detail/operators/adl.hpp

0001 /*!
0002 @file
0003 Defines `boost::hana::detail::operators::adl`.
0004
0005 Copyright Louis Dionne 2013-2022
0006 Distributed under the Boost Software License, Version 1.0.
0007 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
0008  */
0009
0010 #ifndef BOOST_HANA_DETAIL_OPERATORS_ADL_HPP
0011 #define BOOST_HANA_DETAIL_OPERATORS_ADL_HPP
0012
0013 #include <boost/hana/config.hpp>
0014
0015
0016 namespace boost { namespace hana { namespace detail { namespace operators {
0017     //! @ingroup group-details
0018     //! Enables [ADL](http://en.cppreference.com/w/cpp/language/adl) in the
0019     //! `hana::detail::operators` namespace.
0020     //!
0021     //! This is used by containers in Hana as a quick way to automatically
0022     //! define the operators associated to some concepts, in conjunction
0023     //! with the `detail::xxx_operators` family of metafunctions.
0024     //!
0025     //! Note that `adl` can be passed template arguments to make it unique
0026     //! amongst a set of derived classes. This allows a set of derived classes
0027     //! not to possess a common base class, which would disable the EBO when
0028     //! many of these derived classes are stored in a Hana container. If EBO
0029     //! is not a concern, `adl<>` can simply be used.
0030     template <typename ...>
0031     struct adl { };
0032 }} }} // end namespace boost::hana
0033
0034 #endif // !BOOST_HANA_DETAIL_OPERATORS_ADL_HPP