Separate access and traversal for iterator_adaptor

[SVN r20162]

doc/counting_iterator_ref.rst

@@ -1,12 +1,18 @@
 ::
 
-  template <class Incrementable, class Category = use_default, class Difference = use_default>
+  template <
+      class Incrementable
+    , unsigned Access = use_default_access
+    , class Traversal = use_default
+    , class Difference = use_default
+  >
   class counting_iterator
     : public iterator_adaptor<
-          counting_iterator<Incrementable, Category, Difference>
+          counting_iterator<Incrementable, Access, Traversal, Difference>
         , Incrementable
         , Incrementable
-        , /* see details for category */
+        , Access
+        , /* see details for traversal category */
         , Incrementable const&
         , Incrementable const*
         , /* distance = Difference or a signed integral type */>

doc/facade-and-adaptor.html

@@ -219,7 +219,7 @@ Lab</a>, University of Hanover <a class="last reference" href="http://www.ive.un
 Railway Operation and Construction</a></td></tr>
 <tr><th class="docinfo-name">Date:</th>
 <td>2003-09-22</td></tr>
-<tr class="field"><th class="docinfo-name">Number:</th><td class="field-body"><strong>This document is a revised version of the official</strong> N1476=03-0059</td>
+<tr class="field"><th class="docinfo-name">Number:</th><td class="field-body">N1530=03-0113</td>
 </tr>
 <tr><th class="docinfo-name">Copyright:</th>
 <td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All rights reserved</td></tr>
@@ -642,17 +642,18 @@ above. The <tt class="literal"><span class="pre">Base</span></tt> type need not
 iterator. It need only support the operations used by the core
 interface functions of <tt class="literal"><span class="pre">iterator_adaptor</span></tt> that have not been
 redefined in the user's derived class.</p>
-<p>Several of the template parameters of <tt class="literal"><span class="pre">iterator_adaptor</span></tt> default to
+<p>Several of the template parameters of <tt class="literal"><span class="pre">iterator_adaptor</span></tt> default
-<tt class="literal"><span class="pre">use_default</span></tt>. This allows the user to make use of a default
+to <tt class="literal"><span class="pre">use_default</span></tt> (or <tt class="literal"><span class="pre">use_default_access</span></tt>). This allows the
-parameter even when the user wants to specify a parameter later in the
+user to make use of a default parameter even when she wants to
-parameter list.  Also, the defaults for the corresponding associated
+specify a parameter later in the parameter list.  Also, the
-types are fairly complicated, so metaprogramming is required to
+defaults for the corresponding associated types are somewhat
-compute them, and <tt class="literal"><span class="pre">use_default</span></tt> can help to simplify the
+complicated, so metaprogramming is required to compute them, and
-implementation.  Finally, <tt class="literal"><span class="pre">use_default</span></tt> is not left unspecified
+<tt class="literal"><span class="pre">use_default</span></tt> can help to simplify the implementation.  Finally,
+the identity of the <tt class="literal"><span class="pre">use_default</span></tt> type is not left unspecified
 because specification helps to highlight that the <tt class="literal"><span class="pre">Reference</span></tt>
 template parameter may not always be identical to the iterator's
-<tt class="literal"><span class="pre">reference</span></tt> type, and will keep users making mistakes based on that
+<tt class="literal"><span class="pre">reference</span></tt> type, and will keep users making mistakes based on
-assumption.</p>
+that assumption.</p>
 </div>
 <div class="section" id="specialized-adaptors">
 <h2><a class="toc-backref" href="#id28" name="specialized-adaptors">Specialized Adaptors</a></h2>
@@ -697,13 +698,14 @@ Standard compliant iterators).</p>
 <h2><a class="toc-backref" href="#id30" name="header-iterator-helper-synopsis-lib-iterator-helper-synopsis">Header <tt class="literal"><span class="pre">&lt;iterator_helper&gt;</span></tt> synopsis    [lib.iterator.helper.synopsis]</a></h2>
 <pre class="literal-block">
 struct use_default;
+const unsigned use_default_access = -1;
 
 struct iterator_core_access { /* implementation detail */ };
 
 template &lt;
     class Derived
   , class Value
-  , class AccessCategory
+  , unsigned AccessCategory
   , class TraversalCategory
   , class Reference  = Value&amp;
   , class Difference = ptrdiff_t
@@ -714,7 +716,8 @@ template &lt;
     class Derived
   , class Base
   , class Value      = use_default
-  , class Category   = use_default
+  , unsigned Access  = use_default_access
+  , class Traversal  = use_default
   , class Reference  = use_default
   , class Difference = use_default
 &gt;
@@ -723,7 +726,8 @@ class iterator_adaptor;
 template &lt;
     class Iterator
   , class Value = use_default
-  , class Category = use_default
+  , unsigned Access  = use_default_access
+  , class Traversal  = use_default
   , class Reference = use_default
   , class Difference = use_default
 &gt;
@@ -745,7 +749,8 @@ class filter_iterator;
 
 template &lt;
     class Incrementable
-  , class Category = use_default
+  , unsigned Access  = use_default_access
+  , class Traversal  = use_default
   , class Difference = use_default
 &gt;
 class counting_iterator
@@ -765,7 +770,7 @@ and associated types, to be supplied by a derived iterator class.</p>
 template &lt;
     class Derived
   , class Value
-  , class AccessCategory
+  , unsigned AccessCategory
   , class TraversalCategory
   , class Reference  = /* see <a class="reference" href="#iterator-facade-requirements">below</a> */
   , class Difference = ptrdiff_t
@@ -855,11 +860,21 @@ out of the overload set when the types are not interoperable.]</p>
 title prevents an automatic link from being generated -->
 <a class="target" id="iterator-facade-requirements" name="iterator-facade-requirements"></a><div class="section" id="id13">
 <h4><a class="toc-backref" href="#id33" name="id13"><tt class="literal"><span class="pre">iterator_facade</span></tt> requirements</a></h4>
+<p>Some of the constraints on template parameters to
+<tt class="literal"><span class="pre">iterator_facade</span></tt> are expressed in terms of resulting nested
+types and should be viewed in the context of their impact on
+<tt class="literal"><span class="pre">iterator_traits&lt;Derived&gt;</span></tt>.</p>
 <p>The <tt class="literal"><span class="pre">Derived</span></tt> template parameter must be a class derived from
 <tt class="literal"><span class="pre">iterator_facade</span></tt>.</p>
-<p>The default for the <tt class="literal"><span class="pre">Reference</span></tt> parameter is <tt class="literal"><span class="pre">Value&amp;</span></tt> if the
+<p>The nested <tt class="literal"><span class="pre">::value_type</span></tt> type will be the same as
-access category for <tt class="literal"><span class="pre">iterator_facade</span></tt> is implicitly convertible to
+<tt class="literal"><span class="pre">remove_cv&lt;Value&gt;::type</span></tt>, so the <tt class="literal"><span class="pre">Value</span></tt> parameter must be
-<tt class="literal"><span class="pre">writable_iterator_tag</span></tt>, and <tt class="literal"><span class="pre">const</span> <span class="pre">Value&amp;</span></tt> otherwise.</p>
+an (optionally <tt class="literal"><span class="pre">const</span></tt>-qualified) non-reference type.</p>
+<p><tt class="literal"><span class="pre">AccessCategory</span></tt> must be an unsigned value which uses no more
+bits than the greatest value of <tt class="literal"><span class="pre">iterator_access</span></tt>.</p>
+<p>The nested <tt class="literal"><span class="pre">::reference</span></tt> will be the same as the <tt class="literal"><span class="pre">Reference</span></tt>
+parameter; it must be a suitable reference type for the resulting
+iterator.  The default for the <tt class="literal"><span class="pre">Reference</span></tt> parameter is
+<tt class="literal"><span class="pre">Value&amp;</span></tt>.</p>
 <p>The following table describes the other requirements on the
 <tt class="literal"><span class="pre">Derived</span></tt> parameter.  Depending on the resulting iterator's
 <tt class="literal"><span class="pre">iterator_category</span></tt>, a subset of the expressions listed in the table
@@ -973,8 +988,8 @@ of type <tt class="literal"><span class="pre">X::pointer</span></tt> equal to:</
 <p>Otherwise returns an object of unspecified type such that, given an
 object <tt class="literal"><span class="pre">a</span></tt> of type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">a-&gt;m</span></tt> is equivalent to <tt class="literal"><span class="pre">(w</span> <span class="pre">=</span> <span class="pre">*a,</span>
 <span class="pre">w.m)</span></tt> for some temporary object <tt class="literal"><span class="pre">w</span></tt> of type <tt class="literal"><span class="pre">X::value_type</span></tt>.</p>
-<p class="last">The type <tt class="literal"><span class="pre">X::pointer</span></tt> is <tt class="literal"><span class="pre">Value*</span></tt> if the access category for
+<p class="last">The type <tt class="literal"><span class="pre">X::pointer</span></tt> is <tt class="literal"><span class="pre">Value*</span></tt> if
-<tt class="literal"><span class="pre">X</span></tt> is implicitly convertible to <tt class="literal"><span class="pre">writable_iterator_tag</span></tt>, and
+<tt class="literal"><span class="pre">is_writable_iterator&lt;X&gt;::value</span></tt> is <tt class="literal"><span class="pre">true</span></tt>, and
 <tt class="literal"><span class="pre">Value</span> <span class="pre">const*</span></tt> otherwise.</p>
 </td>
 </tr>
@@ -1107,11 +1122,13 @@ core interface functions of <tt class="literal"><span class="pre">iterator_facad
 <div class="section" id="class-template-iterator-adaptor">
 <h3><a class="toc-backref" href="#id36" name="class-template-iterator-adaptor">Class template <tt class="literal"><span class="pre">iterator_adaptor</span></tt></a></h3>
 <pre class="literal-block">
+bool
 template &lt;
     class Derived
   , class Base
   , class Value      = use_default
-  , class Category   = use_default
+  , unsigned Access  = use_default_access
+  , class Traversal  = use_default
   , class Reference  = use_default
   , class Difference = use_default
 &gt;
@@ -1163,54 +1180,47 @@ parameters specify the types for the member typedefs in
 <tt class="literal"><span class="pre">iterator_facade</span></tt>.  The following pseudo-code specifies the
 traits types for <tt class="literal"><span class="pre">iterator_adaptor</span></tt>.</p>
 <pre class="literal-block">
-if (Value == use_default)
+if (Value != use_default)
-    value_type = iterator_traits&lt;Base&gt;::value_type;
+     value_type = remove_cv&lt;Value&gt;::type;
-else 
-    value_type = remove_cv&lt;Value&gt;::type;
-
-if (Reference == use_default) {
-    if (Value == use_default)
-        reference = iterator_traits&lt;Base&gt;::reference;
-    else 
-        reference = Value&amp;;
-} else
-    reference = Reference;
-
-if (Distance == use_default)
-    difference_type = iterator_traits&lt;Base&gt;::difference_type;
 else
-    difference_type = Distance;
+     value_type = iterator_traits&lt;Base&gt;::value_type;
 
-if (Category == use_default)
-    iterator_category = iterator_tag&lt; 
-        access_category&lt; Base &gt;,
-        traversal_category&lt; Base &gt;
-    &gt;
-else if (Category is convertible to a standard access tag)
-    iterator_category = iterator_tag&lt;
-        Category
-    else if (Category has a nested traversal type)
-         if (reference is not a reference-to-const)
-             Category::access
-         else
-             if (Category
-        
 
-else if (Category is convertable to a standard traversal tag)
+if (Traversal != use_default)
-    ...
+    traversal_category = Traversal
 else
-    iterator_category = Category;
+    traversal_category = traversal_category&lt; Base &gt;::type
-    // Actually the above is wrong.  See the use of
+
-    // access_category_tag and
+iterator_category = iterator_tag&lt;
-    // new_category_to_access/iter_category_to_access.
+                         access_category
+                       , traversal_category
+                     &gt;
+
+if (Access != use_default)
+{
+   access_category = Access
+}
+else
+{
+   access_category
+     = access_category&lt; Base &gt;::value
+
+   if (is_const&lt;Value&gt;)
+       access_category &amp;= ~writable_iterator;
+}
+
+iterator_category = iterator_tag&lt;
+                         access_category
+                       , traversal_category
+                     &gt;
+
+if (Reference != use_default)
+    reference = Reference
+else if (Value != use_default)
+    reference = Value&amp;
+else
+    reference = iterator_traits&lt;Base&gt;::reference
 </pre>
-<!-- Replaced with new semantics - -thw
-if (Category == use_default)
-    iterator_category = iterator_traits<Base>::iterator_category;
-else
-    iterator_category = Category;
-
-Fix this up!! -->
 </div>
 <div class="section" id="iterator-adaptor-public-operations">
 <h3><a class="toc-backref" href="#id38" name="iterator-adaptor-public-operations"><tt class="literal"><span class="pre">iterator_adaptor</span></tt> public operations</a></h3>
@@ -1362,7 +1372,8 @@ iterators over smart pointers, which the impl handles. -JGS -->
 template &lt;
     class Iterator
   , class Value = use_default
-  , class Category = use_default
+  , unsigned Access  = use_default_access
+  , class Traversal  = use_default
   , class Reference = use_default
   , class Difference = use_default
 &gt;
@@ -1374,12 +1385,12 @@ class indirect_iterator
     indirect_iterator();
     indirect_iterator(Iterator x);
     template &lt;
-        class Iterator2, class Value2, class Category2
+        class Iterator2, class Value2, unsigned Access2, class Traversal2
       , class Reference2, class Difference2
     &gt;
     indirect_iterator(
         indirect_iterator&lt;
-             Iterator2, Value2, Category2, Reference2, Difference2
+             Iterator2, Value2, Access2, Traversal2, Reference2, Difference2
         &gt; const&amp; y
       , typename enable_if_convertible&lt;Iterator2, Iterator&gt;::type* = 0 // exposition
     );
@@ -1408,9 +1419,10 @@ specialization of <tt class="literal"><span class="pre">iterator_traits</span></
 iterator.</p>
 <p>The <tt class="literal"><span class="pre">Reference</span></tt> parameter will be the <tt class="literal"><span class="pre">reference</span></tt> type of the
 <tt class="literal"><span class="pre">indirect_iterator</span></tt>. The default is <tt class="literal"><span class="pre">Value&amp;</span></tt>.</p>
-<p>The <tt class="literal"><span class="pre">Category</span></tt> parameter is the <tt class="literal"><span class="pre">iterator_category</span></tt> type for the
+<p>The <tt class="literal"><span class="pre">Access</span></tt> and <tt class="literal"><span class="pre">Traversal</span></tt> parameters are passed unchanged to
-<tt class="literal"><span class="pre">indirect_iterator</span></tt>. The default is 
+the corresponding parameters of the <tt class="literal"><span class="pre">iterator_adaptor</span></tt> base
-<tt class="literal"><span class="pre">iterator_traits&lt;Iterator&gt;::iterator_category</span></tt>.</p>
+class, and  the <tt class="literal"><span class="pre">Iterator</span></tt> parameter is passed unchanged as the
+<tt class="literal"><span class="pre">Base</span></tt> parameter to the <tt class="literal"><span class="pre">iterator_adaptor</span></tt> base class.</p>
 <p>The indirect iterator will model the most refined standard traversal
 concept that is modeled by the <tt class="literal"><span class="pre">Iterator</span></tt> type.  The indirect
 iterator will model the most refined standard access concept that is
@@ -1442,12 +1454,12 @@ the <tt class="literal"><span class="pre">iterator_adaptor</span></tt> subobject
 </table>
 <pre class="literal-block">
 template &lt;
-    class Iterator2, class Value2, class Category2
+    class Iterator2, class Value2, unsigned Access, class Traversal
   , class Reference2, class Difference2
 &gt;
 indirect_iterator(
     indirect_iterator&lt;
-         Iterator2, Value2, Category2, Reference2, Difference2
+         Iterator2, Value2, Access, Traversal, Reference2, Difference2
     &gt; const&amp; y
   , typename enable_if_convertible&lt;Iterator2, Iterator&gt;::type* = 0 // exposition
 );
@@ -1733,12 +1745,13 @@ class filter_iterator
 </div>
 <div class="section" id="filter-iterator-requirements">
 <h3><a class="toc-backref" href="#id56" name="filter-iterator-requirements"><tt class="literal"><span class="pre">filter_iterator</span></tt> requirements</a></h3>
-<p>The base <tt class="literal"><span class="pre">Iterator</span></tt> parameter must be a model of Readable Iterator
+<p>The base <tt class="literal"><span class="pre">Iterator</span></tt> parameter must be a model of Readable
-and Single Pass Iterator. The resulting <tt class="literal"><span class="pre">filter_iterator</span></tt> will be a
+Iterator and Single Pass Iterator. The resulting
-model of Forward Traversal Iterator if <tt class="literal"><span class="pre">Iterator</span></tt> is, otherwise the
+<tt class="literal"><span class="pre">filter_iterator</span></tt> will be a model of Forward Traversal Iterator
-<tt class="literal"><span class="pre">filter_iterator</span></tt> will be a model of Single Pass Iterator. The
+if <tt class="literal"><span class="pre">Iterator</span></tt> is, otherwise the <tt class="literal"><span class="pre">filter_iterator</span></tt> will be a
-access category of the <tt class="literal"><span class="pre">filter_iterator</span></tt> will be the most refined
+model of Single Pass Iterator. The access category of the
-standard access category that is modeled by <tt class="literal"><span class="pre">Iterator</span></tt>.</p>
+<tt class="literal"><span class="pre">filter_iterator</span></tt> will be the same as the access category of
+<tt class="literal"><span class="pre">Iterator</span></tt>.</p>
 <!-- Thomas is going to try implementing filter_iterator so that
 it will be bidirectional if the underlying iterator is. -JGS -->
 <p>The <tt class="literal"><span class="pre">Predicate</span></tt> must be Assignable, Copy Constructible, and the
@@ -1830,13 +1843,19 @@ the base <tt class="literal"><span class="pre">m_iterator</span></tt>, as per th
 <div class="section" id="class-template-counting-iterator">
 <h4><a class="toc-backref" href="#id59" name="class-template-counting-iterator">Class template <tt class="literal"><span class="pre">counting_iterator</span></tt></a></h4>
 <pre class="literal-block">
-template &lt;class Incrementable, class Category = use_default, class Difference = use_default&gt;
+template &lt;
+    class Incrementable
+  , unsigned Access = use_default_access
+  , class Traversal = use_default
+  , class Difference = use_default
+&gt;
 class counting_iterator
   : public iterator_adaptor&lt;
-        counting_iterator&lt;Incrementable, Category, Difference&gt;
+        counting_iterator&lt;Incrementable, Access, Traversal, Difference&gt;
       , Incrementable
       , Incrementable
-      , /* see details for category */
+      , Access
+      , /* see details for traversal category */
       , Incrementable const&amp;
       , Incrementable const*
       , /* distance = Difference or a signed integral type */&gt;
@@ -1935,7 +1954,7 @@ template &lt;class UnaryFunction&gt;
 class function_output_iterator {
 public:
   typedef iterator_tag&lt;
-        writable_iterator_tag
+        writable_iterator
       , incrementable_traversal_tag
   &gt; iterator_category;
   typedef void                value_type;
@@ -2043,7 +2062,7 @@ LocalWords:  OtherIncrementable Coplien -->
 <hr class="footer" />
 <div class="footer">
 <a class="reference" href="facade-and-adaptor.rst">View document source</a>.
-Generated on: 2003-09-22 14:17 UTC.
+Generated on: 2003-09-22 16:48 UTC.
 Generated by <a class="reference" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
 </div>
 </body>

doc/facade-and-adaptor.rst

@@ -8,7 +8,7 @@
                Lab`_, University of Hanover `Institute for Transport
                Railway Operation and Construction`_
 :date: $Date$
-:Number: **This document is a revised version of the official** N1476=03-0059
+:Number: N1530=03-0113
 :copyright: Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All rights reserved
 
 .. _`Boost Consulting`: http://www.boost-consulting.com
@@ -226,13 +226,14 @@ Header ``<iterator_helper>`` synopsis    [lib.iterator.helper.synopsis]
 ::
 
   struct use_default;
+  const unsigned use_default_access = -1;
 
   struct iterator_core_access { /* implementation detail */ };
   
   template <
       class Derived
     , class Value
-    , class AccessCategory
+    , unsigned AccessCategory
     , class TraversalCategory
     , class Reference  = Value&
     , class Difference = ptrdiff_t
@@ -243,7 +244,8 @@ Header ``<iterator_helper>`` synopsis    [lib.iterator.helper.synopsis]
       class Derived
     , class Base
     , class Value      = use_default
-    , class Category   = use_default
+    , unsigned Access  = use_default_access
+    , class Traversal  = use_default
     , class Reference  = use_default
     , class Difference = use_default
   >
@@ -252,7 +254,8 @@ Header ``<iterator_helper>`` synopsis    [lib.iterator.helper.synopsis]
   template <
       class Iterator
     , class Value = use_default
-    , class Category = use_default
+    , unsigned Access  = use_default_access
+    , class Traversal  = use_default
     , class Reference = use_default
     , class Difference = use_default
   >
@@ -274,7 +277,8 @@ Header ``<iterator_helper>`` synopsis    [lib.iterator.helper.synopsis]
 
   template <
       class Incrementable
-    , class Category = use_default
+    , unsigned Access  = use_default_access
+    , class Traversal  = use_default
     , class Difference = use_default
   >
   class counting_iterator

doc/filter_iterator_ref.rst

@@ -41,12 +41,13 @@
 ``filter_iterator`` requirements
 --------------------------------
 
-The base ``Iterator`` parameter must be a model of Readable Iterator
+The base ``Iterator`` parameter must be a model of Readable
-and Single Pass Iterator. The resulting ``filter_iterator`` will be a
+Iterator and Single Pass Iterator. The resulting
-model of Forward Traversal Iterator if ``Iterator`` is, otherwise the
+``filter_iterator`` will be a model of Forward Traversal Iterator
-``filter_iterator`` will be a model of Single Pass Iterator. The
+if ``Iterator`` is, otherwise the ``filter_iterator`` will be a
-access category of the ``filter_iterator`` will be the most refined
+model of Single Pass Iterator. The access category of the
-standard access category that is modeled by ``Iterator``.
+``filter_iterator`` will be the same as the access category of
+``Iterator``.
 
 .. Thomas is going to try implementing filter_iterator so that
    it will be bidirectional if the underlying iterator is. -JGS

doc/function_output_iterator_ref.rst

@@ -4,7 +4,7 @@
   class function_output_iterator {
   public:
     typedef iterator_tag<
-          writable_iterator_tag
+          writable_iterator
         , incrementable_traversal_tag
     > iterator_category;
     typedef void                value_type;

doc/indirect_iterator_ref.rst

@@ -3,7 +3,8 @@
   template <
       class Iterator
     , class Value = use_default
-    , class Category = use_default
+    , unsigned Access  = use_default_access
+    , class Traversal  = use_default
     , class Reference = use_default
     , class Difference = use_default
   >
@@ -15,12 +16,12 @@
       indirect_iterator();
       indirect_iterator(Iterator x);
       template <
-          class Iterator2, class Value2, class Category2
+          class Iterator2, class Value2, unsigned Access2, class Traversal2
         , class Reference2, class Difference2
       >
       indirect_iterator(
           indirect_iterator<
-               Iterator2, Value2, Category2, Reference2, Difference2
+               Iterator2, Value2, Access2, Traversal2, Reference2, Difference2
           > const& y
         , typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition
       );
@@ -53,9 +54,10 @@ iterator.
 The ``Reference`` parameter will be the ``reference`` type of the
 ``indirect_iterator``. The default is ``Value&``.
 
-The ``Category`` parameter is the ``iterator_category`` type for the
+The ``Access`` and ``Traversal`` parameters are passed unchanged to
-``indirect_iterator``. The default is 
+the corresponding parameters of the ``iterator_adaptor`` base
-``iterator_traits<Iterator>::iterator_category``.
+class, and  the ``Iterator`` parameter is passed unchanged as the
+``Base`` parameter to the ``iterator_adaptor`` base class.
 
 The indirect iterator will model the most refined standard traversal
 concept that is modeled by the ``Iterator`` type.  The indirect
@@ -81,12 +83,12 @@ modeled by the value type of ``Iterator``.
 ::
 
   template <
-      class Iterator2, class Value2, class Category2
+      class Iterator2, class Value2, unsigned Access, class Traversal
     , class Reference2, class Difference2
   >
   indirect_iterator(
       indirect_iterator<
-           Iterator2, Value2, Category2, Reference2, Difference2
+           Iterator2, Value2, Access, Traversal, Reference2, Difference2
       > const& y
     , typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition
   );

doc/iterator_adaptor_body.rst

@@ -18,15 +18,16 @@ iterator. It need only support the operations used by the core
 interface functions of ``iterator_adaptor`` that have not been
 redefined in the user's derived class.
 
-Several of the template parameters of ``iterator_adaptor`` default to
+Several of the template parameters of ``iterator_adaptor`` default
-``use_default``. This allows the user to make use of a default
+to ``use_default`` (or ``use_default_access``). This allows the
-parameter even when the user wants to specify a parameter later in the
+user to make use of a default parameter even when she wants to
-parameter list.  Also, the defaults for the corresponding associated
+specify a parameter later in the parameter list.  Also, the
-types are fairly complicated, so metaprogramming is required to
+defaults for the corresponding associated types are somewhat
-compute them, and ``use_default`` can help to simplify the
+complicated, so metaprogramming is required to compute them, and
-implementation.  Finally, ``use_default`` is not left unspecified
+``use_default`` can help to simplify the implementation.  Finally,
+the identity of the ``use_default`` type is not left unspecified
 because specification helps to highlight that the ``Reference``
 template parameter may not always be identical to the iterator's
-``reference`` type, and will keep users making mistakes based on that
+``reference`` type, and will keep users making mistakes based on
-assumption.
+that assumption.
 

doc/iterator_adaptor_ref.rst

@@ -1,10 +1,12 @@
 .. parsed-literal::
   
+  bool
   template <
       class Derived
     , class Base
     , class Value      = use_default
-    , class Category   = use_default
+    , unsigned Access  = use_default_access
+    , class Traversal  = use_default
     , class Reference  = use_default
     , class Difference = use_default
   >
@@ -60,55 +62,46 @@ traits types for ``iterator_adaptor``.
 
 ::
 
-    if (Value == use_default)
+   if (Value != use_default)
-        value_type = iterator_traits<Base>::value_type;
-    else 
         value_type = remove_cv<Value>::type;
-
+   else
-    if (Reference == use_default) {
+        value_type = iterator_traits<Base>::value_type;
-        if (Value == use_default)
-            reference = iterator_traits<Base>::reference;
-        else 
-            reference = Value&;
-    } else
-        reference = Reference;
-
-    if (Distance == use_default)
-        difference_type = iterator_traits<Base>::difference_type;
-    else
-        difference_type = Distance;
-
-    if (Category == use_default)
-        iterator_category = iterator_tag< 
-            access_category< Base >,
-            traversal_category< Base >
-        >
-    else if (Category is convertible to a standard access tag)
-        iterator_category = iterator_tag<
-            Category
-        else if (Category has a nested traversal type)
-             if (reference is not a reference-to-const)
-                 Category::access
-             else
-                 if (Category
-            
-    
-    else if (Category is convertable to a standard traversal tag)
-        ...
-    else
-        iterator_category = Category;
-        // Actually the above is wrong.  See the use of
-        // access_category_tag and
-        // new_category_to_access/iter_category_to_access.
 
 
-..  Replaced with new semantics --thw
+   if (Traversal != use_default)
-    if (Category == use_default)
+       traversal_category = Traversal
-        iterator_category = iterator_traits<Base>::iterator_category;
+   else
-    else
+       traversal_category = traversal_category< Base >::type
-        iterator_category = Category;
 
-    Fix this up!!
+   iterator_category = iterator_tag<
+                            access_category
+                          , traversal_category
+                        >
+
+   if (Access != use_default)
+   {
+      access_category = Access
+   }
+   else
+   {
+      access_category
+        = access_category< Base >::value
+
+      if (is_const<Value>)
+          access_category &= ~writable_iterator;
+   }
+
+   iterator_category = iterator_tag<
+                            access_category
+                          , traversal_category
+                        >
+
+   if (Reference != use_default)
+       reference = Reference
+   else if (Value != use_default)
+       reference = Value&
+   else
+       reference = iterator_traits<Base>::reference
 
 
 ``iterator_adaptor`` public operations

doc/iterator_facade_ref.rst

@@ -3,7 +3,7 @@
   template <
       class Derived
     , class Value
-    , class AccessCategory
+    , unsigned AccessCategory
     , class TraversalCategory
     , class Reference  = /* see below__ \*/
     , class Difference = ptrdiff_t
@@ -108,12 +108,25 @@ out of the overload set when the types are not interoperable.]
 ``iterator_facade`` requirements
 ................................
 
+Some of the constraints on template parameters to
+``iterator_facade`` are expressed in terms of resulting nested
+types and should be viewed in the context of their impact on
+``iterator_traits<Derived>``.
+
 The ``Derived`` template parameter must be a class derived from
 ``iterator_facade``.
 
-The default for the ``Reference`` parameter is ``Value&`` if the
+The nested ``::value_type`` type will be the same as
-access category for ``iterator_facade`` is implicitly convertible to
+``remove_cv<Value>::type``, so the ``Value`` parameter must be
-``writable_iterator_tag``, and ``const Value&`` otherwise.
+an (optionally ``const``\ -qualified) non-reference type.
+
+``AccessCategory`` must be an unsigned value which uses no more
+bits than the greatest value of ``iterator_access``.
+
+The nested ``::reference`` will be the same as the ``Reference``
+parameter; it must be a suitable reference type for the resulting
+iterator.  The default for the ``Reference`` parameter is
+``Value&``.
 
 The following table describes the other requirements on the
 ``Derived`` parameter.  Depending on the resulting iterator's
@@ -188,8 +201,8 @@ __ `operator arrow`_
   object ``a`` of type ``X``, ``a->m`` is equivalent to ``(w = *a,
   w.m)`` for some temporary object ``w`` of type ``X::value_type``.
 
-  The type ``X::pointer`` is ``Value*`` if the access category for
+  The type ``X::pointer`` is ``Value*`` if
-  ``X`` is implicitly convertible to ``writable_iterator_tag``, and
+  ``is_writable_iterator<X>::value`` is ``true``, and
   ``Value const*`` otherwise.
 
 

doc/new-iter-concepts.html

@@ -3,13 +3,204 @@
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-<meta name="generator" content="Docutils 0.3.0: http://docutils.sourceforge.net/" />
+<meta name="generator" content="Docutils 0.3.1: http://docutils.sourceforge.net/" />
 <title>New Iterator Concepts</title>
 <meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
 <meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, University of Hanover Institute for Transport Railway Operation and Construction" />
 <meta name="date" content="2003-09-22" />
 <meta name="copyright" content="Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All rights reserved" />
-<link rel="stylesheet" href="default.css" type="text/css" />
+<style type="text/css"><!--
+
+/*
+:Author: David Goodger
+:Contact: goodger@users.sourceforge.net
+:date: $Date$
+:version: $Revision$
+:copyright: This stylesheet has been placed in the public domain.
+
+Default cascading style sheet for the HTML output of Docutils.
+*/
+
+.first {
+  margin-top: 0 }
+
+.last {
+  margin-bottom: 0 }
+
+a.toc-backref {
+  text-decoration: none ;
+  color: black }
+
+dd {
+  margin-bottom: 0.5em }
+
+div.abstract {
+  margin: 2em 5em }
+
+div.abstract p.topic-title {
+  font-weight: bold ;
+  text-align: center }
+
+div.attention, div.caution, div.danger, div.error, div.hint,
+div.important, div.note, div.tip, div.warning {
+  margin: 2em ;
+  border: medium outset ;
+  padding: 1em }
+
+div.attention p.admonition-title, div.caution p.admonition-title,
+div.danger p.admonition-title, div.error p.admonition-title,
+div.warning p.admonition-title {
+  color: red ;
+  font-weight: bold ;
+  font-family: sans-serif }
+
+div.hint p.admonition-title, div.important p.admonition-title,
+div.note p.admonition-title, div.tip p.admonition-title {
+  font-weight: bold ;
+  font-family: sans-serif }
+
+div.dedication {
+  margin: 2em 5em ;
+  text-align: center ;
+  font-style: italic }
+
+div.dedication p.topic-title {
+  font-weight: bold ;
+  font-style: normal }
+
+div.figure {
+  margin-left: 2em }
+
+div.footer, div.header {
+  font-size: smaller }
+
+div.system-messages {
+  margin: 5em }
+
+div.system-messages h1 {
+  color: red }
+
+div.system-message {
+  border: medium outset ;
+  padding: 1em }
+
+div.system-message p.system-message-title {
+  color: red ;
+  font-weight: bold }
+
+div.topic {
+  margin: 2em }
+
+h1.title {
+  text-align: center }
+
+h2.subtitle {
+  text-align: center }
+
+hr {
+  width: 75% }
+
+ol.simple, ul.simple {
+  margin-bottom: 1em }
+
+ol.arabic {
+  list-style: decimal }
+
+ol.loweralpha {
+  list-style: lower-alpha }
+
+ol.upperalpha {
+  list-style: upper-alpha }
+
+ol.lowerroman {
+  list-style: lower-roman }
+
+ol.upperroman {
+  list-style: upper-roman }
+
+p.caption {
+  font-style: italic }
+
+p.credits {
+  font-style: italic ;
+  font-size: smaller }
+
+p.label {
+  white-space: nowrap }
+
+p.topic-title {
+  font-weight: bold }
+
+pre.address {
+  margin-bottom: 0 ;
+  margin-top: 0 ;
+  font-family: serif ;
+  font-size: 100% }
+
+pre.line-block {
+  font-family: serif ;
+  font-size: 100% }
+
+pre.literal-block, pre.doctest-block {
+  margin-left: 2em ;
+  margin-right: 2em ;
+  background-color: #eeeeee }
+
+span.classifier {
+  font-family: sans-serif ;
+  font-style: oblique }
+
+span.classifier-delimiter {
+  font-family: sans-serif ;
+  font-weight: bold }
+
+span.interpreted {
+  font-family: sans-serif }
+
+span.option-argument {
+  font-style: italic }
+
+span.pre {
+  white-space: pre }
+
+span.problematic {
+  color: red }
+
+table {
+  margin-top: 0.5em ;
+  margin-bottom: 0.5em }
+
+table.citation {
+  border-left: solid thin gray ;
+  padding-left: 0.5ex }
+
+table.docinfo {
+  margin: 2em 4em }
+
+table.footnote {
+  border-left: solid thin black ;
+  padding-left: 0.5ex }
+
+td, th {
+  padding-left: 0.5em ;
+  padding-right: 0.5em ;
+  vertical-align: top }
+
+th.docinfo-name, th.field-name {
+  font-weight: bold ;
+  text-align: left ;
+  white-space: nowrap }
+
+h1 tt, h2 tt, h3 tt, h4 tt, h5 tt, h6 tt {
+  font-size: 100% }
+
+tt {
+  background-color: #eeeeee }
+
+ul.auto-toc {
+  list-style-type: none }
+
+--></style>
 </head>
 <body>
 <div class="document" id="new-iterator-concepts">
@@ -963,5 +1154,11 @@ LocalWords:  TraversalTag typename lvalues DWA Hmm JGS mis enum -->
 </div>
 </div>
 </div>
+<hr class="footer" />
+<div class="footer">
+<a class="reference" href="new-iter-concepts.rst">View document source</a>.
+Generated on: 2003-09-22 19:48 UTC.
+Generated by <a class="reference" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
+</div>
 </body>
 </html>

doc/permutation_iterator_ref.rst

@@ -3,7 +3,8 @@
   template< class ElementIterator
 	  , class IndexIterator
 	  , class ValueT        = use_default
-	  , class CategoryT     = use_default
+      , unsigned access     = use_default_access
+	  , class Traversal     = use_default
 	  , class ReferenceT    = use_default
 	  , class DifferenceT   = use_default >
   class permutation_iterator

doc/style.tex

@@ -0,0 +1,78 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%% docutils.sty: A style for docutils latex output %%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%
+%% o author: Alexander Schmolck (a.schmolck@gmx.net)
+%% o created: 2002-07-07 10:50:31+00:40
+%% o last modified: $Date: 2003/09/22 19:55:01 $
+%% o keywords: 
+%% o license: 
+%XXX titlesec
+%% XXX geometry
+\usepackage{graphicx}
+\usepackage{latexsym} % extra symbols
+\usepackage{url} % !!!: pay attention when using in other commands!!!
+\usepackage{verbatim} % normal verbatim has lenght-limit
+\usepackage{enumerate} % easy style choice with e.g: ``\begin{enumerate}[Ex i.]``
+\usepackage{hyperref} %href, htarget and hlink XXX: pdfauthor, pdfcreator etc.
+\usepackage{xr} %XXX do we need this?
+% need this to have ``fboxes`` in ``enviroments``, as well as ``verbatim``s
+\usepackage{fancybox} 
+\usepackage{mdwtab} % better tables and arrays (fixes spacing and adds
+                    % vertical align and multirows (m))
+\usepackage{ltxtable} % long and autoscaling tables (use X for autoscaled
+                      % columns)
+\newcommand{\transition}{\vspace{2em}\par\hrule{}\par\vspace{2em}}
+\newcommand{\classifier}[1]{(\textit{#1})}
+\newenvironment{topic}[1]%
+{\begin{Sbox}%
+    \begin{minipage}{.8\textwidth}%
+      \protect{\large{\textbf{#1}}}\par\vspace{.5em}}%
+{\end{minipage}\end{Sbox}\fbox{\TheSbox}\par\vspace{.5em}}
+%XXX shadow box for warnings?
+\newenvironment{admonition}[1]%
+{\begin{center}%
+  \begin{Sbox}%
+    \begin{minipage}{.9\textwidth}%
+      \protect{\textsc{#1}}\par\vspace{.2em}}%
+{\end{minipage}\end{Sbox}\fbox{\TheSbox}\par\vspace{.5em}\end{center}}
+
+\newenvironment{doctest}%
+{\VerbatimEnvironment
+ \begin{Verbatim}}%
+{\end{Verbatim}}
+% {%
+%     \begin{Sbox}%
+%     \begin{minipage}{.8\textwidth}%
+%       \protect{\large{\textsc{#1}}\par\vspace{.5em}}}%
+% {\end{minipage}\end{Sbox}\fbox{\TheSbox}\par\vspace{.5em}}
+%{\end{minipage}\end{Sbox}\fbox{\TheSbox}}
+
+
+%% just a piece of example code
+% \newcommand{\vitem}%
+% {\SaveVerb[{\item[\UseVerb{\MyTemp}]}]{\MyTemp}}
+
+%%%%%%%%%%%%%%%%%%% Added by DWA  %%%%%%%%%%%%%%%%%%%%%%%%%
+
+% donot indent first line.
+\setlength{\parindent}{0pt}
+\setlength{\parskip}{5pt plus 2pt minus 1pt}
+
+% sloppy
+% ------
+% Less strict (opposite to default fussy) space size between words. Therefore
+% less hyphenation.
+\sloppy
+
+% fonts
+% -----
+% times for pdf generation, gives smaller pdf files.
+%
+% But in standard postscript fonts: courier and times/helvetica do not fit.
+% Maybe use pslatex.
+\usepackage{times} 
+\usepackage{pslatex} 
+
+% pagestyle
+\pagestyle{headings}