Finished iterator_adaptor tutorial

Added example test code
Rolled forward old counting_iterator abstract for boost docs.


[SVN r21649]

example/Jamfile

@@ -9,4 +9,5 @@ test-suite iterator_examples
   : [ run reverse_iterator.cpp ]
     [ run node_iterator1.cpp ]
     [ run node_iterator2.cpp ]
+    [ run node_iterator3.cpp ]
       ;

example/node_iterator2.hpp

@@ -5,7 +5,7 @@
 # define NODE_ITERATOR2_DWA2004110_HPP
 
 # include "node.hpp"
-# include <boost/iterator/iterator_facade.hpp>
+# include <boost/iterator/iterator_adaptor.hpp>
 
 # ifndef BOOST_NO_SFINAE
 #  include <boost/type_traits/is_convertible.hpp>
@@ -14,21 +14,26 @@
 
 template <class Value>
 class node_iter
-  : public boost::iterator_facade<
-        node_iter<Value>
-      , Value
-      , boost::forward_traversal_tag
+  : public boost::iterator_adaptor<
+        node_iter<Value>                // Derived
+      , Value*                          // Base
+      , boost::use_default              // Value
+      , boost::forward_traversal_tag    // CategoryOrTraversal
     >
 {
  private:
     struct enabler {};  // a private type avoids misuse
 
+    typedef boost::iterator_adaptor<
+        node_iter<Value>, Value*, boost::use_default, boost::forward_traversal_tag
+    > super_t;
+    
  public:
     node_iter()
-      : m_node(0) {}
+      : super_t(0) {}
 
     explicit node_iter(Value* p)
-      : m_node(p) {}
+      : super_t(p) {}
 
     template <class OtherValue>
     node_iter(
@@ -42,29 +47,9 @@ class node_iter
     )
       : m_node(other.m_node) {}
 
-
-# if !BOOST_WORKAROUND(__GNUC__, == 2)
- private: // GCC2 can't even grant that friendship to template member functions
-# endif 
-    friend class boost::iterator_core_access;
-
-    template <class OtherValue>
-    bool equal(node_iter<OtherValue> const& other) const
-    {
-        return this->m_node == other.m_node;
-    }
-
  private:
+    friend class boost::iterator_core_access;
     void increment() { m_node = m_node->next(); }
-
-    Value& dereference() const { return *m_node; }
-
-# ifdef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
- public:
-# else 
-    template <class> friend class node_iter;
-# endif 
-    Value* m_node;
 };
 
 typedef node_iter<node_base> node_iterator;

example/node_iterator3.cpp

@@ -0,0 +1,43 @@
+// Copyright David Abrahams 2004. Use, modification and distribution is
+// subject to the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include "node_iterator3.hpp"
+#include <string>
+#include <memory>
+#include <iostream>
+#include <algorithm>
+#include <boost/mem_fn.hpp>
+#include <cassert>
+
+int main()
+{
+    std::auto_ptr<node<int> > nodes(new node<int>(42));
+    nodes->append(new node<std::string>(" is greater than "));
+    nodes->append(new node<int>(13));
+
+    // Check interoperability
+    assert(node_iterator(nodes.get()) == node_const_iterator(nodes.get()));
+    assert(node_const_iterator(nodes.get()) == node_iterator(nodes.get()));
+    
+    assert(node_iterator(nodes.get()) != node_const_iterator());
+    assert(node_const_iterator(nodes.get()) != node_iterator());
+    
+    std::copy(
+        node_iterator(nodes.get()), node_iterator()
+      , std::ostream_iterator<node_base>(std::cout, " ")
+    );
+    std::cout << std::endl;
+    
+    std::for_each(
+        node_iterator(nodes.get()), node_iterator()
+      , boost::mem_fn(&node_base::double_me)
+    );
+
+    std::copy(
+        node_const_iterator(nodes.get()), node_const_iterator()
+      , std::ostream_iterator<node_base>(std::cout, "/")
+    );
+    std::cout << std::endl;
+    return 0;
+}

example/node_iterator3.hpp

@@ -0,0 +1,58 @@
+// Copyright David Abrahams 2004. Use, modification and distribution is
+// subject to the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#ifndef NODE_ITERATOR3_DWA2004110_HPP
+# define NODE_ITERATOR3_DWA2004110_HPP
+
+# include "node.hpp"
+# include <boost/iterator/iterator_adaptor.hpp>
+
+# ifndef BOOST_NO_SFINAE
+#  include <boost/type_traits/is_convertible.hpp>
+#  include <boost/utility/enable_if.hpp>
+# endif
+
+template <class Value>
+class node_iter
+  : public boost::iterator_adaptor<
+        node_iter<Value>                // Derived
+      , Value*                          // Base
+      , boost::use_default              // Value
+      , boost::forward_traversal_tag    // CategoryOrTraversal
+    >
+{
+ private:
+    struct enabler {};  // a private type avoids misuse
+
+    typedef boost::iterator_adaptor<
+        node_iter<Value>, Value*, boost::use_default, boost::forward_traversal_tag
+    > super_t;
+    
+ public:
+    node_iter()
+      : super_t(0) {}
+
+    explicit node_iter(Value* p)
+      : super_t(p) {}
+
+    template <class OtherValue>
+    node_iter(
+        node_iter<OtherValue> const& other
+# ifndef BOOST_NO_SFINAE
+      , typename boost::enable_if<
+            boost::is_convertible<OtherValue*,Value*>
+          , enabler
+        >::type = enabler()
+# endif 
+    )
+      : m_node(other.m_node) {}
+
+ private:
+    friend class boost::iterator_core_access;
+    void increment() { this->base_reference() = this->base()->next(); }
+};
+
+typedef node_iter<node_base> node_iterator;
+typedef node_iter<node_base const> node_const_iterator;
+
+#endif // NODE_ITERATOR3_DWA2004110_HPP