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added transform_iterator_ref.diff's to 9.37
[SVN r21811]
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@ -922,9 +922,9 @@ provide rather than how they're implemented.
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:Proposed resolution:
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Remove the specfication of inheritance, and explicit specification of
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all the functionality that was inherited from the specialized
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iterators.
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Remove the specfication of inheritance, and add explicit
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specification of all the functionality that was inherited from the
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specialized iterators.
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In iterator_adaptor, inheritance is retained, sorry NAD. Also,
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the Interoperable Iterators concept is added to the new iterator
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@ -932,6 +932,160 @@ provide rather than how they're implemented.
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iterator adaptors.
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In [lib.iterator.special.adaptors]
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Change::
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class transform_iterator
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: public iterator_adaptor</* see discussion */>
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{
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friend class iterator_core_access;
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to::
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class transform_iterator
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{
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public:
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typedef /* see below */ value_type;
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typedef /* see below */ reference;
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typedef /* see below */ pointer;
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typedef iterator_traits<Iterator>::difference_type difference_type;
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typedef /* see below */ iterator_category;
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Add::
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Iterator base() const;
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reference operator*() const;
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transform_iterator& operator++();
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transform_iterator& operator--();
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Change::
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private:
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typename transform_iterator::value_type dereference() const;
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UnaryFunction m_f;
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};
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to::
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private:
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Iterator m_iterator; // exposition only
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UnaryFunction m_f; // exposition only
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};
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Add:
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If ``Iterator`` models Readable Lvalue Iterator and if ``Iterator``
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models Random Access Traversal Iterator, then ``iterator_category`` is
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convertible to ``random_access_iterator_tag``. Otherwise, if
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``Iterator`` models Bidirectional Traversal Iterator, then
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``iterator_category`` is convertible to
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``bidirectional_iterator_tag``. Otherwise ``iterator_category`` is
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convertible to ``forward_iterator_tag``. If ``Iterator`` does not
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model Readable Lvalue Iterator then ``iterator_category`` is
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convertible to ``input_iterator_tag``.
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In the requirements section, change:
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The type ``Iterator`` must at least model Readable Iterator. The
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resulting ``transform_iterator`` models the most refined of the
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following options that is also modeled by ``Iterator``.
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* Writable Lvalue Iterator if ``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type`` is a non-const reference.
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* Readable Lvalue Iterator if ``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type`` is a const
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reference.
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* Readable Iterator otherwise.
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The ``transform_iterator`` models the most refined standard traversal
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concept that is modeled by ``Iterator``.
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The ``reference`` type of ``transform_iterator`` is
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``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type``.
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The ``value_type`` is ``remove_cv<remove_reference<reference> >::type``.
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to:
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The argument ``Iterator`` shall model Readable Iterator.
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Add a new models section:
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The resulting ``transform_iterator`` models the most refined of the
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following options that is also modeled by ``Iterator``.
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* Writable Lvalue Iterator if ``transform_iterator::reference`` is a non-const reference.
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* Readable Lvalue Iterator if ``transform_iterator::reference`` is a const reference.
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* Readable Iterator otherwise.
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The ``transform_iterator`` models the most refined standard traversal
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concept that is modeled by the ``Iterator`` argument.
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If ``transform_iterator`` is a model of Readable Lvalue Iterator then
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it models the following original iterator concepts depending on what
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the ``Iterator`` argument models.
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+-----------------------------------+---------------------------------+
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| If ``Iterator`` models | then ``filter_iterator`` models |
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+===================================+=================================+
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| Single Pass Iterator | Input Iterator |
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+-----------------------------------+---------------------------------+
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| Forward Traversal Iterator | Forward Iterator |
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+-----------------------------------+---------------------------------+
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| Bidirectional Traversal Iterator | Bidirectional Iterator |
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+-----------------------------------+---------------------------------+
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| Random Access Traversal Iterator | Random Access Iterator |
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+-----------------------------------+---------------------------------+
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If ``transform_iterator`` models Writable Lvalue Iterator then it is a
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mutable iterator (as defined in the old iterator requirements).
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``transform_iterator<F1, X, R1, V1>`` is interoperable with
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``transform_iterator<F2, Y, R2, V2>`` if and only if ``X`` is
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interoperable with ``Y``.
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Remove the private operations section heading and remove::
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``typename transform_iterator::value_type dereference() const;``
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:Returns: ``m_f(transform_iterator::dereference());``
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Add::
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``Iterator base() const;``
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:Returns: ``m_iterator``
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``reference operator*() const;``
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:Returns: ``m_f(*m_iterator)``
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``transform_iterator& operator++();``
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:Effects: ``++m_iterator``
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:Returns: ``*this``
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``transform_iterator& operator--();``
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:Effects: ``--m_iterator``
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:Returns: ``*this``
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9.38x Problem with specification of a->m in Readable Iterator
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=============================================================
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