From 77a124a3d9b9f3a0d521603b1e5e514ecb77a268 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Wed, 30 Nov 2022 17:57:27 +0100
Subject: [PATCH] feat: `quantity_of` and `weak_quantity_of` now support
 references

---
 src/core/include/units/concepts.h | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/core/include/units/concepts.h b/src/core/include/units/concepts.h
index eb9330a1..5a909819 100644
--- a/src/core/include/units/concepts.h
+++ b/src/core/include/units/concepts.h
@@ -101,22 +101,25 @@ inline constexpr bool is_quantity<quantity<R, Rep>> = true;
 }  // namespace detail
 
 /**
- * @brief A concept matching all quantities with provided dimension
+ * @brief A concept matching all quantities with provided dimension or reference
  *
- * Satisfied by all quantities with a dimension being the instantiation derived from
- * the provided dimension type.
+ * Satisfied by all quantities with a dimension/reference being the instantiation derived from
+ * the provided dimension/reference type.
  */
-template<typename Q, Dimension auto D>
-concept quantity_of = Quantity<Q> && Dimension<std::remove_const_t<decltype(D)>> && (Q::dimension == D);
+template<typename Q, auto V>
+concept quantity_of = Quantity<Q> && ((Dimension<std::remove_const_t<decltype(V)>> && Q::dimension == V) ||
+                                      (Reference<std::remove_const_t<decltype(V)>> && Q::reference == V));
 
 /**
  * @brief A concept matching all quantities with provided dimension or reference
  *
- * Satisfied by all quantities with a dimension being the instantiation derived from
- * the provided dimension type.
+ * Satisfied by all quantities with a dimension/reference being the instantiation derived from
+ * the provided dimension/reference type.
  */
-template<typename Q, Dimension auto D>
-concept weak_quantity_of = Quantity<Q> && Dimension<std::remove_const_t<decltype(D)>> &&
-                           (interconvertible(Q::dimension, D));
+template<typename Q, auto V>
+concept weak_quantity_of = Quantity<Q> &&
+                           ((Dimension<std::remove_const_t<decltype(V)>> && interconvertible(Q::dimension, V)) ||
+                            (Reference<std::remove_const_t<decltype(V)>> &&
+                             interconvertible(Q::dimension, V.dimension) && Q::unit == V.unit));
 
 }  // namespace units