Add boost::icl::interval_map

boost/mpl/tag.hpp

@@ -0,0 +1,52 @@
+
+#ifndef BOOST_MPL_TAG_HPP_INCLUDED
+#define BOOST_MPL_TAG_HPP_INCLUDED
+
+// Copyright Aleksey Gurtovoy 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.
+
+// $Id$
+// $Date$
+// $Revision$
+
+#include <boost/mpl/eval_if.hpp>
+#include <boost/mpl/void.hpp>
+#include <boost/mpl/aux_/has_tag.hpp>
+#include <boost/mpl/aux_/config/eti.hpp>
+
+namespace boost { namespace mpl {
+
+namespace aux {
+template< typename T > struct tag_impl
+{
+    typedef typename T::tag type;
+};
+}
+
+template< typename T, typename Default = void_ > struct tag
+#if !defined(BOOST_MPL_CFG_MSVC_ETI_BUG)
+    : if_< 
+          aux::has_tag<T>
+        , aux::tag_impl<T>
+        , Default
+        >::type
+{
+#else
+{
+    typedef typename eval_if< 
+          aux::has_tag<T>
+        , aux::tag_impl<T>
+        , Default
+        >::type type;
+
+#endif
+};
+
+}}
+
+#endif // BOOST_MPL_TAG_HPP_INCLUDED