From a89bfc6c2154cac17116fe548b107d569c90be14 Mon Sep 17 00:00:00 2001
From: Jonas Hoppe <162709928+czjhoppe@users.noreply.github.com>
Date: Tue, 3 Sep 2024 12:14:42 +0200
Subject: [PATCH] [hacks] add MP_UNITS_IS_VALUE

---
 src/core/include/mp-units/bits/hacks.h             |  2 ++
 .../mp-units/framework/construction_helpers.h      |  4 ++--
 src/systems/include/mp-units/systems/si/chrono.h   |  4 ++--
 src/systems/include/mp-units/systems/si/math.h     | 14 +++++++-------
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/core/include/mp-units/bits/hacks.h b/src/core/include/mp-units/bits/hacks.h
index 905aea8f..bbd3eec7 100644
--- a/src/core/include/mp-units/bits/hacks.h
+++ b/src/core/include/mp-units/bits/hacks.h
@@ -81,11 +81,13 @@
 
 #define MP_UNITS_TYPENAME typename
 #define MP_UNITS_EXPRESSION(x) (x)
+#define MP_UNITS_IS_VALUE(x) (x)
 
 #else
 
 #define MP_UNITS_TYPENAME
 #define MP_UNITS_EXPRESSION(x) x
+#define MP_UNITS_IS_VALUE(x)
 
 #endif
 
diff --git a/src/core/include/mp-units/framework/construction_helpers.h b/src/core/include/mp-units/framework/construction_helpers.h
index c0226e47..43e44c81 100644
--- a/src/core/include/mp-units/framework/construction_helpers.h
+++ b/src/core/include/mp-units/framework/construction_helpers.h
@@ -41,7 +41,7 @@ template<Reference R>
 struct delta_ {
   template<typename Rep>
     requires RepresentationOf<std::remove_cvref_t<Rep>, get_quantity_spec(R{}).character>
-  [[nodiscard]] constexpr quantity<(R{}), std::remove_cvref_t<Rep>> operator()(Rep&& lhs) const
+  [[nodiscard]] constexpr quantity<MP_UNITS_EXPRESSION(R{}), std::remove_cvref_t<Rep>> operator()(Rep&& lhs) const
   {
     return quantity{std::forward<Rep>(lhs), R{}};
   }
@@ -51,7 +51,7 @@ template<Reference R>
 struct absolute_ {
   template<typename Rep>
     requires RepresentationOf<std::remove_cvref_t<Rep>, get_quantity_spec(R{}).character>
-  [[nodiscard]] constexpr quantity_point<(R{}), default_point_origin(R{}), std::remove_cvref_t<Rep>> operator()(
+  [[nodiscard]] constexpr quantity_point<MP_UNITS_EXPRESSION(R{}), default_point_origin(R{}), std::remove_cvref_t<Rep>> operator()(
     Rep&& lhs) const
   {
     return quantity_point{quantity{std::forward<Rep>(lhs), R{}}};
diff --git a/src/systems/include/mp-units/systems/si/chrono.h b/src/systems/include/mp-units/systems/si/chrono.h
index 0fad31e1..c018e8d1 100644
--- a/src/systems/include/mp-units/systems/si/chrono.h
+++ b/src/systems/include/mp-units/systems/si/chrono.h
@@ -127,13 +127,13 @@ namespace detail {
 
 }  // namespace detail
 
-template<QuantityOf<(isq::time)> Q>
+template<QuantityOf<MP_UNITS_IS_VALUE(isq::time)> Q>
 [[nodiscard]] constexpr auto to_chrono_duration(const Q& q)
 {
   return std::chrono::duration<typename Q::rep, decltype(detail::as_ratio(get_canonical_unit(Q::unit).mag))>{q};
 }
 
-template<QuantityPointOf<(isq::time)> QP>
+template<QuantityPointOf<MP_UNITS_IS_VALUE(isq::time)> QP>
   requires is_specialization_of<std::remove_const_t<decltype(QP::absolute_point_origin)>, chrono_point_origin_>
 [[nodiscard]] constexpr auto to_chrono_time_point(const QP& qp)
 {
diff --git a/src/systems/include/mp-units/systems/si/math.h b/src/systems/include/mp-units/systems/si/math.h
index 202ea76d..0a863585 100644
--- a/src/systems/include/mp-units/systems/si/math.h
+++ b/src/systems/include/mp-units/systems/si/math.h
@@ -43,7 +43,7 @@ import std;
 
 MP_UNITS_EXPORT
 namespace mp_units::si {
-template<ReferenceOf<(isq::angular_measure)> auto R, typename Rep>
+template<ReferenceOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto R, typename Rep>
   requires requires(Rep v) { sin(v); } || requires(Rep v) { std::sin(v); }
 [[nodiscard]] inline QuantityOf<dimensionless> auto sin(const quantity<R, Rep>& q) noexcept
 {
@@ -57,7 +57,7 @@ template<ReferenceOf<(isq::angular_measure)> auto R, typename Rep>
     return quantity{sin(q.numerical_value_in(radian)), one};
 }
 
-template<ReferenceOf<(isq::angular_measure)> auto R, typename Rep>
+template<ReferenceOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto R, typename Rep>
   requires requires(Rep v) { cos(v); } || requires(Rep v) { std::cos(v); }
 [[nodiscard]] inline QuantityOf<dimensionless> auto cos(const quantity<R, Rep>& q) noexcept
 {
@@ -71,7 +71,7 @@ template<ReferenceOf<(isq::angular_measure)> auto R, typename Rep>
     return quantity{cos(q.numerical_value_in(radian)), one};
 }
 
-template<ReferenceOf<(isq::angular_measure)> auto R, typename Rep>
+template<ReferenceOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto R, typename Rep>
   requires requires(Rep v) { tan(v); } || requires(Rep v) { std::tan(v); }
 [[nodiscard]] inline QuantityOf<dimensionless> auto tan(const quantity<R, Rep>& q) noexcept
 {
@@ -87,7 +87,7 @@ template<ReferenceOf<(isq::angular_measure)> auto R, typename Rep>
 
 template<ReferenceOf<dimensionless> auto R, typename Rep>
   requires requires(Rep v) { asin(v); } || requires(Rep v) { std::asin(v); }
-[[nodiscard]] inline QuantityOf<(isq::angular_measure)> auto asin(const quantity<R, Rep>& q) noexcept
+[[nodiscard]] inline QuantityOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto asin(const quantity<R, Rep>& q) noexcept
 {
   using std::asin;
   if constexpr (!treat_as_floating_point<Rep>) {
@@ -101,7 +101,7 @@ template<ReferenceOf<dimensionless> auto R, typename Rep>
 
 template<ReferenceOf<dimensionless> auto R, typename Rep>
   requires requires(Rep v) { acos(v); } || requires(Rep v) { std::acos(v); }
-[[nodiscard]] inline QuantityOf<(isq::angular_measure)> auto acos(const quantity<R, Rep>& q) noexcept
+[[nodiscard]] inline QuantityOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto acos(const quantity<R, Rep>& q) noexcept
 {
   using std::acos;
   if constexpr (!treat_as_floating_point<Rep>) {
@@ -115,7 +115,7 @@ template<ReferenceOf<dimensionless> auto R, typename Rep>
 
 template<ReferenceOf<dimensionless> auto R, typename Rep>
   requires requires(Rep v) { atan(v); } || requires(Rep v) { std::atan(v); }
-[[nodiscard]] inline QuantityOf<(isq::angular_measure)> auto atan(const quantity<R, Rep>& q) noexcept
+[[nodiscard]] inline QuantityOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto atan(const quantity<R, Rep>& q) noexcept
 {
   using std::atan;
   if constexpr (!treat_as_floating_point<Rep>) {
@@ -132,7 +132,7 @@ template<auto R1, typename Rep1, auto R2, typename Rep2>
     common_reference(R1, R2);
     requires requires { atan2(v1, v2); } || requires { std::atan2(v1, v2); };
   }
-[[nodiscard]] inline QuantityOf<(isq::angular_measure)> auto atan2(const quantity<R1, Rep1>& y,
+[[nodiscard]] inline QuantityOf<MP_UNITS_IS_VALUE(isq::angular_measure)> auto atan2(const quantity<R1, Rep1>& y,
                                                                  const quantity<R2, Rep2>& x) noexcept
 {
   constexpr auto ref = common_reference(R1, R2);