forked from mpusz/mp-units
563b358d5e
Dimensionless quantities are now represented by quantity types rather than by plain representation types. Only dimensionless quantities with `unitless` unit are implicitly convertible from representation types. `units::exp()` now is a function doing std::exp() on a representation type (previous `units::exp` class template was renamed to `units::exponent`). BREAKING_CHANGE: gcc-9.3 support removed BREAKING_CHANGE: `exp` and `Exp` renamed to `exponent` and `Exponent` Resolves #27 Resolves #42
76 lines
2.8 KiB
ReStructuredText
76 lines
2.8 KiB
ReStructuredText
Concepts
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========
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.. namespace:: units
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.. note::
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All names defined in this chapter reside in the :any:`units` namespace unless
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specified otherwise.
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.. concept:: template<typename T> PrefixFamily
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A concept matching a prefix family. Satisfied by all types derived from :class:`prefix_family`.
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.. concept:: template<typename T> Prefix
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A concept matching a symbol prefix. Satisfied by all instantiations of :class:`prefix`.
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.. concept:: template<ratio R> UnitRatio
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Satisfied by all ratio values for which :expr:`R.num > 0` and :expr:`R.den > 0`.
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.. concept:: template<typename T> BaseDimension
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A concept matching all base dimensions in the library. Satisfied by all dimension types
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derived from the instantiation of :class:`base_dimension`.
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.. concept:: template<typename T> Exponent
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A concept matching dimension's exponents. Satisfied by all instantiations of :class:`exponent`.
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.. concept:: template<typename T> DerivedDimension
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A concept matching all derived dimensions in the library. Satisfied by all dimension
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types derived from the instantiation of :class:`detail::derived_dimension_base`.
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.. concept:: template<typename T> Dimension
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A concept matching all dimensions in the library. Satisfied by all dimension types for
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which either :expr:`BaseDimension<T>` or :expr:`DerivedDimension<T>` is ``true``.
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.. concept:: template<typename T> Unit
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A concept matching all unit types in the library. Satisfied by all unit types derived
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from the instantiation of :class:`scaled_unit`.
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.. concept:: template<typename U, typename D> UnitOf
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A concept matching only units of a specified dimension. Satisfied by all unit types that
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satisfy :expr:`Unit<U>`, :expr:`Dimension<D>`, and for which :expr:`U::reference` and
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:expr:`dimension_unit<D>::reference` denote the same unit type.
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:tparam U: Type to verify against concept constraints.
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:tparam D: Dimension type to use for verification.
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.. concept:: template<typename T> Quantity
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A concept matching all quantities in the library. Satisfied by all instantiations of :class:`quantity`.
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.. concept:: template<typename T> WrappedQuantity
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A concept matching types that wrap quantity objects. Satisfied by all wrapper types that
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satisfy :expr:`Quantity<typename T::value_type>` recursively
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(i.e. :expr:`std::optional<si::length<si::metre>>`).
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.. concept:: template<typename T> Scalar
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A concept matching non-Quantity types. Satisfied by types that match
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:expr:`(!Quantity<T>) && (!WrappedQuantity<T>) && std::regular<T>` and satisfy one of the
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following:
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- if type :expr:`T` is constructible from ``std::int64_t`` (which is the type that stores
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the elements of `ratio`), :expr:`T * T` and :expr:`T / T` must be valid,
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- otherwise, :expr:`T * std::int64_t`, :expr:`std::int64_t * T`, and :expr:`T / std::int64_t`
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must be valid.
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