From 1df7fc1dcad0023693cb4065fd1dcc851ae858d1 Mon Sep 17 00:00:00 2001
From: Kohei Takahashi <flast@flast.jp>
Date: Tue, 8 Sep 2015 13:59:48 +0900
Subject: [PATCH] Revert "Remove unnecessary overloads, state should always be
 const."

This reverts commit 9b77c26a24500a19612589ef54235f64ede41a40.

As discussed on github, the original code was wrong.
---
 .../algorithm/iteration/detail/fold.hpp       | 24 +++++++++++++++++++
 .../fusion/algorithm/iteration/fold_fwd.hpp   | 18 ++++++++++++++
 .../algorithm/iteration/iter_fold_fwd.hpp     | 18 ++++++++++++++
 .../algorithm/iteration/reverse_fold_fwd.hpp  | 18 ++++++++++++++
 .../iteration/reverse_iter_fold_fwd.hpp       | 18 ++++++++++++++
 5 files changed, 96 insertions(+)

diff --git a/include/boost/fusion/algorithm/iteration/detail/fold.hpp b/include/boost/fusion/algorithm/iteration/detail/fold.hpp
index 5c3ec765..22cb6ecd 100644
--- a/include/boost/fusion/algorithm/iteration/detail/fold.hpp
+++ b/include/boost/fusion/algorithm/iteration/detail/fold.hpp
@@ -194,6 +194,30 @@ namespace boost { namespace fusion
     {
         return detail::BOOST_FUSION_FOLD_NAME<Seq const, State const, F>(seq, state, f);
     }
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::BOOST_FUSION_FOLD_NAME<
+        Seq
+      , State const
+      , F
+    >::type
+    BOOST_FUSION_FOLD_NAME(Seq& seq, State& state, F f)
+    {
+        return detail::BOOST_FUSION_FOLD_NAME<Seq, State, F>(seq, state, f);
+    }
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::BOOST_FUSION_FOLD_NAME<
+        Seq const
+      , State const
+      , F
+    >::type
+    BOOST_FUSION_FOLD_NAME(Seq const& seq, State& state, F f)
+    {
+        return detail::BOOST_FUSION_FOLD_NAME<Seq const, State, F>(seq, state, f);
+    }
 }}
 
 #undef BOOST_FUSION_FOLD_NAME
diff --git a/include/boost/fusion/algorithm/iteration/fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/fold_fwd.hpp
index 06dd6dda..f8328e80 100644
--- a/include/boost/fusion/algorithm/iteration/fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/fold_fwd.hpp
@@ -33,6 +33,24 @@ namespace boost { namespace fusion
       , F
     >::type
     fold(Seq const& seq, State const& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::fold<
+        Seq
+      , State const
+      , F
+    >::type
+    fold(Seq& seq, State& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::fold<
+        Seq const
+      , State const
+      , F
+    >::type
+    fold(Seq const& seq, State& state, F f);
 }}
 
 #endif
diff --git a/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp
index e7b7f434..6c595cf1 100644
--- a/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/iter_fold_fwd.hpp
@@ -33,6 +33,24 @@ namespace boost { namespace fusion
       , F
     >::type
     iter_fold(Seq const& seq, State const& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::iter_fold<
+        Seq
+      , State const
+      , F
+    >::type
+    iter_fold(Seq& seq, State& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::iter_fold<
+        Seq const
+      , State const
+      , F
+    >::type
+    iter_fold(Seq const& seq, State& state, F f);
 }}
 
 #endif
diff --git a/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp
index f1dd8ac7..42c8ac21 100644
--- a/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/reverse_fold_fwd.hpp
@@ -33,6 +33,24 @@ namespace boost { namespace fusion
       , F
     >::type
     reverse_fold(Seq const& seq, State const& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::reverse_fold<
+        Seq
+      , State const
+      , F
+    >::type
+    reverse_fold(Seq& seq, State& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::reverse_fold<
+        Seq const
+      , State const
+      , F
+    >::type
+    reverse_fold(Seq const& seq, State& state, F f);
 }}
 
 #endif
diff --git a/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp b/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp
index 6a60931d..21d99dee 100644
--- a/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp
+++ b/include/boost/fusion/algorithm/iteration/reverse_iter_fold_fwd.hpp
@@ -33,6 +33,24 @@ namespace boost { namespace fusion
       , F
     >::type
     reverse_iter_fold(Seq const& seq, State const& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::reverse_iter_fold<
+        Seq
+      , State const
+      , F
+    >::type
+    reverse_iter_fold(Seq& seq, State& state, F f);
+
+    template<typename Seq, typename State, typename F>
+    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
+    inline typename result_of::reverse_iter_fold<
+        Seq const
+      , State const
+      , F
+    >::type
+    reverse_iter_fold(Seq const& seq, State& state, F f);
 }}
 
 #endif