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1 | /*! |
2 | @file | |
3 | Forward declares `boost::hana::remove_range` and `boost::hana::remove_range_c`. | |
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_FWD_REMOVE_RANGE_HPP | |
11 | #define BOOST_HANA_FWD_REMOVE_RANGE_HPP | |
12 | ||
13 | #include <boost/hana/config.hpp> | |
14 | #include <boost/hana/core/when.hpp> | |
15 | ||
16 | #include <cstddef> | |
17 | ||
18 | ||
19 | BOOST_HANA_NAMESPACE_BEGIN | |
20 | //! Remove the elements inside a given range of indices from a sequence. | |
21 | //! @ingroup group-Sequence | |
22 | //! | |
23 | //! `remove_range` returns a new sequence identical to the original, | |
24 | //! except that elements at indices in the provided range are removed. | |
25 | //! Specifically, `remove_range([x0, ..., xn], from, to)` is a new | |
26 | //! sequence equivalent to `[x0, ..., x_from-1, x_to, ..., xn]`. | |
27 | //! | |
28 | //! | |
29 | //! @note | |
30 | //! The behavior is undefined if the range contains any index out of the | |
31 | //! bounds of the sequence. | |
32 | //! | |
33 | //! | |
34 | //! @param xs | |
35 | //! A sequence from which elements are removed. | |
36 | //! | |
37 | //! @param [from, to) | |
38 | //! An half-open interval of `IntegralConstant`s representing the indices | |
39 | //! of the elements to be removed from the sequence. The `IntegralConstant`s | |
40 | //! in the half-open interval must be non-negative and in the bounds of | |
41 | //! the sequence. The half-open interval must also be valid, meaning that | |
42 | //! `from <= to`. | |
43 | //! | |
44 | //! | |
45 | //! Example | |
46 | //! ------- | |
47 | //! @include example/remove_range.cpp | |
48 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
49 | constexpr auto remove_range = [](auto&& xs, auto const& from, auto const& to) { | |
50 | return tag-dispatched; | |
51 | }; | |
52 | #else | |
53 | template <typename S, typename = void> | |
54 | struct remove_range_impl : remove_range_impl<S, when<true>> { }; | |
55 | ||
56 | struct remove_range_t { | |
57 | template <typename Xs, typename From, typename To> | |
58 | constexpr auto operator()(Xs&& xs, From const& from, To const& to) const; | |
59 | }; | |
60 | ||
61 | constexpr remove_range_t remove_range{}; | |
62 | #endif | |
63 | ||
64 | //! Equivalent to `remove_range`; provided for convenience. | |
65 | //! @ingroup group-Sequence | |
66 | //! | |
67 | //! | |
68 | //! Example | |
69 | //! ------- | |
70 | //! @include example/remove_range_c.cpp | |
71 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
72 | template <std::size_t from, std::size_t to> | |
73 | constexpr auto remove_range_c = [](auto&& xs) { | |
74 | return hana::remove_range(forwarded(xs), hana::size_c<from>, hana::size_c<to>); | |
75 | }; | |
76 | #else | |
77 | template <std::size_t from, std::size_t to> | |
78 | struct remove_range_c_t; | |
79 | ||
80 | template <std::size_t from, std::size_t to> | |
81 | constexpr remove_range_c_t<from, to> remove_range_c{}; | |
82 | #endif | |
83 | BOOST_HANA_NAMESPACE_END | |
84 | ||
85 | #endif // !BOOST_HANA_FWD_REMOVE_RANGE_HPP |