toying with concepts

k0zmo · Oct 27, 2020 · 45df321 · 45df321
1 parent 86e54cb
commit 45df321
Show file tree

Hide file tree

Showing 4 changed files with 23 additions and 44 deletions.
diff --git a/include/kl/ctti.hpp b/include/kl/ctti.hpp
@@ -9,51 +9,40 @@
 #include <string>
 
 namespace kl {
-namespace detail {
 
-KL_VALID_EXPR_HELPER(has_reflect_struct,
-                     reflect_struct(0, std::declval<T&>(), record<T>))
-
-} // namespace detail
+template <typename T>
+concept reflectable =
+    requires(T&& a) {
+        { reflect_struct(0, a, kl::record<std::remove_cvref_t<T>>) };
+    };
 
 template <typename T>
-using is_reflectable = detail::has_reflect_struct<T>;
+using is_reflectable = std::bool_constant<reflectable<T>>;
 
 template <typename T>
 inline constexpr bool is_reflectable_v = is_reflectable<T>::value;
 
 struct ctti
 {
-    template <typename T>
-    static constexpr bool is_reflectable = kl::is_reflectable_v<T>;
-
-    template <typename Reflected>
+    template <typename R>
     static std::string name()
     {
-        return boost::typeindex::type_id<Reflected>().pretty_name();
+        return boost::typeindex::type_id<R>().pretty_name();
     }
 
-    template <typename Reflected, typename Visitor>
-    static constexpr void reflect(Reflected&& r, Visitor&& v)
+    template <reflectable R, typename Visitor>
+    static constexpr void reflect(R&& r, Visitor&& v)
     {
-        using R = remove_cvref_t<Reflected>;
-
-        static_assert(
-            detail::has_reflect_struct_v<R>,
-            "Can't reflect this type. Define reflect_struct function");
-        reflect_struct(std::forward<Visitor>(v), std::forward<Reflected>(r),
-                       record<R>);
+        using PlainR = std::remove_cvref_t<R>;
+        reflect_struct(std::forward<Visitor>(v), std::forward<R>(r),
+                       record<PlainR>);
     }
 
-    template <typename Reflected>
+    template <reflectable R>
     static constexpr std::size_t num_fields() noexcept
     {
-        using R = remove_cvref_t<Reflected>;
-
-        static_assert(
-            detail::has_reflect_struct_v<R>,
-            "Can't reflect this type. Define reflect_struct function");
-        return reflect_num_fields(record<R>);
+        using PlainR = std::remove_cvref_t<R>;
+        return reflect_num_fields(record<PlainR>);
     }
 };
 } // namespace kl
diff --git a/include/kl/type_traits.hpp b/include/kl/type_traits.hpp
@@ -94,16 +94,6 @@ template <typename T, typename U>
 struct is_same<T, U> : std::integral_constant<bool, std::is_same_v<T, U>>
 {
 };
-
-// C++20 stuff
-template <typename T>
-struct remove_cvref
-{
-    using type = std::remove_cv_t<std::remove_reference_t<T>>;
-};
-
-template <typename T>
-using remove_cvref_t = typename remove_cvref<T>::type;
 } // namespace kl
 
 #define KL_HAS_TYPEDEF_HELPER(type)                                            \

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
@@ -1,5 +1,5 @@
 add_library(kl_cxx_flags INTERFACE)
-target_compile_features(kl_cxx_flags INTERFACE cxx_std_17)
+target_compile_features(kl_cxx_flags INTERFACE cxx_std_20)
 
 if(KL_DEV_BUILD)
     include(DevFlags)

diff --git a/tests/ctti_test.cpp b/tests/ctti_test.cpp
@@ -123,12 +123,12 @@ TEST_CASE("ctti")
     SECTION("type not registered")
     {
         using T = std::vector<int>;
-        REQUIRE(!kl::ctti::is_reflectable<T>);
+        REQUIRE(!kl::is_reflectable_v<T>);
     }
 
     SECTION("global type A")
     {
-        REQUIRE(kl::ctti::is_reflectable<A>);
+        REQUIRE(kl::is_reflectable_v<A>);
         REQUIRE(kl::ctti::num_fields<A>() == 2);
 
         std::ostringstream ss;
@@ -144,7 +144,7 @@ TEST_CASE("ctti")
     {
         using B = ns::B;
 
-        REQUIRE(kl::ctti::is_reflectable<B>);
+        REQUIRE(kl::is_reflectable_v<B>);
         REQUIRE(kl::ctti::num_fields<B>() == 3);
 
         std::ostringstream ss;
@@ -181,7 +181,7 @@ TEST_CASE("ctti")
 
     SECTION("type S in namespace ns with std::array<>")
     {
-        REQUIRE(kl::ctti::is_reflectable<S>);
+        REQUIRE(kl::reflectable<S>);
         static_assert(kl::ctti::num_fields<S>() == 4);
 
         const S s = {5, false, {3.14f}, A{"ZXC", {1, 2, 3, 4, 5, 6}, 0}};
@@ -198,7 +198,7 @@ TEST_CASE("ctti")
 
     SECTION("type Sdev")
     {
-        REQUIRE(kl::ctti::is_reflectable<Sdev>);
+        REQUIRE(kl::reflectable<Sdev>);
         static_assert(kl::ctti::num_fields<Sdev>() == 3);
 
         Sdev sd{};
@@ -219,7 +219,7 @@ TEST_CASE("ctti")
     {
         using T = ns::inner::T;
 
-        REQUIRE(kl::ctti::is_reflectable<T>);
+        REQUIRE(kl::reflectable<T>);
         REQUIRE(kl::ctti::num_fields<T>() == 2 + 2+ 4);
 
         T t{"HELLO",{"WORLD", "Hello"}};