indirect_iterator_ref.diff

C++的一个好库。。。现在很流行

Index: indirect_iterator_ref.rst
===================================================================
RCS file: /cvsroot/boost/boost/libs/iterator/doc/indirect_iterator_ref.rst,v
retrieving revision 1.2
retrieving revision 1.21
diff -w -d -u -b -r1.2 -r1.21
--- indirect_iterator_ref.rst	22 Sep 2003 19:55:00 -0000	1.2
+++ indirect_iterator_ref.rst	15 Jan 2004 00:01:33 -0000	1.21



@@ -3,82 +3,139 @@
   template <
       class Iterator
     , class Value = use_default

Issue 9.15

-    , unsigned Access  = use_default_access
-    , class Traversal  = use_default
+    , class CategoryOrTraversal = use_default
     , class Reference = use_default
     , class Difference = use_default
   >
   class indirect_iterator

Issue 9.37x

-    : public iterator_adaptor</* see discussion */>
   {
-      friend class iterator_core_access;
    public:
+      typedef /* see below */ value_type;
+      typedef /* see below */ reference;
+      typedef /* see below */ pointer;
+      typedef /* see below */ difference_type;
+      typedef /* see below */ iterator_category;
+
       indirect_iterator();
       indirect_iterator(Iterator x);
+

Issue 9.15

       template <
-          class Iterator2, class Value2, unsigned Access2, class Traversal2
+          class Iterator2, class Value2, class Category2
         , class Reference2, class Difference2
       >
       indirect_iterator(
           indirect_iterator<
-               Iterator2, Value2, Access2, Traversal2, Reference2, Difference2
+               Iterator2, Value2, Category2, Reference2, Difference2
           > const& y
         , typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition
       );

Issue 9.37x

-  private: // as-if specification
-      typename indirect_iterator::reference dereference() const
-      {
-          return **this->base();
-      }
+
+      Iterator const& base() const;
+      reference operator*() const;
+      indirect_iterator& operator++();
+      indirect_iterator& operator--();
+  private:
+     Iterator m_iterator; // exposition
   };
 
+
+The member types of ``indirect_iterator`` are defined according to
+the following pseudo-code, where ``V`` is
+``iterator_traits<Iterator>::value_type``
+
+.. parsed-literal::
+
+  if (Value is use_default) then
+      typedef remove_const<pointee<V>::type>::type value_type;
+  else
+      typedef remove_const<Value>::type value_type;
+
+  if (Reference is use_default) then
+      if (Value is use_default) then
+          typedef indirect_reference<V>::type reference;
+      else
+          typedef Value& reference;
+  else
+      typedef Reference reference;
+
+  if (Value is use_default) then 
+      typedef pointee<V>::type\* pointer;
+  else 
+      typedef Value\* pointer;
+
+  if (Difference is use_default)
+      typedef iterator_traits<Iterator>::difference_type difference_type;
+  else
+      typedef Difference difference_type;
+
+  if (CategoryOrTraversal is use_default)
+      typedef |iterator-category|_\ (
+          iterator_traversal<Iterator>::type,``reference``,``value_type``
+      ) iterator_category;
+  else
+      typedef |iterator-category|_\ (
+          CategoryOrTraversal,``reference``,``value_type``
+      ) iterator_category;
+
+

 ``indirect_iterator`` requirements
 ..................................

Issue 9.40x
 
-The ``value_type`` of the ``Iterator`` template parameter should
-itself be dereferenceable. The return type of the ``operator*`` for
-the ``value_type`` must be the same type as the ``Reference`` template
-parameter. The ``Value`` template parameter will be the ``value_type``
-for the ``indirect_iterator``, unless ``Value`` is const. If ``Value``
-is ``const X``, then ``value_type`` will be *non-* ``const X``.  The
-default for ``Value`` is
+The expression ``*v``, where ``v`` is an object of
+``iterator_traits<Iterator>::value_type``, shall be valid
+expression and convertible to ``reference``.  ``Iterator`` shall
+model the traversal concept indicated by ``iterator_category``.
+``Value``, ``Reference``, and ``Difference`` shall be chosen so
+that ``value_type``, ``reference``, and ``difference_type`` meet
+the requirements indicated by ``iterator_category``.
 
-::
+[Note: there are further requirements on the
+``iterator_traits<Iterator>::value_type`` if the ``Value``
+parameter is not ``use_default``, as implied by the algorithm for
+deducing the default for the ``value_type`` member.]
 
-  iterator_traits< iterator_traits<Iterator>::value_type >::value_type

Issue 9.37x

+``indirect_iterator`` models
+............................
 
-If the default is used for ``Value``, then there must be a valid
-specialization of ``iterator_traits`` for the value type of the base
-iterator.
+In addition to the concepts indicated by ``iterator_category``
+and by ``iterator_traversal<indirect_iterator>::type``, a
+specialization of ``indirect_iterator`` models the following
+concepts, Where ``v`` is an object of
+``iterator_traits<Iterator>::value_type``:
 
-The ``Reference`` parameter will be the ``reference`` type of the
-``indirect_iterator``. The default is ``Value&``.
+  * Readable Iterator if ``reference(*v)`` is convertible to
+    ``value_type``.
 
-The ``Access`` and ``Traversal`` parameters are passed unchanged to
-the corresponding parameters of the ``iterator_adaptor`` base
-class, and  the ``Iterator`` parameter is passed unchanged as the
-``Base`` parameter to the ``iterator_adaptor`` base class.
+  * Writable Iterator if ``reference(*v) = t`` is a valid
+    expression (where ``t`` is an object of type
+    ``indirect_iterator::value_type``)
 
-The indirect iterator will model the most refined standard traversal
-concept that is modeled by the ``Iterator`` type.  The indirect
-iterator will model the most refined standard access concept that is
-modeled by the value type of ``Iterator``.
+  * Lvalue Iterator if ``reference`` is a reference type.
+
+``indirect_iterator<X,V1,C1,R1,D1>`` is interoperable with
+``indirect_iterator<Y,V2,C2,R2,D2>`` if and only if ``X`` is
+interoperable with ``Y``.
 
 
 ``indirect_iterator`` operations
 ................................

Issue 9.37x
 
+In addition to the operations required by the concepts described
+above, specializations of ``indirect_iterator`` provide the
+following operations.
+
+

Issue 9.28 and 9.37x

 ``indirect_iterator();``
 
 :Requires: ``Iterator`` must be Default Constructible.
 :Returns: An instance of ``indirect_iterator`` with
-    a default constructed base object.
+   a default-constructed ``m_iterator``.
 

Issue 9.37x
 
 ``indirect_iterator(Iterator x);``
 
 :Returns: An instance of ``indirect_iterator`` with
-    the ``iterator_adaptor`` subobject copy constructed from ``x``.
+    ``m_iterator`` copy constructed from ``x``.
 
 ::
 

Issue 9.29

@@ -94,5 +151,27 @@
   );
 
 :Requires: ``Iterator2`` is implicitly convertible to ``Iterator``.
-:Returns: An instance of ``indirect_iterator`` that is a copy of ``y``.
+:Returns: An instance of ``indirect_iterator`` whose 
+    ``m_iterator`` subobject is constructed from ``y.base()``.
+

Issue 9.37x

+``Iterator const& base() const;``
 
+:Returns: ``m_iterator``
+
+
+``reference operator*() const;``
+
+:Returns:  ``**m_iterator``
+
+
+``indirect_iterator& operator++();``
+
+:Effects: ``++m_iterator``
+:Returns: ``*this``
+
+
+``indirect_iterator& operator--();``
+
+:Effects: ``--m_iterator``
+:Returns: ``*this``