--- /dev/null
+// Boost.Bimap
+//
+// Copyright (c) 2006-2007 Matias Capeletto
+//
+// 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)
+
+/// \file support/data_type_by.hpp
+/// \brief Metafunction to access the data types of a bimap
+
+#ifndef BOOST_BIMAP_SUPPORT_DATA_TYPE_BY_HPP
+#define BOOST_BIMAP_SUPPORT_DATA_TYPE_BY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER>=1200)
+#pragma once
+#endif
+
+#include <boost/config.hpp>
+
+#include <boost/bimap/relation/detail/metadata_access_builder.hpp>
+
+/** \struct boost::bimaps::support::data_type_by
+
+\brief Metafunction to obtain the data type of one of the sides in a bimap
+
+The tag parameter can be either a user defined tag or \c member_at::{side}.
+This is the actual data type stored in the bimap.
+\code
+
+template< class Tag, class Bimap >
+struct data_type_by
+{
+ typedef typename Bimap::{side}_data_type type;
+};
+
+\endcode
+
+The following holds:
+
+\code
+
+BOOST_STATIC_ASSERT
+(
+ is_same< data_type_by< member_at::left, bimap<A,B> >::type, A >::value
+)
+
+\endcode
+
+See also member_at.
+\ingroup bimap_group
+ **/
+
+namespace boost {
+namespace bimaps {
+namespace support {
+
+// Implementation of data type of metafunction
+
+BOOST_BIMAP_SYMMETRIC_METADATA_ACCESS_BUILDER
+(
+ data_type_by,
+ left_data_type,
+ right_data_type
+)
+
+} // namespace support
+} // namespace bimaps
+} // namespace boost
+
+
+#endif // BOOST_BIMAP_SUPPORT_DATA_TYPE_BY_HPP
+