Merge pull request #577 from mpusz/hidden_friends

refactor: binary operators of `quantity` and `quantity_point` are now hidden friends
mpusz · Jul 11, 2024 · dd52808 · dd52808
2 parents c8849e5 + 175fd04
commit dd52808
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -68,6 +68,7 @@
 - refactor: `terminate` replaced with `abort` and a header file added
 - refactor: most `std::remove_const_t` removed and some replaced with the GCC-specific workaround
 - refactor: not needed `remove_reference_t` and `remove_cvref_t` removed
+- refactor: binary operators of `quantity` and `quantity_point` are now hidden friends
 - fix: `QuantityLike` conversions required `Q::rep` instead of using one provided by `quantity_like_traits`
 - fix: `QuantitySpec[Unit]` replaced with `make_reference` in `value_cast`
 - fix: `ice_point` is now defined with the integral offset from `absolute_zero`

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -27,7 +27,7 @@ list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
 
 set(projectPrefix MP_UNITS_)
 
-option(${projectPrefix}DEV_BUILD_LA "Build code depending on the linear algebra library" ON)
+option(${projectPrefix}DEV_BUILD_LA "Build code depending on the linear algebra library" OFF)
 option(${projectPrefix}DEV_IWYU "Enables include-what-you-use" OFF)
 option(${projectPrefix}DEV_CLANG_TIDY "Enables clang-tidy" OFF)
 

diff --git a/conanfile.py b/conanfile.py
@@ -178,7 +178,8 @@ def _build_all(self):
 
     @property
     def _skip_la(self):
-        return bool(self.conf.get("user.mp-units.build:skip_la", default=False))
+        # broken until https://github.com/BobSteagall/wg21/issues/77 is fixed
+        return bool(self.conf.get("user.mp-units.build:skip_la", default=True))
 
     @property
     def _run_clang_tidy(self):

diff --git a/docs/getting_started/installation_and_usage.md b/docs/getting_started/installation_and_usage.md
@@ -304,7 +304,7 @@ tools.build:compiler_executables={"c": "gcc-12", "cpp": "g++-12"}
 
 [`user.mp-units.build:skip_la`](#user-skip-la){ #user-skip-la }
 
-:   [:octicons-tag-24: 2.2.0][conan skip la support] · :octicons-milestone-24: `True`/`False` (Default: `False`)
+:   [:octicons-tag-24: 2.2.0][conan skip la support] · :octicons-milestone-24: `True`/`False` (Default: `True`)
 
     If `user.mp-units.build:all` is enabled, among others, Conan installs the external
     [wg21-linear_algebra](https://conan.io/center/recipes/wg21-linear_algebra)

diff --git a/src/core/include/mp-units/framework/quantity.h b/src/core/include/mp-units/framework/quantity.h
@@ -461,124 +461,126 @@ class quantity {
     lhs.numerical_value_is_an_implementation_detail_ /= rhs.numerical_value_is_an_implementation_detail_;
     return std::forward<Q1>(lhs);
   }
-};
 
-// CTAD
-template<typename Value, Reference R>
-  requires RepresentationOf<Value, get_quantity_spec(R{}).character>
-quantity(Value v, R) -> quantity<R{}, Value>;
+  // binary operators on quantities
+  template<auto R2, typename Rep2>
+    requires detail::CommonlyInvocableQuantities<std::plus<>, quantity, quantity<R2, Rep2>>
+  [[nodiscard]] friend constexpr Quantity auto operator+(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    using ret = detail::common_quantity_for<std::plus<>, quantity, quantity<R2, Rep2>>;
+    const ret ret_lhs(lhs);
+    const ret ret_rhs(rhs);
+    return ::mp_units::quantity{ret_lhs.numerical_value_ref_in(ret::unit) + ret_rhs.numerical_value_ref_in(ret::unit),
+                                ret::reference};
+  }
 
-template<QuantityLike Q>
-explicit(
-  is_specialization_of<decltype(quantity_like_traits<Q>::to_numerical_value(std::declval<Q>())), convert_explicitly>)
-  quantity(Q) -> quantity<quantity_like_traits<Q>::reference, typename quantity_like_traits<Q>::rep>;
+  template<auto R2, typename Rep2>
+    requires detail::CommonlyInvocableQuantities<std::minus<>, quantity, quantity<R2, Rep2>>
+  [[nodiscard]] friend constexpr Quantity auto operator-(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    using ret = detail::common_quantity_for<std::minus<>, quantity, quantity<R2, Rep2>>;
+    const ret ret_lhs(lhs);
+    const ret ret_rhs(rhs);
+    return ::mp_units::quantity{ret_lhs.numerical_value_ref_in(ret::unit) - ret_rhs.numerical_value_ref_in(ret::unit),
+                                ret::reference};
+  }
 
-// binary operators on quantities
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires detail::CommonlyInvocableQuantities<std::plus<>, quantity<R1, Rep1>, quantity<R2, Rep2>>
-[[nodiscard]] constexpr Quantity auto operator+(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  using ret = detail::common_quantity_for<std::plus<>, quantity<R1, Rep1>, quantity<R2, Rep2>>;
-  const ret ret_lhs(lhs);
-  const ret ret_rhs(rhs);
-  return quantity{ret_lhs.numerical_value_ref_in(ret::unit) + ret_rhs.numerical_value_ref_in(ret::unit),
-                  ret::reference};
-}
+  template<auto R2, typename Rep2>
+    requires(!treat_as_floating_point<Rep>) && (!treat_as_floating_point<Rep2>) &&
+            detail::CommonlyInvocableQuantities<std::modulus<>, quantity, quantity<R2, Rep2>>
+  [[nodiscard]] friend constexpr Quantity auto operator%(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    MP_UNITS_EXPECTS_DEBUG(rhs != rhs.zero());
+    using ret = detail::common_quantity_for<std::modulus<>, quantity, quantity<R2, Rep2>>;
+    const ret ret_lhs(lhs);
+    const ret ret_rhs(rhs);
+    return ::mp_units::quantity{ret_lhs.numerical_value_ref_in(ret::unit) % ret_rhs.numerical_value_ref_in(ret::unit),
+                                ret::reference};
+  }
 
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires detail::CommonlyInvocableQuantities<std::minus<>, quantity<R1, Rep1>, quantity<R2, Rep2>>
-[[nodiscard]] constexpr Quantity auto operator-(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  using ret = detail::common_quantity_for<std::minus<>, quantity<R1, Rep1>, quantity<R2, Rep2>>;
-  const ret ret_lhs(lhs);
-  const ret ret_rhs(rhs);
-  return quantity{ret_lhs.numerical_value_ref_in(ret::unit) - ret_rhs.numerical_value_ref_in(ret::unit),
-                  ret::reference};
-}
+  template<auto R2, typename Rep2>
+    requires detail::InvocableQuantities<std::multiplies<>, quantity, quantity<R2, Rep2>>
+  [[nodiscard]] friend constexpr Quantity auto operator*(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    return ::mp_units::quantity{lhs.numerical_value_ref_in(get_unit(R)) * rhs.numerical_value_ref_in(get_unit(R2)),
+                                R * R2};
+  }
 
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires(!treat_as_floating_point<Rep1>) && (!treat_as_floating_point<Rep2>) &&
-          detail::CommonlyInvocableQuantities<std::modulus<>, quantity<R1, Rep1>, quantity<R2, Rep2>>
-[[nodiscard]] constexpr Quantity auto operator%(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  MP_UNITS_EXPECTS_DEBUG(rhs != rhs.zero());
-  using ret = detail::common_quantity_for<std::modulus<>, quantity<R1, Rep1>, quantity<R2, Rep2>>;
-  const ret ret_lhs(lhs);
-  const ret ret_rhs(rhs);
-  return quantity{ret_lhs.numerical_value_ref_in(ret::unit) % ret_rhs.numerical_value_ref_in(ret::unit),
-                  ret::reference};
-}
+  template<typename Value>
+    requires(!Quantity<Value>) && (!Reference<Value>) &&
+            detail::InvokeResultOf<get_quantity_spec(R).character, std::multiplies<>, Rep, const Value&>
+  [[nodiscard]] friend constexpr QuantityOf<get_quantity_spec(R)> auto operator*(const quantity& q, const Value& v)
+  {
+    return ::mp_units::quantity{q.numerical_value_ref_in(get_unit(R)) * v, R};
+  }
 
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires detail::InvocableQuantities<std::multiplies<>, quantity<R1, Rep1>, quantity<R2, Rep2>>
-[[nodiscard]] constexpr Quantity auto operator*(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  return quantity{lhs.numerical_value_ref_in(get_unit(R1)) * rhs.numerical_value_ref_in(get_unit(R2)), R1 * R2};
-}
+  template<typename Value>
+    requires(!Quantity<Value>) && (!Reference<Value>) &&
+            detail::InvokeResultOf<get_quantity_spec(R).character, std::multiplies<>, const Value&, Rep>
+  [[nodiscard]] friend constexpr QuantityOf<get_quantity_spec(R)> auto operator*(const Value& v, const quantity& q)
+  {
+    return ::mp_units::quantity{v * q.numerical_value_ref_in(get_unit(R)), R};
+  }
 
-template<auto R, typename Rep, typename Value>
-  requires(!Quantity<Value>) && (!Reference<Value>) &&
-          detail::InvokeResultOf<get_quantity_spec(R).character, std::multiplies<>, Rep, const Value&>
-[[nodiscard]] constexpr QuantityOf<get_quantity_spec(R)> auto operator*(const quantity<R, Rep>& q, const Value& v)
-{
-  return quantity{q.numerical_value_ref_in(get_unit(R)) * v, R};
-}
+  template<auto R2, typename Rep2>
+    requires detail::InvocableQuantities<std::divides<>, quantity, quantity<R2, Rep2>>
+  [[nodiscard]] friend constexpr Quantity auto operator/(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    MP_UNITS_EXPECTS_DEBUG(rhs != rhs.zero());
+    return ::mp_units::quantity{lhs.numerical_value_ref_in(get_unit(R)) / rhs.numerical_value_ref_in(get_unit(R2)),
+                                R / R2};
+  }
 
-template<typename Value, auto R, typename Rep>
-  requires(!Quantity<Value>) && (!Reference<Value>) &&
-          detail::InvokeResultOf<get_quantity_spec(R).character, std::multiplies<>, const Value&, Rep>
-[[nodiscard]] constexpr QuantityOf<get_quantity_spec(R)> auto operator*(const Value& v, const quantity<R, Rep>& q)
-{
-  return quantity{v * q.numerical_value_ref_in(get_unit(R)), R};
-}
+  template<typename Value>
+    requires(!Quantity<Value>) && (!Reference<Value>) &&
+            detail::InvokeResultOf<get_quantity_spec(R).character, std::divides<>, Rep, const Value&>
+  [[nodiscard]] friend constexpr QuantityOf<get_quantity_spec(R)> auto operator/(const quantity& q, const Value& v)
+  {
+    MP_UNITS_EXPECTS_DEBUG(v != quantity_values<Value>::zero());
+    return ::mp_units::quantity{q.numerical_value_ref_in(get_unit(R)) / v, R};
+  }
 
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires detail::InvocableQuantities<std::divides<>, quantity<R1, Rep1>, quantity<R2, Rep2>>
-[[nodiscard]] constexpr Quantity auto operator/(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  MP_UNITS_EXPECTS_DEBUG(rhs != rhs.zero());
-  return quantity{lhs.numerical_value_ref_in(get_unit(R1)) / rhs.numerical_value_ref_in(get_unit(R2)), R1 / R2};
-}
+  template<typename Value>
+    requires(!Quantity<Value>) && (!Reference<Value>) &&
+            detail::InvokeResultOf<get_quantity_spec(R).character, std::divides<>, const Value&, Rep>
+  [[nodiscard]] friend constexpr QuantityOf<inverse(get_quantity_spec(R))> auto operator/(const Value& v,
+                                                                                          const quantity& q)
+  {
+    return ::mp_units::quantity{v / q.numerical_value_ref_in(get_unit(R)), ::mp_units::one / R};
+  }
 
-template<auto R, typename Rep, typename Value>
-  requires(!Quantity<Value>) && (!Reference<Value>) &&
-          detail::InvokeResultOf<get_quantity_spec(R).character, std::divides<>, Rep, const Value&>
-[[nodiscard]] constexpr QuantityOf<get_quantity_spec(R)> auto operator/(const quantity<R, Rep>& q, const Value& v)
-{
-  MP_UNITS_EXPECTS_DEBUG(v != quantity_values<Value>::zero());
-  return quantity{q.numerical_value_ref_in(get_unit(R)) / v, R};
-}
+  template<auto R2, typename Rep2>
+    requires requires { typename std::common_type_t<quantity, quantity<R2, Rep2>>; } &&
+             std::equality_comparable<typename std::common_type_t<quantity, quantity<R2, Rep2>>::rep>
+  [[nodiscard]] friend constexpr bool operator==(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    using ct = std::common_type_t<quantity, quantity<R2, Rep2>>;
+    const ct ct_lhs(lhs);
+    const ct ct_rhs(rhs);
+    return ct_lhs.numerical_value_ref_in(ct::unit) == ct_rhs.numerical_value_ref_in(ct::unit);
+  }
 
-template<typename Value, auto R, typename Rep>
-  requires(!Quantity<Value>) && (!Reference<Value>) &&
-          detail::InvokeResultOf<get_quantity_spec(R).character, std::divides<>, const Value&, Rep>
-[[nodiscard]] constexpr QuantityOf<inverse(get_quantity_spec(R))> auto operator/(const Value& v,
-                                                                                 const quantity<R, Rep>& q)
-{
-  return quantity{v / q.numerical_value_ref_in(get_unit(R)), ::mp_units::one / R};
-}
+  template<auto R2, typename Rep2>
+    requires requires { typename std::common_type_t<quantity, quantity<R2, Rep2>>; } &&
+             std::three_way_comparable<typename std::common_type_t<quantity, quantity<R2, Rep2>>::rep>
+  [[nodiscard]] friend constexpr auto operator<=>(const quantity& lhs, const quantity<R2, Rep2>& rhs)
+  {
+    using ct = std::common_type_t<quantity, quantity<R2, Rep2>>;
+    const ct ct_lhs(lhs);
+    const ct ct_rhs(rhs);
+    return ct_lhs.numerical_value_ref_in(ct::unit) <=> ct_rhs.numerical_value_ref_in(ct::unit);
+  }
+};
 
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires requires { typename std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>; } &&
-           std::equality_comparable<typename std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>::rep>
-[[nodiscard]] constexpr bool operator==(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  using ct = std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>;
-  const ct ct_lhs(lhs);
-  const ct ct_rhs(rhs);
-  return ct_lhs.numerical_value_ref_in(ct::unit) == ct_rhs.numerical_value_ref_in(ct::unit);
-}
+// CTAD
+template<typename Value, Reference R>
+  requires RepresentationOf<Value, get_quantity_spec(R{}).character>
+quantity(Value v, R) -> quantity<R{}, Value>;
 
-template<auto R1, typename Rep1, auto R2, typename Rep2>
-  requires requires { typename std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>; } &&
-           std::three_way_comparable<typename std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>::rep>
-[[nodiscard]] constexpr auto operator<=>(const quantity<R1, Rep1>& lhs, const quantity<R2, Rep2>& rhs)
-{
-  using ct = std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>;
-  const ct ct_lhs(lhs);
-  const ct ct_rhs(rhs);
-  return ct_lhs.numerical_value_ref_in(ct::unit) <=> ct_rhs.numerical_value_ref_in(ct::unit);
-}
+template<QuantityLike Q>
+explicit(
+  is_specialization_of<decltype(quantity_like_traits<Q>::to_numerical_value(std::declval<Q>())), convert_explicitly>)
+  quantity(Q) -> quantity<quantity_like_traits<Q>::reference, typename quantity_like_traits<Q>::rep>;
 
 MP_UNITS_EXPORT_END