]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | /*! |
2 | @file | |
3 | Defines `boost::hana::detail::any_of`. | |
4 | ||
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) | |
8 | */ | |
9 | ||
10 | #ifndef BOOST_HANA_DETAIL_ANY_OF_HPP | |
11 | #define BOOST_HANA_DETAIL_ANY_OF_HPP | |
12 | ||
13 | #include <boost/hana/config.hpp> | |
14 | ||
15 | #include <type_traits> | |
16 | #include <utility> | |
17 | ||
18 | ||
19 | BOOST_HANA_NAMESPACE_BEGIN namespace detail { | |
20 | std::false_type expand(...); | |
21 | ||
22 | template <template <typename ...> class Predicate, typename ...T> | |
23 | decltype(expand( | |
24 | typename std::enable_if<!Predicate<T>::value, void*>::type{}... | |
25 | )) any_of_impl(int); | |
26 | ||
27 | template <template <typename ...> class Predicate, typename ...T> | |
28 | std::true_type any_of_impl(...); | |
29 | ||
30 | //! @ingroup group-details | |
31 | //! Returns whether the `Predicate` is satisfied by any of the `T...`. | |
32 | //! | |
33 | //! This metafunction will short-circuit the evaluation at the first | |
34 | //! type satisfying the predicate, if such a type exists. | |
35 | //! | |
36 | //! | |
37 | //! @note | |
38 | //! The implementation technique used here was originally shown to | |
39 | //! me by Eric Fiselier. All credits where due. | |
40 | template <template <typename ...> class Predicate, typename ...T> | |
41 | struct any_of | |
42 | : decltype(any_of_impl<Predicate, T...>(int{})) | |
43 | { }; | |
44 | } BOOST_HANA_NAMESPACE_END | |
45 | ||
46 | #endif // !BOOST_HANA_DETAIL_ANY_OF_HPP |