refactor: IWYU applied to the source files

`alternative_namespaces` examples left out as I consider them a subject for removal in the nearest future.

example/avg_speed.cpp

@@ -20,10 +20,15 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/isq/si/cgs/speed.h>
+#include <units/isq/si/cgs/length.h>
-#include <units/isq/si/international/speed.h>
+#include <units/isq/si/cgs/speed.h> // IWYU pragma: keep
+#include <units/isq/si/international/length.h>
+#include <units/isq/si/international/speed.h> // IWYU pragma: keep
+#include <units/isq/si/length.h> // IWYU pragma: keep
+#include <units/isq/si/time.h>
 #include <units/isq/si/speed.h>
 #include <units/quantity_io.h>
+#include <exception>
 #include <iostream>
 
 namespace {

example/box_example.cpp

@@ -1,14 +1,40 @@
-#include <units/isq/si/constants.h>
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#include <units/format.h>
+#include <units/generic/dimensionless.h>
+#include <units/isq/si/amount_of_substance.h>
 #include <units/isq/si/area.h>
-#include <units/isq/si/speed.h>
+#include <units/isq/si/constants.h>
 #include <units/isq/si/density.h>
 #include <units/isq/si/force.h>
+#include <units/isq/si/length.h>
 #include <units/isq/si/mass.h>
+#include <units/isq/si/speed.h> // IWYU pragma: keep
 #include <units/isq/si/time.h>
 #include <units/isq/si/volume.h>
-#include <units/format.h>
 #include <cassert>
 #include <iostream>
+#include <utility>
 
 namespace {
 

example/capacitor_time_curve.cpp

@@ -20,11 +20,13 @@
     physical_quantities
 */
 
+#include <units/generic/dimensionless.h>
+#include <units/isq/dimensions/electric_current.h>
 #include <units/isq/si/capacitance.h>
 #include <units/isq/si/resistance.h>
 #include <units/isq/si/time.h>
 #include <units/isq/si/voltage.h>
-#include <units/math.h>
+#include <units/math.h> // IWYU pragma: keep
 #include <units/quantity_io.h>
 #include <iostream>
 

example/clcpp_response.cpp

@@ -24,7 +24,6 @@
 #include <units/isq/si/time.h>
 #include <units/isq/si/typographic/length.h>
 #include <units/isq/si/us/length.h>
-#include <units/isq/si/volume.h>
 #include <units/quantity_io.h>
 #include <iostream>
 

example/conversion_factor.cpp

@@ -15,10 +15,10 @@
  along with this program. If not, see http://www.gnu.org/licenses./
 */
 
-#include <units/isq/si/length.h>
 #include <units/format.h>
-#include <units/quantity_io.h>
+#include <units/isq/si/length.h>
 #include <iostream>
+#include <type_traits>
 
 /*
   get conversion factor from one dimensionally equivalent

example/custom_systems.cpp

@@ -20,9 +20,13 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/quantity_io.h>
+#include <units/base_dimension.h>
 #include <units/isq/si/prefixes.h>
+#include <units/quantity.h>
+#include <units/quantity_io.h>
+#include <units/unit.h>
 #include <iostream>
+#include <type_traits>
 
 using namespace units;
 

example/experimental_angle.cpp

@@ -20,23 +20,24 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/format.h>
 #include <units/generic/angle.h>
-#include <units/isq/si/length.h>
 #include <units/isq/si/energy.h>
-#include <units/isq/si/torque.h>
+#include <units/isq/si/force.h>
+#include <units/isq/si/length.h>
+#include <units/isq/si/torque.h> // IWYU pragma: keep
 #include <units/quantity_io.h>
 #include <iostream>
 
-using namespace units;
-using namespace units::isq::si::literals;
-
 int main()
 {
-  auto torque = 20.0_q_Nm_per_rad;
+  using namespace units::references;
-  auto energy = 20.0_q_J;
+  using namespace units::isq;
+  using namespace units::isq::si::references;
 
-  Angle auto angle = energy / torque;
+  Torque auto torque = 20.0 * (N * m / rad);
+  Energy auto energy = 20.0 * J;
+
+  units::Angle auto angle = energy / torque;
 
   std::cout << angle << '\n';
 }

example/foot_pound_second.cpp

@@ -20,21 +20,19 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/concepts.h>
 #include <units/format.h>
 #include <units/isq/si/fps/density.h>
 #include <units/isq/si/fps/length.h>
 #include <units/isq/si/fps/mass.h>
 #include <units/isq/si/fps/power.h>
 #include <units/isq/si/fps/speed.h>
-#include <units/isq/si/fps/volume.h>
 #include <units/isq/si/length.h>
 #include <units/isq/si/mass.h>
 #include <units/isq/si/power.h>
 #include <units/isq/si/speed.h>
 #include <units/isq/si/volume.h>
-#include <units/quantity.h>
 #include <iostream>
+#include <string_view>
 
 using namespace units::isq;
 

example/geographic.cpp

@@ -23,6 +23,7 @@
 #include "geographic.h"
 #include <cmath>
 #include <numbers>
+#include <type_traits>
 
 namespace {
 

example/geographic.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
-#include <units/format.h>
 #include <units/isq/si/length.h>
 #include <units/quantity_kind.h>
+#include <fmt/format.h>
+#include <limits>
+#include <ostream>
+
+// IWYU pragma: begin_exports
 #include <compare>
+// IWYU pragma: end_exports
 
 namespace geographic {
 

example/glide_computer.cpp

@@ -21,9 +21,13 @@
 // SOFTWARE.
 
 #include "glide_computer.h"
+#include <numeric>
+#include <string_view>
 
 namespace glide_computer {
 
+using namespace units::isq;
+
 task::legs task::make_legs(const waypoints& wpts)
 {
   task::legs res;

example/glide_computer.h

@@ -22,12 +22,24 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include "geographic.h"
-#include <units/format.h>
+#include <units/isq/si/length.h>
-#include <units/math.h>
 #include <units/isq/si/speed.h>
-#include <units/isq/si/international/length.h>
+#include <units/isq/si/time.h>
 #include <units/quantity_point_kind.h>
+// IWYU pragma: end_exports
+
+#include <units/format.h>
+#include <units/math.h> // IWYU pragma: keep
+#include <algorithm>
+#include <array>
+#include <initializer_list>
+#include <iterator>
+#include <ostream>
+#include <ranges>
+#include <string> // IWYU pragma: keep
+#include <vector>
 
 // An example of a really simplified tactical glide computer
 // Simplifications:
@@ -43,9 +55,6 @@
 // - no ground obstacles (i.e. mountains) to pass
 // - flight path exactly on a shortest possible line to destination
 
-using namespace units;
-using namespace units::isq;
-
 template<units::QuantityKind QK>
 struct fmt::formatter<QK> : formatter<typename QK::quantity_type> {
   template<typename FormatContext>
@@ -57,8 +66,8 @@ struct fmt::formatter<QK> : formatter<typename QK::quantity_type> {
 
 namespace glide_computer {
 
-template<QuantityKind QK1, QuantityKind QK2>
+template<units::QuantityKind QK1, units::QuantityKind QK2>
-constexpr Dimensionless auto operator/(const QK1& lhs, const QK2& rhs)
+constexpr units::Dimensionless auto operator/(const QK1& lhs, const QK2& rhs)
   requires(!units::QuantityKindRelatedTo<QK1, QK2>) && requires { lhs.common() / rhs.common();}
 {
   return lhs.common() / rhs.common();
@@ -66,24 +75,24 @@ constexpr Dimensionless auto operator/(const QK1& lhs, const QK2& rhs)
 
 // kinds
 using horizontal_kind = geographic::horizontal_kind;
-struct vertical_kind : kind<vertical_kind, si::dim_length> {};
+struct vertical_kind : units::kind<vertical_kind, units::isq::si::dim_length> {};
-struct vertical_point_kind : point_kind<vertical_point_kind, vertical_kind> {};
+struct vertical_point_kind : units::point_kind<vertical_point_kind, vertical_kind> {};
-struct velocity_kind : derived_kind<velocity_kind, horizontal_kind, si::dim_speed> {};
+struct velocity_kind : units::derived_kind<velocity_kind, horizontal_kind, units::isq::si::dim_speed> {};
-struct rate_of_climb_kind : derived_kind<rate_of_climb_kind, vertical_kind, si::dim_speed> {};
+struct rate_of_climb_kind : units::derived_kind<rate_of_climb_kind, vertical_kind, units::isq::si::dim_speed> {};
 
 // https://en.wikipedia.org/wiki/Flight_planning#Units_of_measurement
 // length
-using distance = quantity_kind<horizontal_kind, si::kilometre>;
+using distance = units::quantity_kind<horizontal_kind, units::isq::si::kilometre>;
-using height = quantity_kind<vertical_kind, si::metre>;
+using height = units::quantity_kind<vertical_kind, units::isq::si::metre>;
-using altitude = quantity_point_kind<vertical_point_kind, si::metre>;
+using altitude = units::quantity_point_kind<vertical_point_kind, units::isq::si::metre>;
 
 // time
-using duration = si::time<si::second>;
+using duration = units::isq::si::time<units::isq::si::second>;
-using timestamp = quantity_point<si::dim_time, si::second>;
+using timestamp = units::quantity_point<units::isq::si::dim_time, units::isq::si::second>;
 
 // speed
-using velocity = quantity_kind<velocity_kind, si::kilometre_per_hour>;
+using velocity = units::quantity_kind<velocity_kind, units::isq::si::kilometre_per_hour>;
-using rate_of_climb = quantity_kind<rate_of_climb_kind, si::metre_per_second>;
+using rate_of_climb = units::quantity_kind<rate_of_climb_kind, units::isq::si::metre_per_second>;
 
 // text output
 template<class CharT, class Traits>
@@ -117,7 +126,7 @@ struct glider {
   std::array<polar_point, 1> polar;
 };
 
-constexpr Dimensionless auto glide_ratio(const glider::polar_point& polar) { return polar.v / -polar.climb; }
+constexpr units::Dimensionless auto glide_ratio(const glider::polar_point& polar) { return polar.v / -polar.climb; }
 
 struct weather {
   height cloud_base;
@@ -160,10 +169,10 @@ public:
 
   distance get_length() const { return length_; }
 
-  distance get_leg_dist_offset(size_t leg_index) const { return leg_index == 0 ? distance{} : leg_total_distances_[leg_index - 1]; }
+  distance get_leg_dist_offset(std::size_t leg_index) const { return leg_index == 0 ? distance{} : leg_total_distances_[leg_index - 1]; }
-  size_t get_leg_index(distance dist) const
+  std::size_t get_leg_index(distance dist) const
   {
-    return static_cast<size_t>(std::ranges::distance(leg_total_distances_.cbegin(), std::ranges::lower_bound(leg_total_distances_, dist)));
+    return static_cast<std::size_t>(std::ranges::distance(leg_total_distances_.cbegin(), std::ranges::lower_bound(leg_total_distances_, dist)));
   }
 
 private:
@@ -188,7 +197,7 @@ struct aircraft_tow {
 struct flight_point {
   timestamp ts;
   altitude alt;
-  size_t leg_idx = 0;
+  std::size_t leg_idx = 0;
   distance dist{};
 };
 
@@ -196,7 +205,7 @@ altitude terrain_level_alt(const task& t, const flight_point& pos);
 
 constexpr height agl(altitude glider_alt, altitude terrain_level) { return glider_alt - terrain_level; }
 
-inline si::length<si::kilometre> length_3d(distance dist, height h)
+inline units::isq::si::length<units::isq::si::kilometre> length_3d(distance dist, height h)
 {
   // TODO support for hypot(q, q)
   return sqrt(pow<2>(dist.common()) + pow<2>(h.common()));

example/glide_computer_example.cpp

@@ -21,14 +21,25 @@
 // SOFTWARE.
 
 #include "glide_computer.h"
+#include <units/bits/external/hacks.h>
 #include <units/chrono.h>
+#include <units/generic/dimensionless.h>
+#include <units/isq/si/international/length.h>
+#include <fmt/format.h>
 #include <array>
+#include <exception>
 #include <iostream>
+#include <iterator>
+#include <string>
+#include <utility>
+#include <vector>
 
 namespace {
 
 using namespace glide_computer;
 
+using namespace units::isq;
+
 auto get_gliders()
 {
   using namespace si::references;
@@ -74,7 +85,7 @@ void print(const R& gliders)
     std::cout << "- Name: " << g.name << "\n";
     std::cout << "- Polar:\n";
     for (const auto& p : g.polar)
-      fmt::print("  * {:%.4Q %q} @ {:%.1Q %q} -> {:%.1Q %q}\n", p.climb, p.v, quantity_cast<one>(glide_ratio(g.polar[0])));
+      fmt::print("  * {:%.4Q %q} @ {:%.1Q %q} -> {:%.1Q %q}\n", p.climb, p.v, quantity_cast<units::one>(glide_ratio(g.polar[0])));
     std::cout << "\n";
   }
 }

example/hello_units.cpp

@@ -21,8 +21,11 @@
 // SOFTWARE.
 
 #include <units/format.h>
-#include <units/isq/si/international/speed.h>
+#include <units/isq/si/international/length.h>
-#include <units/isq/si/speed.h>
+#include <units/isq/si/international/speed.h> // IWYU pragma: keep
+#include <units/isq/si/length.h>
+#include <units/isq/si/speed.h> // IWYU pragma: keep
+#include <units/isq/si/time.h>
 #include <units/quantity_io.h>
 #include <iostream>
 

example/kalman_filter-alpha_beta_filter_example2.cpp

@@ -1,5 +1,29 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
 #include <units/format.h>
+#include <units/isq/si/length.h>
 #include <units/isq/si/speed.h>
+#include <units/isq/si/time.h>
 #include <iostream>
 #include <array>
 

example/linear_algebra.cpp

@@ -20,9 +20,10 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/isq/si/speed.h>
+#include <units/isq/si/energy.h> // IWYU pragma: keep
 #include <units/isq/si/force.h>
-#include <units/isq/si/energy.h>
+#include <units/isq/si/length.h>
+#include <units/isq/si/speed.h> // IWYU pragma: keep
 #include <units/format.h>
 #include <units/quantity_io.h>
 #include <linear_algebra.hpp>

example/measurement.cpp

@@ -21,9 +21,12 @@
 // SOFTWARE.
 
 #include <units/isq/si/acceleration.h>
+#include <units/isq/si/length.h>
+#include <units/isq/si/speed.h>
+#include <units/isq/si/time.h>
 #include <units/quantity_io.h>
 #include <cmath>
-#include <compare>
+#include <exception>
 #include <iostream>
 
 namespace {

example/total_energy.cpp

@@ -20,13 +20,15 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/isq/natural/constants.h>
+#include <units/isq/natural/natural.h>
 #include <units/isq/si/energy.h>
+#include <units/isq/si/mass.h>
 #include <units/isq/si/momentum.h>
-#include <units/isq/si/speed.h>
+#include <units/isq/si/speed.h> // IWYU pragma: keep
 #include <units/isq/si/constants.h>
 #include <units/math.h>
 #include <units/quantity_io.h>
+#include <exception>
 #include <iostream>
 
 namespace {

example/unknown_dimension.cpp

@@ -20,8 +20,11 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/isq/si/speed.h>
+#include <units/isq/si/length.h>
+#include <units/isq/si/speed.h> // IWYU pragma: keep
+#include <units/isq/si/time.h>
 #include <units/quantity_io.h>
+#include <exception>
 #include <iostream>
 
 namespace {

src/core-fmt/include/units/format.h

@@ -31,8 +31,12 @@
 #pragma warning (disable:4702) // C4702: unreachable code
 #endif //_MSC_VER
 
+// IWYU pragma: begin_exports
 #include <fmt/format.h>
 #include <fmt/locale.h>
+// IWYU pragma: end_exports
+
+// #include <string>
 
 #ifdef _MSC_VER
 #pragma warning (pop)

src/core-io/include/units/quantity_io.h

@@ -23,9 +23,12 @@
 
 #pragma once
 
-#include <units/bits/external/fixed_string_io.h>
 #include <units/quantity.h>
+
+// IWYU pragma: begin_exports
+#include <units/bits/external/fixed_string_io.h>
 #include <sstream>
+// IWYU pragma: end_exports
 
 namespace units {
 

src/core/include/units/base_dimension.h

@@ -22,8 +22,11 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/bits/external/fixed_string.h>
 #include <units/bits/basic_concepts.h>
+// IWYU pragma: end_exports
+
 #include <type_traits>
 
 namespace units {

src/core/include/units/bits/basic_concepts.h

@@ -22,12 +22,15 @@
 
 #pragma once
 
-#include <units/bits/external/downcasting.h>
-#include <units/bits/external/fixed_string.h>
 #include <units/bits/external/hacks.h>
+
+// IWYU pragma: begin_exports
+#include <units/bits/external/fixed_string.h>
 #include <units/customization_points.h>
 #include <units/ratio.h>
 #include <units/bits/external/type_traits.h>
+// IWYU pragma: end_exports
+
 #include <cstdint>
 #include <utility>
 

src/core/include/units/bits/dimension_op.h

@@ -22,6 +22,11 @@
 
 #pragma once
 
+#include <units/bits/derived_dimension_base.h>
+#include <units/bits/dim_consolidate.h>
+#include <units/bits/external/downcasting.h>
+#include <units/bits/external/hacks.h>
+#include <units/bits/external/type_list.h>
 #include <units/derived_dimension.h>
 #include <units/unit.h>
 

src/core/include/units/bits/external/fixed_string.h

@@ -22,9 +22,12 @@
 
 #pragma once
 
-#include <units/bits/external/hacks.h>
+// IWYU pragma: begin_exports
 #include <cstdlib>
 #include <compare>
+// IWYU pragma: end_exports
+
+#include <cstddef>
 
 // TODO use <algorithm> when moved to C++20 modules (parsing takes too long for each translation unit)
 

src/core/include/units/bits/external/type_list.h

@@ -22,7 +22,9 @@
 
 #pragma once
 
+#include <units/bits/external/hacks.h>
 #include <units/bits/external/type_traits.h>
+#include <cstddef>
 
 #ifdef _MSC_VER
 #pragma warning (push)

src/core/include/units/chrono.h

@@ -23,8 +23,10 @@
 #pragma once
 
 #include <units/customization_points.h>
+// IWYU pragma: begin_exports
 #include <units/isq/si/time.h>
 #include <chrono>
+// IWYU pragma: end_exports
 
 namespace units {
 

src/core/include/units/concepts.h

@@ -22,5 +22,7 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/bits/basic_concepts.h>
 #include <units/bits/quantity_of.h>
+// IWYU pragma: end_exports

src/core/include/units/derived_dimension.h

@@ -29,7 +29,10 @@
 #include <units/bits/dim_unpack.h>
 #include <units/bits/external/downcasting.h>
 #include <units/bits/external/type_list.h>
+
+// IWYU pragma: begin_exports
 #include <units/exponent.h>
+// IWYU pragma: end_exports
 
 namespace units {
 

src/core/include/units/generic/angle.h

@@ -22,8 +22,13 @@
 
 #pragma once
 
-#include <units/isq/si/prefixes.h>
+// IWYU pragma: begin_exports
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/prefixes.h>
 
 namespace units {
 
@@ -46,7 +51,7 @@ constexpr auto operator"" _q_rad(long double l) { return angle<radian, long doub
 
 }  // namespace literals
 
-inline namespace references {
+namespace references {
 
 inline constexpr auto rad = reference<dim_angle<>, radian>{};
 

src/core/include/units/generic/dimensionless.h

@@ -22,6 +22,10 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/quantity_cast.h>
 
 namespace units {

src/core/include/units/math.h

@@ -22,9 +22,17 @@
 
 #pragma once
 
-#include <units/concepts.h>
+#include <units/bits/dimension_op.h>
+#include <units/bits/external/hacks.h>
+#include <units/generic/dimensionless.h>
 #include <units/quantity.h>
+#include <units/unit.h>
+
+// IWYU pragma: begin_exports
 #include <cmath>
+#include <cstdint>
+// IWYU pragma: end_exports
+
 #include <limits>
 
 namespace units {

src/core/include/units/prefix.h

@@ -24,8 +24,10 @@
 
 #include <units/bits/external/downcasting.h>
 #include <units/bits/basic_concepts.h>
+// IWYU pragma: begin_exports
 #include <units/ratio.h>
 #include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units {
 

src/core/include/units/quantity.h

@@ -24,12 +24,16 @@
 #pragma once
 
 #include <units/bits/common_quantity.h>
-#include <units/bits/pow.h>
-#include <units/bits/unit_text.h>
 #include <units/generic/dimensionless.h>
+
+// IWYU pragma: begin_exports
+#include <units/bits/unit_text.h>
 #include <units/quantity_cast.h>
-#include <units/reference.h>
+#include <units/ratio.h>
 #include <compare>
+// IWYU pragma: end_exports
+
+#include <units/reference.h>
 #include <utility>
 
 namespace units {

src/core/include/units/quantity_kind.h

@@ -23,8 +23,11 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/kind.h>
 #include <units/quantity.h>
+// IWYU pragma: end_exports
+
 #include <concepts>
 #include <type_traits>
 #include <utility>

src/core/include/units/quantity_point.h

@@ -23,8 +23,13 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/quantity.h>
 #include <compare>
+// IWYU pragma: end_exports
+
+#include <units/customization_points.h>
+#include <units/generic/dimensionless.h>
 
 namespace units {
 

src/core/include/units/quantity_point_kind.h

@@ -23,9 +23,11 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/quantity_kind.h>
 #include <units/quantity_point.h>
 #include <compare>
+// IWYU pragma: end_exports
 
 namespace units {
 

src/core/include/units/random.h

@@ -22,9 +22,9 @@
 
 #pragma once
 
+#include <units/concepts.h>
 #include <random>
 #include <functional>
-#include <units/concepts.h>
 
 namespace units {
 

src/core/include/units/ratio.h

@@ -22,15 +22,16 @@
 
 #pragma once
 
-#include <units/bits/external/hacks.h>
+// IWYU pragma: begin_exports
 #include <units/bits/math_concepts.h>
-#include <units/bits/ratio_maths.h>
 #include <units/bits/pow.h>
+#include <units/bits/ratio_maths.h>
 #include <units/bits/root.h>
 #include <cstdint>
+// IWYU pragma: end_exports
+
+#include <array>
 #include <numeric>
-#include <type_traits>
-#include <tuple>
 #include <gsl/gsl-lite.hpp>
 
 namespace units {

src/core/include/units/symbol_text.h

@@ -22,10 +22,14 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/bits/external/fixed_string.h>
-#include <units/bits/external/hacks.h>
-#include <gsl/gsl-lite.hpp>
 #include <compare>
+#include <cstdint>
+#include <cstddef>
+// IWYU pragma: end_exports
+
+#include <gsl/gsl-lite.hpp>
 
 namespace units {
 

src/core/include/units/unit.h

@@ -23,15 +23,15 @@
 #pragma once
 
 #include <units/bits/deduced_symbol_text.h>
-#include <units/bits/deduced_unit.h>
 #include <units/bits/external/downcasting.h>
+
+// IWYU pragma: begin_exports
+#include <units/bits/deduced_unit.h> 
 #include <units/bits/external/fixed_string.h>
-#include <units/bits/external/text_tools.h>
-#include <units/bits/external/type_traits.h>
-#include <units/derived_dimension.h>
 #include <units/prefix.h> 
 #include <units/ratio.h>
 #include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units {
 

src/systems/isq-iec80000/include/units/isq/iec80000/iec80000.h

@@ -22,7 +22,9 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/iec80000/modulation_rate.h>
 #include <units/isq/iec80000/storage_capacity.h>
 #include <units/isq/iec80000/traffic_intensity.h>
 #include <units/isq/iec80000/transfer_rate.h>
+// IWYU pragma: end_exports

src/systems/isq-iec80000/include/units/isq/iec80000/modulation_rate.h

@@ -23,7 +23,14 @@
 #pragma once
 
 #include <units/isq/si/frequency.h>
+#include <units/isq/si/prefixes.h>
+#include <units/unit.h>
+
+// IWYU pragma: begin_exports
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units::isq::iec80000 {
 

src/systems/isq-iec80000/include/units/isq/iec80000/storage_capacity.h

@@ -24,9 +24,14 @@
 
 #include <units/base_dimension.h>
 #include <units/isq/iec80000/binary_prefixes.h>
+#include <units/isq/si/prefixes.h>
+#include <units/unit.h>
+
+// IWYU pragma: begin_exports
 #include <units/quantity.h>
 #include <units/reference.h>
-#include <units/unit.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units::isq::iec80000 {
 

src/systems/isq-iec80000/include/units/isq/iec80000/traffic_intensity.h

@@ -23,9 +23,13 @@
 #pragma once
 
 #include <units/base_dimension.h>
+#include <units/unit.h>
+
+// IWYU pragma: begin_exports
 #include <units/quantity.h>
 #include <units/reference.h>
-#include <units/unit.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units::isq::iec80000 {
 

src/systems/isq-iec80000/include/units/isq/iec80000/transfer_rate.h

@@ -25,7 +25,12 @@
 #include <units/derived_dimension.h>
 #include <units/isq/iec80000/storage_capacity.h>
 #include <units/isq/si/time.h>
+#include <units/unit.h>
+
+// IWYU pragma: begin_exports
 #include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units::isq::iec80000 {
 

src/systems/isq-natural/include/units/isq/natural/constants.h

@@ -22,7 +22,7 @@
 
 #pragma once
 
-#include <units/isq/natural/bits/dimensions.h>
+#include <units/isq/natural/dimensions.h>
 
 namespace units::isq::natural {
 

src/systems/isq-natural/include/units/isq/natural/dimensions.h

@@ -22,9 +22,11 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions.h>
-#include <units/isq/natural/bits/units.h>
+#include <units/isq/natural/units.h>
 #include <units/quantity.h>
+// IWYU pragma: end_exports
 
 namespace units::isq::natural {
 

src/systems/isq-natural/include/units/isq/natural/natural.h

@@ -22,9 +22,8 @@
 
 #pragma once
 
-#define MP_UNITS_SYSTEM_NATURAL
+// IWYU pragma: begin_exports
-
+#include "dimensions.h"
-#include "bits/dimensions.h"
+#include "units.h"
-#include "bits/units.h"
-
 #include "constants.h"
+// IWYU pragma: end_exports

src/systems/isq-natural/include/units/isq/natural/units.h

@@ -22,8 +22,12 @@
 
 #pragma once
 
-#include <units/unit.h>
+// IWYU pragma: begin_exports
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/prefixes.h>
+#include <units/unit.h>
 
 namespace units::isq::natural {
 

src/systems/isq/include/units/isq/dimensions.h

@@ -22,6 +22,7 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/absorbed_dose.h>
 #include <units/isq/dimensions/acceleration.h>
 #include <units/isq/dimensions/amount_of_substance.h>
@@ -68,3 +69,4 @@
 #include <units/isq/dimensions/torque.h>
 #include <units/isq/dimensions/voltage.h>
 #include <units/isq/dimensions/volume.h>
+// IWYU pragma: end_exports

src/systems/si-cgs/include/units/isq/si/cgs/acceleration.h

@@ -22,9 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/acceleration.h>
-#include <units/isq/si/cgs/speed.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/cgs/speed.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/area.h

@@ -22,9 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/area.h>
 #include <units/isq/si/area.h>
-#include <units/isq/si/cgs/length.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/cgs/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/cgs.h

@@ -22,6 +22,7 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/cgs/length.h>
 #include <units/isq/si/cgs/mass.h>
 #include <units/isq/si/cgs/time.h>
@@ -33,3 +34,4 @@
 #include <units/isq/si/cgs/power.h>
 #include <units/isq/si/cgs/pressure.h>
 #include <units/isq/si/cgs/speed.h>
+// IWYU pragma: end_exports

src/systems/si-cgs/include/units/isq/si/cgs/energy.h

@@ -22,10 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/energy.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/cgs/force.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/force.h

@@ -22,11 +22,17 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/force.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/cgs/acceleration.h>
 #include <units/isq/si/cgs/mass.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/length.h

@@ -22,8 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
 #include <units/isq/si/length.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/mass.h

@@ -22,8 +22,15 @@
 
 #pragma once
 
-#include <units/isq/si/mass.h>
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/mass.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/mass.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/power.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/power.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/cgs/energy.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/pressure.h

@@ -22,11 +22,17 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/pressure.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/cgs/area.h>
 #include <units/isq/si/cgs/force.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/speed.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/speed.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/cgs/length.h>
 #include <units/isq/si/cgs/time.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::cgs {
 

src/systems/si-cgs/include/units/isq/si/cgs/time.h

@@ -22,8 +22,13 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/time.h>
 #include <units/isq/si/time.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
 
 namespace units::isq::si::cgs {
 

src/systems/si-fps/include/units/isq/si/fps/acceleration.h

@@ -22,9 +22,14 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/acceleration.h>
-#include <units/isq/si/fps/speed.h>
 #include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/fps/speed.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/area.h

@@ -22,9 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/area.h>
-#include <units/isq/si/fps/length.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/fps/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/density.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/density.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/fps/mass.h>
 #include <units/isq/si/fps/length.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/energy.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/energy.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/fps/force.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 
@@ -37,12 +42,9 @@ struct dim_energy : isq::dim_energy<dim_energy, foot_poundal, dim_force, dim_len
 // https://en.wikipedia.org/wiki/Foot-pound_(energy)
 struct foot_pound_force : noble_deduced_unit<foot_pound_force, dim_energy, pound_force, foot> {};
 
-
-
 template<UnitOf<dim_energy> U, Representation Rep = double>
 using energy = quantity<dim_energy, U, Rep>;
 
-
 inline namespace literals {
 
 // foot poundal
@@ -55,11 +57,4 @@ constexpr auto operator"" _q_ft_lbf(long double l) { return energy<foot_pound_fo
 
 }  // namespace literals
 
-namespace references {
-
-inline constexpr auto ft_pdl = reference<dim_energy, foot_poundal>{};
-inline constexpr auto ft_lbf = reference<dim_energy, foot_pound_force>{};
-
-}  // namespace references
-
 }  // namespace units::isq::si::fps

src/systems/si-fps/include/units/isq/si/fps/force.h

@@ -22,11 +22,17 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/force.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/fps/acceleration.h>
 #include <units/isq/si/fps/mass.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/fps.h

@@ -22,6 +22,7 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/fps/length.h>
 #include <units/isq/si/fps/mass.h>
 #include <units/isq/si/fps/time.h>
@@ -35,3 +36,4 @@
 #include <units/isq/si/fps/pressure.h>
 #include <units/isq/si/fps/speed.h>
 #include <units/isq/si/fps/volume.h>
+// IWYU pragma: end_exports

src/systems/si-fps/include/units/isq/si/fps/length.h

@@ -22,8 +22,15 @@
 
 #pragma once
 
-#include <units/isq/si/length.h>
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 
@@ -47,8 +54,6 @@ struct mile : named_scaled_unit<mile, "mile", no_prefix, ratio(5'280), foot> {};
 
 struct nautical_mile : named_scaled_unit<nautical_mile, "mi(naut)", no_prefix, ratio(2'000), yard> {};
 
-
-
 struct dim_length : isq::dim_length<foot> {};
 
 template<UnitOf<dim_length> U, Representation Rep = double>

src/systems/si-fps/include/units/isq/si/fps/mass.h

@@ -22,8 +22,15 @@
 
 #pragma once
 
-#include <units/isq/si/mass.h>
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/mass.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/mass.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/power.h

@@ -22,10 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/power.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/fps/energy.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/pressure.h

@@ -22,11 +22,17 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/pressure.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/fps/area.h>
 #include <units/isq/si/fps/force.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/speed.h

@@ -22,10 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/speed.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/fps/length.h>
 #include <units/isq/si/fps/time.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/time.h

@@ -22,8 +22,15 @@
 
 #pragma once
 
-#include <units/isq/si/time.h>
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/time.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/time.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-fps/include/units/isq/si/fps/volume.h

@@ -22,9 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/volume.h>
-#include <units/isq/si/fps/length.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/fps/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::fps {
 

src/systems/si-iau/include/units/isq/si/iau/iau.h

@@ -22,4 +22,6 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/iau/length.h>
+// IWYU pragma: end_exports

src/systems/si-iau/include/units/isq/si/iau/length.h

@@ -23,7 +23,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::iau {
 

src/systems/si-imperial/include/units/isq/si/imperial/imperial.h

@@ -22,4 +22,6 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/imperial/length.h>
+// IWYU pragma: end_exports

src/systems/si-imperial/include/units/isq/si/imperial/length.h

@@ -22,7 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/international/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::imperial {
 

src/systems/si-international/include/units/isq/si/international/area.h

@@ -22,8 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/area.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/area.h>
 #include <units/isq/si/international/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::international {
 

src/systems/si-international/include/units/isq/si/international/international.h

@@ -22,8 +22,10 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/international/length.h>
 
 #include <units/isq/si/international/area.h>
 #include <units/isq/si/international/speed.h>
 #include <units/isq/si/international/volume.h>
+// IWYU pragma: end_exports

src/systems/si-international/include/units/isq/si/international/length.h

@@ -23,7 +23,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::international {
 

src/systems/si-international/include/units/isq/si/international/speed.h

@@ -22,8 +22,15 @@
 
 #pragma once
 
-#include <units/isq/si/speed.h>
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/speed.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/international/length.h>
+#include <units/isq/si/speed.h>
+#include <units/unit.h>
 
 namespace units::isq::si::international {
 

src/systems/si-international/include/units/isq/si/international/volume.h

@@ -22,8 +22,16 @@
 
 #pragma once
 
-#include <units/isq/si/volume.h>
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/volume.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/international/length.h>
+#include <units/isq/si/volume.h>
+#include <units/unit.h>
 
 namespace units::isq::si::international {
 

src/systems/si-typographic/include/units/isq/si/typographic/length.h

@@ -23,7 +23,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::typographic {
 

src/systems/si-typographic/include/units/isq/si/typographic/typographic.h

@@ -22,4 +22,6 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/typographic/length.h>
+// IWYU pragma: end_exports

src/systems/si-us/include/units/isq/si/us/length.h

@@ -22,7 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
+#include <units/isq/dimensions/length.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si::us {
 

src/systems/si-us/include/units/isq/si/us/us.h

@@ -22,4 +22,6 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/si/us/length.h>
+// IWYU pragma: end_exports

src/systems/si/include/units/isq/si/absorbed_dose.h

@@ -22,10 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/absorbed_dose.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/energy.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/acceleration.h

@@ -22,9 +22,14 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/acceleration.h>
-#include <units/isq/si/speed.h>
 #include <units/quantity.h>
+#include <units/symbol_text.h>
+#include <units/unit.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/speed.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/amount_of_substance.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
-#include <units/reference.h>
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/amount_of_substance.h>
-#include <units/isq/si/prefixes.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/prefixes.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/angular_velocity.h

@@ -22,11 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/angular_velocity.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/generic/angle.h>
 #include <units/isq/si/time.h>
-
+#include <units/unit.h>
-#include <units/quantity.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/area.h

@@ -22,9 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/area.h>
-#include <units/isq/si/length.h>
 #include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
+#include <units/isq/si/length.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/capacitance.h

@@ -22,11 +22,17 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/capacitance.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/electric_charge.h>
 #include <units/isq/si/voltage.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/catalytic_activity.h

@@ -22,11 +22,17 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/catalytic_activity.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/amount_of_substance.h>
 #include <units/isq/si/time.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/charge_density.h

@@ -22,11 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/charge_density.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/electric_charge.h>
 #include <units/isq/si/length.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/concentration.h

@@ -22,10 +22,15 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/concentration.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/length.h>
 #include <units/isq/si/amount_of_substance.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/conductance.h

@@ -22,10 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/conductance.h>
+#include <units/quantity.h>
+#include <units/reference.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/resistance.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/current_density.h

@@ -22,11 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/current_density.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/electric_current.h>
 #include <units/isq/si/length.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {
 

src/systems/si/include/units/isq/si/density.h

@@ -22,11 +22,16 @@
 
 #pragma once
 
+// IWYU pragma: begin_exports
 #include <units/isq/dimensions/density.h>
+#include <units/quantity.h>
+#include <units/symbol_text.h>
+// IWYU pragma: end_exports
+
 #include <units/isq/si/mass.h>
 #include <units/isq/si/length.h>
 #include <units/isq/si/prefixes.h>
-#include <units/quantity.h>
+#include <units/unit.h>
 
 namespace units::isq::si {