feat: quantity_spec support added

example/box_example.cpp

@@ -34,15 +34,14 @@
 namespace {
 
 using namespace units;
-using namespace units::si;
 using namespace units::si::unit_symbols;
 
-inline constexpr auto g = 1 * standard_gravity;
+inline constexpr auto g = 1 * si::standard_gravity;
 inline constexpr auto air_density = 1.225 * isq::mass_density[kg / m3];
 
 class Box {
   quantity<isq::area[m2]> base_;
-  quantity<isq::length[m]> height_;
+  quantity<isq::height[m]> height_;
   quantity<isq::mass_density[kg / m3]> density_ = air_density;
 public:
   constexpr Box(const quantity<isq::length[m]>& length, const quantity<isq::length[m]>& width,
@@ -51,11 +50,11 @@ public:
   {
   }
 
-  [[nodiscard]] constexpr auto filled_weight() const
+  [[nodiscard]] constexpr quantity_of<isq::weight> auto filled_weight() const
   {
     const weak_quantity_of<isq::volume> auto volume = base_ * height_;
-    const quantity_of<isq::mass> auto mass = density_ * volume;
-    return mass * g;
+    const weak_quantity_of<isq::mass> auto mass = density_ * volume;
+    return quantity_cast<isq::weight>(mass * g);
   }
 
   [[nodiscard]] constexpr quantity<isq::length[m]> fill_level(const quantity<isq::mass[kg]>& measured_mass) const
@@ -80,7 +79,9 @@ public:
 
 int main()
 {
-  const auto mm = isq::length[unit_symbols::mm];  // helper reference value
+  using namespace units::si;
+
+  constexpr auto mm = isq::length[unit_symbols::mm];  // helper reference object
 
   const auto height = (200.0 * mm)[metre];
   auto box = Box(1000.0 * mm, 500.0 * mm, height);

example/glide_computer/include/glide_computer.h

@@ -152,7 +152,7 @@ public:
     leg(const waypoint& b, const waypoint& e) noexcept : begin_(&b), end_(&e) {}
     constexpr const waypoint& begin() const { return *begin_; };
     constexpr const waypoint& end() const { return *end_; }
-    constexpr const distance get_length() const { return length_; }
+    constexpr distance get_length() const { return length_; }
   };
   using legs = std::vector<leg>;
 

example/hello_units.cpp

@@ -30,7 +30,7 @@
 
 using namespace units;
 
-constexpr quantity_of<isq::speed> auto avg_speed(quantity_of<isq::length> auto d, quantity_of<isq::time> auto t)
+constexpr quantity_of<isq::speed> auto avg_speed(quantity_of<isq::distance> auto d, quantity_of<isq::duration> auto t)
 {
   return quantity_cast<isq::speed>(d / t);
 }
@@ -42,8 +42,8 @@ int main()
 
   constexpr auto v1 = 110 * isq::speed[km / h];
   constexpr auto v2 = 70. * isq::speed[mph];
-  constexpr auto v3 = avg_speed(220 * isq::length[km], 2 * isq::time[h]);
-  constexpr auto v4 = avg_speed(quantity<isq::length[mi]>{140}, quantity<isq::time[h]>{2});
+  constexpr auto v3 = avg_speed(220 * isq::distance[km], 2 * isq::duration[h]);
+  constexpr auto v4 = avg_speed(quantity<isq::distance[mi]>{140}, quantity<isq::duration[h]>{2});
   constexpr auto v5 = quantity_cast<quantity<isq::speed[m / s]>>(v3);
   constexpr auto v6 = quantity_cast<m / s>(v4);
   constexpr auto v7 = quantity_cast<int>(v6);