call_traits and type_traits updates for VC6

[SVN r7882]

call_traits.htm

@@ -27,10 +27,16 @@ never occur, and that parameters are passed in the most efficient
 manner possible (see <a href="#examples">examples</a>). In each
 case if your existing practice is to use the type defined on the
 left, then replace it with the call_traits defined type on the
-right. Note that for compilers that do not support partial
+right. </p>
-specialization, no benefit will occur from using call_traits: the
+
-call_traits defined types will always be the same as the existing
+<p>Note that for compilers that do not support either partial
-practice in this case.</p>
+specialization or member templates, no benefit will occur from
+using call_traits: the call_traits defined types will always be
+the same as the existing practice in this case. In addition if
+only member templates and not partial template specialisation is
+support by the compiler (for example Visual C++ 6) then call_traits
+can not be used with array types (although it can be used to
+solve the reference to reference problem).</p>
 
 <table border="0" cellpadding="7" cellspacing="1" width="797">
     <tr>
@@ -569,7 +575,9 @@ std::pair&lt;
 degraded to pointers if the deduced types are arrays, similar
 situations occur in the standard binders and adapters: in
 principle in any function that &quot;wraps&quot; a temporary
-whose type is deduced.</p>
+whose type is deduced. Note that the function arguments to make_pair
+are not expressed in terms of call_traits: doing so would prevent
+template argument deduction from functioning.</p>
 
 <h4><a name="ex4"></a>Example 4 (optimising fill):</h4>
 
@@ -632,6 +640,14 @@ Exactly how much mileage you will get from this depends upon your
 compiler - we could really use some accurate benchmarking
 software as part of boost for cases like this.</p>
 
+<p>Note that the function arguments to fill are not expressed in
+terms of call_traits: doing so would prevent template argument
+deduction from functioning. Instead fill acts as a &quot;thin
+wrapper&quot; that is there to perform template argument
+deduction, the compiler will optimise away the call to fill all
+together, replacing it with the call to filler&lt;&gt;::do_fill,
+which does use call_traits.</p>
+
 <h3>Rationale</h3>
 
 <p>The following notes are intended to briefly describe the
@@ -713,7 +729,7 @@ specialisation).</p>
 
 <hr>
 
-<p>Revised 18 June 2000</p>
+<p>Revised 01 September 2000</p>
 
 <p>© Copyright boost.org 2000. Permission to copy, use, modify,
 sell and distribute this document is granted provided this

include/boost/detail/ob_call_traits.hpp

@@ -9,6 +9,14 @@
 //  Crippled version for crippled compilers:
 //  see libs/utility/call_traits.htm
 //
+
+/* Release notes:
+   01st October 2000:
+      Fixed call_traits on VC6, using "poor man's partial specialisation",
+      using ideas taken from "Generative programming" by Krzysztof Czarnecki 
+      & Ulrich Eisenecker.
+*/
+
 #ifndef BOOST_OB_CALL_TRAITS_HPP
 #define BOOST_OB_CALL_TRAITS_HPP
 
@@ -22,6 +30,85 @@
 
 namespace boost{
 
+#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
+//
+// use member templates to emulate
+// partial specialisation:
+//
+namespace detail{
+
+template <class T>
+struct standard_call_traits
+{
+   typedef T value_type;
+   typedef T& reference;
+   typedef const T& const_reference;
+   typedef const T& param_type;
+};
+template <class T>
+struct simple_call_traits
+{
+   typedef T value_type;
+   typedef T& reference;
+   typedef const T& const_reference;
+   typedef const T param_type;
+};
+template <class T>
+struct reference_call_traits
+{
+   typedef T value_type;
+   typedef T reference;
+   typedef T const_reference;
+   typedef T param_type;
+};
+template <bool simple, bool reference>
+struct call_traits_chooser
+{
+   template <class T>
+   struct rebind
+   {
+      typedef standard_call_traits<T> type;
+   };
+};
+template <>
+struct call_traits_chooser<true, false>
+{
+   template <class T>
+   struct rebind
+   {
+      typedef simple_call_traits<T> type;
+   };
+};
+template <>
+struct call_traits_chooser<false, true>
+{
+   template <class T>
+   struct rebind
+   {
+      typedef reference_call_traits<T> type;
+   };
+};
+} // namespace detail
+template <typename T>
+struct call_traits
+{
+private:
+   typedef detail::call_traits_chooser<(is_pointer<T>::value || is_arithmetic<T>::value) && sizeof(T) <= sizeof(void*), is_reference<T>::value> chooser;
+   typedef typename chooser::template rebind<T> bound_type;
+   typedef typename bound_type::type call_traits_type;
+public:
+   typedef typename call_traits_type::value_type       value_type;
+   typedef typename call_traits_type::reference        reference;
+   typedef typename call_traits_type::const_reference  const_reference;
+   typedef typename call_traits_type::param_type       param_type;
+};
+
+#else
+//
+// sorry call_traits is completely non-functional
+// blame your broken compiler:
+//
+
 template <typename T>
 struct call_traits
 {
@@ -31,6 +118,8 @@ struct call_traits
    typedef const T& param_type;
 };
 
+#endif // member templates
+
 }
 
 #endif // BOOST_OB_CALL_TRAITS_HPP

type_traits.htm

@@ -126,8 +126,7 @@ is always defined as a compile time constant).</p>
         <td width="36%"><p align="center">True if T and U are the
         same type.</p>
         </td>
-        <td width="27%"><p align="center">P</p>
+        <td width="27%">&nbsp; </td>
-        </td>
     </tr>
     <tr>
         <td width="37%"><div align="center"><center><pre>is_convertible&lt;T,U&gt;::value</pre>
@@ -170,15 +169,13 @@ on a type (see 3.93).</p>
         <td valign="top" width="37%"><code>is_const&lt;T&gt;::value</code></td>
         <td valign="top" width="37%">True if type T is top-level
         const qualified.</td>
-        <td valign="top" width="27%"><p align="center">P</p>
+        <td valign="top" width="27%">&nbsp; </td>
-        </td>
     </tr>
     <tr>
         <td valign="top" width="37%"><code>is_volatile&lt;T&gt;::value</code></td>
         <td valign="top" width="37%">True if type T is top-level
         volatile qualified.</td>
-        <td valign="top" width="27%"><p align="center">P</p>
+        <td valign="top" width="27%">&nbsp; </td>
-        </td>
     </tr>
 </table>
 
@@ -348,22 +345,19 @@ as defined by the Standard.&nbsp;</p>
         <td valign="top" width="45%">True if T is a regular
         pointer type - including function pointers - but
         excluding pointers to member functions (3.9.2 p1 and 8.3.1).</td>
-        <td valign="top" width="33%"><p align="center">P</p>
+        <td valign="top" width="33%">&nbsp; </td>
-        </td>
     </tr>
     <tr>
         <td valign="top" width="45%"><code>is_member_pointer&lt;T&gt;::value</code></td>
         <td valign="top" width="45%">True if T is a pointer to a
         non-static class member (3.9.2 p1 and 8.3.1).</td>
-        <td valign="top" width="33%"><p align="center">P</p>
+        <td valign="top" width="33%">&nbsp; </td>
-        </td>
     </tr>
     <tr>
         <td valign="top" width="45%"><code>is_reference&lt;T&gt;::value</code></td>
         <td valign="top" width="45%">True if T is a reference
         type (3.9.2 p1 and 8.3.2).</td>
-        <td valign="top" width="33%"><p align="center">P</p>
+        <td valign="top" width="33%">&nbsp; </td>
-        </td>
     </tr>
     <tr>
         <td valign="top" width="45%"><code>is_class&lt;T&gt;::value</code></td>
@@ -607,7 +601,7 @@ familiar standard library algorithms.</p>
 
 <hr>
 
-<p>Revised 08<sup>th</sup> March 2000</p>
+<p>Revised 01 September 2000</p>
 
 <p>© Copyright boost.org 2000. Permission to copy, use, modify,
 sell and distribute this document is granted provided this