Branch to work on filename handling without disturbing trunk.

[SVN r68345]

development/boost/iterator_categories.hpp

@@ -1,159 +0,0 @@
-#ifndef BOOST_ITERATOR_CATEGORIES_HPP
-#define BOOST_ITERATOR_CATEGORIES_HPP
-
-#include <boost/config.hpp>
-#include <boost/type_traits/conversion_traits.hpp>
-#include <boost/type_traits/cv_traits.hpp>
-#include <boost/pending/ct_if.hpp>
-#include <boost/detail/iterator.hpp>
-
-namespace boost {
-
-  // Return Type Categories
-  struct readable_iterator_tag { };
-  struct writable_iterator_tag { };
-  struct swappable_iterator_tag { };
-  struct mutable_lvalue_iterator_tag : 
-    virtual public writable_iterator_tag,
-    virtual public readable_iterator_tag { };
-  struct constant_lvalue_iterator_tag : 
-    virtual public readable_iterator_tag { };
-
-  // Traversal Categories
-  struct forward_traversal_tag { };
-  struct bidirectional_traversal_tag : public forward_traversal_tag { };
-  struct random_access_traversal_tag : public bidirectional_traversal_tag { };
-
-  struct error_iterator_tag { };
-
-  // Inherit from iterator_base if your iterator defines its own
-  // return_category and traversal_category. Otherwise, the "old style"
-  // iterator category will be mapped to the return_category and
-  // traversal_category.
-  struct new_iterator_base { };
-
-  namespace detail {
-
-    struct return_category_from_nested_type {
-      template <typename Iterator> struct bind {
-        typedef typename Iterator::return_category type;
-      };
-    };
-
-    struct traversal_category_from_nested_type {
-      template <typename Iterator> struct bind {
-        typedef typename Iterator::traversal_category type;
-      };
-    };
-
-    template <typename ValueType>
-    struct choose_lvalue_return {
-      typedef typename ct_if<is_const<ValueType>::value,
-                             boost::constant_lvalue_iterator_tag,
-                             boost::mutable_lvalue_iterator_tag>::type type;
-    };
-    
-    
-    template <typename Category, typename ValueType>
-    struct iter_category_to_return {
-      typedef typename ct_if<
-        is_convertible<Category*, std::forward_iterator_tag*>::value,
-        typename choose_lvalue_return<ValueType>::type,
-        typename ct_if<
-          is_convertible<Category*, std::input_iterator_tag*>::value,
-          boost::readable_iterator_tag,
-          typename ct_if<
-            is_convertible<Category*, std::output_iterator_tag*>::value,
-            boost::writable_iterator_tag,
-            boost::error_iterator_tag
-          >::type
-       >::type
-      >::type type;
-    };
-
-    template <typename Category>
-    struct iter_category_to_traversal {
-      typedef typename ct_if<
-        is_convertible<Category*, std::random_access_iterator_tag*>::value,
-        random_access_traversal_tag,
-        typename ct_if<
-          is_convertible<Category*, std::bidirectional_iterator_tag*>::value,
-          bidirectional_traversal_tag,
-          forward_traversal_tag
-          >::type
-        >::type type;
-    };
-
-    struct return_category_from_old_traits {
-      template <typename Iterator> class bind {
-        typedef boost::detail::iterator_traits<Iterator> OldTraits;
-        typedef typename OldTraits::iterator_category Cat;
-        typedef typename OldTraits::value_type value_type;
-      public:
-        typedef iter_category_to_return<Cat, value_type>::type type;
-      };      
-    };
-
-    struct traversal_category_from_old_traits {
-      template <typename Iterator> class bind {
-        typedef boost::detail::iterator_traits<Iterator> OldTraits;
-        typedef typename OldTraits::iterator_category Cat;
-      public:
-        typedef iter_category_to_traversal<Cat>::type type;
-      };      
-    };
-
-    template <typename Iterator>
-    class choose_return_category {
-      typedef typename ct_if<is_convertible<Iterator*,
-                                            new_iterator_base*>::value,
-                             return_category_from_nested_type,
-                             return_category_from_old_traits>::type Choice;
-    public:
-      typedef typename Choice:: template bind<Iterator>::type type;
-    };
-
-    template <typename Iterator>
-    class choose_traversal_category {
-      typedef typename ct_if<is_convertible<Iterator*,
-                                            new_iterator_base*>::value,
-                             traversal_category_from_nested_type,
-                             traversal_category_from_old_traits>::type Choice;
-    public:
-      typedef typename Choice:: template bind<Iterator>::type type;
-    };
-    
-  } // namespace detail
-  
-  template <class Iterator>
-  struct return_category {
-    typedef typename detail::choose_return_category<Iterator>::type type;
-  };
-
-
-  template <class Iterator>
-  struct traversal_category {
-    typedef typename detail::choose_traversal_category<Iterator>::type type;
-  };
-
-#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
-
-  template <typename T>
-  struct return_category<T*>
-  {
-    typedef typename ct_if<is_const<T>::value,
-      constant_lvalue_iterator_tag,
-      mutable_lvalue_iterator_tag>::type type;
-  };
-
-  template <typename T>
-  struct traversal_category<T*>
-  {
-    typedef random_access_traversal_tag type;
-  };
-
-#endif
-
-} // namespace boost
-
-#endif // BOOST_ITERATOR_CATEGORIES_HPP

development/boost/iterator_concepts.hpp

@@ -1,172 +0,0 @@
-#ifndef BOOST_ITERATOR_CONCEPTS_HPP
-#define BOOST_ITERATOR_CONCEPTS_HPP
-
-#include <boost/concept_check.hpp>
-#include <boost/iterator_categories.hpp>
-#include <boost/type_traits/conversion_traits.hpp>
-#include <boost/static_assert.hpp>
-
-namespace boost_concepts {
-  // Used a different namespace here (instead of "boost") so that the
-  // concept descriptions do not take for granted the names in
-  // namespace boost.
-
-
-  //===========================================================================
-  // Iterator Access Concepts
-
-  template <typename Iterator>
-  class ReadableIteratorConcept {
-  public:
-    typedef typename std::iterator_traits<Iterator>::value_type value_type;
-    typedef typename std::iterator_traits<Iterator>::reference reference;
-    typedef typename boost::return_category<Iterator>::type return_category;
-
-    void constraints() {
-      boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
-      boost::function_requires< boost::EqualityComparableConcept<Iterator> >();
-      boost::function_requires< 
-        boost::DefaultConstructibleConcept<Iterator> >();
-      
-      BOOST_STATIC_ASSERT((boost::is_convertible<return_category*,
-                           boost::readable_iterator_tag*>::value));
-                          
-      reference r = *i; // or perhaps read(x)
-      value_type v(r);
-      boost::ignore_unused_variable_warning(v);
-    }
-    Iterator i;
-  };
-  
-  template <typename Iterator, typename ValueType>
-  class WritableIteratorConcept {
-  public:
-    typedef typename boost::return_category<Iterator>::type return_category;
-
-    void constraints() {
-      boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
-      boost::function_requires< boost::EqualityComparableConcept<Iterator> >();
-      boost::function_requires< 
-        boost::DefaultConstructibleConcept<Iterator> >();
-      
-      BOOST_STATIC_ASSERT((boost::is_convertible<return_category*,
-                           boost::writable_iterator_tag*>::value));
-
-      *i = v; // a good alternative could be something like write(x, v)
-    }
-    ValueType v;
-    Iterator i;
-  };
-  
-  template <typename Iterator>
-  class ConstantLvalueIteratorConcept {
-  public:
-    typedef typename std::iterator_traits<Iterator>::value_type value_type;
-    typedef typename std::iterator_traits<Iterator>::reference reference;
-    typedef typename boost::return_category<Iterator>::type return_category;
-
-    void constraints() {
-      boost::function_requires< ReadableIteratorConcept<Iterator> >();
-
-      BOOST_STATIC_ASSERT((boost::is_convertible<return_category*, 
-                           boost::constant_lvalue_iterator_tag*>::value));
-
-      BOOST_STATIC_ASSERT((boost::is_same<reference, 
-                           const value_type&>::value));
-
-      reference v = *i;
-      boost::ignore_unused_variable_warning(v);
-    }
-    Iterator i;
-  };
-
-  template <typename Iterator>
-  class MutableLvalueIteratorConcept {
-  public:
-    typedef typename std::iterator_traits<Iterator>::value_type value_type;
-    typedef typename std::iterator_traits<Iterator>::reference reference;
-    typedef typename boost::return_category<Iterator>::type return_category;
-
-    void constraints() {
-      boost::function_requires< ReadableIteratorConcept<Iterator> >();
-      boost::function_requires< 
-        WritableIteratorConcept<Iterator, value_type> >();
-      
-      BOOST_STATIC_ASSERT((boost::is_convertible<return_category*, 
-                           boost::mutable_lvalue_iterator_tag*>::value));
-
-      BOOST_STATIC_ASSERT((boost::is_same<reference, value_type&>::value));
-
-      reference v = *i;
-      boost::ignore_unused_variable_warning(v);
-    }
-    Iterator i;
-  };
-  
-  //===========================================================================
-  // Iterator Traversal Concepts
-
-  template <typename Iterator>
-  class ForwardIteratorConcept {
-  public:
-    typedef typename boost::traversal_category<Iterator>::type traversal_category;
-
-    void constraints() {
-      boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
-      boost::function_requires< boost::EqualityComparableConcept<Iterator> >();
-      boost::function_requires< 
-        boost::DefaultConstructibleConcept<Iterator> >();
-
-      BOOST_STATIC_ASSERT((boost::is_convertible<traversal_category*, 
-                           boost::forward_traversal_tag*>::value));
-      ++i;
-      (void)i++;
-    }
-    Iterator i;
-  };
-  
-  template <typename Iterator>
-  class BidirectionalIteratorConcept {
-  public:
-    typedef typename boost::traversal_category<Iterator>::type traversal_category;
-
-    void constraints() {
-      boost::function_requires< ForwardIteratorConcept<Iterator> >();
-      
-      BOOST_STATIC_ASSERT((boost::is_convertible<traversal_category*, 
-                           boost::bidirectional_traversal_tag*>::value));
-
-      --i;
-      (void)i--;
-    }
-    Iterator i;
-  };
-
-  template <typename Iterator>
-  class RandomAccessIteratorConcept {
-  public:
-    typedef typename boost::traversal_category<Iterator>::type traversal_category;
-    typedef typename std::iterator_traits<Iterator>::difference_type
-      difference_type;
-
-    void constraints() {
-      boost::function_requires< BidirectionalIteratorConcept<Iterator> >();
-
-      BOOST_STATIC_ASSERT((boost::is_convertible<traversal_category*, 
-                           boost::random_access_traversal_tag*>::value));
-      
-      i += n;
-      i = i + n;
-      i = n + i;
-      i -= n;
-      i = i - n;
-      n = i - j;
-    }
-    difference_type n;
-    Iterator i, j;
-  };
-
-} // namespace boost_concepts
-
-
-#endif // BOOST_ITERATOR_CONCEPTS_HPP

development/libs/iterator/concept_tests.cpp

@@ -1,73 +0,0 @@
-#include <boost/iterator_concepts.hpp>
-#include <boost/operators.hpp>
-
-struct new_iterator
-  : public boost::iterator<std::random_access_iterator_tag, int>,
-    public boost::new_iterator_base
-{
-  typedef boost::random_access_traversal_tag traversal_category;
-  typedef boost::mutable_lvalue_iterator_tag return_category;
-
-  int& operator*() const { return *m_x; }
-  new_iterator& operator++() { return *this; }
-  new_iterator operator++(int) { return *this; }
-  new_iterator& operator--() { return *this; }
-  new_iterator operator--(int) { return *this; }
-  new_iterator& operator+=(std::ptrdiff_t) { return *this; }
-  new_iterator operator+(std::ptrdiff_t) { return *this; }
-  new_iterator& operator-=(std::ptrdiff_t) { return *this; }
-  std::ptrdiff_t operator-(const new_iterator&) const { return 0; }
-  new_iterator operator-(std::ptrdiff_t) const { return *this; }
-  bool operator==(const new_iterator&) const { return false; }
-  bool operator!=(const new_iterator&) const { return false; }
-  bool operator<(const new_iterator&) const { return false; }
-  int* m_x;
-};
-new_iterator operator+(std::ptrdiff_t, new_iterator x) { return x; }
-
-struct old_iterator
-  : public boost::iterator<std::random_access_iterator_tag, int>
-{
-  int& operator*() const { return *m_x; }
-  old_iterator& operator++() { return *this; }
-  old_iterator operator++(int) { return *this; }
-  old_iterator& operator--() { return *this; }
-  old_iterator operator--(int) { return *this; }
-  old_iterator& operator+=(std::ptrdiff_t) { return *this; }
-  old_iterator operator+(std::ptrdiff_t) { return *this; }
-  old_iterator& operator-=(std::ptrdiff_t) { return *this; }
-  old_iterator operator-(std::ptrdiff_t) const { return *this; }
-  std::ptrdiff_t operator-(const old_iterator&) const { return 0; }
-  bool operator==(const old_iterator&) const { return false; }
-  bool operator!=(const old_iterator&) const { return false; }
-  bool operator<(const old_iterator&) const { return false; }
-  int* m_x;
-};
-old_iterator operator+(std::ptrdiff_t, old_iterator x) { return x; }
-
-int
-main()
-{
-#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
-  boost::function_requires<
-    boost_concepts::MutableLvalueIteratorConcept<int*> >();
-  boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<int*> >();
-
-  boost::function_requires<
-    boost_concepts::ConstantLvalueIteratorConcept<const int*> >();
-  boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<const int*> >();
-#endif
-
-  boost::function_requires<
-    boost_concepts::MutableLvalueIteratorConcept<new_iterator> >();
-  boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<new_iterator> >();
-
-  boost::function_requires<
-    boost_concepts::MutableLvalueIteratorConcept<old_iterator> >();
-  boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<old_iterator> >();
-  return 0;
-}

development/libs/iterator/iterator_categories.htm

@@ -1,160 +0,0 @@
-<html>
-<!--
-  -- Copyright (c) Jeremy Siek 2000,2001
-  --
-  -- Permission to use, copy, modify, distribute and sell this software
-  -- and its documentation for any purpose is hereby granted without fee,
-  -- provided that the above copyright notice appears in all copies and
-  -- that both that copyright notice and this permission notice appear
-  -- in supporting documentation.  I make no representations about the
-  -- suitability of this software for any purpose.  It is provided "as is"
-  -- without express or implied warranty.
-  -->
-  <head>
-    <title>Boost Iterator Traits</title>
-  </head>
-
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" 
-	ALINK="#ff0000"> 
-<IMG SRC="../../../../c++boost.gif" 
-     ALT="C++ Boost" width="277" height="86"> 
-<BR Clear>
-
-    <h1>Boost Iterator Category Traits</h1>
-Header <tt><a href="../../boost/iterator_categories.hpp">boost/iterator_categories.hpp</a></tt>
-
-<p>
-The <tt>boost::traversal_category</tt> and
-<tt>boost::return_category</tt> traits classes provides access to the
-category tags for iterators that model the Boost <a
-href="./iterator_concepts.htm">Iterator Concepts</a>, which are a
-replacement for the iterator requirements in the C++ standard.  The
-other associated types of the Boost iterator concepts are accessed
-through the <tt>std::iterator_traits</tt> class.
-
-<ul>
-  <li><tt>traversal_category&lt;Iter&gt;::type</tt>&nbsp;&nbsp; Can the iterator go forward, backward, etc.?
-  <li><tt>return_category&lt;Iter&gt;::type</tt>&nbsp;&nbsp; Is the iterator read or write only?
-    Is the dereferenced type an lvalue?
-</ul>
-
-<p>
-An important feature of the <tt>boost::traversal_category</tt> and
-<tt>boost::return_category</tt> classes is that they are <b>backwards
-compatible</b>, i.e., they automatically work for iterators for which
-there are valid definitions of <tt>std::iterator_traits</tt>. The old
-<tt>iterator_category</tt> is mapped to the appropriate traversal and
-return categories.
-
-<p>
-When creating a new iterator type that is meant to work with
-<tt>boost::traversal_category</tt> and
-<tt>boost::return_category</tt>, you can either create a
-specialization of these classes for your iterator type, or you can
-provide all the necessary associated types as nested typedefs.  In
-this case, your iterator class will need to inherit from
-<tt>new_iterator_base</tt> to let the category traits know
-that it will be able to find typedefs for <tt>traversal_category</tt>
-and <tt>return_category</tt> in you iterator class.
-
-
-Each of the new iterator requirements will need a category tag.
-
-<pre>
-namespace boost {
-
-  // Return Type Categories
-  struct readable_iterator_tag { };
-  struct writable_iterator_tag { };
-  struct swappable_iterator_tag { };
-  struct mutable_lvalue_iterator_tag : virtual public writable_iterator_tag,
-    virtual public readable_iterator_tag { };
-  struct constant_lvalue_iterator_tag : public readable_iterator_tag { };
-
-  // Traversal Categories
-  struct forward_traversal_tag { };
-  struct bidirectional_traversal_tag : public forward_traversal_tag { };
-  struct random_access_traversal_tag : public bidirectional_traversal_tag { };
-
-}
-</pre>  
-
-<p>
-The following is pseudo-code for the iterator category traits classes.
-
-<pre>
-namespace boost {
-
-  <i>// Inherit from iterator_base if your iterator defines its own
-  // return_category and traversal_category. Otherwise, the "old style"
-  // iterator category will be mapped to the return_category and
-  // traversal_category.</i>
-  struct new_iterator_base { };
-
-  template &lt;typename Iterator&gt;
-  struct return_category
-  {
-    <b><i>// Pseudo-code</i></b>
-    if (Iterator inherits from new_iterator_base) {
-      typedef typename Iterator::return_category type;
-    } else {
-      typedef std::iterator_traits&lt;Iterator&gt; OldTraits;
-      typedef typename OldTraits::iterator_category Cat;
-      if (Cat inherits from std::forward_iterator_tag)
-	if (is-const(T))
-	  typedef boost::constant_lvalue_iterator_tag type;
-	else
-	  typedef boost::mutable_lvalue_iterator_tag type;
-      else if (Cat inherits from std::input_iterator_tag)
-	typedef boost::readable_iterator_tag type;
-      else if (Cat inherits from std::output_iterator_tag)
-	typedef boost::writable_iterator_tag type;
-    }
-  };
-
-  template &lt;typename T&gt;
-  struct return_category&lt;T*&gt;
-  {
-    <b><i>// Pseudo-code</i></b>
-    if (is-const(T))
-      typedef boost::constant_lvalue_iterator_tag type;
-    else
-      typedef boost::mutable_lvalue_iterator_tag type;
-  };
-
-  template &lt;typename Iterator&gt;
-  struct traversal_category
-  {
-    <b><i>// Pseudo-code</i></b>
-    if (Iterator inherits from new_iterator_base) {
-      typedef typename Iterator::traversal_category type;
-    } else {
-      typedef std::iterator_traits&lt;Iterator&gt; OldTraits;
-      typedef typename OldTraits::iterator_category Cat;
-
-      if (Cat inherits from std::random_access_iterator_tag)
-	typedef boost::random_access_traversal_tag type;
-      else if (Cat inherits from std::bidirectional_iterator_tag)
-	typedef boost::bidirectional_traversal_tag type;
-      else if (Cat inherits from std::forward_iterator_tag)
-	typedef boost::forward_traversal_tag type;
-    }
-  };
-
-  template &lt;typename T&gt;
-  struct traversal_category&lt;T*&gt;
-  {
-    typedef boost::random_access_traversal_tag type;
-  };
-
-}
-</pre>
-
-    <hr>
-    <address><a href="mailto:jsiek@lsc.nd.edu">jeremy siek</a></address>
-<!-- Created: Sun Mar 18 14:06:57 EST 2001 -->
-<!-- hhmts start -->
-Last modified: Mon Mar 19 12:59:30 EST 2001
-<!-- hhmts end -->
-  </body>
-</html>

development/libs/iterator/iterator_concepts.fig

@@ -1,37 +0,0 @@
-#FIG 3.2
-Landscape
-Center
-Inches
-Letter  
-100.00
-Single
--2
-1200 2
-6 150 2325 4275 4350
-2 1 0 1 0 7 100 0 -1 4.000 0 0 -1 1 0 2
-	1 1 1.00 60.00 120.00
-	 1725 4050 1725 3450
-2 1 0 1 0 7 100 0 -1 4.000 0 0 -1 1 0 2
-	1 1 1.00 60.00 120.00
-	 1725 3150 1725 2550
-4 0 0 100 0 19 18 0.0000 4 210 3180 375 2550 ForwardTraversalIterator\001
-4 0 0 100 0 19 18 0.0000 4 210 3765 225 3450 BidirectionalTraversalIterator\001
-4 0 0 100 0 19 18 0.0000 4 210 4125 150 4350 RandomAccessTraversalIterator\001
--6
-2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
-	1 1 1.00 60.00 120.00
-	 4800 3600 4800 2400
-2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
-	1 1 1.00 60.00 120.00
-	 6900 3000 5400 2400
-2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
-	1 1 1.00 60.00 120.00
-	 6900 3000 7500 2400
-2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
-	1 1 1.00 60.00 120.00
-	 6900 3000 9075 2475
-4 0 0 100 0 19 18 0.0000 4 210 2040 6600 2400 WritableIterator\001
-4 0 0 100 0 19 18 0.0000 4 210 2145 3900 2400 ReadableIterator\001
-4 0 0 50 0 19 18 0.0000 4 210 2835 5700 3300 MutableLvalueIterator\001
-4 0 0 50 0 19 18 0.0000 4 270 2355 9075 2400 SwappableIterator\001
-4 0 0 50 0 19 18 0.0000 4 210 2970 3825 3900 ConstantLvalueIterator\001

development/libs/iterator/iterator_concepts.htm

@@ -1,663 +0,0 @@
-<HTML>
-<!--
-  -- Copyright (c) Jeremy Siek 2000
-  --
-  -- Permission to use, copy, modify, distribute and sell this software
-  -- and its documentation for any purpose is hereby granted without fee,
-  -- provided that the above copyright notice appears in all copies and
-  -- that both that copyright notice and this permission notice appear
-  -- in supporting documentation.  I make no representations about the
-  -- suitability of this software for any purpose.  It is provided "as is"
-  -- without express or implied warranty.
-  -->
-<!--
-  -- Copyright (c) 1996-1999
-  -- Silicon Graphics Computer Systems, Inc.
-  --
-  -- Permission to use, copy, modify, distribute and sell this software
-  -- and its documentation for any purpose is hereby granted without fee,
-  -- provided that the above copyright notice appears in all copies and
-  -- that both that copyright notice and this permission notice appear
-  -- in supporting documentation.  Silicon Graphics makes no
-  -- representations about the suitability of this software for any
-  -- purpose.  It is provided "as is" without express or implied warranty.
-  --
-  -- Copyright (c) 1994
-  -- Hewlett-Packard Company
-  --
-  -- Permission to use, copy, modify, distribute and sell this software
-  -- and its documentation for any purpose is hereby granted without fee,
-  -- provided that the above copyright notice appears in all copies and
-  -- that both that copyright notice and this permission notice appear
-  -- in supporting documentation.  Hewlett-Packard Company makes no
-  -- representations about the suitability of this software for any
-  -- purpose.  It is provided "as is" without express or implied warranty.
-  --
-  -->
-<Head>
-<Title>Iterator Concepts</Title>
-<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" 
-	ALINK="#ff0000"> 
-<IMG SRC="../../../../c++boost.gif" 
-     ALT="C++ Boost" width="277" height="86"> 
-
-<BR Clear>
-
-
-<h1>Iterator Concepts</h1>
-
-<p>The standard iterator categories and requirements are flawed because
-they use a single hierarchy of requirements to address two orthogonal
-issues: <b><i>iterator traversal</i></b> and <b><i>dereference return
-type</i></b>. The current iterator requirement hierarchy is mainly
-geared towards iterator traversal (hence the category names), while
-requirements that address dereference return type sneak in at various
-places. 
-
-<p>
-The iterator requirements should be separated into two hierarchies.
-One set of concepts handles the return type semantics: 
-<ul>
-  <li><a href="#concept:ReadableIterator">Readable Iterator</a></li>
-  <li><a href="#concept:WritableIterator">Writable Iterator</a></li>
-  <li><a href="#concept:SwappableIterator">Swappable Iterator</a></li>
-  <li><a href="#concept:ConstantLvalueIterator">Constant Lvalue Iterator</a></li>
-  <li><a href="#concept:MutableLvalueIterator">Mutable Lvalue Iterator</a></li>
-</ul>
-
-The other set of concepts handles iterator traversal: 
-
-<ul>
-  <li><a href="#concept:ForwardTraversalIterator">Forward Traversal Iterator</a></li>
-  <li><a href="#concept:BidirectionalTraversalIterator">Bidirectional Traversal Iterator</a></li>
-  <li><a href="#concept:RandomAccessTraversalIterator">Random Access Traversal Iterator</a></li>
-</ul>
-
-The current Input Iterator and Output Iterator requirements will
-continue to be used as is. Note that Input Iterator implies Readable
-Iterator and Output Iterator implies Writable Iterator.
-
-<p>
-Note: we considered defining a Single-Pass Iterator, which could be
-combined with Readable or Writable Iterator to replace the Input and
-Output Iterator requirements. We rejected this idea because there are
-some differences between Input and Output Iterators that make it hard
-to merge them: for example Input Iterator requires Equality Comparable
-while Output Iterator does not.
-
-
-<p></p>
-<DIV ALIGN="CENTER"><A NAME="fig:graph-concepts"></A></A>
-<TABLE>
-<CAPTION ALIGN="TOP"><STRONG>Figure 1:</STRONG>
-The iterator concepts and refinement relationships.
-</CAPTION>
-<TR><TD><IMG SRC="./iterator_concepts.gif" ></TD></TR>
-</TABLE>
-</DIV>
-<p></p>
-
-
-<h2>Relationship with the standard iterator concepts</h2>
-
-<p>
-std::Input Iterator implies boost::ReadableIterator.
-
-<p>
-std::Output Iterator implies boost::Writable Iterator.
-
-<p>
-std::Forward Iterator refines boost::Forward Iterator and
-boost::Constant Lvalue Iterator or boost::Mutable Lvalue Iterator.
-
-<p>
-std::Bidirectional Iterator refines boost::Bidirectional Iterator and
-boost::Constant Lvalue Iterator or boost::Mutable Lvalue Iterator.
-
-<p>
-std::Random Access Iterator refines boost::Random Access Iterator and
-boost::Constant Lvalue Iterator or boost::Mutable Lvalue Iterator.
-
-
-<h3>Notation</h3>
-<Table>
-  <tr>
-    <td><tt>X</tt></td>
-    <td>The iterator type.</td>
-  </tr>
-  <tr>
-    <td><tt>T</tt></td>
-    <td>The value type of <tt>X</tt>, i.e., <tt>std::iterator_traits&lt;X&gt;::value_type</tt>.</td>
-  </tr>
-  <tr>
-    <td><tt>x</tt>, <tt>y</tt></td>
-    <td>An object of type <tt>X</tt>.</td>
-  </tr>
-  <tr>
-    <td><tt>t</tt></td>
-    <td>An object of type <tt>T</tt>.</td>
-  </tr>
-</table>
-
-<p>
-
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:ReadableIterator"></A>
-Readable Iterator
-</H3>
-
-A Readable Iterator is an iterator that dereferences to produce an
-rvalue that is convertible to the <tt>value_type</tt> of the
-iterator. 
-
-<h3>Associated Types</h3>
-
-<Table border>
-
-  <tr>
-    <td>Value type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::value_type</tt></td>
-    <td>The type of the objects pointed to by the iterator.</td>
-  </tr>
-
-  <tr>
-    <td>Reference type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-    <td>
-    The return type of dereferencing the iterator. This
-    type must be convertible to <tt>T</tt>.
-    </td>
-  </tr>
-
-  <tr>
-    <td>Return Category</td>
-    <td><tt>std::return_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::readable_iterator_tag</tt>
-    </td>
-  </tr>
-
-</Table>
-
-<h3>Refinement of</h3>
-
-<A href="http://www.boost.org/libs/utility/CopyConstructible.html">Copy Constructible</A>
-
-<h3>Valid expressions</h3>
-
-<Table border>
-<tr><TH>Name</TH><TH>Expression</TH><TH>Type requirements</TH><TH>Return type</TH></tr>
-<tr>
- <td>Dereference</td>
- <td><tt>*x</tt></td>
- <td>&nbsp;</td>
- <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-</tr>
-<tr>
- <td>Member access</td>
- <td><tt>x-&gt;m</tt></td>
- <td><tt>T</tt> is a type with a member named <tt>m</tt>.</td>
- <td>
-If <tt>m</tt> is a data member, the type of <tt>m</tt>.
-If <tt>m</tt> is a member function, the return type of <tt>m</tt>.
- </td>
-</tr>
-</table>
-
-<p>
-
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:WritableIterator"></A>
-Writable Iterator
-</H3>
-
-A Writable Iterator is an iterator that can be used to store a value
-using the dereference-assignment expression.
-
-<h3>Definitions</h3>
-
-If <tt>x</tt> is an Writable Iterator of type <tt>X</tt>, then the
-expression <tt>*x = a;</tt> stores the value <tt>a</tt> into
-<tt>x</tt>.  Note that <tt>operator=</tt>, like other C++ functions,
-may be overloaded; it may, in fact, even be a template function.  In
-general, then, <tt>a</tt> may be any of several different types.  A
-type <tt>A</tt> belongs to the <i>set of value types</i> of <tt>X</tt>
-if, for an object <tt>a</tt> of type <tt>A</tt>, <tt>*x = a;</tt> is
-well-defined and does not require performing any non-trivial
-conversions on <tt>a</tt>.
-
-<h3>Associated Types</h3>
-
-<Table border>
-
-  <tr>
-    <td>Return Category</td>
-    <td><tt>std::return_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::writable_iterator_tag</tt>
-    </td>
-  </tr>
-
-</Table>
-
-
-
-<h3>Refinement of</h3>
-
-<A href="http://www.boost.org/libs/utility/CopyConstructible.html">Copy Constructible</A>
-
-<h3>Valid expressions</h3>
-
-<Table border>
-  <tr>
-    <TH>Name</TH><TH>Expression</TH><TH>Return type</TH>
-  </tr>
-  <tr>
-    <td>Dereference assignment</td>
-    <td><tt>*x = a</tt></td>
-    <td>unspecified</td>
-  </tr>
-</table>
-
-<p>
-
-
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:SwappableIterator"></A>
-Swappable Iterator
-</H3>
-
-A Swappable Iterator is an iterator whose dereferenced values can be
-swapped.
-
-<p>
-Note: the requirements for Swappable Iterator are dependent on the
-issues surrounding <tt>std::swap()</tt> being resolved. Here we assume
-that the issue will be resolved by allowing the overload of
-<tt>std::swap()</tt> for user-defined types.
-
-<p>
-Note: Readable Iterator and Writable Iterator combined implies
-Swappable Iterator because of the fully templated
-<tt>std::swap()</tt>.  However, Swappable Iterator does not imply
-Readable Iterator nor Writable Iterator.
-
-<h3>Associated Types</h3>
-
-<Table border>
-
-  <tr>
-    <td>Return Category</td>
-    <td><tt>std::return_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::swappable_iterator_tag</tt>
-    </td>
-  </tr>
-
-</Table>
-
-
-<h3>Valid expressions</h3>
-
-Of the two valid expressions listed below, only one <b>OR</b> the
-other is required. If <tt>std::iter_swap()</tt> is overloaded for
-<tt>X</tt> then <tt>std::swap()</tt> is not required. If
-<tt>std::iter_swap()</tt> is not overloaded for <tt>X</tt> then the
-default (fully templated) version is used, which will call
-<tt>std::swap()</tt> (this means changing the current requirements for
-<tt>std::iter_swap()</tt>).
-
-<p>
-<Table border>
-  <tr>
-    <TH>Name</TH><TH>Expression</TH><TH>Return type</TH>
-  </tr>
-
-  <tr>
-    <td>Iterator Swap</td>
-    <td><tt>std::iter_swap(x, y)</tt></td>
-    <td>void</td>
-  </tr>
-
-  <tr>
-    <td>Dereference and Swap</td>
-    <td><tt>std::swap(*x, *y)</tt></td>
-    <td>void</td>
-  </tr>
-
-</table>
-
-<p>
-
-
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:ConstantLvalueIterator"></A>
-Constant Lvalue Iterator
-</H3>
-
-A Constant Lvalue Iterator is an iterator that dereferences to produce a
-const reference to the pointed-to object, i.e., the associated
-<tt>reference</tt> type is <tt>const T&amp;</tt>. Changing the value
-of or destroying an iterator that models Constant Lvalue Iterator does
-not invalidate pointers and references previously obtained from that
-iterator.
-
- 
-<h3>Refinement of</h3>
-
-<a href="#concept:ReadableIterator">Readable Iterator</a> 
-
-<h3>Associated Types</h3>
-
-<Table border>
-
-  <tr>
-    <td>Reference type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-    <td>
-     The return type of dereferencing the iterator, which must be
-     <tt>const T&amp;</tt>.
-    </td>
-  </tr>
-
-<!--  I don't think this is needed
-  <tr>
-    <td>Pointer type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::pointer</tt></td>
-    <td>
-     The pointer to the value type, which must be <tt>const T*</tt>.
-    </td>
-  </tr>
--->
-
-  <tr>
-    <td>Return Category</td>
-    <td><tt>std::return_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::constant_lvalue_iterator_tag</tt>
-    </td>
-  </tr>
-
-</table>
-
-<!-- these are not necessary now that we use reference as operator* return type
-<h3>Valid expressions</h3>
-
-<Table border>
-<tr><TH>Name</TH><TH>Expression</TH><TH>Type requirements</TH><TH>Return type</TH></tr>
-<tr>
- <td>Dereference</td>
- <td><tt>*x</tt></td>
- <td>&nbsp;</td>
- <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-</tr>
-<tr>
- <td>Member access</td>
- <td><tt>x-&gt;m</tt></td>
- <td><tt>T</tt> is a type with a member named <tt>m</tt>.</td>
- <td>
- &nbsp;
- </td>
-</tr>
-</table>
-
--->
-
-<p>
-
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:MutableLvalueIterator"></A>
-Mutable Lvalue Iterator
-</H3>
-
-A Mutable Lvalue Iterator is an iterator that dereferences to produce a
-reference to the pointed-to object. The associated <tt>reference</tt>
-type is <tt>T&amp;</tt>.  Changing the value of or destroying an
-iterator that models Mutable Lvalue Iterator does not invalidate
-pointers and references previously obtained from that iterator.
- 
-<h3>Refinement of</h3>
-
-<a href="#concept:ReadableIterator">Readable Iterator</a>,
-<a href="#concept:WritableIterator">Writable Iterator</a>,
-and <a href="#concept:SwappableIterator">Swappable Iterator</a>.
-
-
-
-<h3>Associated Types</h3>
-
-<Table border>
-
-  <tr>
-    <td>Reference type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-    <td>The return type of dereferencing the iterator, which must be
-     <tt>T&amp;</tt>.</td>
-  </tr>
-
-<!-- I don't think this is necessary
-  <tr>
-    <td>Pointer type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::pointer</tt></td>
-    <td>
-     The pointer to the value type, which is <tt>T*</tt>.
-    </td>
-  </tr>
--->
-
-  <tr>
-    <td>Return Category</td>
-    <td><tt>std::return_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::mutable_lvalue_iterator_tag</tt>
-    </td>
-  </tr>
-
-</table>
-
-<!-- no longer needed since the return type is specified as reference in the readable iterator
-<h3>Valid expressions</h3>
-
-<Table border>
-<tr><TH>Name</TH><TH>Expression</TH><TH>Type requirements</TH><TH>Return type</TH></tr>
-<tr>
- <td>Dereference</td>
- <td><tt>*x</tt></td>
- <td>&nbsp;</td>
- <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-</tr>
-<tr>
- <td>Member access</td>
- <td><tt>x-&gt;m</tt></td>
- <td><tt>T</tt> is a type with a member named <tt>m</tt>.</td>
- <td>
- &nbsp;
- </td>
-</tr>
-</table>
-
--->
-
-<p>
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:ForwardTraversalIterator"></A>
-Forward Traversal Iterator
-</H3>
-
-The Forward Iterator is an iterator that can be incremented. Also, it
-is permissible to make multiple passes through the iterator's range.
-
-<h3>Refinement of</h3>
-
-<A href="http://www.boost.org/libs/utility/CopyConstructible.html">Copy Constructible</A>,
-<A href="http://www.boost.org/libs/utility/Assignable.html">Assignable</A>,
-<A href="http://www.sgi.com/tech/stl/DefaultConstructible.html">Default Constructible</A>, and 
-<A href="http://www.sgi.com/tech/stl/EqualityComparable.html">Equality Comparable</A>
-
-
-<h3>Associated types</h3>
-
-<Table border>
-
-  <tr>
-    <td>Difference Type</td>
-    <td><tt>std::iterator_traits&lt;X&gt;::difference_type</tt></td>
-    <td>
-    A signed integral type used for representing distances
-    between iterators that point into the same range.
-    </td>
-  </tr>
-
-  <tr>
-    <td>Traversal Category</td>
-    <td><tt>std::traversal_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::forward_traversal_tag</tt>
-    </td>
-  </tr>
-</Table>
-
-<h3>Valid expressions</h3>
-
-<Table border>
-  <tr>
-    <TH>Name</TH><TH>Expression</TH><TH>Type requirements</TH>
-      <TH>Return type</TH>
-  </tr>
-  <tr>
-    <td>Preincrement</td>
-    <td><tt>++i</tt></td><td>&nbsp;</td><td><tt>X&amp;</tt></td>
-  </tr>
-  <tr>
-    <td>Postincrement</td>
-    <td><tt>i++</tt></td><td>&nbsp;</td><td>convertible to <tt>const X&amp;</tt></td>
-  </tr>
-</Table>
-
-<p>
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:BidirectionalTraversalIterator"></A>
-Bidirectional Traversal Iterator
-</H3>
-
-An iterator that can be incremented and decremented.
-
-<h3>Refinement of</h3>
-
-<a href="#concept:ForwardTraversalIterator">Forward Traversal Iterator</a>
-
-<h3>Associated types</h3>
-
-<Table border>
-  <tr>
-    <td>Traversal Category</td>
-    <td><tt>std::traversal_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::bidirectional_traversal_tag</tt>
-    </td>
-  </tr>
-</Table>
-
-<h3>Valid expressions</h3>
-
-<Table border>
-  <tr>
-  <TH>Name</TH><TH>Expression</TH><TH>Type requirements</TH>
-      <TH>Return type</TH>
-  </tr>
-  <tr><td>Predecrement</td>
-      <td><tt>--i</tt></td><td>&nbsp;</td><td><tt>X&amp;</tt></td>
-  </tr>
-  <tr><td>Postdecrement</td>
-      <td><tt>i--</tt></td><td>&nbsp;</td><td>convertible to <tt>const X&amp;</tt></td>
-  </tr>
-</table>
-
-<p>
-<hr>
-<!--------------------------------------------------------------------------->
-
-<H3><A NAME="concept:RandomAccessTraversalIterator"></A>
-Random Access Traversal Iterator
-</H3>
-
-An iterator that provides constant-time methods for moving forward and
-backward in arbitrary-sized steps.
-
-<h3>Refinement of</h3>
-
-<a href="#concept:BidirectionalTraversalIterator">Bidirectional Traversal Iterator</a> and
-<A href="http://www.sgi.com/tech/stl/LessThanComparable.html">Less Than Comparable</A> where <tt>&lt;</tt> is a total ordering
-
-<h3>Associated types</h3>
-
-<Table border>
-  <tr>
-    <td>Traversal Category</td>
-    <td><tt>std::traversal_category&lt;X&gt;::type</tt></td>
-    <td>
-    A type convertible to <tt>std::random_access_traversal_tag</tt>
-    </td>
-  </tr>
-</Table>
-
-<h3>Valid expressions</h3>
-
-<Table border>
-<tr><TH>Name</TH><TH>Expression</TH><TH>Type requirements</TH>
-    <TH>Return type</TH>
-</tr>
-<tr><td>Iterator addition</td>
-    <td><tt>i += n</tt></td><td>&nbsp;</td><td><tt>X&amp;</tt></td>
-</tr>
-<tr><td>Iterator addition</td>
-    <td><tt>i + n</tt> or <tt>n + i</tt></td><td>&nbsp;</td><td><tt>X</tt></td>
-</tr>
-<tr><td>Iterator subtraction</td>
-   <td><tt>i -= n</tt></td><td>&nbsp;</td><td><tt>X&amp;</tt></td>
-</tr>
-<tr><td>Iterator subtraction</td>
-    <td><tt>i - n</tt></td><td>&nbsp;</td><td><tt>X</tt></td>
-</tr>
-<tr><td>Difference</td>
-    <td><tt>i - j</tt></td><td>&nbsp;</td><td><tt>std::iterator_traits&lt;X&gt;::difference_type</tt></td>
-</tr>
-<tr><td>Element operator</td>
-    <td><tt>i[n]</tt></td>
-    <td><tt>X</tt> must also be a model of
-     <a href="#concept:ReadableIterator">Readable Iterator</a>. </td>
-    <td><tt>std::iterator_traits&lt;X&gt;::reference</tt></td>
-</tr>
-<tr><td>Element assignment</td>
-    <td><tt>i[n] = t</tt></td>
-    <td><tt>X</tt> must also be a model of
-      <a href="#concept:WritableIterator">Writable Iterator</a>.</td>
-    <td>unspecified</td>
-</tr>
-</table>
-
-<p>
-
-<HR>
-<TABLE>
-<TR valign=top>
-<TD nowrap>Copyright &copy 2000</TD><TD>
-<A HREF="../../../../people/jeremy_siek.htm">Jeremy Siek</A>, Univ.of Notre Dame (<A HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>)
-</TD></TR></TABLE>
-
-</body>
-</html>