Adding remove_cvref and type_identity

cmake/unit_testing.cmake

@@ -27,3 +27,5 @@ endfunction()
 #######################################################################
 
 add_subdirectory( src/tools/Log/test )
+
+add_subdirectory( src/tools/std20/type_traits/test )

src/tools.hpp

@@ -1,4 +1,5 @@
 #include "tools/overload.hpp"
-#include "tools/concepts.hpp"
 
 #include "tools/Log.hpp"
+
+#include "tools/std20/type_traits.hpp"

src/tools/std20/type_traits.hpp

@@ -0,0 +1,33 @@
+#ifndef NJOY_TOOLS_STD20_TYPE_TRAITS
+#define NJOY_TOOLS_STD20_TYPE_TRAITS
+
+// system includes
+#include <type_traits>
+
+// other includes
+
+namespace njoy {
+namespace tools {
+namespace std20 {
+
+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;
+
+template < typename T >
+struct type_identity {
+  using type = T;
+};
+
+template < typename T >
+using type_identity_t = typename type_identity< T >::type;
+
+} // std20 namespace
+} // tools namespace
+} // njoy namespace
+
+#endif

src/tools/std20/type_traits/test/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_cpp_test( std20.type_traits.remove_cvref remove_cvref.test.cpp )
+add_cpp_test( std20.type_traits.type_identity type_identity.test.cpp )

src/tools/std20/type_traits/test/remove_cvref.test.cpp

@@ -0,0 +1,31 @@
+// include Catch2
+#include <catch2/catch_test_macros.hpp>
+
+// what we are testing
+#include "tools/std20/type_traits.hpp"
+
+// other includes
+
+// convenience typedefs
+using namespace njoy::tools;
+
+SCENARIO( "remove_cvref and remove_cvref_t" ) {
+
+  CHECK( std::is_same_v< std20::remove_cvref< int >::type, int > );
+  CHECK( std::is_same_v< std20::remove_cvref< int& >::type, int > );
+  CHECK( std::is_same_v< std20::remove_cvref< int&& >::type, int > );
+  CHECK( std::is_same_v< std20::remove_cvref< const int& >::type, int > );
+  CHECK( std::is_same_v< std20::remove_cvref< int[2] >::type, int[2] > );
+  CHECK( std::is_same_v< std20::remove_cvref< const int[2] >::type, int[2] > );
+  CHECK( std::is_same_v< std20::remove_cvref< const int(&)[2] >::type, int[2] > );
+  CHECK( std::is_same_v< std20::remove_cvref< int(int) >::type, int(int) > );
+
+  CHECK( std::is_same_v< std20::remove_cvref_t< int >, int > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< int& >, int > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< int&& >, int > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< const int& >, int > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< int[2] >, int[2] > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< const int[2] >, int[2] > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< const int(&)[2] >, int[2] > );
+  CHECK( std::is_same_v< std20::remove_cvref_t< int(int) >, int(int) > );
+} // SCENARIO

src/tools/std20/type_traits/test/type_identity.test.cpp

@@ -0,0 +1,31 @@
+// include Catch2
+#include <catch2/catch_test_macros.hpp>
+
+// what we are testing
+#include "tools/std20/type_traits.hpp"
+
+// other includes
+
+// convenience typedefs
+using namespace njoy::tools;
+
+SCENARIO( "type_identity and type_identity_t" ) {
+
+  CHECK( std::is_same_v< std20::type_identity< int >::type, int > );
+  CHECK( std::is_same_v< std20::type_identity< int& >::type, int& > );
+  CHECK( std::is_same_v< std20::type_identity< int&& >::type, int&& > );
+  CHECK( std::is_same_v< std20::type_identity< const int& >::type, const int& > );
+  CHECK( std::is_same_v< std20::type_identity< int[2] >::type, int[2] > );
+  CHECK( std::is_same_v< std20::type_identity< const int[2] >::type, const int[2] > );
+  CHECK( std::is_same_v< std20::type_identity< const int(&)[2] >::type, const int(&)[2] > );
+  CHECK( std::is_same_v< std20::type_identity< int(int) >::type, int(int) > );
+
+  CHECK( std::is_same_v< std20::type_identity_t< int >, int > );
+  CHECK( std::is_same_v< std20::type_identity_t< int& >, int& > );
+  CHECK( std::is_same_v< std20::type_identity_t< int&& >, int&& > );
+  CHECK( std::is_same_v< std20::type_identity_t< const int& >, const int& > );
+  CHECK( std::is_same_v< std20::type_identity_t< int[2] >, int[2] > );
+  CHECK( std::is_same_v< std20::type_identity_t< const int[2] >, const int[2] > );
+  CHECK( std::is_same_v< std20::type_identity_t< const int(&)[2] >, const int(&)[2] > );
+  CHECK( std::is_same_v< std20::type_identity_t< int(int) >, int(int) > );
+} // SCENARIO