added as_map

fixed bug: wrong iterator category for map_iterator

[SVN r82721]

include/boost/fusion/container/map/detail/build_map.hpp

@@ -0,0 +1,75 @@
+/*=============================================================================
+    Copyright (c) 2005-2013 Joel de Guzman
+
+    Distributed under 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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_BUILD_MAP_02042013_1448)
+#define BOOST_FUSION_BUILD_MAP_02042013_1448
+
+#include <boost/fusion/iterator/equal_to.hpp>
+#include <boost/fusion/iterator/next.hpp>
+#include <boost/fusion/iterator/value_of.hpp>
+#include <boost/fusion/iterator/deref.hpp>
+#include <boost/fusion/sequence/intrinsic/begin.hpp>
+#include <boost/fusion/sequence/intrinsic/end.hpp>
+#include <boost/fusion/container/map/map.hpp>
+#include <boost/fusion/algorithm/transformation/push_front.hpp>
+
+namespace boost { namespace fusion { namespace detail
+{
+    template <typename First, typename Last
+      , bool is_empty = result_of::equal_to<First, Last>::value>
+    struct build_map;
+
+    template <typename First, typename Last>
+    struct build_map<First, Last, true>
+    {
+        typedef map<> type;
+        static type
+        call(First const&, Last const&)
+        {
+            return type();
+        }
+    };
+
+    template <typename T, typename Rest>
+    struct push_front_map;
+
+    template <typename T, typename ...Rest>
+    struct push_front_map<T, map<Rest...>>
+    {
+        typedef map<T, Rest...> type;
+
+        static type
+        call(T const& first, map<Rest...> const& rest)
+        {
+            return type(push_front(rest, first));
+        }
+    };
+
+    template <typename First, typename Last>
+    struct build_map<First, Last, false>
+    {
+        typedef
+            build_map<typename result_of::next<First>::type, Last>
+        next_build_map;
+
+        typedef push_front_map<
+            typename result_of::value_of<First>::type
+          , typename next_build_map::type>
+        push_front;
+
+        typedef typename push_front::type type;
+
+        static type
+        call(First const& f, Last const& l)
+        {
+            typename result_of::value_of<First>::type v = *f;
+            return push_front::call(
+                v, next_build_map::call(fusion::next(f), l));
+        }
+    };
+}}}
+
+#endif