feat: PrefixableUnit concept introduced

example/v2_framework.cpp

@@ -34,16 +34,16 @@ inline constexpr struct activity : system_reference<activity_dim, si::becquerel>
 
 // check for invalid prefixes
 
-template<Unit auto V1>
+template<template<auto U> typename prefix, Unit auto V1>
-concept can_not_be_prefixed = !requires { typename si::milli_<V1>; };
+concept can_not_be_prefixed = !requires { typename prefix<V1>; };
 
-static_assert(can_not_be_prefixed<si::degree_Celsius>);
+static_assert(can_not_be_prefixed<si::milli_, si::degree_Celsius>);
-static_assert(can_not_be_prefixed<si::minute>);
+static_assert(can_not_be_prefixed<si::milli_, si::minute>);
-static_assert(can_not_be_prefixed<si::hour>);
+static_assert(can_not_be_prefixed<si::milli_, si::hour>);
-static_assert(can_not_be_prefixed<si::day>);
+static_assert(can_not_be_prefixed<si::milli_, si::day>);
-static_assert(can_not_be_prefixed<si::kilogram>);
+static_assert(can_not_be_prefixed<si::milli_, si::kilogram>);
-static_assert(can_not_be_prefixed<si::hectare>);
+static_assert(can_not_be_prefixed<si::milli_, si::hectare>);
-static_assert(can_not_be_prefixed<si::metre / si::second>);
+static_assert(can_not_be_prefixed<si::milli_, si::metre / si::second>);
 
 // Named quantity/dimension and unit
 static_assert(

src/core/include/units/unit.h

@@ -92,6 +92,9 @@ concept NamedUnit = Unit<T> && requires(T* t) { detail::to_base_specialization_o
 template<Unit auto V>
 inline constexpr bool unit_can_be_prefixed = NamedUnit<std::remove_const_t<decltype(V)>>;
 
+template<typename T>
+concept PrefixableUnit = NamedUnit<T> && unit_can_be_prefixed<T{}>;
+
 /**
  * @brief A prefixed unit
  *
@@ -103,8 +106,7 @@ inline constexpr bool unit_can_be_prefixed = NamedUnit<std::remove_const_t<declt
  * @tparam P prefix to be appied to the coherent_unit unit
  * @tparam U coherent_unit unit
  */
-template<basic_symbol_text Symbol, Magnitude auto M, NamedUnit auto U>
+template<basic_symbol_text Symbol, Magnitude auto M, PrefixableUnit auto U>
-  requires unit_can_be_prefixed<U>
 struct prefixed_unit : std::remove_const_t<decltype(M * U)> {
   static constexpr auto symbol = Symbol + U.symbol;
 };

src/systems/si/include/units/si/prefixes.h

@@ -26,86 +26,86 @@
 
 namespace units::si {
 
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct yocto_ : prefixed_unit<"y", mag_power<10, -24>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct zepto_ : prefixed_unit<"z", mag_power<10, -21>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct atto_ : prefixed_unit<"a", mag_power<10, -18>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct femto_ : prefixed_unit<"f", mag_power<10, -15>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct pico_ : prefixed_unit<"p", mag_power<10, -12>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct nano_ : prefixed_unit<"n", mag_power<10, -9>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct micro_ : prefixed_unit<basic_symbol_text{"\u00b5", "u"}, mag_power<10, -6>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct milli_ : prefixed_unit<"m", mag_power<10, -3>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct centi_ : prefixed_unit<"c", mag_power<10, -2>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct deci_ : prefixed_unit<"d", mag_power<10, -1>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct deca_ : prefixed_unit<"da", mag_power<10, 1>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct hecto_ : prefixed_unit<"h", mag_power<10, 2>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct kilo_ : prefixed_unit<"k", mag_power<10, 3>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct mega_ : prefixed_unit<"M", mag_power<10, 6>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct giga_ : prefixed_unit<"G", mag_power<10, 9>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct tera_ : prefixed_unit<"T", mag_power<10, 12>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct peta_ : prefixed_unit<"P", mag_power<10, 15>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct exa_ : prefixed_unit<"E", mag_power<10, 18>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct zetta_ : prefixed_unit<"Z", mag_power<10, 21>, U> {};
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 struct yotta_ : prefixed_unit<"Y", mag_power<10, 24>, U> {};
 
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr yocto_<U> yocto;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr zepto_<U> zepto;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr atto_<U> atto;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr femto_<U> femto;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr pico_<U> pico;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr nano_<U> nano;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr micro_<U> micro;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr milli_<U> milli;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr centi_<U> centi;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr deci_<U> deci;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr deca_<U> deca;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr hecto_<U> hecto;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr kilo_<U> kilo;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr mega_<U> mega;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr giga_<U> giga;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr tera_<U> tera;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr peta_<U> peta;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr exa_<U> exa;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr zetta_<U> zetta;
-template<NamedUnit auto U>
+template<PrefixableUnit auto U>
 inline constexpr yotta_<U> yotta;
 
 }  // namespace units::si