morph::units::NamedQuantity< Name, U > Struct Template Reference

A Quantity that names itself on construction and slices losslessly back to a plain Quantity. The name lives in the shared history. More...

#include <quantity.hpp>

Inheritance diagram for morph::units::NamedQuantity< Name, U >:

Public Types
using	Base = Quantity<U>
	The plain base quantity type.

Public Member Functions
	NamedQuantity ()
	Constructs empty, then names.
	NamedQuantity (std::optional< math::Rational > adopted)
	Constructs from a payload, then names.
	NamedQuantity (Base quantity)
	Constructs from a plain quantity, then names.
Public Member Functions inherited from morph::units::Quantity< U >
constexpr	Quantity () noexcept=default
	Constructs the empty state (no recorded derivation).
	Quantity (math::Rational engaged)
	Engages with engaged (which keeps its own runtime precision).
	Quantity (std::optional< math::Rational > adopted)
	Adopts an optional payload as-is.
	Quantity (const Quantity< U, OtherDecimals > &other)
	Converts from the same unit at another declared precision; the value, its runtime tag, and its derivation carry over unchanged.
constexpr bool	hasValue () const noexcept
	Whether a value has been entered/measured.
constexpr bool	withinDeclaredBounds () const noexcept
	Pre-decode validation seam: whether the current payload falls within this field's unit-declared bounds (UnitTraits<E>::bounds), when the unit declares any. An empty payload, or a unit with no declared bounds() (HasUnitBounds not satisfied), is always within bounds — this is an opt-in check, not a new default restriction, so a unit system that declares no bounds behaves exactly as it did before this feature existed.
constexpr const std::optional< math::Rational > &	value () const noexcept
	The payload, for pattern-matching / -> access.
constexpr math::Rational	value_or (const math::Rational &fallback) const noexcept
	The payload if engaged, otherwise a caller-supplied fallback.
constexpr const math::Rational &	operator* () const noexcept
	Unchecked access to the engaged value (UB when empty, exactly like std::optional::operator*).
Quantity	withDecimalPlaces (math::DecimalPlaces newPrecision) const
	Retags the value's runtime precision (the exact value itself is unchanged — precision only affects rounding and formatting).
Quantity	roundedToDecimalPlaces (math::DecimalPlaces newPrecision, math::RoundingMode mode=math::RoundingMode::HalfAwayFromZero) const
	Rounds the value to a runtime precision, changing the exact value as well as the tag — unlike withDecimalPlaces, which retags only and leaves display and storage free to disagree.
Quantity	atDeclaredPrecision () const
	Rounds the value to this field's declared precision — the one the generated schema advertises as x-decimalPlaces.
Quantity	named (std::string label) const
	Seals this value with a name: equation() shows the name instead of expanding its derivation. Builds a fresh node (never mutates a shared one); a no-op returning empty on empty or with tracing off.
std::vector< std::string >	equation (std::size_t maxSteps=kDefaultEquationSteps) const
	The worked derivation as print-ready lines (see docs/spec/util/quantity_type.md).
	operator Quantity< To > () const
	Implicit within-dimension conversion to another unit; delegates to convert, propagates empty, and records a provenance step.

Static Public Member Functions
static NamedQuantity	fromDouble (double raw)
	Names a floating-point reading.
Static Public Member Functions inherited from morph::units::Quantity< U >
static constexpr UnitMeta	unitMeta () noexcept
	The unit's static metadata (id, display text, default decimals).
static constexpr math::DecimalPlaces	declaredPrecision () noexcept
	The declared precision as a DecimalPlaces strong type.
static constexpr std::span< const UnitAlternative< decltype(U)> >	unitAlternatives () noexcept
	The convertible display/entry units for this field's unit, derived from UnitTraits::relations.
static Quantity	fromDouble (double raw) noexcept
	Converts a floating-point reading at the declared precision.
static Quantity	fromOptional (std::optional< math::Rational > adopted)
	Wraps an optional payload, preserving the declared precision.

Additional Inherited Members
Public Attributes inherited from morph::units::Quantity< U >
std::optional< math::Rational >	payload
	The payload; std::nullopt means "not entered / not measured".
Static Public Attributes inherited from morph::units::Quantity< U >
static constexpr auto	unit
	The unit this quantity is denominated in (compile-time).
static constexpr std::uint32_t	declaredDecimals
	Declared decimal places of this field (compile-time).

Detailed Description

template<detail::FixedString Name, auto U>
struct morph::units::NamedQuantity< Name, U >

A Quantity that names itself on construction and slices losslessly back to a plain Quantity. The name lives in the shared history.

Template Parameters

Name	Compile-time symbol name.
U	Unit enumerator.

Definition at line 1157 of file quantity.hpp.

Member Typedef Documentation

Base

template<detail::FixedString Name, auto U>

using morph::units::NamedQuantity< Name, U >::Base = Quantity<U>

The plain base quantity type.

Definition at line 1159 of file quantity.hpp.

Constructor & Destructor Documentation

NamedQuantity() [1/3]

template<detail::FixedString Name, auto U>

morph::units::NamedQuantity< Name, U >::NamedQuantity ( )

inline

Constructs empty, then names.

Definition at line 1162 of file quantity.hpp.

NamedQuantity() [2/3]

template<detail::FixedString Name, auto U>

morph::units::NamedQuantity< Name, U >::NamedQuantity ( std::optional< math::Rational > adopted )

inline

Constructs from a payload, then names.

Parameters

adopted

Engaged or empty payload.

Definition at line 1166 of file quantity.hpp.

NamedQuantity() [3/3]

template<detail::FixedString Name, auto U>

morph::units::NamedQuantity< Name, U >::NamedQuantity ( Base quantity )

inline

Constructs from a plain quantity, then names.

Parameters

quantity

The source quantity.

Definition at line 1171 of file quantity.hpp.

Member Function Documentation

fromDouble()

template<detail::FixedString Name, auto U>

NamedQuantity morph::units::NamedQuantity< Name, U >::fromDouble ( double raw )

inlinestaticnodiscard

Names a floating-point reading.

Not noexcept: unlike Base::fromDouble, this wraps the result in a NamedQuantity, whose construction calls named() — and with MORPH_QUANTITY_PROVENANCE enabled named() allocates an ASTNode (std::make_shared), which can throw std::bad_alloc.

Parameters

raw	The value to convert.

Returns

The named quantity.

Definition at line 1181 of file quantity.hpp.

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

• morph/util/quantity.hpp