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refactor: 💥 from now on point origins must be marked final + absolute_point_origin does not use CRTP anymore

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Mateusz Pusz
2024-06-13 19:24:40 +02:00
parent bd6b1e654d
commit 05fc1e29c8
15 changed files with 93 additions and 97 deletions
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26
docs/blog/posts/2.2.0-released.md
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@@ -205,7 +205,7 @@ origins. For example:
=== "Before"
```cpp
constexpr struct zero : absolute_point_origin<zero, currency> {} zero;
constexpr struct zero final : absolute_point_origin<currency> {} zero;
quantity_point price_usd = zero + 100 * USD;
```
@@ -300,16 +300,24 @@ is why it was renamed to `symbol_text` (:boom: **breaking change** :boom:).
```
## Changes to dimension and quantity specification definitions
## Changes to dimension, quantity specification, and point origins definitions
Similarly to units, now also all dimensions and quantity specifications have to be marked final
(:boom: **breaking change** :boom:).
Similarly to units, now also all dimensions, quantity specifications, and point origins have to be
marked `final` (:boom: **breaking change** :boom:).
=== "Now"
```cpp
inline constexpr struct dim_length final : base_dimension<"L"> {} dim_length;
inline constexpr struct length final : quantity_spec<dim_length> {} length;
inline constexpr struct absolute_zero final : absolute_point_origin<isq::thermodynamic_temperature> {} absolute_zero;
inline constexpr auto zeroth_kelvin = absolute_zero;
inline constexpr struct kelvin final : named_unit<"K", kind_of<isq::thermodynamic_temperature>, zeroth_kelvin> {} kelvin;
inline constexpr struct ice_point final : relative_point_origin<quantity_point{273'150 * milli<kelvin>}> {} ice_point;
inline constexpr auto zeroth_degree_Celsius = ice_point;
inline constexpr struct degree_Celsius final : named_unit<symbol_text{u8"°C", "`C"}, kelvin, zeroth_degree_Celsius> {} degree_Celsius;
```
=== "Before"
@@ -317,8 +325,18 @@ Similarly to units, now also all dimensions and quantity specifications have to
```cpp
inline constexpr struct dim_length : base_dimension<"L"> {} dim_length;
inline constexpr struct length : quantity_spec<dim_length> {} length;
inline constexpr struct absolute_zero : absolute_point_origin<absolute_zero, isq::thermodynamic_temperature> {} absolute_zero;
inline constexpr struct zeroth_kelvin : decltype(absolute_zero) {} zeroth_kelvin;
inline constexpr struct kelvin : named_unit<"K", kind_of<isq::thermodynamic_temperature>, zeroth_kelvin> {} kelvin;
inline constexpr struct ice_point : relative_point_origin<quantity_point{273'150 * milli<kelvin>}> {} ice_point;
inline constexpr struct zeroth_degree_Celsius : decltype(ice_point) {} zeroth_degree_Celsius;
inline constexpr struct degree_Celsius : named_unit<symbol_text{u8"°C", "`C"}, kelvin, zeroth_degree_Celsius> {} degree_Celsius;
```
Please also note, that the `absolute_point_origin` does not use CRTP idiom anymore (:boom: **breaking change** :boom:).
## Improved text output

8
docs/users_guide/framework_basics/concepts.md
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@@ -16,6 +16,8 @@ or derived [quantity](../../appendix/glossary.md#quantity):
by the library's framework based on the [quantity equation](../../appendix/glossary.md#quantity-equation)
provided in the [quantity specification](../../appendix/glossary.md#quantity_spec).
All of the above dimensions have to be marked as `final`.
### `DimensionOf<T, V>` { #DimensionOf }
@@ -42,6 +44,8 @@ including:
- Intermediate [derived quantity](../../appendix/glossary.md#derived-quantity) specifications being
a result of a [quantity equations](../../appendix/glossary.md#quantity-equation) on other specifications.
All of the above quantity specifications have to be marked as `final`.
### `QuantitySpecOf<T, V>` { #QuantitySpecOf }
@@ -237,7 +241,7 @@ implicitly convertible from quantity specification `V`, which means that `V` mus
However, if we define `mean_sea_level` in the following way:
```cpp
inline constexpr struct mean_sea_level : absolute_point_origin<isq::altitude> {} mean_sea_level;
inline constexpr struct mean_sea_level final : absolute_point_origin<isq::altitude> {} mean_sea_level;
```
then it can't be used as a point origin for _points_ of `isq::length` or `isq::width` as none of them
@@ -330,7 +334,7 @@ for which an instantiation of `quantity_point_like_traits` type trait yields a v
struct mp_units::quantity_point_like_traits<std::chrono::time_point<C, std::chrono::seconds>> {
using T = std::chrono::time_point<C, std::chrono::seconds>;
static constexpr auto reference = si::second;
static constexpr struct point_origin : absolute_point_origin<isq::time> {} point_origin{};
static constexpr struct point_origin final : absolute_point_origin<isq::time> {} point_origin{};
using rep = std::chrono::seconds::rep;
[[nodiscard]] static constexpr convert_implicitly<quantity<reference, rep>> to_quantity(const T& qp)

4
docs/users_guide/framework_basics/design_overview.md
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@@ -346,13 +346,13 @@ For example:
- the absolute point origin can be defined in the following way:
```cpp
inline constexpr struct absolute_zero : absolute_point_origin<isq::thermodynamic_temperature> {} absolute_zero;
inline constexpr struct absolute_zero final : absolute_point_origin<isq::thermodynamic_temperature> {} absolute_zero;
```
- the relative point origin can be defined in the following way:
```cpp
inline constexpr struct ice_point : relative_point_origin<absolute_zero + 273'150 * milli<kelvin>> {} ice_point;
inline constexpr struct ice_point final : relative_point_origin<absolute_zero + 273'150 * milli<kelvin>> {} ice_point;
```

34
docs/users_guide/framework_basics/the_affine_space.md
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@@ -172,7 +172,7 @@ origin.
![affine_space_2](affine_space_2.svg){style="width:80%;display: block;margin: 0 auto;"}
```cpp
inline constexpr struct origin : absolute_point_origin<origin, isq::distance> {} origin;
inline constexpr struct origin final : absolute_point_origin<isq::distance> {} origin;
// quantity_point<si::metre, origin> qp1{100 * m}; // Compile-time error
// quantity_point<si::metre, origin> qp2{120 * m}; // Compile-time error
@@ -197,14 +197,6 @@ assert(origin - qp2 == -120 * m);
// assert(origin - origin == 0 * m); // Compile-time error
```
!!! info
The `absolute_point_origin` class template uses the CRTP idiom to enforce the uniqueness of
such a type. You should pass the type of a derived class as the first argument of the template
instantiation.
*[CRTP]: Curiously Recurring Template Parameter
We can't construct a quantity point directly from the quantity anymore when a custom, named origin
is used. To prevent potential safety and maintenance issues, we always need to
explicitly provide both a compatible origin and a quantity measured from it to construct a quantity
@@ -249,8 +241,8 @@ type and unit is being used:
![affine_space_3](affine_space_3.svg){style="width:80%;display: block;margin: 0 auto;"}
```cpp
inline constexpr struct origin1 : absolute_point_origin<origin1, isq::distance> {} origin1;
inline constexpr struct origin2 : absolute_point_origin<origin2, isq::distance> {} origin2;
inline constexpr struct origin1 final : absolute_point_origin<isq::distance> {} origin1;
inline constexpr struct origin2 final : absolute_point_origin<isq::distance> {} origin2;
quantity_point qp1 = origin1 + 100 * m;
quantity_point qp2 = origin2 + 120 * m;
@@ -284,10 +276,10 @@ For such cases, relative point origins should be used:
![affine_space_4](affine_space_4.svg){style="width:80%;display: block;margin: 0 auto;"}
```cpp
inline constexpr struct A : absolute_point_origin<A, isq::distance> {} A;
inline constexpr struct B : relative_point_origin<A + 10 * m> {} B;
inline constexpr struct C : relative_point_origin<B + 10 * m> {} C;
inline constexpr struct D : relative_point_origin<A + 30 * m> {} D;
inline constexpr struct A final : absolute_point_origin<isq::distance> {} A;
inline constexpr struct B final : relative_point_origin<A + 10 * m> {} B;
inline constexpr struct C final : relative_point_origin<B + 10 * m> {} C;
inline constexpr struct D final : relative_point_origin<A + 30 * m> {} D;
quantity_point qp1 = C + 100 * m;
quantity_point qp2 = D + 120 * m;
@@ -392,17 +384,17 @@ point origins for this purpose:
```cpp
namespace si {
inline constexpr struct absolute_zero : absolute_point_origin<absolute_zero, isq::thermodynamic_temperature> {} absolute_zero;
inline constexpr struct zeroth_kelvin : decltype(absolute_zero) {} zeroth_kelvin;
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 : relative_point_origin<quantity_point{273'150 * milli<kelvin>}> {} ice_point;
inline constexpr struct zeroth_degree_Celsius : decltype(ice_point) {} zeroth_degree_Celsius;
inline constexpr struct ice_point final : relative_point_origin<quantity_point{273'150 * milli<kelvin>}> {} ice_point;
inline constexpr auto zeroth_degree_Celsius = ice_point;
}
namespace usc {
inline constexpr struct zeroth_degree_Fahrenheit :
inline constexpr struct zeroth_degree_Fahrenheit final :
relative_point_origin<quantity_point{-32 * (mag_ratio<5, 9> * si::degree_Celsius)}> {} zeroth_degree_Fahrenheit;
}
@@ -481,7 +473,7 @@ the following way:
![affine_space_6](affine_space_6.svg){style="width:80%;display: block;margin: 0 auto;"}
```cpp
constexpr struct room_reference_temp : relative_point_origin<quantity_point{21 * deg_C}> {} room_reference_temp;
constexpr struct room_reference_temp final : relative_point_origin<quantity_point{21 * deg_C}> {} room_reference_temp;
using room_temp = quantity_point<isq::Celsius_temperature[deg_C], room_reference_temp>;
constexpr auto step_delta = isq::Celsius_temperature(0.5 * deg_C);

4
docs/users_guide/use_cases/interoperability_with_other_libraries.md
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@@ -256,8 +256,8 @@ include the _mp-units/systems/si/chrono.h_ file to benefit from it. This file pr
to the `std::chrono` abstractions:
```cpp
inline constexpr struct ts_origin : relative_point_origin<chrono_point_origin<system_clock> + 1 * h> {} ts_origin;
inline constexpr struct my_origin : absolute_point_origin<my_origin, isq::time> {} my_origin;
inline constexpr struct ts_origin final : relative_point_origin<chrono_point_origin<system_clock> + 1 * h> {} ts_origin;
inline constexpr struct my_origin final : absolute_point_origin<isq::time> {} my_origin;
quantity_point qp1 = sys_seconds{1s};
auto tp1 = to_chrono_time_point(qp1); // OK