refactor: absolute renamed to point

Resolves #645

docs/getting_started/quick_start.md

@@ -261,7 +261,7 @@ This introduces an additional type-safety.
       using namespace mp_units::si::unit_symbols;
       using namespace mp_units::usc::unit_symbols;
 
-      quantity_point temp = absolute<deg_C>(20.);
+      quantity_point temp = point<deg_C>(20.);
       std::println("Temperature: {} ({})",
                    temp.quantity_from_zero(),
                    temp.in(deg_F).quantity_from_zero());
@@ -282,7 +282,7 @@ This introduces an additional type-safety.
       using namespace mp_units::si::unit_symbols;
       using namespace mp_units::usc::unit_symbols;
 
-      quantity_point temp = absolute<deg_C>(20.);
+      quantity_point temp = point<deg_C>(20.);
       std::println("Temperature: {} ({})",
                    temp.quantity_from_zero(),
                    temp.in(deg_F).quantity_from_zero());

docs/users_guide/framework_basics/the_affine_space.md

@@ -118,7 +118,7 @@ scale zeroth point using the following rules:
 - otherwise, an instantiation of `zeroth_point_origin<QuantitySpec>` is being used which
   provides a well-established zeroth point for a specific quantity type.
 
-Quantity points with default point origins may be constructed with the `absolute` construction
+Quantity points with default point origins may be constructed with the `point` construction
 helper or forcing an explicit conversion from the `quantity`:
 
 ```cpp
@@ -128,9 +128,9 @@ helper or forcing an explicit conversion from the `quantity`:
 quantity_point qp4(42 * m);
 quantity_point qp5(42 * K);
 quantity_point qp6(delta<deg_C>(42));
-quantity_point qp7 = absolute<m>(42);
-quantity_point qp8 = absolute<K>(42);
-quantity_point qp9 = absolute<deg_C>(42);
+quantity_point qp7 = point<m>(42);
+quantity_point qp8 = point<K>(42);
+quantity_point qp9 = point<deg_C>(42);
 ```
 
 !!! tip
@@ -149,7 +149,7 @@ for this domain.
 
 ```cpp
 quantity_point<isq::distance[si::metre]> qp1(100 * m);
-quantity_point<isq::distance[si::metre]> qp2 = absolute<m>(120);
+quantity_point<isq::distance[si::metre]> qp2 = point<m>(120);
 
 assert(qp1.quantity_from_zero() == 100 * m);
 assert(qp2.quantity_from_zero() == 120 * m);
@@ -178,7 +178,7 @@ compatible:
 
 ```cpp
 quantity_point<si::metre> qp1{isq::distance(100 * m)};
-quantity_point<si::metre> qp2 = absolute<isq::height[m]>(120);
+quantity_point<si::metre> qp2 = point<isq::height[m]>(120);
 
 assert(qp2.quantity_from(qp1) == 20 * m);
 assert(qp1.quantity_from(qp2) == -20 * m);
@@ -411,15 +411,15 @@ namespace si {
 inline constexpr struct absolute_zero final : absolute_point_origin<isq::thermodynamic_temperature> {} absolute_zero;
 inline constexpr auto zeroth_kelvin = absolute_zero;
 
-inline constexpr struct ice_point final : relative_point_origin<absolute<milli<kelvin>>(273'150)}> {} ice_point;
+inline constexpr struct ice_point final : relative_point_origin<point<milli<kelvin>>(273'150)}> {} ice_point;
 inline constexpr auto zeroth_degree_Celsius = ice_point;
 
 }
 
 namespace usc {
 
 inline constexpr struct zeroth_degree_Fahrenheit final :
-  relative_point_origin<absolute<mag_ratio<5, 9> * si::degree_Celsius>(-32)> {} zeroth_degree_Fahrenheit;
+  relative_point_origin<point<mag_ratio<5, 9> * si::degree_Celsius>(-32)> {} zeroth_degree_Fahrenheit;
 
 }
 ```
@@ -471,7 +471,7 @@ choose from here. Depending on our needs or tastes, we can:
     quantity_point<si::degree_Celsius, si::zeroth_degree_Celsius> q1 = si::zeroth_degree_Celsius + delta<deg_C>(20.5);
     quantity_point<si::degree_Celsius, si::zeroth_degree_Celsius> q2{delta<deg_C>(20.5), si::zeroth_degree_Celsius};
     quantity_point<si::degree_Celsius, si::zeroth_degree_Celsius> q3{delta<deg_C>(20.5)};
-    quantity_point<si::degree_Celsius, si::zeroth_degree_Celsius> q4 = absolute<deg_C>(20.5);
+    quantity_point<si::degree_Celsius, si::zeroth_degree_Celsius> q4 = point<deg_C>(20.5);
     ```
 
 - specify a unit and use its zeroth point origin implicitly:
@@ -480,7 +480,7 @@ choose from here. Depending on our needs or tastes, we can:
     quantity_point<si::degree_Celsius> q5 = si::zeroth_degree_Celsius + delta<deg_C>(20.5);
     quantity_point<si::degree_Celsius> q6{delta<deg_C>(20.5), si::zeroth_degree_Celsius};
     quantity_point<si::degree_Celsius> q7{delta<deg_C>(20.5)};
-    quantity_point<si::degree_Celsius> q8 = absolute<deg_C>(20.5);
+    quantity_point<si::degree_Celsius> q8 = point<deg_C>(20.5);
     ```
 
 - benefit from CTAD:
@@ -489,7 +489,7 @@ choose from here. Depending on our needs or tastes, we can:
     quantity_point q9 = si::zeroth_degree_Celsius + delta<deg_C>(20.5);
     quantity_point q10{delta<deg_C>(20.5), si::zeroth_degree_Celsius};
     quantity_point q11{delta<deg_C>(20.5)};
-    quantity_point q12 = absolute<deg_C>(20.5);
+    quantity_point q12 = point<deg_C>(20.5);
     ```
 
 In all of the above cases, we end up with the `quantity_point` of the same type and value.
@@ -500,7 +500,7 @@ the following way:
 ![affine_space_6](affine_space_6.svg){style="width:80%;display: block;margin: 0 auto;"}
 
 ```cpp
-constexpr struct room_reference_temp final : relative_point_origin<absolute<deg_C>(21)> {} room_reference_temp;
+constexpr struct room_reference_temp final : relative_point_origin<point<deg_C>(21)> {} room_reference_temp;
 using room_temp = quantity_point<isq::Celsius_temperature[deg_C], room_reference_temp>;
 
 constexpr auto step_delta = delta<isq::Celsius_temperature<deg_C>>(0.5);

example/hw_voltage.cpp

@@ -59,7 +59,7 @@ inline constexpr voltage_hw_t voltage_hw_zero = voltage_hw_range / 2;
 
 // clang-format off
 inline constexpr struct hw_voltage_origin final :
-  relative_point_origin<absolute<si::volt>(min_voltage)> {} hw_voltage_origin;
+  relative_point_origin<point<si::volt>(min_voltage)> {} hw_voltage_origin;
 
 inline constexpr struct hw_voltage_unit final :
   named_unit<"hwV", mag_ratio<voltage_range, voltage_hw_range> * si::volt, hw_voltage_origin> {} hw_voltage_unit;
@@ -74,7 +74,7 @@ std::optional<hw_voltage_quantity_point> read_hw_voltage()
 {
   voltage_hw_t local_copy = hw_voltage_value;
   if (local_copy == voltage_hw_error) return std::nullopt;
-  return absolute<hw_voltage_unit>(local_copy);
+  return point<hw_voltage_unit>(local_copy);
 }
 
 void print(QuantityPoint auto qp)

src/core/include/mp-units/framework/construction_helpers.h

@@ -47,7 +47,7 @@ struct delta_ {
 };
 
 template<Reference R>
-struct absolute_ {
+struct point_ {
   template<typename FwdRep, RepresentationOf<get_quantity_spec(R{})> Rep = std::remove_cvref_t<FwdRep>>
   [[nodiscard]] constexpr quantity_point<MP_UNITS_EXPRESSION_WORKAROUND(R{}), default_point_origin(R{}), Rep>
   operator()(FwdRep&& lhs) const
@@ -62,7 +62,10 @@ template<Reference auto R>
 constexpr delta_<MP_UNITS_REMOVE_CONST(decltype(R))> delta{};
 
 template<Reference auto R>
-constexpr absolute_<MP_UNITS_REMOVE_CONST(decltype(R))> absolute{};
+constexpr point_<MP_UNITS_REMOVE_CONST(decltype(R))> point{};
+
+template<Reference auto R>
+[[deprecated("Use `point` instead")]] constexpr point_<MP_UNITS_REMOVE_CONST(decltype(R))> absolute{};
 
 MP_UNITS_EXPORT_END
 

src/core/include/mp-units/framework/reference.h

@@ -207,7 +207,7 @@ template<typename FwdRep, Reference R, RepresentationOf<get_quantity_spec(R{})>
 template<typename FwdRep, Reference R, RepresentationOf<get_quantity_spec(R{})> Rep = std::remove_cvref_t<FwdRep>>
   requires detail::OffsetUnit<decltype(get_unit(R{}))>
 [[deprecated(
-  "References using offset units (e.g., temperatures) should be constructed with the `delta` or `absolute` "
+  "References using offset units (e.g., temperatures) should be constructed with the `delta` or `point` "
   "helpers")]] constexpr auto
 operator*(FwdRep&& lhs, R r)
 {
@@ -217,7 +217,7 @@ operator*(FwdRep&& lhs, R r)
 template<typename FwdRep, Reference R, RepresentationOf<get_quantity_spec(R{})> Rep = std::remove_cvref_t<FwdRep>>
   requires detail::OffsetUnit<decltype(get_unit(R{}))>
 [[deprecated(
-  "References using offset units (e.g., temperatures) should be constructed with the `delta` or `absolute` "
+  "References using offset units (e.g., temperatures) should be constructed with the `delta` or `point` "
   "helpers")]] constexpr auto
 operator/(FwdRep&& lhs, R)
 {

src/systems/include/mp-units/systems/si/units.h

@@ -78,7 +78,7 @@ inline constexpr struct weber final : named_unit<"Wb", volt * second> {} weber;
 inline constexpr struct tesla final : named_unit<"T", weber / square(metre)> {} tesla;
 inline constexpr struct henry final : named_unit<"H", weber / ampere> {} henry;
 
-inline constexpr struct ice_point final : relative_point_origin<absolute<milli<kelvin>>(273'150)> {} ice_point;
+inline constexpr struct ice_point final : relative_point_origin<::mp_units::point<milli<kelvin>>(273'150)> {} ice_point;
 inline constexpr auto zeroth_degree_Celsius = ice_point;
 inline constexpr struct degree_Celsius final : named_unit<symbol_text{u8"℃", "`C"}, kelvin, zeroth_degree_Celsius> {} degree_Celsius;
 

src/systems/include/mp-units/systems/usc.h

@@ -127,7 +127,7 @@ inline constexpr struct inch_of_mercury final : named_unit<"inHg", mag_ratio<3'3
 #endif
 
 // https://en.wikipedia.org/wiki/United_States_customary_units#Temperature
-inline constexpr struct zeroth_degree_Fahrenheit final : relative_point_origin<absolute<mag_ratio<5, 9> * si::degree_Celsius>(-32)> {} zeroth_degree_Fahrenheit;
+inline constexpr struct zeroth_degree_Fahrenheit final : relative_point_origin<::mp_units::point<mag_ratio<5, 9> * si::degree_Celsius>(-32)> {} zeroth_degree_Fahrenheit;
 inline constexpr struct degree_Fahrenheit final : named_unit<symbol_text{u8"℉", "`F"}, mag_ratio<5, 9> * si::degree_Celsius, zeroth_degree_Fahrenheit> {} degree_Fahrenheit;
 
 // clang-format on

test/static/quantity_point_test.cpp

@@ -808,8 +808,8 @@ static_assert(quantity_point{42 * m}.quantity_from_zero() == 42 * m);
 static_assert(quantity_point{isq::height(42 * m)}.quantity_from_zero() == 42 * m);
 static_assert(quantity_point{delta<deg_C>(20)}.quantity_from_zero() == delta<deg_C>(20));
 static_assert(quantity_point{delta<deg_C>(20.)}.in(deg_F).quantity_from_zero() == delta<deg_F>(68));
-static_assert(absolute<deg_C>(20).quantity_from_zero() == delta<deg_C>(20));
-static_assert(absolute<deg_C>(20.).in(deg_F).quantity_from_zero() == delta<deg_F>(68));
+static_assert(point<deg_C>(20).quantity_from_zero() == delta<deg_C>(20));
+static_assert(point<deg_C>(20.).in(deg_F).quantity_from_zero() == delta<deg_F>(68));
 
 static_assert((mean_sea_level + 42 * m).quantity_from_zero() == 42 * m);
 static_assert((ground_level + 42 * m).quantity_from_zero() == 84 * m);