From 2aea153be0d56781866052a7948cc1979e1563a4 Mon Sep 17 00:00:00 2001
From: Kohei Takahashi <flast@flast.jp>
Date: Wed, 14 Mar 2018 14:53:07 +0900
Subject: [PATCH] Use fold expression to improbe compile speed

---
 include/boost/fusion/support/detail/and.hpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/boost/fusion/support/detail/and.hpp b/include/boost/fusion/support/detail/and.hpp
index 1b310dda..b45fb0e3 100644
--- a/include/boost/fusion/support/detail/and.hpp
+++ b/include/boost/fusion/support/detail/and.hpp
@@ -15,6 +15,7 @@
 #endif
 
 namespace boost { namespace fusion { namespace detail {
+#if defined(BOOST_NO_CXX17_FOLD_EXPRESSIONS)
     template<typename ...Cond>
     struct and_impl : false_type {};
 
@@ -34,6 +35,10 @@ namespace boost { namespace fusion { namespace detail {
          recursive. */
     template<typename ...Cond>
     struct and_ : and_impl1<Cond::value...> {};
+#else
+    template <typename ...Cond>
+    struct and_ : integral_constant<bool, ((bool)Cond::value && ...)> {};
+#endif
 }}}
 
 #endif // FUSION_AND_07152016_1625