From 78ff3d883114d0422db0f782188be1ff250bf63d Mon Sep 17 00:00:00 2001
From: Joel de Guzman <djowel@gmail.com>
Date: Tue, 4 Sep 2012 13:40:38 +0000
Subject: [PATCH] Fixed code to allow decltype implementation of
 boost::result_of with BOOST_RESULT_OF_USE_DECLTYPE defined.

[SVN r80395]
---
 .../fusion/functional/invocation/invoke.hpp   | 81 +++++++++++++++++--
 1 file changed, 73 insertions(+), 8 deletions(-)

diff --git a/include/boost/fusion/functional/invocation/invoke.hpp b/include/boost/fusion/functional/invocation/invoke.hpp
index 085beb7e..1a491702 100644
--- a/include/boost/fusion/functional/invocation/invoke.hpp
+++ b/include/boost/fusion/functional/invocation/invoke.hpp
@@ -57,13 +57,13 @@ namespace boost { namespace fusion
         template <typename Function, class Sequence> struct invoke;
     }
 
-    template <typename Function, class Sequence>
-    inline typename result_of::invoke<Function, Sequence>::type
-    invoke(Function, Sequence &);
+    //~ template <typename Function, class Sequence>
+    //~ inline typename result_of::invoke<Function, Sequence>::type
+    //~ invoke(Function, Sequence &);
 
-    template <typename Function, class Sequence>
-    inline typename result_of::invoke<Function, Sequence const>::type
-    invoke(Function, Sequence const &);
+    //~ template <typename Function, class Sequence>
+    //~ inline typename result_of::invoke<Function, Sequence const>::type
+    //~ invoke(Function, Sequence const &);
 
     //----- ---- --- -- - -  -   -
 
@@ -85,6 +85,9 @@ namespace boost { namespace fusion
         template <typename T, class Sequence>
         struct invoke_data_member;
 
+        template <typename Function, class Sequence, int N, bool RandomAccess>
+        struct invoke_fn_ptr;
+
         template <typename Function, class Sequence, int N, bool RandomAccess>
         struct invoke_mem_fn;
 
@@ -95,10 +98,10 @@ namespace boost { namespace fusion
         template <typename F, class Sequence, int N, bool RandomAccess>
         struct invoke_nonmember_builtin
         // use same implementation as for function objects but...
-            : invoke_impl< // ...work around boost::result_of bugs
+            : invoke_fn_ptr< // ...work around boost::result_of bugs
                 typename mpl::eval_if< ft::is_function<F>,
                     boost::add_reference<F>, boost::remove_cv<F> >::type,
-                Sequence, N, false, RandomAccess >
+                Sequence, N, RandomAccess >
         { };
 
         template <typename Function, class Sequence, int N, bool RandomAccess>
@@ -199,6 +202,35 @@ namespace boost { namespace fusion
                     Function(BOOST_PP_ENUM(N,M,~)) >::type result_type;
 #undef M
 
+#if N > 0
+
+            template <typename F>
+            static inline result_type
+            call(F & f, Sequence & s)
+            {
+#define M(z,j,data) fusion::at_c<j>(s)
+                return f( BOOST_PP_ENUM(N,M,~) );
+            }
+
+#else
+            template <typename F>
+            static inline result_type
+            call(F & f, Sequence & /*s*/)
+            {
+                return f();
+            }
+
+#endif
+
+        };
+
+        template <typename Function, class Sequence>
+        struct invoke_fn_ptr<Function,Sequence,N,true>
+        {
+        public:
+
+            typedef typename ft::result_type<Function>::type result_type;
+
 #if N > 0
 
             template <typename F>
@@ -278,6 +310,39 @@ namespace boost { namespace fusion
                 return f();
             }
 
+#endif
+
+        };
+
+        template <typename Function, class Sequence>
+        struct invoke_fn_ptr<Function,Sequence,N,false>
+        {
+        private:
+            typedef invoke_param_types<Sequence,N> seq;
+        public:
+
+            typedef typename ft::result_type<Function>::type result_type;
+
+#if N > 0
+
+            template <typename F>
+            static inline result_type
+            call(F & f, Sequence & s)
+            {
+                typename seq::I0 i0 = fusion::begin(s);
+                BOOST_PP_REPEAT_FROM_TO(1,N,M,~)
+                return f( BOOST_PP_ENUM_PARAMS(N,*i) );
+            }
+
+#else
+
+            template <typename F>
+            static inline result_type
+            call(F & f, Sequence & /*s*/)
+            {
+                return f();
+            }
+
 #endif
 
         };