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

   1 /*!
   2 @file
   3 Forward declares `boost::hana::fold`.
   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_FOLD_HPP
  11 #define BOOST_HANA_FWD_FOLD_HPP
  12
  13 #include <boost/hana/config.hpp>
  14 #include <boost/hana/fwd/fold_left.hpp>
  15
  16
  17 BOOST_HANA_NAMESPACE_BEGIN
  18     //! Equivalent to `fold_left`; provided for convenience.
  19     //! @ingroup group-Foldable
  20     //!
  21     //! `fold` is equivalent to `fold_left`. However, it is not tag-dispatched
  22     //! on its own because it is just an alias to `fold_left`. Also note that
  23     //! `fold` can be called with or without an initial state, just like
  24     //! `fold_left`:
  25     //!
  26     //! @code
  27     //!     fold(xs, state, f) == fold_left(xs, state, f)
  28     //!     fold(xs, f) == fold_left(xs, f)
  29     //! @endcode
  30     //!
  31     //!
  32     //! Example
  33     //! -------
  34     //! @include example/fold.cpp
  35     constexpr auto fold = fold_left;
  36 BOOST_HANA_NAMESPACE_END
  37
  38 #endif // !BOOST_HANA_FWD_FOLD_HPP