units::affine::basic_kind< Tag, U > Class Template Reference

A quantity distinguished by a string TAG — a "kind of quantity" that shares a unit and a dimension with others but is semantically distinct (radial vs. More...

#include <kind.h>

Public Types
using	unit_type = U
using	underlying_type = typename traits::unit_traits<U>::underlying_type
	< the wrapped unit type

Public Member Functions
constexpr	basic_kind () noexcept=default
	< the wrapped unit's numeric type
constexpr	basic_kind (const U &value) noexcept
	A plain unit converts INTO a kind by copy-initialization or assignment — the intent (this value IS a Tag kind) is explicit at the assignment site, so this ctor is non-explicit.
constexpr	basic_kind (underlying_type value) noexcept
	Construct from the underlying numeric value (in U's own unit) — explicit, since a bare number carries no unit intent.
constexpr basic_kind &	operator= (const U &value) noexcept
	Assign a plain unit into this kind (same clear-intent conversion as copy-initialization).
constexpr auto	value () const noexcept
	The numeric value in its own unit.
constexpr auto	raw () const noexcept
	The raw (linearized) value.
constexpr auto	to_linearized () const noexcept
	The linearized value (as the wrapped unit's to_linearized()).
constexpr const char *	abbreviation () const noexcept
	The abbreviation is the wrapped unit's (a kind does not change the abbreviation — "m" for a kind<"radial", meters<double>>).
std::string	name () const
	The name is the tag followed by the wrapped unit's name — e.g. "radial meters".
template<ArithmeticType Arithmetic>
constexpr Arithmetic	to () const noexcept
	Express this kind's value as a plain arithmetic type — the numeric value in its own unit, matching the wrapped unit's to<Arithmetic>().
template<UnitType PlainTarget> requires traits::is_same_dimension_unit_v<U, PlainTarget>
constexpr PlainTarget	to () const noexcept
	Express this kind as a PLAIN unit of the same dimension — unwraps (dropping the tag), scale-only.
template<KindType WrapperTarget> requires (WrapperTarget::tag() == Tag && traits::is_same_dimension_unit_v<U, typename WrapperTarget::unit_type>)
constexpr WrapperTarget	to () const noexcept
	Express this kind as another kind<Tag, V> — the tag is KEPT (radial metres → radial feet).

Static Public Member Functions
static constexpr auto	tag () noexcept
	The tag of this kind.

Detailed Description

template<fixed_string Tag, UnitType U>
class units::affine::basic_kind< Tag, U >

A quantity distinguished by a string TAG — a "kind of quantity" that shares a unit and a dimension with others but is semantically distinct (radial vs.

straight-line distance, torque vs. energy). Two DIFFERENT tags never interoperate; the same tag does.

Template Parameters

Tag	a fixed_string naming the kind (e.g. "radial").
U	the wrapped unit type.

Users spell it units::kind<Tag, U> (the top-level alias); this is the underlying class the alias resolves to. A kind carries no datum; it wraps a plain magnitude and converts by scale like the unit it wraps, keeping its tag. Cross to the plain unit only explicitly, via to<PlainUnit>().

Constructor & Destructor Documentation

basic_kind()

template<fixed_string Tag, UnitType U>

units::affine::basic_kind< Tag, U >::basic_kind ( const U & value )

inlineconstexprnoexcept

A plain unit converts INTO a kind by copy-initialization or assignment — the intent (this value IS a Tag kind) is explicit at the assignment site, so this ctor is non-explicit.

What is NOT allowed is MIXING a plain unit with a kind in arithmetic (aKind + plainUnit); that stays ill-formed, so a value only ever enters a kind where you name it, never silently mid-expression.

Member Function Documentation

to() [1/2]

template<fixed_string Tag, UnitType U>

template<KindType WrapperTarget>
requires (WrapperTarget::tag() == Tag && traits::is_same_dimension_unit_v<U, typename WrapperTarget::unit_type>)

WrapperTarget units::affine::basic_kind< Tag, U >::to ( ) const

inlineconstexprnoexcept

Express this kind as another kind<Tag, V> — the tag is KEPT (radial metres → radial feet).

Only a SAME-tag kind target is viable; a different-tag kind target has no matching overload (converting a radial distance into a straight-line distance is meaningless).

to() [2/2]

template<fixed_string Tag, UnitType U>

template<UnitType PlainTarget>
requires traits::is_same_dimension_unit_v<U, PlainTarget>

PlainTarget units::affine::basic_kind< Tag, U >::to ( ) const

inlineconstexprnoexcept

Express this kind as a PLAIN unit of the same dimension — unwraps (dropping the tag), scale-only.

radial.to<feet<double>>() is plain feet; .to<meters<double>>() is the plain wrapped value.

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The documentation for this class was generated from the following file:

• /home/runner/work/units/units/include/units/kind.h