diff options
Diffstat (limited to 'boost/bimap/relation/support/member_with_tag.hpp')
| -rw-r--r-- | boost/bimap/relation/support/member_with_tag.hpp | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/boost/bimap/relation/support/member_with_tag.hpp b/boost/bimap/relation/support/member_with_tag.hpp new file mode 100644 index 0000000000..a8324ff281 --- /dev/null +++ b/boost/bimap/relation/support/member_with_tag.hpp @@ -0,0 +1,180 @@ +// 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 relation/support/member_with_tag.hpp +/// \brief member_with_tag<tag,relation> metafunction + +#ifndef BOOST_BIMAP_RELATION_SUPPORT_MEMBER_WITH_TAG_HPP +#define BOOST_BIMAP_RELATION_SUPPORT_MEMBER_WITH_TAG_HPP + +#if defined(_MSC_VER) && (_MSC_VER>=1200) +#pragma once +#endif + +#include <boost/config.hpp> + +#include <boost/bimap/relation/member_at.hpp> +#include <boost/bimap/detail/debug/static_error.hpp> +#include <boost/utility/enable_if.hpp> +#include <boost/type_traits/is_same.hpp> +#include <boost/mpl/bool.hpp> +#include <boost/mpl/not.hpp> +#include <boost/mpl/and.hpp> + +/** \struct boost::bimaps::relation::support::member_with_tag + +\brief Metafunction to convert user tags to the member_at idiom. + +\code + +template< class Tag, class Relation > +struct member_with_tag +{ + typedef member_at::{side} type; +}; + +\endcode + +We have to allow that all the metafunctions that works with tags +and retrieves data from a Relation will work with member_at idiom +even if the type was tagged. This will be great for the user, +because he can choose to tag a member after he is using the +relation and the code will still work. + +If we perform this check in every metafunction it will be very +tedious and error prone, so instead of that all metafunctions +that works with relations first call this metafunction that +convert the tag to a member_at tag. + +See also member_at, is_tag_of_member_at_left, is_tag_of_member_at_right. +\ingroup relation_group + **/ + +#ifndef BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +namespace boost { +namespace bimaps { +namespace relation { +namespace support { + +template +< + class Tag, + class Relation, + class Enable = void +> +struct member_with_tag +{ + BOOST_BIMAP_STATIC_ERROR( MEMBER_WITH_TAG_FAILURE, (Relation,Tag) ); +}; + +template< class Relation > +struct member_with_tag +< + member_at::left, Relation, void +> +{ + typedef member_at::left type; +}; + +template< class Relation > +struct member_with_tag +< + member_at::right, Relation, void +> +{ + typedef member_at::right type; +}; + +template< class Relation > +struct member_with_tag +< + member_at::info, Relation, void +> +{ + typedef member_at::info type; +}; + + +template< class Tag, class Relation > +struct member_with_tag +< + Tag, Relation, + BOOST_DEDUCED_TYPENAME enable_if + < + mpl::and_ + < + mpl::not_< is_same<Tag,member_at::left> >, + is_same + < + Tag, + BOOST_DEDUCED_TYPENAME Relation::left_tag + > + > + + >::type +> +{ + typedef member_at::left type; +}; + +template< class Tag, class Relation > +struct member_with_tag +< + Tag, + Relation, + BOOST_DEDUCED_TYPENAME enable_if + < + mpl::and_ + < + mpl::not_< is_same<Tag,member_at::right> >, + is_same + < + Tag, + BOOST_DEDUCED_TYPENAME Relation::right_tag + > + > + + >::type +> +{ + typedef member_at::right type; +}; + +template< class Tag, class Relation > +struct member_with_tag +< + Tag, Relation, + BOOST_DEDUCED_TYPENAME enable_if + < + mpl::and_ + < + mpl::not_< is_same<Tag,member_at::info> >, + is_same + < + Tag, + BOOST_DEDUCED_TYPENAME Relation::info_tag + > + > + + >::type +> +{ + typedef member_at::info type; +}; + +} // namespace support +} // namespace relation +} // namespace bimaps +} // namespace boost + +#endif // BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +#endif // BOOST_BIMAP_RELATION_SUPPORT_MEMBER_WITH_TAG_HPP + + |