From 9c4671790e454ec0f179010573852110d0ab7036 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Fri, 29 Nov 2024 11:10:20 +0100
Subject: [PATCH] refactor: `all_are_kinds` removed and
 `get_associated_quantity` simplified

---
 .../mp-units/bits/get_associated_quantity.h   | 67 +++----------------
 .../include/mp-units/framework/reference.h    |  2 +-
 2 files changed, 11 insertions(+), 58 deletions(-)

diff --git a/src/core/include/mp-units/bits/get_associated_quantity.h b/src/core/include/mp-units/bits/get_associated_quantity.h
index d6140d18..5d7674e7 100644
--- a/src/core/include/mp-units/bits/get_associated_quantity.h
+++ b/src/core/include/mp-units/bits/get_associated_quantity.h
@@ -34,73 +34,26 @@ struct common_unit;
 namespace detail {
 
 template<AssociatedUnit U>
-[[nodiscard]] consteval auto all_are_kinds(U);
-
-template<typename U, auto... Vs>
-[[nodiscard]] consteval auto all_are_kinds(power<U, Vs...>)
-{
-  return all_are_kinds(U{});
-}
-
-template<typename... Nums, typename... Dens>
-[[nodiscard]] consteval bool all_are_kinds(type_list<Nums...>, type_list<Dens...>)
-{
-  return (... && all_are_kinds(Nums{})) && (... && all_are_kinds(Dens{}));
-}
-
-template<AssociatedUnit U>
-[[nodiscard]] consteval auto all_are_kinds(U)
-{
-  if constexpr (requires { U::_quantity_spec_; })
-    return QuantityKindSpec<MP_UNITS_NONCONST_TYPE(U::_quantity_spec_)>;
-  else if constexpr (requires { U::_reference_unit_; })
-    return all_are_kinds(U::_reference_unit_);
-  else if constexpr (requires { typename U::_num_; }) {
-    return all_are_kinds(typename U::_num_{}, typename U::_den_{});
-  }
-}
-
-template<AssociatedUnit U>
-[[nodiscard]] consteval auto determine_associated_quantity(U u);
-
-template<AssociatedUnit U>
-using to_quantity_spec = decltype(determine_associated_quantity(U{}));
+[[nodiscard]] consteval auto get_associated_quantity(U u);
 
 template<typename... Us>
-[[nodiscard]] consteval auto determine_associated_quantity_impl(common_unit<Us...>)
+[[nodiscard]] consteval auto get_associated_quantity_impl(common_unit<Us...>)
 {
-  return get_common_quantity_spec(determine_associated_quantity(Us{})...);
+  return get_common_quantity_spec(get_associated_quantity(Us{})...);
 }
 
 template<AssociatedUnit U>
-[[nodiscard]] consteval auto determine_associated_quantity_impl(U u)
-{
-  if constexpr (requires { U::_quantity_spec_; })
-    return remove_kind(U::_quantity_spec_);
-  else if constexpr (requires { U::_reference_unit_; })
-    return determine_associated_quantity(U::_reference_unit_);
-  else if constexpr (requires { typename U::_num_; }) {
-    return expr_map<to_quantity_spec, derived_quantity_spec, struct dimensionless>(u);
-  }
-}
-
-template<AssociatedUnit U>
-constexpr auto determine_associated_quantity_result = determine_associated_quantity_impl(U{});
-
-template<AssociatedUnit U>
-[[nodiscard]] consteval auto determine_associated_quantity(U)
-{
-  return determine_associated_quantity_result<U>;
-}
+using to_quantity_spec = decltype(get_associated_quantity(U{}));
 
 template<AssociatedUnit U>
 [[nodiscard]] consteval auto get_associated_quantity_impl(U u)
 {
-  constexpr bool all_kinds = all_are_kinds(U{});
-  if constexpr (all_kinds)
-    return kind_of<determine_associated_quantity(U{})>;
-  else
-    return determine_associated_quantity(u);
+  if constexpr (requires { U::_quantity_spec_; })
+    return remove_kind(U::_quantity_spec_);
+  else if constexpr (requires { U::_reference_unit_; })
+    return get_associated_quantity(U::_reference_unit_);
+  else if constexpr (requires { typename U::_num_; })
+    return expr_map<to_quantity_spec, derived_quantity_spec, struct dimensionless>(u);
 }
 
 template<AssociatedUnit U>
diff --git a/src/core/include/mp-units/framework/reference.h b/src/core/include/mp-units/framework/reference.h
index 82343482..e2336fff 100644
--- a/src/core/include/mp-units/framework/reference.h
+++ b/src/core/include/mp-units/framework/reference.h
@@ -51,7 +51,7 @@ MP_UNITS_EXPORT_BEGIN
 
 [[nodiscard]] consteval QuantitySpec auto get_quantity_spec(AssociatedUnit auto u)
 {
-  return detail::get_associated_quantity(u);
+  return kind_of<detail::get_associated_quantity(u)>;
 }
 
 /**