Patches from Nathan Ridge using SFINAE to disable the Fusion algorithms for non-{Fusion sequence} types

[SVN r78463]

include/boost/fusion/algorithm/iteration/accumulate.hpp

@@ -9,6 +9,8 @@
 
 #include <boost/fusion/algorithm/iteration/accumulate_fwd.hpp>
 #include <boost/fusion/algorithm/iteration/fold.hpp>
+#include <boost/fusion/support/is_sequence.hpp>
+#include <boost/utility/enable_if.hpp>
 
 namespace boost { namespace fusion
 {
@@ -23,14 +25,24 @@ namespace boost { namespace fusion
     }
 
     template <typename Sequence, typename State, typename F>
-    inline typename result_of::accumulate<Sequence, State const, F>::type
+    inline 
+    typename
+        lazy_enable_if<
+            traits::is_sequence<Sequence>
+          , result_of::accumulate<Sequence, State const, F>
+        >::type
     accumulate(Sequence& seq, State const& state, F f)
     {
         return fusion::fold(seq, state, f);
     }
 
     template <typename Sequence, typename State, typename F>
-    inline typename result_of::accumulate<Sequence const, State const, F>::type
+    inline 
+    typename
+        lazy_enable_if<
+            traits::is_sequence<Sequence>
+          , result_of::accumulate<Sequence const, State const, F>
+        >::type
     accumulate(Sequence const& seq, State const& state, F f)
     {
         return fusion::fold(seq, state, f);

include/boost/fusion/algorithm/iteration/accumulate_fwd.hpp

@@ -7,6 +7,9 @@
 #if !defined(BOOST_FUSION_ACCUMULATE_FWD_HPP_INCLUDED)
 #define BOOST_FUSION_ACCUMULATE_FWD_HPP_INCLUDED
 
+#include <boost/fusion/support/is_sequence.hpp>
+#include <boost/utility/enable_if.hpp>
+
 namespace boost { namespace fusion
 {
     namespace result_of
@@ -16,11 +19,19 @@ namespace boost { namespace fusion
     }
 
     template <typename Sequence, typename State, typename F>
-    typename result_of::accumulate<Sequence, State const, F>::type
+    typename
+        lazy_enable_if<
+            traits::is_sequence<Sequence>
+          , result_of::accumulate<Sequence, State const, F>
+        >::type
     accumulate(Sequence& seq, State const& state, F f);
 
     template <typename Sequence, typename State, typename F>
-    typename result_of::accumulate<Sequence const, State const, F>::type
+    typename
+        lazy_enable_if<
+            traits::is_sequence<Sequence>
+          , result_of::accumulate<Sequence const, State const, F>
+        >::type
     accumulate(Sequence const& seq, State const& state, F f);
 }}
 

include/boost/fusion/algorithm/iteration/for_each.hpp

@@ -11,6 +11,8 @@
 #include <boost/fusion/algorithm/iteration/detail/for_each.hpp>
 #include <boost/fusion/algorithm/iteration/detail/segmented_for_each.hpp>
 #include <boost/fusion/support/is_segmented.hpp>
+#include <boost/fusion/support/is_sequence.hpp>
+#include <boost/utility/enable_if.hpp>
 
 namespace boost { namespace fusion
 {
@@ -24,14 +26,24 @@ namespace boost { namespace fusion
     }
 
     template <typename Sequence, typename F>
-    inline void
+    inline
+    typename
+        enable_if<
+            traits::is_sequence<Sequence>
+          , void
+        >::type
     for_each(Sequence& seq, F const& f)
     {
         detail::for_each(seq, f, typename traits::is_segmented<Sequence>::type());
     }
 
     template <typename Sequence, typename F>
-    inline void
+    inline
+    typename
+        enable_if<
+            traits::is_sequence<Sequence>
+          , void
+        >::type
     for_each(Sequence const& seq, F const& f)
     {
         detail::for_each(seq, f, typename traits::is_segmented<Sequence>::type());

include/boost/fusion/algorithm/iteration/for_each_fwd.hpp

@@ -7,6 +7,9 @@
 #if !defined(BOOST_FUSION_FOR_EACH_FWD_HPP_INCLUDED)
 #define BOOST_FUSION_FOR_EACH_FWD_HPP_INCLUDED
 
+#include <boost/fusion/support/is_sequence.hpp>
+#include <boost/utility/enable_if.hpp>
+
 namespace boost { namespace fusion
 {
     namespace result_of
@@ -16,11 +19,21 @@ namespace boost { namespace fusion
     }
 
     template <typename Sequence, typename F>
-    void
+    inline
+    typename
+        enable_if<
+            traits::is_sequence<Sequence>
+          , void
+        >::type
     for_each(Sequence& seq, F const& f);
 
     template <typename Sequence, typename F>
-    void
+    inline
+    typename
+        enable_if<
+            traits::is_sequence<Sequence>
+          , void
+        >::type
     for_each(Sequence const& seq, F const& f);
 }}