Merge pull request #6 from KlasMvW/use_concepts_nottype_traits

Use concepts not type traits

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
 
 set(CMAKE_CXX_STANDARD 20)
 
-project(TS VERSION 0.2.0 LANGUAGES CXX)
+project(TS VERSION 0.2.1 LANGUAGES CXX)
 
 enable_testing()
 

TSConfigVersion.cmake

@@ -9,16 +9,52 @@
 # The variable CVF_VERSION must be set before calling configure_file().
 
 
-set(PACKAGE_VERSION "0.2.0")
+if (PACKAGE_FIND_VERSION_RANGE)
+ message(AUTHOR_WARNING
+ "`find_package()` specify a version range but the version strategy "
+ "(ExactVersion) of the module `${PACKAGE_FIND_NAME}` is incompatible "
+ "with this request. Only the lower endpoint of the range will be used.")
+endif()
+
+set(PACKAGE_VERSION "0.2.1")
+
+if("0.2.1" MATCHES "^([0-9]+)\\.([0-9]+)\\.([0-9]+)") # strip the tweak version
+ set(CVF_VERSION_MAJOR "${CMAKE_MATCH_1}")
+ set(CVF_VERSION_MINOR "${CMAKE_MATCH_2}")
+ set(CVF_VERSION_PATCH "${CMAKE_MATCH_3}")
 
-if("0.2.0" MATCHES "^([0-9]+\\.[0-9]+\\.[0-9]+)\\.") # strip the tweak version
- set(CVF_VERSION_NO_TWEAK "${CMAKE_MATCH_1}")
+ if(NOT CVF_VERSION_MAJOR VERSION_EQUAL 0)
+ string(REGEX REPLACE "^0+" "" CVF_VERSION_MAJOR "${CVF_VERSION_MAJOR}")
+ endif()
+ if(NOT CVF_VERSION_MINOR VERSION_EQUAL 0)
+ string(REGEX REPLACE "^0+" "" CVF_VERSION_MINOR "${CVF_VERSION_MINOR}")
+ endif()
+ if(NOT CVF_VERSION_PATCH VERSION_EQUAL 0)
+ string(REGEX REPLACE "^0+" "" CVF_VERSION_PATCH "${CVF_VERSION_PATCH}")
+ endif()
+
+ set(CVF_VERSION_NO_TWEAK "${CVF_VERSION_MAJOR}.${CVF_VERSION_MINOR}.${CVF_VERSION_PATCH}")
 else()
- set(CVF_VERSION_NO_TWEAK "0.2.0")
+ set(CVF_VERSION_NO_TWEAK "0.2.1")
 endif()
 
-if(PACKAGE_FIND_VERSION MATCHES "^([0-9]+\\.[0-9]+\\.[0-9]+)\\.") # strip the tweak version
- set(REQUESTED_VERSION_NO_TWEAK "${CMAKE_MATCH_1}")
+if(PACKAGE_FIND_VERSION MATCHES "^([0-9]+)\\.([0-9]+)\\.([0-9]+)") # strip the tweak version
+ set(REQUESTED_VERSION_MAJOR "${CMAKE_MATCH_1}")
+ set(REQUESTED_VERSION_MINOR "${CMAKE_MATCH_2}")
+ set(REQUESTED_VERSION_PATCH "${CMAKE_MATCH_3}")
+
+ if(NOT REQUESTED_VERSION_MAJOR VERSION_EQUAL 0)
+ string(REGEX REPLACE "^0+" "" REQUESTED_VERSION_MAJOR "${REQUESTED_VERSION_MAJOR}")
+ endif()
+ if(NOT REQUESTED_VERSION_MINOR VERSION_EQUAL 0)
+ string(REGEX REPLACE "^0+" "" REQUESTED_VERSION_MINOR "${REQUESTED_VERSION_MINOR}")
+ endif()
+ if(NOT REQUESTED_VERSION_PATCH VERSION_EQUAL 0)
+ string(REGEX REPLACE "^0+" "" REQUESTED_VERSION_PATCH "${REQUESTED_VERSION_PATCH}")
+ endif()
+
+ set(REQUESTED_VERSION_NO_TWEAK
+ "${REQUESTED_VERSION_MAJOR}.${REQUESTED_VERSION_MINOR}.${REQUESTED_VERSION_PATCH}")
 else()
  set(REQUESTED_VERSION_NO_TWEAK "${PACKAGE_FIND_VERSION}")
 endif()

include/ts/typesafe_coordinate_systems.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <type_traits>
+#include <concepts>
 
 // This file implements type-safe coordinate transformations.
 //
@@ -91,34 +91,17 @@
 // This is more complicated than finding all 'to_parent' functions as under 1. This is because
 // the parent systems are not aware of their children.
 // This a recursive procedure and the responsible function is 'down'.
-// To detect existing to_child functions we use SFINAE (Substitution Failure Is Not An Error).
-// The responsible functions are the overoaded find_function::to_child functions.
+// To detect existing to_child functions we use 'concepts'
 
 namespace ts{
 namespace find_function {
 
-// Compile time check if a to_child function with specific arguments exists.
-namespace internal {
+template <typename... Args>
+concept to_child = requires(Args ... args)
+{
+ transform::to_child(args...);
+};
 
-// Define template variable to_child that defaults to false.
-template <typename, typename, typename = void, typename...>
-constexpr bool to_child = false;
-
-// Specialization of templateVariable to_child.
-// The template argument std::void_t<decltype(transform::to_child(std::declval<Arg1>(), std::declval<Arg2>(), std::declval<GeometryState>()...))>
-// has the 'type' ´void´ if the decltype expression is valid after substitution.
-template <typename Arg1, typename Arg2, typename... GeometryState>
-constexpr bool to_child<Arg1,
- Arg2,
- std::void_t<decltype(transform::to_child(std::declval<Arg1>(), std::declval<Arg2>(), std::declval<GeometryState>()...))>,
- GeometryState...> = true;
-} // namespace internal
-
-// Interface variable to internal::to_child.
-// template arguments, Arg1, Arg2, void, GeometryState..., will match the specialization above if the decltype expression can be evaluated and
-// find_function::to_child will evaluate to true. Else find_function::to_child will be false.
-template <typename Arg1, typename Arg2, typename... GeometryState>
-constexpr bool to_child = internal::to_child<Arg1, Arg2, void, GeometryState...>;
 } // namespace find_function
 
 // Compile time detection of the common ancestor type of S1 and S2.