1 files changed, 7 insertions, 39 deletions

diff --git a/boost/spirit/home/x3/support/context.hpp b/boost/spirit/home/x3/support/context.hpp
index 93bcb24070..592ce3ff76 100644
--- a/boost/spirit/home/x3/support/context.hpp
+++ b/boost/spirit/home/x3/support/context.hpp
@@ -8,10 +8,6 @@
 #if !defined(BOOST_SPIRIT_X3_CONTEXT_JAN_4_2012_1215PM)
 #define BOOST_SPIRIT_X3_CONTEXT_JAN_4_2012_1215PM
 
-#if defined(_MSC_VER)
-#pragma once
-#endif
-
 #include <boost/spirit/home/x3/support/unused.hpp>
 #include <boost/mpl/identity.hpp>
 
@@ -23,26 +19,13 @@ namespace boost { namespace spirit { namespace x3
         context(T& val, Next const& next)
             : val(val), next(next) {}
 
-        template <typename ID_, typename Unused = void>
-        struct get_result
-        {
-            typedef typename Next::template get_result<ID_>::type type;
-        };
-
-        template <typename Unused>
-        struct get_result<mpl::identity<ID>, Unused>
-        {
-            typedef T& type;
-        };
-
         T& get(mpl::identity<ID>) const
         {
             return val;
         }
 
         template <typename ID_>
-        typename Next::template get_result<ID_>::type
-        get(ID_ id) const
+        decltype(auto) get(ID_ id) const
         {
             return next.get(id);
         }
@@ -60,37 +43,22 @@ namespace boost { namespace spirit { namespace x3
         context(T& val, unused_type)
             : val(val) {}
 
-        template <typename ID_, typename Unused = void>
-        struct get_result
-        {
-            typedef unused_type type;
-        };
-
-        template <typename Unused>
-        struct get_result<mpl::identity<ID>, Unused>
-        {
-            typedef T& type;
-        };
-
         T& get(mpl::identity<ID>) const
         {
             return val;
         }
 
         template <typename ID_>
-        unused_type
-        get(ID_) const
+        unused_type get(ID_) const
         {
-            return unused;
+            return {};
         }
 
         T& val;
     };
 
     template <typename Tag, typename Context>
-    inline auto
-    get(Context const& context)
-        -> decltype(context.get(mpl::identity<Tag>()))
+    inline decltype(auto) get(Context const& context)
     {
         return context.get(mpl::identity<Tag>());
     }
@@ -98,13 +66,13 @@ namespace boost { namespace spirit { namespace x3
     template <typename ID, typename T, typename Next>
     inline context<ID, T, Next> make_context(T& val, Next const& next)
     {
-        return context<ID, T, Next>(val, next);
+        return { val, next };
     }
 
     template <typename ID, typename T>
     inline context<ID, T> make_context(T& val)
     {
-        return context<ID, T>(val);
+        return { val };
     }
     
     namespace detail
@@ -120,7 +88,7 @@ namespace boost { namespace spirit { namespace x3
         inline context<ID, T, Next>
         make_unique_context(T& val, Next const& next, unused_type)
         {
-            return context<ID, T, Next>(val, next);
+            return { val, next };
         }
     }