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// 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

/// \file tags/support/default_tagged.hpp
/// \brief Weak tagging


#if defined(_MSC_VER)
#pragma once

#include <boost/config.hpp>

#include <boost/bimap/tags/tagged.hpp>

/** \struct boost::bimaps::tags::support::default_tagged
\brief Weak tagging metafunction

template< class Type, class Tag >
struct default_tagged
    typedef {TaggedType} type;

If the type is not tagged, this metafunction returns a tagged type with the
default tag. If it is tagged, the returns the type unchanged.

See also tagged, overwrite_tagged.


namespace boost {
namespace bimaps {
namespace tags {
namespace support {

// Default Tagging
// A metafunction that create a tagged type with a default tag value.

template< class Type, class DefaultTag >
struct default_tagged
    typedef tagged<Type,DefaultTag> type;

template< class Type, class OldTag, class NewTag >
struct default_tagged< tagged< Type, OldTag >, NewTag >
    typedef tagged<Type,OldTag> type;

} // namespace support
} // namespace tags
} // namespace bimaps
} // namespace boost