3 Forward declares `boost::hana::none_of`.
5 @copyright Louis Dionne 2013-2016
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)
10 #ifndef BOOST_HANA_FWD_NONE_OF_HPP
11 #define BOOST_HANA_FWD_NONE_OF_HPP
13 #include <boost/hana/config.hpp>
14 #include <boost/hana/core/when.hpp>
17 BOOST_HANA_NAMESPACE_BEGIN
18 //! Returns whether none of the keys of the structure satisfy the
20 //! @ingroup group-Searchable
22 //! If the structure is not finite, `predicate` has to return a true-
23 //! valued `Logical` after looking at a finite number of keys for this
28 //! The structure to search.
31 //! A function called as `predicate(k)`, where `k` is a key of the
32 //! structure, and returning a `Logical`.
37 //! @include example/none_of.cpp
38 #ifdef BOOST_HANA_DOXYGEN_INVOKED
39 constexpr auto none_of = [](auto&& xs, auto&& predicate) {
40 return tag-dispatched;
43 template <typename S, typename = void>
44 struct none_of_impl : none_of_impl<S, when<true>> { };
47 template <typename Xs, typename Pred>
48 constexpr auto operator()(Xs&& xs, Pred&& pred) const;
51 constexpr none_of_t none_of{};
53 BOOST_HANA_NAMESPACE_END
55 #endif // !BOOST_HANA_FWD_NONE_OF_HPP