Updated to current proposal.

[SVN r1209]

include/boost/iterator/counting_iterator.hpp

@@ -71,7 +71,7 @@ namespace detail
   struct counting_iterator_base
   {
       typedef typename mpl::apply_if<
-          is_same<Category, not_specified>
+          is_same<Category, use_default>
         , mpl::apply_if<
               is_numeric<Incrementable>
             , mpl::identity<std::random_access_iterator_tag>
@@ -81,7 +81,7 @@ namespace detail
       >::type category;
       
       typedef typename mpl::apply_if<
-          is_same<Difference, not_specified>
+          is_same<Difference, use_default>
         , mpl::apply_if<
               is_numeric<Incrementable>
             , numeric_difference<Incrementable>
@@ -129,7 +129,7 @@ namespace detail
   };
 }
 
-template <class Incrementable, class Category = not_specified, class Difference = not_specified>
+template <class Incrementable, class Category = use_default, class Difference = use_default>
 class counting_iterator
   : public detail::counting_iterator_base<Incrementable, Category, Difference>::type
 {

include/boost/iterator/filter_iterator.hpp

@@ -35,13 +35,13 @@ namespace boost
   class filter_iterator
       : public iterator_adaptor<
             filter_iterator<Predicate, Iterator>, Iterator
-          , not_specified
+          , use_default
           , typename detail::filter_iterator_category<Iterator>::type
         >
   {
       typedef iterator_adaptor<
             filter_iterator<Predicate, Iterator>, Iterator
-          , not_specified
+          , use_default
           , typename detail::filter_iterator_category<Iterator>::type
         > super_t;
 

include/boost/iterator/indirect_iterator.hpp

@@ -154,11 +154,11 @@ namespace boost
 
   template <
       class Iterator
-    , class Value = not_specified
+    , class Value = use_default
-    , class Category = not_specified
+    , class Category = use_default
-    , class Reference = not_specified
+    , class Reference = use_default
-    , class Pointer = not_specified
+    , class Pointer = use_default
-    , class Difference = not_specified
+    , class Difference = use_default
   >
   class indirect_iterator
     : public detail::indirect_base<

include/boost/iterator/iterator_adaptor.hpp

@@ -172,7 +172,7 @@ namespace boost
     struct ia_dflt_help
       : mpl::apply_if<
             mpl::and_<
-                is_same<T, not_specified>
+                is_same<T, use_default>
               , Condition
             >
           , DefaultNullaryFn
@@ -196,8 +196,8 @@ namespace boost
             Derived
           , typename detail::ia_dflt_help<Value       , mpl::true_                     , iterator_value<Base> >::type
           , typename detail::ia_dflt_help<Category    , mpl::true_                     , BOOST_ITERATOR_CATEGORY<Base> >::type
-          , typename detail::ia_dflt_help<Reference   , is_same<Value, not_specified>    , iterator_reference<Base> >::type
+          , typename detail::ia_dflt_help<Reference   , is_same<Value, use_default>    , iterator_reference<Base> >::type
-          , typename detail::ia_dflt_help<Pointer     , is_same<Value, not_specified>    , iterator_pointer<Base> >::type
+          , typename detail::ia_dflt_help<Pointer     , is_same<Value, use_default>    , iterator_pointer<Base> >::type
           , typename detail::ia_dflt_help<Difference  , mpl::true_                     , iterator_difference<Base> >::type
         >
         type;
@@ -211,11 +211,11 @@ namespace boost
   template <
       class Derived
     , class Base
-    , class Value        = not_specified
+    , class Value        = use_default
-    , class Category     = not_specified
+    , class Category     = use_default
-    , class Reference    = not_specified
+    , class Reference    = use_default
-    , class Pointer      = not_specified
+    , class Pointer      = use_default
-    , class Difference   = not_specified
+    , class Difference   = use_default
   >
   class iterator_adaptor
     : public detail::iterator_adaptor_base<

include/boost/iterator/iterator_facade.hpp

@@ -29,7 +29,7 @@
 namespace boost
 {
 
-  struct not_specified;
+  struct use_default;
   
   namespace detail
   {
@@ -67,6 +67,12 @@ namespace boost
     // Generates the corresponding std::iterator specialization
     // from the given iterator traits type
     //
+    // The use_default support is needed for iterator_adaptor.
+    // For practical reasons iterator_adaptor needs to specify
+    // fixed number of template arguments of iterator_facade.
+    // So use_default is its way to say what I really mean
+    // is youre default parameter.
+    //
     template <class Value, class Category, class Reference, class Pointer, class Difference>
     struct iterator_facade_base
     {
@@ -78,13 +84,13 @@ namespace boost
           , Difference
 
           , typename mpl::if_<
-                is_same<Pointer, not_specified>
+                is_same<Pointer, use_default>
               , Value*
               , Pointer
             >::type
 
           , typename mpl::if_<
-                is_same<Reference, not_specified>
+                is_same<Reference, use_default>
               , Value&
               , Reference
             >::type
@@ -263,9 +269,9 @@ namespace boost
       class Derived
     , class Value
     , class Category
-    , class Reference        = not_specified
+    , class Reference        = Value&
-    , class Pointer          = not_specified
+    , class Pointer          = Value*
-    , class Difference       = not_specified
+    , class Difference       = std::ptrdiff_t
   >
   class iterator_facade
       : public detail::iterator_facade_base<Value, Category, Reference, Pointer, Difference>::type

include/boost/iterator/transform_iterator.hpp

@@ -24,16 +24,22 @@ namespace boost
 
   namespace detail 
   {
+
     // Given the transform iterator's transformation and iterator, this
     // is the type used as its traits.
     template <class UnaryFunction, class Iterator>
     struct transform_iterator_base
     {
     private:
+
+      // transform_iterator does not support writable/swappable iterators
+#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
+      BOOST_STATIC_ASSERT((is_tag< readable_iterator_tag, typename access_category<Iterator>::type >::value));
+#endif
+ 
       typedef typename UnaryFunction::result_type result_type;
 
       typedef typename remove_reference< result_type >::type cv_value_type;
-      typedef typename remove_cv< cv_value_type >::type      value_type;
 
       typedef typename mpl::if_< 
           is_reference< result_type >
@@ -62,6 +68,7 @@ namespace boost
         , result_type  
       > type;
     };
+
   }
 
   template <class AdaptableUnaryFunction, class Iterator>