From a447303946427f89914f4911fc8e9c3d7125c39c Mon Sep 17 00:00:00 2001
From: Aleksey Gurtovoy <agurtovoy@meta-comm.com>
Date: Sat, 13 Nov 2004 20:19:44 +0000
Subject: [PATCH] empty_sequence checkin

[SVN r26201]
---
 include/boost/mpl/empty_sequence.hpp | 42 ++++++++++++++++++++++++++++
 test/empty_sequence.cpp              | 36 ++++++++++++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 include/boost/mpl/empty_sequence.hpp
 create mode 100644 test/empty_sequence.cpp

diff --git a/include/boost/mpl/empty_sequence.hpp b/include/boost/mpl/empty_sequence.hpp
new file mode 100644
index 0000000..be4113b
--- /dev/null
+++ b/include/boost/mpl/empty_sequence.hpp
@@ -0,0 +1,42 @@
+
+#ifndef BOOST_MPL_EMPTY_SEQUENCE_HPP_INCLUDED
+#define BOOST_MPL_EMPTY_SEQUENCE_HPP_INCLUDED
+
+// Copyright Aleksey Gurtovoy 2004
+// Copyright Alexander Nasonov 2004
+//
+// Distributed under the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at 
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/mpl for documentation.
+
+// $Source$
+// $Date$
+// $Revision$
+
+#include <boost/mpl/size_fwd.hpp>
+#include <boost/mpl/int.hpp>
+#include <boost/mpl/iterator_tags.hpp>
+
+namespace boost { namespace mpl {
+
+struct empty_sequence
+{
+    struct tag; 
+    struct begin { typedef random_access_iterator_tag category; };    
+    typedef begin end;
+};
+
+template<>
+struct size_impl<empty_sequence::tag>
+{
+    template< typename Sequence > struct apply
+        : int_<0>
+    {
+    };
+};
+
+}}
+
+#endif // #ifndef BOOST_MPL_EMPTY_SEQUENCE_HPP_INCLUDED
diff --git a/test/empty_sequence.cpp b/test/empty_sequence.cpp
new file mode 100644
index 0000000..7332a14
--- /dev/null
+++ b/test/empty_sequence.cpp
@@ -0,0 +1,36 @@
+
+// Copyright Aleksey Gurtovoy 2004
+// Copyright Alexander Nasonov 2004
+//
+// Distributed under the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at 
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/mpl for documentation.
+
+// $Source$
+// $Date$
+// $Revision$
+
+#include <boost/mpl/empty_sequence.hpp>
+#include <boost/mpl/size.hpp>
+#include <boost/mpl/distance.hpp>
+#include <boost/mpl/advance.hpp>
+#include <boost/mpl/begin_end.hpp>
+#include <boost/mpl/aux_/test.hpp>
+
+#include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/add_pointer.hpp>
+
+MPL_TEST_CASE()
+{
+    typedef begin<empty_sequence>::type begin;
+    typedef end<empty_sequence>::type end;
+
+    MPL_ASSERT(( is_same<begin,end> ));
+    MPL_ASSERT_RELATION( (mpl::distance<begin,end>::value), ==, 0 );
+    MPL_ASSERT_RELATION( size<empty_sequence>::value, ==, 0 );
+
+    typedef advance_c<begin,0>::type advanced;
+    MPL_ASSERT(( is_same<advanced,end> ));
+}