From 6e6c5c281a1bf33f950a3bd5f828829d918c5ef7 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Tue, 9 Nov 2021 19:26:26 +0100
Subject: [PATCH] feat: math functions can now be safely used with user-defined
 types

Resolves #310
---
 src/core/include/units/math.h | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/core/include/units/math.h b/src/core/include/units/math.h
index 7aa4113c..d20c7261 100644
--- a/src/core/include/units/math.h
+++ b/src/core/include/units/math.h
@@ -49,7 +49,8 @@ namespace units {
  */
 template<std::intmax_t Num, std::intmax_t Den = 1, Quantity Q>
   requires detail::non_zero<Den>
-[[nodiscard]] inline auto pow(const Q& q) noexcept requires requires { std::pow(q.number(), 1.0); }
+[[nodiscard]] inline auto pow(const Q& q) noexcept
+  requires requires { pow(q.number(), 1.0); } || requires { std::pow(q.number(), 1.0); }
 {
   using rep = TYPENAME Q::rep;
   if constexpr (Num == 0) {
@@ -57,8 +58,9 @@ template<std::intmax_t Num, std::intmax_t Den = 1, Quantity Q>
   } else {
     using dim = dimension_pow<typename Q::dimension, Num, Den>;
     using unit = downcast_unit<dim, pow<Num, Den>(Q::unit::ratio)>;
+    using std::pow;
     return quantity<dim, unit, rep>(
-        static_cast<rep>(std::pow(q.number(), static_cast<double>(Num) / static_cast<double>(Den))));
+        static_cast<rep>(pow(q.number(), static_cast<double>(Num) / static_cast<double>(Den))));
   }
 }
 
@@ -72,12 +74,13 @@ template<std::intmax_t Num, std::intmax_t Den = 1, Quantity Q>
  */
 template<Quantity Q>
 [[nodiscard]] inline Quantity auto sqrt(const Q& q) noexcept
-  requires requires { std::sqrt(q.number()); }
+  requires requires { sqrt(q.number()); }  ||  requires { std::sqrt(q.number()); }
 {
   using dim = dimension_pow<typename Q::dimension, 1, 2>;
   using unit = downcast_unit<dim, sqrt(Q::unit::ratio)>;
   using rep = TYPENAME Q::rep;
-  return quantity<dim, unit, rep>(static_cast<rep>(std::sqrt(q.number())));
+  using std::sqrt;
+  return quantity<dim, unit, rep>(static_cast<rep>(sqrt(q.number())));
 }
 
 /**
@@ -90,12 +93,13 @@ template<Quantity Q>
  */
 template<Quantity Q>
 [[nodiscard]] inline Quantity auto cbrt(const Q& q) noexcept
-  requires requires { std::cbrt(q.number()); }
+  requires requires { cbrt(q.number()); } || requires { std::cbrt(q.number()); }
 {
   using dim = dimension_pow<typename Q::dimension, 1, 3>;
   using unit = downcast_unit<dim, cbrt(Q::unit::ratio)>;
   using rep = TYPENAME Q::rep;
-  return quantity<dim, unit, rep>(static_cast<rep>(std::cbrt(q.number())));
+  using std::cbrt;
+  return quantity<dim, unit, rep>(static_cast<rep>(cbrt(q.number())));
 }
 
 /**
@@ -108,8 +112,10 @@ template<Quantity Q>
  */
 template<typename U, typename Rep>
 [[nodiscard]] inline dimensionless<U, Rep> exp(const dimensionless<U, Rep>& q)
+  requires requires { exp(q.number()); } || requires { std::exp(q.number()); }
 {
-  return quantity_cast<U>(dimensionless<one, Rep>(std::exp(quantity_cast<one>(q).number())));
+  using std::exp;
+  return quantity_cast<U>(dimensionless<one, Rep>(exp(quantity_cast<one>(q).number())));
 }
 
 /**
@@ -120,9 +126,10 @@ template<typename U, typename Rep>
  */
 template<typename D, typename U, typename Rep>
 [[nodiscard]] inline quantity<D, U, Rep> abs(const quantity<D, U, Rep>& q) noexcept
-  requires requires { std::abs(q.number()); }
+  requires requires { abs(q.number()); } ||  requires { std::abs(q.number()); }
 {
-  return quantity<D, U, Rep>(std::abs(q.number()));
+  using std::abs;
+  return quantity<D, U, Rep>(abs(q.number()));
 }
 
 /**