Imported Upstream version 1.51.0upstream/1.51.0

1 files changed, 30 insertions, 1 deletions

diff --git a/boost/spirit/home/qi/detail/assign_to.hpp b/boost/spirit/home/qi/detail/assign_to.hpp
index a94010ca91..38142bf1b3 100644
--- a/boost/spirit/home/qi/detail/assign_to.hpp
+++ b/boost/spirit/home/qi/detail/assign_to.hpp
@@ -28,11 +28,25 @@ namespace boost { namespace spirit { namespace traits
     //  accept spirit's unused_type; all no-ops. Compiler optimization will
     //  easily strip these away.
     ///////////////////////////////////////////////////////////////////////////
+    namespace detail
+    {
+        template <typename T>
+        struct is_iter_range : mpl::false_ {};
+
+        template <typename I>
+        struct is_iter_range<boost::iterator_range<I> > : mpl::true_ {};
+
+        template <typename C>
+        struct is_container_of_ranges
+          : is_iter_range<typename C::value_type> {};
+    }
+
     template <typename Attribute, typename Iterator, typename Enable>
     struct assign_to_attribute_from_iterators
     {
+        // Common case
         static void
-        call(Iterator const& first, Iterator const& last, Attribute& attr)
+        call(Iterator const& first, Iterator const& last, Attribute& attr, mpl::false_)
         {
             if (traits::is_empty(attr))
                 attr = Attribute(first, last);
@@ -41,6 +55,21 @@ namespace boost { namespace spirit { namespace traits
                     push_back(attr, *i);
             }
         }
+
+        // If Attribute is a container with value_type==iterator_range<T> just push the
+        // iterator_range into it
+        static void
+        call(Iterator const& first, Iterator const& last, Attribute& attr, mpl::true_)
+        {
+            typename Attribute::value_type rng(first, last);
+            push_back(attr, rng);
+        }
+
+        static void
+        call(Iterator const& first, Iterator const& last, Attribute& attr)
+        {
+            call(first, last, attr, detail::is_container_of_ranges<Attribute>());
+        }
     };
 
     template <typename Attribute, typename Iterator>