From 7a26125e1614670249273975a0787c01700ce130 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Mon, 19 Dec 2022 14:55:54 +0100
Subject: [PATCH] refactor: public headers cleanup

Public headers should be only the ones that a user may have a need to actually include in his/her code.
---
 src/core/CMakeLists.txt                       |  9 ----
 .../include/units/bits/expression_template.h  |  2 +-
 src/core/include/units/{ => bits}/magnitude.h |  6 +--
 .../include/units/{ => bits}/quantity_cast.h  |  4 +-
 .../{concepts.h => bits/quantity_concepts.h}  | 48 +++++++++----------
 src/core/include/units/{ => bits}/ratio.h     |  0
 .../include/units/{ => bits}/symbol_text.h    |  0
 .../units/bits/{external => }/text_tools.h    |  2 +-
 src/core/include/units/dimension.h            |  2 +-
 src/core/include/units/quantity.h             |  6 +--
 src/core/include/units/random.h               |  2 +-
 src/core/include/units/reference.h            |  2 +-
 src/core/include/units/system_reference.h     |  1 -
 src/core/include/units/unit.h                 |  8 ++--
 test/unit_test/static/magnitude_test.cpp      |  4 +-
 test/unit_test/static/ratio_test.cpp          |  2 +-
 16 files changed, 43 insertions(+), 55 deletions(-)
 rename src/core/include/units/{ => bits}/magnitude.h (99%)
 rename src/core/include/units/{ => bits}/quantity_cast.h (99%)
 rename src/core/include/units/{concepts.h => bits/quantity_concepts.h} (75%)
 rename src/core/include/units/{ => bits}/ratio.h (100%)
 rename src/core/include/units/{ => bits}/symbol_text.h (100%)
 rename src/core/include/units/bits/{external => }/text_tools.h (98%)

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index ef00b8e3..04df1b6f 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -38,26 +38,17 @@ add_library(
     mp-units-core
     INTERFACE
     # include/units/chrono.h
-    include/units/concepts.h
     include/units/customization_points.h
     include/units/dimension.h
     # include/units/generic/angle.h
     include/units/generic/dimensionless.h
     # include/units/generic/solid_angle.h
-    # include/units/kind.h
-    include/units/magnitude.h
     include/units/math.h
-    # include/units/point_origin.h
     include/units/quantity.h
-    include/units/quantity_cast.h
-    # include/units/quantity_kind.h
     # include/units/quantity_point.h
-    # include/units/quantity_point_kind.h
     include/units/quantity_spec.h
     include/units/random.h
-    include/units/ratio.h
     include/units/reference.h
-    include/units/symbol_text.h
     include/units/system_reference.h
     include/units/unit.h
 )
diff --git a/src/core/include/units/bits/expression_template.h b/src/core/include/units/bits/expression_template.h
index 07c0e632..a945d757 100644
--- a/src/core/include/units/bits/expression_template.h
+++ b/src/core/include/units/bits/expression_template.h
@@ -25,7 +25,7 @@
 #include <units/bits/external/type_list.h>
 #include <units/bits/external/type_traits.h>
 #include <units/bits/math_concepts.h>
-#include <units/ratio.h>
+#include <units/bits/ratio.h>
 
 namespace units {
 
diff --git a/src/core/include/units/magnitude.h b/src/core/include/units/bits/magnitude.h
similarity index 99%
rename from src/core/include/units/magnitude.h
rename to src/core/include/units/bits/magnitude.h
index 5cb51365..9a2b027a 100644
--- a/src/core/include/units/magnitude.h
+++ b/src/core/include/units/bits/magnitude.h
@@ -24,14 +24,14 @@
 
 #include <units/bits/expression_template.h>
 #include <units/bits/external/hacks.h>
-#include <units/bits/external/text_tools.h>
 #include <units/bits/external/type_name.h>
 #include <units/bits/external/type_traits.h>
 #include <units/bits/math_concepts.h>
 #include <units/bits/prime.h>
+#include <units/bits/ratio.h>
+#include <units/bits/symbol_text.h>
+#include <units/bits/text_tools.h>
 #include <units/customization_points.h>
-#include <units/ratio.h>
-#include <units/symbol_text.h>
 #include <concepts>
 #include <cstdint>
 #include <numbers>
diff --git a/src/core/include/units/quantity_cast.h b/src/core/include/units/bits/quantity_cast.h
similarity index 99%
rename from src/core/include/units/quantity_cast.h
rename to src/core/include/units/bits/quantity_cast.h
index d903040e..a3bbe7e3 100644
--- a/src/core/include/units/quantity_cast.h
+++ b/src/core/include/units/bits/quantity_cast.h
@@ -23,10 +23,10 @@
 #pragma once
 
 #include <units/bits/external/type_traits.h>
-#include <units/concepts.h>
+#include <units/bits/magnitude.h>
+#include <units/bits/quantity_concepts.h>
 #include <units/customization_points.h>
 #include <units/dimension.h>
-#include <units/magnitude.h>
 #include <units/reference.h>
 #include <units/unit.h>
 
diff --git a/src/core/include/units/concepts.h b/src/core/include/units/bits/quantity_concepts.h
similarity index 75%
rename from src/core/include/units/concepts.h
rename to src/core/include/units/bits/quantity_concepts.h
index 19cf418b..f6896341 100644
--- a/src/core/include/units/concepts.h
+++ b/src/core/include/units/bits/quantity_concepts.h
@@ -23,6 +23,7 @@
 #pragma once
 
 #include <units/bits/external/type_traits.h>
+#include <units/customization_points.h>
 #include <units/dimension.h>
 #include <units/quantity_spec.h>
 #include <units/unit.h>
@@ -50,16 +51,6 @@ inline constexpr bool is_specialization_of_reference<reference<Q, U>> = true;
 template<typename T>
 concept Reference = detail::is_specialization_of_reference<T>;
 
-namespace detail {
-
-template<typename T>
-inline constexpr bool is_quantity = false;
-
-}
-
-template<typename T>
-concept Quantity = detail::is_quantity<T>;
-
 template<typename T, typename U>
 concept common_type_with_ =  // exposition only
   (std::same_as<std::common_type_t<T, U>, std::common_type_t<U, T>>) &&
@@ -80,25 +71,33 @@ concept scalable_ =  // exposition only
                           scalable_number_<T, std::common_type_t<typename T::value_type, std::intmax_t>>);
 
 template<typename T>
-concept Representation = (!Quantity<T>) &&
-                         // (!QuantityLike<T>) && (!wrapped_quantity_<T>) &&
-                         std::regular<T> && scalable_<T>;
+concept Representation = (is_scalar<T> || is_vector<T> || is_tensor<T>) && std::regular<T> && scalable_<T>;
 
-template<Reference auto R, Representation Rep>
+template<typename T, quantity_character Ch>
+concept RepresentationOf = Representation<T> && ((Ch == quantity_character::scalar && is_scalar<T>) ||
+                                                 (Ch == quantity_character::vector && is_vector<T>) ||
+                                                 (Ch == quantity_character::tensor && is_tensor<T>));
+
+template<Reference auto R, RepresentationOf<R.quantity_spec.character> Rep>
 class quantity;
 
 namespace detail {
 
-// TODO make the below code from the comment to compile and replace it
 template<auto R, typename Rep>
-inline constexpr bool is_quantity<quantity<R, Rep>> = true;
+void to_base_specialization_of_quantity(const volatile quantity<R, Rep>*);
 
-// template<auto R, typename Rep>
-// void to_base_specialization_of_quantity(const volatile quantity<R, Rep>*);
+}  // namespace detail
 
-// template<typename T>
-//   requires requires(T* t) { to_base_specialization_of_quantity(t); }
-// inline constexpr bool is_quantity<T> = true;
+template<typename T>
+concept Quantity = requires(T* t) { detail::to_base_specialization_of_quantity(t); };
+
+namespace detail {
+
+template<QuantitySpec Q1, QuantitySpec Q2>
+[[nodiscard]] consteval bool is_kind_of(Q1, Q2)
+{
+  return std::derived_from<Q1, Q2>;
+}
 
 }  // namespace detail
 
@@ -109,9 +108,10 @@ inline constexpr bool is_quantity<quantity<R, Rep>> = true;
  * the provided dimension/reference type.
  */
 template<typename Q, auto V>
-concept quantity_of = Quantity<Q> && ((Dimension<std::remove_const_t<decltype(V)>> && Q::dimension == V) ||
-                                      (QuantitySpec<std::remove_const_t<decltype(V)>> && Q::quantity_spec == V) ||
-                                      (Reference<std::remove_const_t<decltype(V)>> && Q::reference == V));
+concept quantity_of = Quantity<Q> &&
+                      ((Dimension<std::remove_const_t<decltype(V)>> && Q::dimension == V) ||
+                       (QuantitySpec<std::remove_const_t<decltype(V)>> && detail::is_kind_of(Q::quantity_spec, V)) ||
+                       (Reference<std::remove_const_t<decltype(V)>> && Q::reference == V));
 
 /**
  * @brief A concept matching all quantities with provided dimension or reference
diff --git a/src/core/include/units/ratio.h b/src/core/include/units/bits/ratio.h
similarity index 100%
rename from src/core/include/units/ratio.h
rename to src/core/include/units/bits/ratio.h
diff --git a/src/core/include/units/symbol_text.h b/src/core/include/units/bits/symbol_text.h
similarity index 100%
rename from src/core/include/units/symbol_text.h
rename to src/core/include/units/bits/symbol_text.h
diff --git a/src/core/include/units/bits/external/text_tools.h b/src/core/include/units/bits/text_tools.h
similarity index 98%
rename from src/core/include/units/bits/external/text_tools.h
rename to src/core/include/units/bits/text_tools.h
index f09b28a9..036caeb7 100644
--- a/src/core/include/units/bits/external/text_tools.h
+++ b/src/core/include/units/bits/text_tools.h
@@ -23,7 +23,7 @@
 #pragma once
 
 #include <units/bits/external/fixed_string.h>
-#include <units/symbol_text.h>
+#include <units/bits/symbol_text.h>
 
 namespace units::detail {
 
diff --git a/src/core/include/units/dimension.h b/src/core/include/units/dimension.h
index f001d448..167294be 100644
--- a/src/core/include/units/dimension.h
+++ b/src/core/include/units/dimension.h
@@ -24,7 +24,7 @@
 
 #include <units/bits/expression_template.h>
 #include <units/bits/external/type_traits.h>
-#include <units/symbol_text.h>
+#include <units/bits/symbol_text.h>
 
 namespace units {
 
diff --git a/src/core/include/units/quantity.h b/src/core/include/units/quantity.h
index f8a98b5b..d8e7f379 100644
--- a/src/core/include/units/quantity.h
+++ b/src/core/include/units/quantity.h
@@ -23,10 +23,8 @@
 
 #pragma once
 
-// IWYU pragma: begin_exports
-#include <units/quantity_cast.h>
-// #include <units/ratio.h>
-#include <units/concepts.h>
+#include <units/bits/quantity_cast.h>
+#include <units/bits/quantity_concepts.h>
 #include <units/customization_points.h>
 #include <units/dimension.h>
 #include <units/quantity_spec.h>
diff --git a/src/core/include/units/random.h b/src/core/include/units/random.h
index 4711695b..1a995fe5 100644
--- a/src/core/include/units/random.h
+++ b/src/core/include/units/random.h
@@ -22,7 +22,7 @@
 
 #pragma once
 
-#include <units/concepts.h>
+#include <units/quantity.h>
 #include <functional>
 #include <random>
 
diff --git a/src/core/include/units/reference.h b/src/core/include/units/reference.h
index 296c0191..21d5e9ca 100644
--- a/src/core/include/units/reference.h
+++ b/src/core/include/units/reference.h
@@ -22,7 +22,7 @@
 
 #pragma once
 
-#include <units/concepts.h>
+#include <units/bits/quantity_concepts.h>
 #include <units/quantity_spec.h>
 #include <units/unit.h>
 
diff --git a/src/core/include/units/system_reference.h b/src/core/include/units/system_reference.h
index f3605622..539b1e02 100644
--- a/src/core/include/units/system_reference.h
+++ b/src/core/include/units/system_reference.h
@@ -22,7 +22,6 @@
 
 #pragma once
 
-#include <units/concepts.h>
 #include <units/quantity_spec.h>
 #include <units/reference.h>
 #include <units/unit.h>
diff --git a/src/core/include/units/unit.h b/src/core/include/units/unit.h
index edb70196..ea2a3e2d 100644
--- a/src/core/include/units/unit.h
+++ b/src/core/include/units/unit.h
@@ -25,13 +25,13 @@
 #include <units/bits/algorithm.h>
 #include <units/bits/expression_template.h>
 #include <units/bits/external/fixed_string.h>
-#include <units/bits/external/text_tools.h>
 #include <units/bits/external/type_name.h>
 #include <units/bits/external/type_traits.h>
+#include <units/bits/magnitude.h>
+#include <units/bits/ratio.h>
+#include <units/bits/symbol_text.h>
+#include <units/bits/text_tools.h>
 #include <units/dimension.h>
-#include <units/magnitude.h>
-#include <units/ratio.h>
-#include <units/symbol_text.h>
 #include <iterator>
 #include <string>
 
diff --git a/test/unit_test/static/magnitude_test.cpp b/test/unit_test/static/magnitude_test.cpp
index c986373e..946a1743 100644
--- a/test/unit_test/static/magnitude_test.cpp
+++ b/test/unit_test/static/magnitude_test.cpp
@@ -20,8 +20,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/magnitude.h>
-#include <units/ratio.h>
+#include <units/bits/magnitude.h>
+#include <units/bits/ratio.h>
 #include <type_traits>
 
 using namespace units;
diff --git a/test/unit_test/static/ratio_test.cpp b/test/unit_test/static/ratio_test.cpp
index 57c8f3e0..0cbd5a76 100644
--- a/test/unit_test/static/ratio_test.cpp
+++ b/test/unit_test/static/ratio_test.cpp
@@ -20,7 +20,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/ratio.h>
+#include <units/bits/ratio.h>
 
 namespace {