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

   1 /*!
   2 @file
   3 Forward declares `boost::hana::replace_if`.
   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_REPLACE_IF_HPP
  11 #define BOOST_HANA_FWD_REPLACE_IF_HPP
  12
  13 #include <boost/hana/config.hpp>
  14 #include <boost/hana/core/when.hpp>
  15
  16
  17 BOOST_HANA_NAMESPACE_BEGIN
  18     //! Replace all the elements of a structure satisfying a `predicate`
  19     //! with a fixed value.
  20     //! @ingroup group-Functor
  21     //!
  22     //!
  23     //! Signature
  24     //! ---------
  25     //! Given `F` a Functor and `Bool` a Logical, the signature is
  26     //! \f$
  27     //!     \mathtt{replace\_if} : F(T) \times (T \to Bool) \times T \to F(T)
  28     //! \f$
  29     //!
  30     //! @param xs
  31     //! The structure to replace elements of.
  32     //!
  33     //! @param predicate
  34     //! A function called as `predicate(x)` for element(s) `x` of the
  35     //! structure and returning a `Logical` representing whether `x`
  36     //! should be replaced by `value`.
  37     //!
  38     //! @param value
  39     //! A value by which every element `x` of the structure for which
  40     //! `predicate` returns a true-valued `Logical` is replaced.
  41     //!
  42     //!
  43     //! Example
  44     //! -------
  45     //! @include example/replace_if.cpp
  46 #ifdef BOOST_HANA_DOXYGEN_INVOKED
  47     constexpr auto replace_if = [](auto&& xs, auto&& predicate, auto&& value) {
  48         return tag-dispatched;
  49     };
  50 #else
  51     template <typename Xs, typename = void>
  52     struct replace_if_impl : replace_if_impl<Xs, when<true>> { };
  53
  54     struct replace_if_t {
  55         template <typename Xs, typename Pred, typename Value>
  56         constexpr auto operator()(Xs&& xs, Pred&& pred, Value&& value) const;
  57     };
  58
  59     constexpr replace_if_t replace_if{};
  60 #endif
  61 BOOST_HANA_NAMESPACE_END
  62
  63 #endif // !BOOST_HANA_FWD_REPLACE_IF_HPP