C++20 ranges support

build_test_all.cmd

@@ -27,6 +27,7 @@ call msbuild /p:Configuration=%target_configuration%,Platform=%target_platform%,
 call msbuild /p:Configuration=%target_configuration%,Platform=%target_platform%,CppWinRTBuildVersion=%target_version% test\nuget\NugetTest.sln
 
 call msbuild /m /p:Configuration=%target_configuration%,Platform=%target_platform%,CppWinRTBuildVersion=%target_version% cppwinrt.sln /t:test\test
+call msbuild /m /p:Configuration=%target_configuration%,Platform=%target_platform%,CppWinRTBuildVersion=%target_version% cppwinrt.sln /t:test\test_cpp20
 call msbuild /m /p:Configuration=%target_configuration%,Platform=%target_platform%,CppWinRTBuildVersion=%target_version% cppwinrt.sln /t:test\test_win7
 call msbuild /m /p:Configuration=%target_configuration%,Platform=%target_platform%,CppWinRTBuildVersion=%target_version% cppwinrt.sln /t:test\test_fast
 call msbuild /m /p:Configuration=%target_configuration%,Platform=%target_platform%,CppWinRTBuildVersion=%target_version% cppwinrt.sln /t:test\test_slow

cppwinrt.sln

@@ -103,6 +103,11 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "test_win7", "test\test_win7
 		{A91B8BF3-28E4-4D9E-8DBA-64B70E4F0270} = {A91B8BF3-28E4-4D9E-8DBA-64B70E4F0270}
 	EndProjectSection
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "test_cpp20", "test\test_cpp20\test_cpp20.vcxproj", "{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}"
+	ProjectSection(ProjectDependencies) = postProject
+		{D613FB39-5035-4043-91E2-BAB323908AF4} = {D613FB39-5035-4043-91E2-BAB323908AF4}
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|ARM = Debug|ARM
@@ -435,6 +440,22 @@ Global
 		{2EF696B9-7F4A-410F-AE5C-5301565C0F08}.Release|x64.Build.0 = Release|x64
 		{2EF696B9-7F4A-410F-AE5C-5301565C0F08}.Release|x86.ActiveCfg = Release|Win32
 		{2EF696B9-7F4A-410F-AE5C-5301565C0F08}.Release|x86.Build.0 = Release|Win32
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|ARM.ActiveCfg = Debug|ARM
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|ARM.Build.0 = Debug|ARM
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|ARM64.ActiveCfg = Debug|ARM64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|ARM64.Build.0 = Debug|ARM64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|x64.ActiveCfg = Debug|x64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|x64.Build.0 = Debug|x64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|x86.ActiveCfg = Debug|Win32
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Debug|x86.Build.0 = Debug|Win32
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|ARM.ActiveCfg = Release|ARM
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|ARM.Build.0 = Release|ARM
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|ARM64.ActiveCfg = Release|ARM64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|ARM64.Build.0 = Release|ARM64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|x64.ActiveCfg = Release|x64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|x64.Build.0 = Release|x64
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|x86.ActiveCfg = Release|Win32
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA}.Release|x86.Build.0 = Release|Win32
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -457,6 +478,7 @@ Global
 		{D48A96C2-8512-4CC3-B6E4-7CFF07ED8ED3} = {3C7EA5F8-6E8C-4376-B499-2CAF596384B0}
 		{08C40663-B6A3-481E-8755-AE32BAD99501} = {3C7EA5F8-6E8C-4376-B499-2CAF596384B0}
 		{2EF696B9-7F4A-410F-AE5C-5301565C0F08} = {3C7EA5F8-6E8C-4376-B499-2CAF596384B0}
+		{5FF6CD6C-515A-4D55-97B6-62AD9BCB77EA} = {3C7EA5F8-6E8C-4376-B499-2CAF596384B0}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {2783B8FD-EA3B-4D6B-9F81-662D289E02AA}

cppwinrt/code_writers.h

@@ -1283,13 +1283,18 @@ namespace cppwinrt
                 static_cast<D&>(*this) = nullptr;
             }
 
-            return *this;
+            return static_cast<D&>(*this);
         }
 
         auto operator*() const
         {
             return Current();
         }
+
+        void operator++(int)
+        {
+            ++(*this);
+        }
 )");
         }
         else if (type_name == "Windows.Storage.Streams.IBuffer")
@@ -1313,13 +1318,18 @@ namespace cppwinrt
                 static_cast<D&>(*this) = nullptr;
             }
 
-            return *this;
+            return static_cast<D&>(*this);
         }
 
         T operator*() const
         {
             return Current();
         }
+
+        void operator++(int)
+        {
+            ++(*this);
+        }
 )");
         }
         else if (type_name == "Windows.Foundation.Collections.IKeyValuePair`2")
@@ -1415,6 +1425,20 @@ namespace cppwinrt
         {
             w.write(R"(        auto get() const;
         auto wait_for(Windows::Foundation::TimeSpan const& timeout) const;
+)");
+        }
+        else if (type_name == "Windows.Foundation.Collections.IIterable`1")
+        {
+            w.write(R"(
+        auto begin() const;
+        auto end() const;
+)");
+        }
+        else if (type_name == "Windows.UI.Xaml.Interop.IBindableIterable")
+        {
+            w.write(R"(
+        auto begin() const;
+        auto end() const;
 )");
         }
     }
@@ -1426,11 +1450,23 @@ namespace cppwinrt
         if (type_name == "Windows.Foundation.Collections.IIterator`1")
         {
             w.write(R"(
+        using iterator_concept = std::input_iterator_tag;
         using iterator_category = std::input_iterator_tag;
         using value_type = T;
         using difference_type = ptrdiff_t;
-        using pointer = T*;
-        using reference = T&;
+        using pointer = void;
+        using reference = T;
+)");
+        }
+        else if (type_name == "Windows.UI.Xaml.Interop.IBindableIterator")
+        {
+            w.write(R"(
+        using iterator_concept = std::input_iterator_tag;
+        using iterator_category = std::input_iterator_tag;
+        using value_type = Windows::Foundation::IInspectable;
+        using difference_type = ptrdiff_t;
+        using pointer = void;
+        using reference = Windows::Foundation::IInspectable;
 )");
         }
         else if (type_name == "Windows.Foundation.IReference`1")

cppwinrt/cppwinrt.vcxproj

@@ -68,6 +68,7 @@
     <ClInclude Include="..\strings\base_identity.h" />
     <ClInclude Include="..\strings\base_implements.h" />
     <ClInclude Include="..\strings\base_includes.h" />
+    <ClInclude Include="..\strings\base_iterator.h" />
     <ClInclude Include="..\strings\base_lock.h" />
     <ClInclude Include="..\strings\base_macros.h" />
     <ClInclude Include="..\strings\base_marshaler.h" />

cppwinrt/cppwinrt.vcxproj.filters

@@ -163,6 +163,9 @@
     <ClInclude Include="..\strings\base_coroutine_system_winui.h">
       <Filter>strings</Filter>
     </ClInclude>
+    <ClInclude Include="..\strings\base_iterator.h">
+      <Filter>strings</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="$(OutDir)version.rc" />

cppwinrt/file_writers.h

@@ -38,6 +38,7 @@ namespace cppwinrt
             w.write(strings::base_chrono);
             w.write(strings::base_security);
             w.write(strings::base_std_hash);
+            w.write(strings::base_iterator);
             w.write(strings::base_coroutine_threadpool);
             w.write(strings::base_natvis);
             w.write(strings::base_version);

run_tests.cmd

@@ -9,6 +9,7 @@ if "%target_platform%"=="" set target_platform=x64
 if "%target_configuration%"=="" set target_configuration=Debug
 
 call :run_test test
+call :run_test test_cpp20
 call :run_test test_win7
 call :run_test test_fast
 call :run_test test_slow

strings/base_collections.h

@@ -3,174 +3,15 @@ namespace winrt::impl
 {
     namespace wfc = Windows::Foundation::Collections;
 
-    template <typename T>
-    struct fast_iterator
+    template <typename D, typename T>
+    auto consume_Windows_Foundation_Collections_IIterable<D, T>::begin() const
     {
-        using iterator_category = std::input_iterator_tag;
-        using value_type = decltype(std::declval<T>().GetAt(0));
-        using difference_type = ptrdiff_t;
-        using pointer = value_type*;
-        using reference = value_type;
-
-        fast_iterator() noexcept : m_collection(nullptr), m_index(0) {}
-
-        fast_iterator(T const& collection, uint32_t const index) noexcept :
-        m_collection(&collection),
-            m_index(index)
-        {}
-
-        fast_iterator& operator++() noexcept
-        {
-            ++m_index;
-            return*this;
-        }
-
-        fast_iterator operator++(int) noexcept
-        {
-            auto previous = *this;
-            ++m_index;
-            return previous;
-        }
-
-        fast_iterator& operator--() noexcept
-        {
-            --m_index;
-            return*this;
-        }
-
-        fast_iterator operator--(int) noexcept
-        {
-            auto previous = *this;
-            --m_index;
-            return previous;
-        }
-
-        fast_iterator& operator+=(difference_type n) noexcept
-        {
-            m_index += static_cast<uint32_t>(n);
-            return*this;
-        }
-
-        fast_iterator operator+(difference_type n) const noexcept
-        {
-            return fast_iterator(*this) += n;
-        }
-
-        fast_iterator& operator-=(difference_type n) noexcept
-        {
-            return *this += -n;
-        }
-
-        fast_iterator operator-(difference_type n) const noexcept
-        {
-            return *this + -n;
-        }
-
-        difference_type operator-(fast_iterator const& other) const noexcept
-        {
-            return static_cast<difference_type>(m_index) - static_cast<difference_type>(other.m_index);
-        }
-
-        reference operator*() const
-        {
-            return m_collection->GetAt(m_index);
-        }
-
-        reference operator[](difference_type n) const
-        {
-            return m_collection->GetAt(m_index + static_cast<uint32_t>(n));
-        }
-
-        bool operator==(fast_iterator const& other) const noexcept
-        {
-            WINRT_ASSERT(m_collection == other.m_collection);
-            return m_index == other.m_index;
-        }
-
-        bool operator<(fast_iterator const& other) const noexcept
-        {
-            WINRT_ASSERT(m_collection == other.m_collection);
-            return m_index < other.m_index;
-        }
-
-        bool operator!=(fast_iterator const& other) const noexcept
-        {
-            return !(*this == other);
-        }
-
-        bool operator>(fast_iterator const& other) const noexcept
-        {
-            return !(*this < other);
-        }
-
-        bool operator<=(fast_iterator const& other) const noexcept
-        {
-            return !(*this > other);
-        }
-
-        bool operator>=(fast_iterator const& other) const noexcept
-        {
-            return !(*this < other);
-        }
-
-    private:
-
-        T const* m_collection{};
-        uint32_t m_index{};
-    };
-
-    template <typename T>
-    class has_GetAt
-    {
-        template <typename U, typename = decltype(std::declval<U>().GetAt(0))> static constexpr bool get_value(int) { return true; }
-        template <typename> static constexpr bool get_value(...) { return false; }
-
-    public:
-
-        static constexpr bool value = get_value<T>(0);
-    };
-
-    template <typename T, std::enable_if_t<!has_GetAt<T>::value, int> = 0>
-    auto begin(T const& collection) -> decltype(collection.First())
-    {
-        auto result = collection.First();
-
-        if (!result.HasCurrent())
-        {
-            return {};
-        }
-
-        return result;
-    }
-
-    template <typename T, std::enable_if_t<!has_GetAt<T>::value, int> = 0>
-    auto end([[maybe_unused]] T const& collection) noexcept -> decltype(collection.First())
-    {
-        return {};
+        return get_begin_iterator(static_cast<D const&>(*this));
     }
-
-    template <typename T, std::enable_if_t<has_GetAt<T>::value, int> = 0>
-    fast_iterator<T> begin(T const& collection) noexcept
-    {
-        return { collection, 0 };
-    }
-
-    template <typename T, std::enable_if_t<has_GetAt<T>::value, int> = 0>
-    fast_iterator<T> end(T const& collection)
-    {
-        return { collection, collection.Size() };
-    }
-
-    template <typename T, std::enable_if_t<has_GetAt<T>::value, int> = 0>
-    auto rbegin(T const& collection)
-    {
-        return std::make_reverse_iterator(end(collection));
-    }
-
-    template <typename T, std::enable_if_t<has_GetAt<T>::value, int> = 0>
-    auto rend(T const& collection)
+    template <typename D, typename T>
+    auto consume_Windows_Foundation_Collections_IIterable<D, T>::end() const
     {
-        return std::make_reverse_iterator(begin(collection));
+        return get_end_iterator(static_cast<D const&>(*this));
     }
 
     template <typename T>