3 Defines `boost::hana::any_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_ANY_OF_HPP
11 #define BOOST_HANA_ANY_OF_HPP
13 #include <boost/hana/fwd/any_of.hpp>
15 #include <boost/hana/accessors.hpp>
16 #include <boost/hana/at.hpp>
17 #include <boost/hana/bool.hpp>
18 #include <boost/hana/concept/searchable.hpp>
19 #include <boost/hana/concept/sequence.hpp>
20 #include <boost/hana/concept/struct.hpp>
21 #include <boost/hana/config.hpp>
22 #include <boost/hana/core/dispatch.hpp>
23 #include <boost/hana/drop_front.hpp>
24 #include <boost/hana/first.hpp>
25 #include <boost/hana/front.hpp>
26 #include <boost/hana/functional/compose.hpp>
27 #include <boost/hana/if.hpp>
28 #include <boost/hana/is_empty.hpp>
29 #include <boost/hana/length.hpp>
34 BOOST_HANA_NAMESPACE_BEGIN
36 template <typename Xs, typename Pred>
37 constexpr auto any_of_t::operator()(Xs&& xs, Pred&& pred) const {
38 using S = typename hana::tag_of<Xs>::type;
39 using AnyOf = BOOST_HANA_DISPATCH_IF(any_of_impl<S>,
40 hana::Searchable<S>::value
43 #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
44 static_assert(hana::Searchable<S>::value,
45 "hana::any_of(xs, pred) requires 'xs' to be a Searchable");
48 return AnyOf::apply(static_cast<Xs&&>(xs), static_cast<Pred&&>(pred));
52 template <typename S, bool condition>
53 struct any_of_impl<S, when<condition>> : default_ {
54 template <typename ...Args>
55 static constexpr auto apply(Args&& ...) = delete;
59 struct any_of_impl<S, when<Sequence<S>::value>> {
61 template <std::size_t k, std::size_t Len>
62 struct any_of_helper {
63 template <typename Xs, typename Pred>
64 static constexpr auto apply(bool prev_cond, Xs&& xs, Pred&& pred) {
65 auto cond = hana::if_(pred(hana::at_c<k>(xs)), hana::true_c,
67 return prev_cond ? hana::true_c
68 : any_of_impl::any_of_helper<k + 1, Len>::apply(cond,
69 static_cast<Xs&&>(xs),
70 static_cast<Pred&&>(pred));
73 template <typename Xs, typename Pred>
74 static constexpr auto apply(hana::true_, Xs&&, Pred&&)
75 { return hana::true_c; }
77 template <typename Xs, typename Pred>
78 static constexpr auto apply(hana::false_, Xs&& xs, Pred&& pred) {
79 auto cond = hana::if_(pred(hana::at_c<k>(xs)), hana::true_c,
81 return any_of_impl::any_of_helper<k + 1, Len>::apply(cond,
82 static_cast<Xs&&>(xs),
83 static_cast<Pred&&>(pred));
87 template <std::size_t Len>
88 struct any_of_helper<Len, Len> {
89 template <typename Cond, typename Xs, typename Pred>
90 static constexpr auto apply(Cond cond, Xs&&, Pred&&)
94 template <typename Xs, typename Pred>
95 static constexpr auto apply(Xs&& xs, Pred&& pred) {
96 constexpr std::size_t len = decltype(hana::length(xs))::value;
97 return any_of_impl::any_of_helper<0, len>::apply(hana::false_c,
98 static_cast<Xs&&>(xs),
99 static_cast<Pred&&>(pred));
104 template <typename It>
105 struct any_of_impl<It, when<
106 hana::Iterable<It>::value &&
109 template <typename Xs, typename Pred>
110 static constexpr auto lazy_any_of_helper(hana::false_, bool prev_cond, Xs&& xs, Pred&& pred) {
111 auto cond = hana::if_(pred(hana::front(xs)), hana::true_c, hana::false_c);
112 decltype(auto) tail = hana::drop_front(static_cast<Xs&&>(xs));
113 constexpr bool done = decltype(hana::is_empty(tail))::value;
114 return prev_cond ? hana::true_c
115 : lazy_any_of_helper(hana::bool_c<done>, cond,
116 static_cast<decltype(tail)&&>(tail),
117 static_cast<Pred&&>(pred));
120 template <typename Xs, typename Pred>
121 static constexpr auto lazy_any_of_helper(hana::false_, hana::true_, Xs&&, Pred&&)
122 { return hana::true_c; }
124 template <typename Xs, typename Pred>
125 static constexpr auto lazy_any_of_helper(hana::false_, hana::false_, Xs&& xs, Pred&& pred) {
126 auto cond = hana::if_(pred(hana::front(xs)), hana::true_c, hana::false_c);
127 constexpr bool done = decltype(hana::is_empty(hana::drop_front(xs)))::value;
128 return lazy_any_of_helper(hana::bool_c<done>, cond,
129 hana::drop_front(static_cast<Xs&&>(xs)),
130 static_cast<Pred&&>(pred));
133 template <typename Cond, typename Xs, typename Pred>
134 static constexpr auto lazy_any_of_helper(hana::true_, Cond cond, Xs&&, Pred&&)
137 template <typename Xs, typename Pred>
138 static constexpr auto apply(Xs&& xs, Pred&& pred) {
139 constexpr bool done = decltype(hana::is_empty(xs))::value;
140 return lazy_any_of_helper(hana::bool_c<done>, hana::false_c,
141 static_cast<Xs&&>(xs),
142 static_cast<Pred&&>(pred));
146 template <typename T, std::size_t N>
147 struct any_of_impl<T[N]> {
148 template <typename Xs, typename Pred>
149 static constexpr bool any_of_helper(bool cond, Xs&& xs, Pred&& pred) {
150 if (cond) return true;
151 for (std::size_t i = 1; i < N; ++i)
152 if (pred(static_cast<Xs&&>(xs)[i]))
157 // Since an array contains homogeneous data, if the predicate returns
158 // a compile-time logical at any index, it must do so at every index
159 // (because the type of the elements won't change)! In this case, we
160 // then only need to evaluate the predicate on the first element.
161 template <typename Xs, typename Pred>
162 static constexpr auto
163 any_of_helper(hana::true_, Xs&& /*xs*/, Pred&&)
164 { return hana::true_c; }
166 template <typename Xs, typename Pred>
167 static constexpr auto
168 any_of_helper(hana::false_, Xs&&, Pred&&)
169 { return hana::false_c; }
171 template <typename Xs, typename Pred>
172 static constexpr auto apply(Xs&& xs, Pred&& pred) {
173 auto cond = hana::if_(pred(static_cast<Xs&&>(xs)[0]), hana::true_c,
175 return any_of_helper(cond, static_cast<Xs&&>(xs),
176 static_cast<Pred&&>(pred));
180 template <typename S>
181 struct any_of_impl<S, when<hana::Struct<S>::value>> {
182 template <typename X, typename Pred>
183 static constexpr decltype(auto) apply(X const&, Pred&& pred) {
184 return hana::any_of(hana::accessors<S>(),
185 hana::compose(static_cast<Pred&&>(pred), hana::first));
188 BOOST_HANA_NAMESPACE_END
190 #endif // !BOOST_HANA_ANY_OF_HPP