[Boost-commit] svn:boost r59540 - in trunk/boost/spirit/home/karma: detail directive

Subject: [Boost-commit] svn:boost r59540 - in trunk/boost/spirit/home/karma: detail directive
From: hartmut.kaiser_at_[hidden]
Date: 2010-02-06 22:56:23

Author: hkaiser
Date: 2010-02-06 22:56:22 EST (Sat, 06 Feb 2010)
New Revision: 59540
URL: http://svn.boost.org/trac/boost/changeset/59540

Log:
Spirit: buffer[buffer[...]] does not result in double buffering anymore
Text files modified: 
   trunk/boost/spirit/home/karma/detail/alternative_function.hpp |    15 +++++++++++++++                         
   trunk/boost/spirit/home/karma/directive/buffer.hpp            |    11 +++++++++++                             
   2 files changed, 26 insertions(+), 0 deletions(-)

Modified: trunk/boost/spirit/home/karma/detail/alternative_function.hpp
==============================================================================
--- trunk/boost/spirit/home/karma/detail/alternative_function.hpp	(original)
+++ trunk/boost/spirit/home/karma/detail/alternative_function.hpp	2010-02-06 22:56:22 EST (Sat, 06 Feb 2010)
@@ -12,6 +12,7 @@
 #endif
 
 #include <boost/spirit/home/karma/domain.hpp>
+#include <boost/spirit/home/karma/directive/buffer.hpp>
 #include <boost/spirit/home/support/unused.hpp>
 #include <boost/spirit/home/support/attributes.hpp>
 #include <boost/spirit/home/support/detail/hold_any.hpp>
@@ -240,6 +241,20 @@
             return r;
         }
 
+        // avoid double buffering
+        template <typename Component>
+        bool operator()(buffer_directive<Component> const& component)
+        {
+            typedef typename 
+                traits::attribute_of<Component, Context>::type
+            expected_type;
+            typedef alternative_generate<
+                buffer_directive<Component>, Attribute, expected_type>
+            generate;
+
+            return generate::call(component, sink, ctx, delim, attr);
+        }
+
         OutputIterator& sink;
         Context& ctx;
         Delimiter const& delim;

Modified: trunk/boost/spirit/home/karma/directive/buffer.hpp
==============================================================================
--- trunk/boost/spirit/home/karma/directive/buffer.hpp	(original)
+++ trunk/boost/spirit/home/karma/directive/buffer.hpp	2010-02-06 22:56:22 EST (Sat, 06 Feb 2010)
@@ -97,6 +97,17 @@
         }
     };
 
+    // make sure buffer[buffer[...]] does not result in double buffering
+    template <typename Subject, typename Modifiers>
+    struct make_directive<tag::buffer, buffer_directive<Subject>, Modifiers>
+    {
+        typedef buffer_directive<Subject> result_type;
+        result_type operator()(unused_type
+          , buffer_directive<Subject> const& subject, unused_type) const
+        {
+            return subject;
+        }
+    };
 }}}
 
 namespace boost { namespace spirit { namespace traits