Support removing the C++11 standard reference wrappers.

doc/notes.qbk

@@ -121,7 +121,7 @@ creates a __list__ of type
 
     __list__<void (*)(int)>
 
-[heading boost::ref]
+[heading Reference Wrappers]
 
 Fusion's generation functions (e.g. __make_list__) by default stores the
 element types as plain non-reference types. Example:
@@ -151,6 +151,8 @@ For example:
 
 See __boost_ref__ for details.
 
+Since C++11, the standard reference wrappers (`std::ref` and `std::cref`) work as well.
+
 [heading adt_attribute_proxy]
 
 To adapt arbitrary data types that do not allow direct access to their members,

doc/support.qbk

@@ -254,7 +254,8 @@ Metafunction to apply __element_conversion__ to the full argument type.
 
 It removes references to `const`, references to array types are kept, even
 if the array is `const`. Reference wrappers are removed (see
-__note_boost_ref__).
+__note_boost_ref__)[footnote Since C++11, the standard reference wrappers
+are also removed.].
 
 [heading Header]
 

include/boost/fusion/support/deduce.hpp

@@ -12,6 +12,10 @@
 #include <boost/fusion/support/config.hpp>
 #include <boost/ref.hpp>
 
+#ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL
+#include <functional>
+#endif
+
 namespace boost { namespace fusion { namespace traits
 {
     template <typename T> struct deduce;
@@ -86,6 +90,21 @@ namespace boost { namespace fusion { namespace traits
         typedef T& type;
     };
 
+    // Also unwrap C++11 std::ref if available (referencee cv is deduced)
+#ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL
+    template <typename T>
+    struct deduce<std::reference_wrapper<T> &>
+    {
+        typedef T& type;
+    };
+
+    template <typename T>
+    struct deduce<std::reference_wrapper<T> const &>
+    {
+        typedef T& type;
+    };
+#endif
+
     // Keep references on arrays, even if const
 
     template <typename T, int N>

include/boost/fusion/support/detail/as_fusion_element.hpp

@@ -11,6 +11,10 @@
 #include <boost/fusion/support/config.hpp>
 #include <boost/ref.hpp>
 
+#ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL
+#include <functional>
+#endif
+
 namespace boost { namespace fusion { namespace detail
 {
     template <typename T>
@@ -25,6 +29,14 @@ namespace boost { namespace fusion { namespace detail
         typedef T& type;
     };
 
+#ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL
+    template <typename T>
+    struct as_fusion_element<std::reference_wrapper<T> >
+    {
+        typedef T& type;
+    };
+#endif
+
     template <typename T, int N>
     struct as_fusion_element<T[N]>
     {

test/sequence/deduce_sequence.cpp

@@ -6,6 +6,7 @@
     http://www.boost.org/LICENSE_1_0.txt).
 ==============================================================================*/
 
+#include <boost/config.hpp>
 #include <boost/fusion/support/deduce_sequence.hpp>
 #include <boost/fusion/mpl.hpp>
 #include <boost/detail/lightweight_test.hpp>
@@ -13,6 +14,9 @@
 #include <boost/mpl/equal.hpp>
 
 #include <boost/ref.hpp>
+#ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL
+#include <functional>
+#endif
 
 using boost::is_same;
 using boost::reference_wrapper;
@@ -66,6 +70,13 @@ int main()
     TEST_SAME_TYPE(deduce< reference_wrapper<int> const & >::type, int &);
     TEST_SAME_TYPE(deduce< reference_wrapper<int const> const & >::type, int const &);
 
+#ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL
+    TEST_SAME_TYPE(deduce< std::reference_wrapper<int> & >::type, int &);
+    TEST_SAME_TYPE(deduce< std::reference_wrapper<int const> & >::type, int const &);
+    TEST_SAME_TYPE(deduce< std::reference_wrapper<int> const & >::type, int &);
+    TEST_SAME_TYPE(deduce< std::reference_wrapper<int const> const & >::type, int const &);
+#endif
+
     TEST_SAME_TYPE(deduce< int(&)[2] >::type, int(&)[2]);
     TEST_SAME_TYPE(deduce< int const (&)[2] >::type, int const (&)[2]);
     TEST_SAME_TYPE(deduce< int volatile (&)[2] >::type, int volatile (&)[2]);