[Boost-commit] svn:boost r74053 - trunk/boost/spirit/home/support

Subject: [Boost-commit] svn:boost r74053 - trunk/boost/spirit/home/support
From: hartmut.kaiser_at_[hidden]
Date: 2011-08-24 18:22:05

Author: hkaiser
Date: 2011-08-24 18:22:04 EDT (Wed, 24 Aug 2011)
New Revision: 74053
URL: http://svn.boost.org/trac/boost/changeset/74053

Log:
Spirit: adding attribute collapsing for optional<optional<>>
Text files modified: 
   trunk/boost/spirit/home/support/attributes.hpp |     8 +++++++-                                
   1 files changed, 7 insertions(+), 1 deletions(-)

Modified: trunk/boost/spirit/home/support/attributes.hpp
==============================================================================
--- trunk/boost/spirit/home/support/attributes.hpp	(original)
+++ trunk/boost/spirit/home/support/attributes.hpp	2011-08-24 18:22:04 EDT (Wed, 24 Aug 2011)
@@ -119,7 +119,7 @@
 
 //        // An exposed attribute is a weak substitute for a supplied container
 //        // attribute if it is a weak substitute for its value_type. This is
-//        // true as all character parsers exposing compatible with a container
+//        // true as all character parsers are compatible with a container
 //        // attribute having the corresponding character type as its value_type.
 //        template <typename T, typename Expected>
 //        struct is_weak_substitute_for_value_type
@@ -604,6 +604,12 @@
         typedef boost::optional<T> type;
     };
 
+    template <typename T>
+    struct build_optional<boost::optional<T> >
+    {
+        typedef boost::optional<T> type;
+    };
+
     template <>
     struct build_optional<unused_type>
     {