1/*!
2@file
3Defines `boost::hana::detail::variadic::split_at`.
4
5Copyright Louis Dionne 2013-2022
6Distributed 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_VARIADIC_SPLIT_AT_HPP
11#define BOOST_HANA_DETAIL_VARIADIC_SPLIT_AT_HPP
12
13#include <boost/hana/config.hpp>
14#include <boost/hana/functional/partial.hpp>
15#include <boost/hana/functional/reverse_partial.hpp>
16
17#include <cstddef>
18
19
20namespace boost { namespace hana { namespace detail { namespace variadic {
21 template <std::size_t n>
22 struct split_at_t {
23 template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename X7, typename X8, typename ...Xs>
24 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, X7&& x7, X8&& x8, Xs&& ...xs) const {
25 return split_at_t<n - 8>{}(
26 hana::partial(static_cast<F&&>(f),
27 static_cast<X1&&>(x1),
28 static_cast<X2&&>(x2),
29 static_cast<X3&&>(x3),
30 static_cast<X4&&>(x4),
31 static_cast<X5&&>(x5),
32 static_cast<X6&&>(x6),
33 static_cast<X7&&>(x7),
34 static_cast<X8&&>(x8)
35 ),
36 static_cast<Xs&&>(xs)...
37 );
38 }
39 };
40
41 template <>
42 struct split_at_t<0> {
43 template <typename F, typename ...Xs>
44 constexpr decltype(auto) operator()(F&& f, Xs&& ...xs) const {
45 return static_cast<F&&>(f)()(static_cast<Xs&&>(xs)...);
46 }
47 };
48
49 template <>
50 struct split_at_t<1> {
51 template <typename F, typename X1, typename ...Xs>
52 constexpr decltype(auto) operator()(F&& f, X1&& x1, Xs&& ...xs) const {
53 return static_cast<F&&>(f)(
54 static_cast<X1&&>(x1)
55 )(static_cast<Xs&&>(xs)...);
56 }
57 };
58
59 template <>
60 struct split_at_t<2> {
61 template <typename F, typename X1, typename X2, typename ...Xs>
62 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, Xs&& ...xs) const {
63 return static_cast<F&&>(f)(
64 static_cast<X1&&>(x1),
65 static_cast<X2&&>(x2)
66 )(static_cast<Xs&&>(xs)...);
67 }
68 };
69
70 template <>
71 struct split_at_t<3> {
72 template <typename F, typename X1, typename X2, typename X3, typename ...Xs>
73 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, Xs&& ...xs) const {
74 return static_cast<F&&>(f)(
75 static_cast<X1&&>(x1),
76 static_cast<X2&&>(x2),
77 static_cast<X3&&>(x3)
78 )(static_cast<Xs&&>(xs)...);
79 }
80 };
81
82 template <>
83 struct split_at_t<4> {
84 template <typename F, typename X1, typename X2, typename X3, typename X4, typename ...Xs>
85 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, Xs&& ...xs) const {
86 return static_cast<F&&>(f)(
87 static_cast<X1&&>(x1),
88 static_cast<X2&&>(x2),
89 static_cast<X3&&>(x3),
90 static_cast<X4&&>(x4)
91 )(static_cast<Xs&&>(xs)...);
92 }
93 };
94
95 template <>
96 struct split_at_t<5> {
97 template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename ...Xs>
98 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, Xs&& ...xs) const {
99 return static_cast<F&&>(f)(
100 static_cast<X1&&>(x1),
101 static_cast<X2&&>(x2),
102 static_cast<X3&&>(x3),
103 static_cast<X4&&>(x4),
104 static_cast<X5&&>(x5)
105 )(static_cast<Xs&&>(xs)...);
106 }
107 };
108
109 template <>
110 struct split_at_t<6> {
111 template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename ...Xs>
112 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, Xs&& ...xs) const {
113 return static_cast<F&&>(f)(
114 static_cast<X1&&>(x1),
115 static_cast<X2&&>(x2),
116 static_cast<X3&&>(x3),
117 static_cast<X4&&>(x4),
118 static_cast<X5&&>(x5),
119 static_cast<X6&&>(x6)
120 )(static_cast<Xs&&>(xs)...);
121 }
122 };
123
124 template <>
125 struct split_at_t<7> {
126 template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename X7, typename ...Xs>
127 constexpr decltype(auto) operator()(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, X7&& x7, Xs&& ...xs) const {
128 return static_cast<F&&>(f)(
129 static_cast<X1&&>(x1),
130 static_cast<X2&&>(x2),
131 static_cast<X3&&>(x3),
132 static_cast<X4&&>(x4),
133 static_cast<X5&&>(x5),
134 static_cast<X6&&>(x6),
135 static_cast<X7&&>(x7)
136 )(static_cast<Xs&&>(xs)...);
137 }
138 };
139
140 template <std::size_t n>
141 struct _makesplit_at_t {
142 template <typename ...Xs>
143 constexpr decltype(auto) operator()(Xs&& ...xs) const {
144 return hana::reverse_partial(split_at_t<n>{},
145 static_cast<Xs&&>(xs)...);
146 }
147 };
148
149 template <std::size_t n>
150 BOOST_HANA_INLINE_VARIABLE constexpr _makesplit_at_t<n> split_at{};
151}} }} // end namespace boost::hana
152
153#endif // !BOOST_HANA_DETAIL_VARIADIC_SPLIT_AT_HPP
154

source code of boost/libs/hana/include/boost/hana/detail/variadic/split_at.hpp