ceph/src/boost/boost/hana/fwd/and.hpp

   1 /*!
   2 @file
   3 Forward declares `boost::hana::and_`.
   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_AND_HPP
  11 #define BOOST_HANA_FWD_AND_HPP
  12
  13 #include <boost/hana/config.hpp>
  14 #include <boost/hana/core/when.hpp>
  15
  16
  17 namespace boost { namespace hana {
  18     //! Return whether all the arguments are true-valued.
  19     //! @ingroup group-Logical
  20     //!
  21     //! `and_` can be called with one argument or more. When called with
  22     //! two arguments, `and_` uses tag-dispatching to find the right
  23     //! implementation. Otherwise,
  24     //! @code
  25     //!     and_(x) == x
  26     //!     and_(x, y, ...z) == and_(and_(x, y), z...)
  27     //! @endcode
  28     //!
  29     //!
  30     //! Example
  31     //! -------
  32     //! @include example/and.cpp
  33 #ifdef BOOST_HANA_DOXYGEN_INVOKED
  34     constexpr auto and_ = [](auto&& x, auto&& ...y) -> decltype(auto) {
  35         return tag-dispatched;
  36     };
  37 #else
  38     template <typename L, typename = void>
  39     struct and_impl : and_impl<L, when<true>> { };
  40
  41     struct and_t {
  42         template <typename X, typename Y>
  43         constexpr decltype(auto) operator()(X&& x, Y&& y) const;
  44
  45         template <typename X, typename ...Y>
  46         constexpr decltype(auto) operator()(X&& x, Y&& ...y) const;
  47     };
  48
  49     BOOST_HANA_INLINE_VARIABLE constexpr and_t and_{};
  50 #endif
  51 }} // end namespace boost::hana
  52
  53 #endif // !BOOST_HANA_FWD_AND_HPP