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Diffstat (limited to 'boost/bimap/tags/support/default_tagged.hpp')
-rw-r--r-- | boost/bimap/tags/support/default_tagged.hpp | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/boost/bimap/tags/support/default_tagged.hpp b/boost/bimap/tags/support/default_tagged.hpp new file mode 100644 index 0000000000..4c02a65952 --- /dev/null +++ b/boost/bimap/tags/support/default_tagged.hpp @@ -0,0 +1,73 @@ +// 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 tags/support/default_tagged.hpp +/// \brief Weak tagging + +#ifndef BOOST_BIMAP_TAGS_SUPPORT_DEFAULT_TAGGED_HPP +#define BOOST_BIMAP_TAGS_SUPPORT_DEFAULT_TAGGED_HPP + +#if defined(_MSC_VER) && (_MSC_VER>=1200) +#pragma once +#endif + +#include <boost/config.hpp> + +#include <boost/bimap/tags/tagged.hpp> + +/** \struct boost::bimaps::tags::support::default_tagged +\brief Weak tagging metafunction + +\code +template< class Type, class Tag > +struct default_tagged +{ + typedef {TaggedType} type; +}; +\endcode + +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. + **/ + +#ifndef BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +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 + +#endif // BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +#endif // BOOST_BIMAP_TAGS_SUPPORT_DEFAULT_TAGGED_HPP + + + |