boost/hana/fwd/members.hpp

   1 /*!
   2 @file
   3 Forward declares `boost::hana::members`.
   4
   5 @copyright Louis Dionne 2013-2017
   6 Distributed under the Boost Software License, Version 1.0.
   7 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   8  */
   9
  10 #ifndef BOOST_HANA_FWD_MEMBERS_HPP
  11 #define BOOST_HANA_FWD_MEMBERS_HPP
  12
  13 #include <boost/hana/config.hpp>
  14 #include <boost/hana/core/when.hpp>
  15
  16
  17 BOOST_HANA_NAMESPACE_BEGIN
  18     //! Returns a `Sequence` containing the members of a `Struct`.
  19     //! @ingroup group-Struct
  20     //!
  21     //! Given a `Struct` object, `members` returns a `Sequence` containing
  22     //! all the members of the `Struct`, in the same order as their respective
  23     //! accessor appears in the `accessors` sequence.
  24     //!
  25     //!
  26     //! Example
  27     //! -------
  28     //! @include example/members.cpp
  29 #ifdef BOOST_HANA_DOXYGEN_INVOKED
  30     constexpr auto members = [](auto&& object) {
  31         return tag-dispatched;
  32     };
  33 #else
  34     template <typename S, typename = void>
  35     struct members_impl : members_impl<S, when<true>> { };
  36
  37     struct members_t {
  38         template <typename Object>
  39         constexpr auto operator()(Object&& object) const;
  40     };
  41
  42     constexpr members_t members{};
  43 #endif
  44 BOOST_HANA_NAMESPACE_END
  45
  46 #endif // !BOOST_HANA_FWD_MEMBERS_HPP