Make fold as a single return stmt due to C++11 constexpr.

Signed-off-by: Kohei Takahashi <flast@flast.jp>

include/boost/fusion/algorithm/iteration/detail/fold.hpp

@@ -57,39 +57,11 @@ namespace boost { namespace fusion
         template<typename Result,int N>
         struct BOOST_PP_CAT(unrolled_,BOOST_FUSION_FOLD_NAME)
         {
-            template<typename State, typename It0, typename F>
+            template<typename State3, typename It3, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
-            call(State const& state,It0 const& it0,F f)
+            call_3(State3 const& state3,It3 const& it3,F& f)
             {
-                typedef typename
-                    result_of::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION<
-                        It0 const
-                    >::type
-                It1;
-                It1 it1 = fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it0);
-                typedef typename
-                    result_of::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION<
-                        It1
-                    >::type
-                It2;
-                It2 it2 = fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it1);
-                typedef typename
-                    result_of::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION<
-                        It2
-                    >::type
-                It3;
-                It3 it3 = fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it2);
-
-                typedef typename BOOST_PP_CAT(BOOST_FUSION_FOLD_NAME, _lvalue_state)<State,It0,F>::type State1;
-                State1 const state1=f(state,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it0));
-
-                typedef typename BOOST_PP_CAT(BOOST_FUSION_FOLD_NAME, _lvalue_state)<State1,It1,F>::type State2;
-                State2 const state2=f(state1,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it1));
-
-                typedef typename BOOST_PP_CAT(BOOST_FUSION_FOLD_NAME, _lvalue_state)<State2,It2,F>::type State3;
-                State3 const state3=f(state2,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it2));
-
                 return BOOST_PP_CAT(unrolled_,BOOST_FUSION_FOLD_NAME)<
                     Result
                   , N-4
@@ -98,54 +70,95 @@ namespace boost { namespace fusion
                     fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it3),
                     f);
             }
-        };
 
-        template<typename Result>
+            template<typename State2, typename It2, typename F>
-        struct BOOST_PP_CAT(unrolled_,BOOST_FUSION_FOLD_NAME)<Result,3>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-        {
+            static Result
+            call_2(State2 const& state2,It2 const& it2,F& f)
+            {
+                return call_3(
+                    f(state2,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it2)),
+                    fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it2),
+                    f);
+            }
+
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it1)),
+                    fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it1),
+                    f);
+            }
+
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename
+                return call_1(
-                    result_of::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION<
+                    f(state,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it0)),
-                        It0 const
+                    fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it0),
-                    >::type
+                    f);
-                It1;
+            }
-                It1 it1 = fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it0);
+        };
-                typedef typename
-                    result_of::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION<
-                        It1
-                    >::type
-                It2;
-                It2 it2 = fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it1);
-
-                typedef typename BOOST_PP_CAT(BOOST_FUSION_FOLD_NAME, _lvalue_state)<State,It0,F>::type State1;
-                State1 const state1=f(state,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it0));
-
-                typedef typename BOOST_PP_CAT(BOOST_FUSION_FOLD_NAME, _lvalue_state)<State1,It1,F>::type State2;
-                State2 const state2=f(state1,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it1));
 
+        template<typename Result>
+        struct BOOST_PP_CAT(unrolled_,BOOST_FUSION_FOLD_NAME)<Result,3>
+        {
+            template<typename State2, typename It2, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_2(State2 const& state2,It2 const& it2,F& f)
+            {
                 return f(state2,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it2));
             }
+
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it1)),
+                    fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it1),
+                    f);
+            }
+
+            template<typename State, typename It0, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call(State const& state,It0 const& it0,F f)
+            {
+                return call_1(
+                    f(state,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it0)),
+                    fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it0),
+                    f);
+            }
         };
 
         template<typename Result>
         struct BOOST_PP_CAT(unrolled_,BOOST_FUSION_FOLD_NAME)<Result,2>
         {
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return f(state1,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it1));
+            }
+
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename BOOST_PP_CAT(BOOST_FUSION_FOLD_NAME, _lvalue_state)<State,It0,F>::type State1;
+                return call_1(
-                State1 const state1=f(state,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it0));
+                    f(state,BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(it0)),
-
+                    fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it0),
-                return f(
+                    f);
-                    state1,
-                    BOOST_FUSION_FOLD_IMPL_INVOKE_IT_TRANSFORM(
-                        fusion::BOOST_FUSION_FOLD_IMPL_NEXT_IT_FUNCTION(it0)));
             }
         };
 

include/boost/fusion/algorithm/iteration/detail/preprocessed/fold.hpp

@@ -23,35 +23,11 @@ namespace boost { namespace fusion
         template<typename Result,int N>
         struct unrolled_fold
         {
-            template<typename State, typename It0, typename F>
+            template<typename State3, typename It3, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
-            call(State const& state,It0 const& it0,F f)
+            call_3(State3 const& state3,It3 const& it3,F& f)
             {
-                typedef typename
-                    result_of::next<
-                        It0 const
-                    >::type
-                It1;
-                It1 it1 = fusion::next(it0);
-                typedef typename
-                    result_of::next<
-                        It1
-                    >::type
-                It2;
-                It2 it2 = fusion::next(it1);
-                typedef typename
-                    result_of::next<
-                        It2
-                    >::type
-                It3;
-                It3 it3 = fusion::next(it2);
-                typedef typename fold_lvalue_state<State,It0,F>::type State1;
-                State1 const state1=f(state,fusion::deref(it0));
-                typedef typename fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,fusion::deref(it1));
-                typedef typename fold_lvalue_state<State2,It2,F>::type State3;
-                State3 const state3=f(state2,fusion::deref(it2));
                 return unrolled_fold<
                     Result
                   , N-4
@@ -60,47 +36,87 @@ namespace boost { namespace fusion
                     fusion::next(it3),
                     f);
             }
-        };
+            template<typename State2, typename It2, typename F>
-        template<typename Result>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-        struct unrolled_fold<Result,3>
+            static Result
-        {
+            call_2(State2 const& state2,It2 const& it2,F& f)
+            {
+                return call_3(
+                    f(state2,fusion::deref(it2)),
+                    fusion::next(it2),
+                    f);
+            }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,fusion::deref(it1)),
+                    fusion::next(it1),
+                    f);
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename
+                return call_1(
-                    result_of::next<
+                    f(state,fusion::deref(it0)),
-                        It0 const
+                    fusion::next(it0),
-                    >::type
+                    f);
-                It1;
+            }
-                It1 it1 = fusion::next(it0);
+        };
-                typedef typename
+        template<typename Result>
-                    result_of::next<
+        struct unrolled_fold<Result,3>
-                        It1
+        {
-                    >::type
+            template<typename State2, typename It2, typename F>
-                It2;
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-                It2 it2 = fusion::next(it1);
+            static Result
-                typedef typename fold_lvalue_state<State,It0,F>::type State1;
+            call_2(State2 const& state2,It2 const& it2,F& f)
-                State1 const state1=f(state,fusion::deref(it0));
+            {
-                typedef typename fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,fusion::deref(it1));
                 return f(state2,fusion::deref(it2));
             }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,fusion::deref(it1)),
+                    fusion::next(it1),
+                    f);
+            }
+            template<typename State, typename It0, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call(State const& state,It0 const& it0,F f)
+            {
+                return call_1(
+                    f(state,fusion::deref(it0)),
+                    fusion::next(it0),
+                    f);
+            }
         };
         template<typename Result>
         struct unrolled_fold<Result,2>
         {
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return f(state1,fusion::deref(it1));
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename fold_lvalue_state<State,It0,F>::type State1;
+                return call_1(
-                State1 const state1=f(state,fusion::deref(it0));
+                    f(state,fusion::deref(it0)),
-                return f(
+                    fusion::next(it0),
-                    state1,
+                    f);
-                    fusion::deref( fusion::next(it0)));
             }
         };
         template<typename Result>

include/boost/fusion/algorithm/iteration/detail/preprocessed/iter_fold.hpp

@@ -22,35 +22,11 @@ namespace boost { namespace fusion
         template<typename Result,int N>
         struct unrolled_iter_fold
         {
-            template<typename State, typename It0, typename F>
+            template<typename State3, typename It3, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
-            call(State const& state,It0 const& it0,F f)
+            call_3(State3 const& state3,It3 const& it3,F& f)
             {
-                typedef typename
-                    result_of::next<
-                        It0 const
-                    >::type
-                It1;
-                It1 it1 = fusion::next(it0);
-                typedef typename
-                    result_of::next<
-                        It1
-                    >::type
-                It2;
-                It2 it2 = fusion::next(it1);
-                typedef typename
-                    result_of::next<
-                        It2
-                    >::type
-                It3;
-                It3 it3 = fusion::next(it2);
-                typedef typename iter_fold_lvalue_state<State,It0,F>::type State1;
-                State1 const state1=f(state,it0);
-                typedef typename iter_fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,it1);
-                typedef typename iter_fold_lvalue_state<State2,It2,F>::type State3;
-                State3 const state3=f(state2,it2);
                 return unrolled_iter_fold<
                     Result
                   , N-4
@@ -59,47 +35,87 @@ namespace boost { namespace fusion
                     fusion::next(it3),
                     f);
             }
-        };
+            template<typename State2, typename It2, typename F>
-        template<typename Result>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-        struct unrolled_iter_fold<Result,3>
+            static Result
-        {
+            call_2(State2 const& state2,It2 const& it2,F& f)
+            {
+                return call_3(
+                    f(state2,it2),
+                    fusion::next(it2),
+                    f);
+            }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,it1),
+                    fusion::next(it1),
+                    f);
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename
+                return call_1(
-                    result_of::next<
+                    f(state,it0),
-                        It0 const
+                    fusion::next(it0),
-                    >::type
+                    f);
-                It1;
+            }
-                It1 it1 = fusion::next(it0);
+        };
-                typedef typename
+        template<typename Result>
-                    result_of::next<
+        struct unrolled_iter_fold<Result,3>
-                        It1
+        {
-                    >::type
+            template<typename State2, typename It2, typename F>
-                It2;
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-                It2 it2 = fusion::next(it1);
+            static Result
-                typedef typename iter_fold_lvalue_state<State,It0,F>::type State1;
+            call_2(State2 const& state2,It2 const& it2,F& f)
-                State1 const state1=f(state,it0);
+            {
-                typedef typename iter_fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,it1);
                 return f(state2,it2);
             }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,it1),
+                    fusion::next(it1),
+                    f);
+            }
+            template<typename State, typename It0, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call(State const& state,It0 const& it0,F f)
+            {
+                return call_1(
+                    f(state,it0),
+                    fusion::next(it0),
+                    f);
+            }
         };
         template<typename Result>
         struct unrolled_iter_fold<Result,2>
         {
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return f(state1,it1);
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename iter_fold_lvalue_state<State,It0,F>::type State1;
+                return call_1(
-                State1 const state1=f(state,it0);
+                    f(state,it0),
-                return f(
+                    fusion::next(it0),
-                    state1,
+                    f);
-                    fusion::next(it0));
             }
         };
         template<typename Result>

include/boost/fusion/algorithm/iteration/detail/preprocessed/reverse_fold.hpp

@@ -22,35 +22,11 @@ namespace boost { namespace fusion
         template<typename Result,int N>
         struct unrolled_reverse_fold
         {
-            template<typename State, typename It0, typename F>
+            template<typename State3, typename It3, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
-            call(State const& state,It0 const& it0,F f)
+            call_3(State3 const& state3,It3 const& it3,F& f)
             {
-                typedef typename
-                    result_of::prior<
-                        It0 const
-                    >::type
-                It1;
-                It1 it1 = fusion::prior(it0);
-                typedef typename
-                    result_of::prior<
-                        It1
-                    >::type
-                It2;
-                It2 it2 = fusion::prior(it1);
-                typedef typename
-                    result_of::prior<
-                        It2
-                    >::type
-                It3;
-                It3 it3 = fusion::prior(it2);
-                typedef typename reverse_fold_lvalue_state<State,It0,F>::type State1;
-                State1 const state1=f(state,fusion::deref(it0));
-                typedef typename reverse_fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,fusion::deref(it1));
-                typedef typename reverse_fold_lvalue_state<State2,It2,F>::type State3;
-                State3 const state3=f(state2,fusion::deref(it2));
                 return unrolled_reverse_fold<
                     Result
                   , N-4
@@ -59,47 +35,87 @@ namespace boost { namespace fusion
                     fusion::prior(it3),
                     f);
             }
-        };
+            template<typename State2, typename It2, typename F>
-        template<typename Result>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-        struct unrolled_reverse_fold<Result,3>
+            static Result
-        {
+            call_2(State2 const& state2,It2 const& it2,F& f)
+            {
+                return call_3(
+                    f(state2,fusion::deref(it2)),
+                    fusion::prior(it2),
+                    f);
+            }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,fusion::deref(it1)),
+                    fusion::prior(it1),
+                    f);
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename
+                return call_1(
-                    result_of::prior<
+                    f(state,fusion::deref(it0)),
-                        It0 const
+                    fusion::prior(it0),
-                    >::type
+                    f);
-                It1;
+            }
-                It1 it1 = fusion::prior(it0);
+        };
-                typedef typename
+        template<typename Result>
-                    result_of::prior<
+        struct unrolled_reverse_fold<Result,3>
-                        It1
+        {
-                    >::type
+            template<typename State2, typename It2, typename F>
-                It2;
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-                It2 it2 = fusion::prior(it1);
+            static Result
-                typedef typename reverse_fold_lvalue_state<State,It0,F>::type State1;
+            call_2(State2 const& state2,It2 const& it2,F& f)
-                State1 const state1=f(state,fusion::deref(it0));
+            {
-                typedef typename reverse_fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,fusion::deref(it1));
                 return f(state2,fusion::deref(it2));
             }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,fusion::deref(it1)),
+                    fusion::prior(it1),
+                    f);
+            }
+            template<typename State, typename It0, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call(State const& state,It0 const& it0,F f)
+            {
+                return call_1(
+                    f(state,fusion::deref(it0)),
+                    fusion::prior(it0),
+                    f);
+            }
         };
         template<typename Result>
         struct unrolled_reverse_fold<Result,2>
         {
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return f(state1,fusion::deref(it1));
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename reverse_fold_lvalue_state<State,It0,F>::type State1;
+                return call_1(
-                State1 const state1=f(state,fusion::deref(it0));
+                    f(state,fusion::deref(it0)),
-                return f(
+                    fusion::prior(it0),
-                    state1,
+                    f);
-                    fusion::deref( fusion::prior(it0)));
             }
         };
         template<typename Result>

include/boost/fusion/algorithm/iteration/detail/preprocessed/reverse_iter_fold.hpp

@@ -22,35 +22,11 @@ namespace boost { namespace fusion
         template<typename Result,int N>
         struct unrolled_reverse_iter_fold
         {
-            template<typename State, typename It0, typename F>
+            template<typename State3, typename It3, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
-            call(State const& state,It0 const& it0,F f)
+            call_3(State3 const& state3,It3 const& it3,F& f)
             {
-                typedef typename
-                    result_of::prior<
-                        It0 const
-                    >::type
-                It1;
-                It1 it1 = fusion::prior(it0);
-                typedef typename
-                    result_of::prior<
-                        It1
-                    >::type
-                It2;
-                It2 it2 = fusion::prior(it1);
-                typedef typename
-                    result_of::prior<
-                        It2
-                    >::type
-                It3;
-                It3 it3 = fusion::prior(it2);
-                typedef typename reverse_iter_fold_lvalue_state<State,It0,F>::type State1;
-                State1 const state1=f(state,it0);
-                typedef typename reverse_iter_fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,it1);
-                typedef typename reverse_iter_fold_lvalue_state<State2,It2,F>::type State3;
-                State3 const state3=f(state2,it2);
                 return unrolled_reverse_iter_fold<
                     Result
                   , N-4
@@ -59,47 +35,87 @@ namespace boost { namespace fusion
                     fusion::prior(it3),
                     f);
             }
-        };
+            template<typename State2, typename It2, typename F>
-        template<typename Result>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-        struct unrolled_reverse_iter_fold<Result,3>
+            static Result
-        {
+            call_2(State2 const& state2,It2 const& it2,F& f)
+            {
+                return call_3(
+                    f(state2,it2),
+                    fusion::prior(it2),
+                    f);
+            }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,it1),
+                    fusion::prior(it1),
+                    f);
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename
+                return call_1(
-                    result_of::prior<
+                    f(state,it0),
-                        It0 const
+                    fusion::prior(it0),
-                    >::type
+                    f);
-                It1;
+            }
-                It1 it1 = fusion::prior(it0);
+        };
-                typedef typename
+        template<typename Result>
-                    result_of::prior<
+        struct unrolled_reverse_iter_fold<Result,3>
-                        It1
+        {
-                    >::type
+            template<typename State2, typename It2, typename F>
-                It2;
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-                It2 it2 = fusion::prior(it1);
+            static Result
-                typedef typename reverse_iter_fold_lvalue_state<State,It0,F>::type State1;
+            call_2(State2 const& state2,It2 const& it2,F& f)
-                State1 const state1=f(state,it0);
+            {
-                typedef typename reverse_iter_fold_lvalue_state<State1,It1,F>::type State2;
-                State2 const state2=f(state1,it1);
                 return f(state2,it2);
             }
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return call_2(
+                    f(state1,it1),
+                    fusion::prior(it1),
+                    f);
+            }
+            template<typename State, typename It0, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call(State const& state,It0 const& it0,F f)
+            {
+                return call_1(
+                    f(state,it0),
+                    fusion::prior(it0),
+                    f);
+            }
         };
         template<typename Result>
         struct unrolled_reverse_iter_fold<Result,2>
         {
+            template<typename State1, typename It1, typename F>
+            BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+            static Result
+            call_1(State1 const& state1,It1 const& it1,F& f)
+            {
+                return f(state1,it1);
+            }
             template<typename State, typename It0, typename F>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             static Result
             call(State const& state,It0 const& it0,F f)
             {
-                typedef typename reverse_iter_fold_lvalue_state<State,It0,F>::type State1;
+                return call_1(
-                State1 const state1=f(state,it0);
+                    f(state,it0),
-                return f(
+                    fusion::prior(it0),
-                    state1,
+                    f);
-                    fusion::prior(it0));
             }
         };
         template<typename Result>