[Boost-commit] svn:boost r55388 - trunk/boost/spirit/home/karma/operator

Subject: [Boost-commit] svn:boost r55388 - trunk/boost/spirit/home/karma/operator
From: hartmut.kaiser_at_[hidden]
Date: 2009-08-03 11:48:35

Author: hkaiser
Date: 2009-08-03 11:48:33 EDT (Mon, 03 Aug 2009)
New Revision: 55388
URL: http://svn.boost.org/trac/boost/changeset/55388

Log:
Spirit: fixed karma alternative generator properties
Text files modified: 
   trunk/boost/spirit/home/karma/operator/alternative.hpp |    31 ++++++++++++++++++++++++++++++-         
   1 files changed, 30 insertions(+), 1 deletions(-)

Modified: trunk/boost/spirit/home/karma/operator/alternative.hpp
==============================================================================
--- trunk/boost/spirit/home/karma/operator/alternative.hpp	(original)
+++ trunk/boost/spirit/home/karma/operator/alternative.hpp	2009-08-03 11:48:33 EDT (Mon, 03 Aug 2009)
@@ -38,12 +38,41 @@
 }}
 
 ///////////////////////////////////////////////////////////////////////////////
+namespace boost { namespace spirit { namespace traits
+{
+    // specialization for sequences
+    template <typename Elements>
+    struct alternative_properties
+    {
+        struct element_properties
+        {
+            template <typename T>
+            struct result;
+
+            template <typename F, typename Element>
+            struct result<F(Element)>
+            {
+                typedef properties_of<Element> type;
+            };
+        };
+
+        typedef typename mpl::accumulate<
+            typename fusion::result_of::transform<
+                Elements, element_properties>::type
+          , mpl::int_<karma::generator_properties::countingbuffer>
+          , mpl::bitor_<mpl::_2, mpl::_1>
+        >::type type;
+    };
+
+}}}
+
 namespace boost { namespace spirit { namespace karma
 {
     template <typename Elements>
     struct alternative : nary_generator<alternative<Elements> >
     {
-        typedef mpl::int_<generator_properties::all_properties> properties;
+        typedef typename traits::alternative_properties<Elements>::type 
+            properties;
 
         template <typename Context, typename Unused = unused_type>
         struct attribute