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playing with named derived units to allow knots to be deduced from

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nautical miles & hours but be called knot instead of mi(naut) / h
This commit is contained in:
Mike Ford
2020-05-31 12:32:14 +01:00
committed by Mateusz Pusz
parent aa84dcb9ef
commit c97a438807
4 changed files with 29 additions and 11 deletions
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2
src/include/units/physical/fps/energy.h
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@@ -35,7 +35,7 @@ struct foot_poundal : unit<foot_poundal> {};
struct dim_energy : physical::dim_energy<dim_energy, foot_poundal, dim_force, dim_length> {};
// https://en.wikipedia.org/wiki/Foot-pound_(energy)
struct foot_pound_force : named_deduced_unit<foot_pound_force, dim_energy, pound_force, foot> {};
struct foot_pound_force : noble_deduced_unit<foot_pound_force, dim_energy, pound_force, foot> {};

2
src/include/units/physical/fps/pressure.h
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@@ -39,7 +39,7 @@ using pressure = quantity<dim_pressure, U, Rep>;
struct pound_force_per_foot_sq : named_scaled_unit<pound_force_per_foot_sq, "lbf ft2", si::prefix, ratio<32'174'049, 1'000'000>, poundal_per_foot_sq> {};
// struct pound_force_per_foot_sq : named_deduced_unit<pound_force_per_foot_sq, dim_pressure, pound_force, square_ft> {};
// struct pound_force_per_foot_sq : noble_deduced_unit<pound_force_per_foot_sq, dim_pressure, pound_force, square_ft> {};
struct pound_force_per_inch_sq : named_scaled_unit<pound_force_per_inch_sq, "psi", si::prefix, ratio<1, 144>, pound_force_per_foot_sq> {};

4
src/include/units/physical/fps/speed.h
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@@ -37,9 +37,9 @@ using speed = quantity<dim_speed, U, Rep>;
struct mile_per_hour : deduced_unit<mile_per_hour, dim_speed, mile, hour>{};
struct nautical_mile_per_hour : deduced_unit<nautical_mile_per_hour, dim_speed, nautical_mile, hour>{};
struct nautical_mile_per_hour :named_deduced_derived_unit<nautical_mile_per_hour, dim_speed, "knot", no_prefix, nautical_mile, hour>{};
struct knot : alias_unit<nautical_mile_per_hour, "knot", si::prefix> {};
struct knot : alias_unit<nautical_mile_per_hour, "knot", no_prefix> {};
inline namespace literals {

32
src/include/units/unit.h
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@@ -182,18 +182,36 @@ struct deduced_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest..
template<typename Child, DerivedDimension Dim, Unit U, Unit... URest>
requires detail::same_scaled_units<typename Dim::recipe, U, URest...> &&
(U::is_named && (URest::is_named && ... && true))
struct named_deduced_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest...>> {
// TODO - 'noble' is placeholder to sort of mean can pass its name on to other deduced units
struct noble_deduced_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest...>> {
static constexpr bool is_named = true;
static constexpr auto symbol = detail::deduced_symbol_text<Dim, U, URest...>();
using prefix_family = no_prefix;
};
// template<typename Child, Dimension Dim, basic_fixed_string Symbol, PrefixFamily PF, Unit U, Unit... Us>
// struct named_deduced_derived_unit : downcast_child<Child, detail::deduced_derived_unit<Dim, U, Us...>> {
// static constexpr bool is_named = true;
// static constexpr auto symbol = Symbol;
// using prefix_family = PF;
// };
/**
* @brief A named unit with a deduced ratio
*
* Defines a new unit with a deduced ratio and the given symbol based on the recipe from the provided
* derived dimension. The number and order of provided units should match the recipe of the
* derived dimension. All of the units provided should also be a named ones so it is possible
* to create a deduced symbol text.
*
* @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
* @tparam Dim a derived dimension recipe to use for deduction
* @tparam Symbol a short text representation of the unit
* @tparam PF no_prefix or a type of prefix family
* @tparam U the unit of the first composite dimension from provided derived dimension's recipe
* @tparam URest the units for the rest of dimensions from the recipe
*/
template<typename Child, DerivedDimension Dim, basic_symbol_text Symbol, PrefixFamily PF, Unit U, Unit... URest>
requires detail::same_scaled_units<typename Dim::recipe, U, URest...>
struct named_deduced_derived_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest...>> {
static constexpr bool is_named = true;
static constexpr auto symbol = Symbol;
using prefix_family = PF;
};
/**
* @brief An aliased named unit