tag dispatch

Kojoley · Feb 26, 2018 · 8b76132 · 8b76132
1 parent 8b93d42
commit 8b76132
Showing 1 changed file with 7 additions and 9 deletions.
diff --git a/include/boost/spirit/home/x3/operator/detail/sequence.hpp b/include/boost/spirit/home/x3/operator/detail/sequence.hpp
@@ -392,26 +392,24 @@ namespace boost { namespace spirit { namespace x3 { namespace detail
       , traits::container_attribute);
 
     template <typename Parser, typename Context>
-    constexpr bool should_sequence_proxy = sequence_size<Parser, Context>::value > 1;
+    using should_sequence_proxy = mpl::bool_<(sequence_size<Parser, Context>::value > 1)>;
 
     template <typename Parser, typename Iterator, typename Context
       , typename RContext, typename Attribute>
-    typename enable_if_c<should_sequence_proxy<Parser, Context>, bool>::type
-    parse_into_container_or_proxy(
+    bool parse_into_container_or_proxy(
         Parser const& parser
       , Iterator& first, Iterator const& last, Context const& context
-      , RContext& rcontext, Attribute& attr)
+      , RContext& rcontext, Attribute& attr, mpl::true_)
     {
         return parser.parse(first, last, context, rcontext, attr);
     }
 
     template <typename Parser, typename Iterator, typename Context
       , typename RContext, typename Attribute>
-    typename disable_if_c<should_sequence_proxy<Parser, Context>, bool>::type
-    parse_into_container_or_proxy(
+    bool parse_into_container_or_proxy(
         Parser const& parser
       , Iterator& first, Iterator const& last, Context const& context
-      , RContext& rcontext, Attribute& attr)
+      , RContext& rcontext, Attribute& attr, mpl::false_)
     {
         return parse_into_container(parser, first, last, context, rcontext, attr);
     }
@@ -424,8 +422,8 @@ namespace boost { namespace spirit { namespace x3 { namespace detail
       , traits::container_attribute)
     {
         Iterator save = first;
-        if (parse_into_container_or_proxy(parser.left, first, last, context, rcontext, attr)
-            && parse_into_container_or_proxy(parser.right, first, last, context, rcontext, attr))
+        if (parse_into_container_or_proxy(parser.left, first, last, context, rcontext, attr, should_sequence_proxy<Parser::left_type, Context>{})
+            && parse_into_container_or_proxy(parser.right, first, last, context, rcontext, attr, should_sequence_proxy<Parser::right_type, Context>{}))
             return true;
         first = save;
         return false;