71 lines
2.1 KiB
ReStructuredText
71 lines
2.1 KiB
ReStructuredText
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Concepts
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========
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All constructs in GIL are models of GIL concepts. A *concept* is a set of
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requirements that a type (or a set of related types) must fulfill to be used
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correctly in generic algorithms. The requirements include syntactic and
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algorithmic guarantees. For example, GIL class ``pixel`` is a model of GIL
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``PixelConcept``. The user may substitute the pixel class with one of their
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own, and, as long as it satisfies the requirements of ``PixelConcept``,
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all other GIL classes and algorithms can be used with it.
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See more about concepts at
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`Generic Programming in ConceptC++ <https://web.archive.org/web/20160324115943/http://www.generic-programming.org/languages/conceptcpp/>`_
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In this document we will use a syntax for defining concepts that is described
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in the C++ standard proposal paper
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`[N2081] Concepts <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2081.pdf>`_.
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Here are some common concepts that will be used in GIL.
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Most of them are defined at the
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`ConceptC++ Concept Web <https://web.archive.org/web/20160326060858/http://www.generic-programming.org/languages/conceptcpp/concept_web.php>`_:
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.. code-block:: cpp
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auto concept DefaultConstructible<typename T>
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{
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T::T();
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};
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auto concept CopyConstructible<typename T>
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{
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T::T(T);
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T::~T();
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};
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auto concept Assignable<typename T, typename U = T>
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{
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typename result_type;
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result_type operator=(T&, U);
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};
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auto concept EqualityComparable<typename T, typename U = T>
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{
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bool operator==(T x, U y);
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bool operator!=(T x, U y) { return !(x==y); }
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};
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concept SameType<typename T, typename U> { /* unspecified */ };
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template<typename T> concept_map SameType<T, T> { /* unspecified */ };
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auto concept Swappable<typename T>
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{
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void swap(T& t, T& u);
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};
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Here are some additional basic concepts that GIL needs:
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.. code-block:: cpp
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auto concept Regular<typename T> :
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DefaultConstructible<T>,
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CopyConstructible<T>,
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EqualityComparable<T>,
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Assignable<T>,
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Swappable<T>
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{};
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auto concept Metafunction<typename T>
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{
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typename type;
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};
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