( std::forward<V1>(v1) ), std::forward<decltype(a)>(a)... ); };
         return visit( f2, std::forward<V2>(v2), std::forward<V>(v)... );

test/Jamfile

@@ -38,3 +38,4 @@ run variant_swap.cpp : : : $(REQ) ;
 run variant_eq_ne.cpp : : : $(REQ) ;
 run variant_destroy.cpp : : : $(REQ) ;
 run variant_visit.cpp : : : $(REQ) ;
+run variant_lt_gt.cpp : : : $(REQ) ;

test/variant_lt_gt.cpp

@@ -0,0 +1,85 @@
+
+// Copyright 2017 Peter Dimov.
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <utility>
+#include <string>
+
+using namespace boost::variant2;
+
+struct X
+{
+};
+
+inline bool operator<( X const&, X const& ) { return false; }
+inline bool operator>( X const&, X const& ) { return false; }
+inline bool operator<=( X const&, X const& ) { return false; }
+inline bool operator>=( X const&, X const& ) { return false; }
+
+#define TEST_EQ( v1, v2 ) \
+    BOOST_TEST_NOT( v1 < v2 ); \
+    BOOST_TEST_NOT( v1 > v2 ); \
+    BOOST_TEST( v1 <= v2 ); \
+    BOOST_TEST( v1 >= v2 );
+
+#define TEST_LE( v1, v3 ) \
+    BOOST_TEST( v1 < v3 ); \
+    BOOST_TEST( v3 > v1 ); \
+    BOOST_TEST_NOT( v1 > v3 ); \
+    BOOST_TEST_NOT( v3 < v1 ); \
+    BOOST_TEST( v1 <= v3 ); \
+    BOOST_TEST( v3 >= v1 ); \
+    BOOST_TEST_NOT( v1 >= v3 ); \
+    BOOST_TEST_NOT( v3 <= v1 );
+
+int main()
+{
+    {
+        variant<int> v1, v2, v3( 1 ), v4( 1 );
+
+        TEST_EQ( v1, v2 )
+        TEST_LE( v1, v3 )
+        TEST_EQ( v3, v4 )
+    }
+
+    {
+        variant<int, float> v1, v2, v3( 1 ), v4( 1 ), v5( 3.14f ), v6( 3.14f );
+
+        TEST_EQ( v1, v2 )
+        TEST_LE( v1, v3 )
+        TEST_EQ( v3, v4 )
+        TEST_LE( v1, v5 )
+        TEST_LE( v3, v5 )
+        TEST_EQ( v5, v6 )
+    }
+
+    {
+        variant<int, int, float> v1, v2, v3( in_place_index<1> ), v4( in_place_index<1> ), v5( 3.14f ), v6( 3.14f );
+
+        TEST_EQ( v1, v2 )
+        TEST_LE( v1, v3 )
+        TEST_EQ( v3, v4 )
+        TEST_LE( v1, v5 )
+        TEST_LE( v3, v5 )
+        TEST_EQ( v5, v6 )
+    }
+
+    {
+        variant<X> v1, v2;
+
+        BOOST_TEST_NOT( v1 < v2 );
+        BOOST_TEST_NOT( v1 > v2 );
+        BOOST_TEST_NOT( v1 <= v2 );
+        BOOST_TEST_NOT( v1 >= v2 );
+    }
+
+    return boost::report_errors();
+}

test/variant_visit.cpp

@@ -7,6 +7,7 @@
 // http://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/variant2/variant.hpp>
+#include <boost/mp11.hpp>
 #include <boost/core/lightweight_test.hpp>
 #include <boost/core/lightweight_test_trait.hpp>
 #include <type_traits>
@@ -15,6 +16,19 @@
 #include <cstdio>
 
 using namespace boost::variant2;
+using boost::mp11::mp_size_t;
+
+struct X
+{
+};
+
+struct F
+{
+    mp_size_t<1> operator()( X& ) const;
+    mp_size_t<2> operator()( X const& ) const;
+    mp_size_t<3> operator()( X&& ) const;
+    mp_size_t<4> operator()( X const&& ) const;
+};
 
 int main()
 {
@@ -84,7 +98,17 @@ int main()
         BOOST_TEST_EQ( (visit( []( auto x1, auto x2, auto x3, auto x4 ){ return (long long)(x1 * 100) * 100000000 + (long long)(x2 * 100) * 100000 + (long long)(x3 * 10000) + (int)x4; }, v1, v2, v3, v4 )), 10031462800 + 'A' );
 
         visit( []( auto x1, auto x2, auto x3, auto x4 ){ BOOST_TEST_EQ( x1, 1 ); BOOST_TEST_EQ( x2, 3.14f ); BOOST_TEST_EQ( x3, 6.28 ); BOOST_TEST_EQ( x4, 'A' ); }, v1, v2, v3, v4 );
-		visit( []( auto x1, auto x2, auto x3, auto x4 ){ BOOST_TEST_EQ( x1, 1 ); BOOST_TEST_EQ( x2, 3.14f ); BOOST_TEST_EQ( x3, 6.28 ); BOOST_TEST_EQ( x4, 'A' ); }, std::move(v1), std::move(v2), std::move(v3), std::move(v4) );
+        visit( []( auto x1, auto x2, auto x3, auto x4 ){ BOOST_TEST_EQ( x1, 1 ); BOOST_TEST_EQ( x2, 3.14f ); BOOST_TEST_EQ( x3, 6.28 ); BOOST_TEST_EQ( x4, 'A' ); }, std::move(v1), std::move(v2), std::move(v3), std::move(v4) );
+    }
+
+    {
+        variant<X> v;
+        variant<X> const cv;
+
+        BOOST_TEST_EQ( decltype(visit(F{}, v))::value, 1 );
+        BOOST_TEST_EQ( decltype(visit(F{}, cv))::value, 2 );
+        BOOST_TEST_EQ( decltype(visit(F{}, std::move(v)))::value, 3 );
+        BOOST_TEST_EQ( decltype(visit(F{}, std::move(cv)))::value, 4 );
     }
 
     return boost::report_errors();