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Diffstat (limited to 'boost/bimap/tags/support/tag_of.hpp')
-rw-r--r-- | boost/bimap/tags/support/tag_of.hpp | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/boost/bimap/tags/support/tag_of.hpp b/boost/bimap/tags/support/tag_of.hpp new file mode 100644 index 0000000000..413703b41c --- /dev/null +++ b/boost/bimap/tags/support/tag_of.hpp @@ -0,0 +1,75 @@ +// 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/tag_of.hpp +/// \brief Safe way to acces the tag of a type + +#ifndef BOOST_BIMAP_TAGS_SUPPORT_TAG_OF_HPP +#define BOOST_BIMAP_TAGS_SUPPORT_TAG_OF_HPP + +#if defined(_MSC_VER) && (_MSC_VER>=1200) +#pragma once +#endif + +#include <boost/config.hpp> + +#include <boost/bimap/tags/tagged.hpp> +#include <boost/bimap/detail/debug/static_error.hpp> + +/** \struct boost::bimaps::tags::support::tag_of +\brief Metafunction to obtain the tag of a type. + +\code +template< class TaggedType > +struct tag_of +{ + typedef {Tag} type; +}; +\endcode + +If the type is not tagged you will get a compile timer error with the following message: + +\verbatim +USING_TAG_OF_WITH_AN_UNTAGGED_TYPE, TaggedType +\endverbatim + +See also tagged, value_type_of. + **/ + +#ifndef BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +namespace boost { +namespace bimaps { +namespace tags { +namespace support { + + +// tag_of metafunction + +template< class Type > +struct tag_of +{ + BOOST_BIMAP_STATIC_ERROR( USING_TAG_OF_WITH_AN_UNTAGGED_TYPE, (Type) ); +}; + +template< class Type, class Tag > +struct tag_of< tagged< Type, Tag > > +{ + typedef Tag type; +}; + + +} // namespace support +} // namespace tags +} // namespace bimaps +} // namespace boost + +#endif // BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +#endif // BOOST_BIMAP_TAGS_SUPPORT_TAG_OF_HPP + |