diff options
Diffstat (limited to 'boost/bimap/tags/support/value_type_of.hpp')
-rw-r--r-- | boost/bimap/tags/support/value_type_of.hpp | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/boost/bimap/tags/support/value_type_of.hpp b/boost/bimap/tags/support/value_type_of.hpp new file mode 100644 index 0000000000..a4ea82814c --- /dev/null +++ b/boost/bimap/tags/support/value_type_of.hpp @@ -0,0 +1,74 @@ +// 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/value_type_of.hpp +/// \brief Consistent way to access the value type of a tagged or untagged type. + +#ifndef BOOST_BIMAP_TAGS_SUPPORT_VALUE_TYPE_OF_HPP +#define BOOST_BIMAP_TAGS_SUPPORT_VALUE_TYPE_OF_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::value_type_of +\brief Metafunction to work with tagged and untagged type uniformly + +\code +template< class Type > +struct value_type_of +{ + typedef {UntaggedType} type; +}; +\endcode + +If the type is tagged this metafunction returns Type::value_type, and if it is not +tagged it return the same type. This allows to work consistenly with tagged and +untagged types. + +See also tagged, tag_of. + **/ + +#ifndef BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + + +namespace boost { +namespace bimaps { +namespace tags { +namespace support { + + +// value_type_of metafunction + +template< class Type > +struct value_type_of +{ + typedef Type type; +}; + +template< class Type, class Tag > +struct value_type_of< tagged< Type, Tag > > +{ + typedef Type type; +}; + + +} // namespace support +} // namespace tags +} // namespace bimaps +} // namespace boost + +#endif // BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES + +#endif // BOOST_BIMAP_TAGS_SUPPORT_VALUE_TYPE_OF_HPP + + |