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1 | /*! |
2 | @file | |
3 | Forward declares `boost::hana::div`. | |
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_DIV_HPP | |
11 | #define BOOST_HANA_FWD_DIV_HPP | |
12 | ||
13 | #include <boost/hana/config.hpp> | |
14 | #include <boost/hana/core/when.hpp> | |
15 | ||
16 | ||
17 | BOOST_HANA_NAMESPACE_BEGIN | |
18 | //! Generalized integer division. | |
19 | //! @ingroup group-EuclideanRing | |
20 | //! | |
21 | //! | |
22 | //! Cross-type version of the method | |
23 | //! -------------------------------- | |
24 | //! The `div` method is "overloaded" to handle distinct data types | |
25 | //! with certain properties. Specifically, `div` is defined for | |
26 | //! _distinct_ data types `A` and `B` such that | |
27 | //! 1. `A` and `B` share a common data type `C`, as determined by the | |
28 | //! `common` metafunction | |
29 | //! 2. `A`, `B` and `C` are all `EuclideanRing`s when taken individually | |
30 | //! 3. `to<C> : A -> B` and `to<C> : B -> C` are `Ring`-embeddings, as | |
31 | //! determined by the `is_embedding` metafunction. | |
32 | //! | |
33 | //! In that case, the `div` method is defined as | |
34 | //! @code | |
35 | //! div(x, y) = div(to<C>(x), to<C>(y)) | |
36 | //! @endcode | |
37 | //! | |
38 | //! | |
39 | //! Example | |
40 | //! ------- | |
41 | //! @include example/div.cpp | |
42 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
43 | constexpr auto div = [](auto&& x, auto&& y) -> decltype(auto) { | |
44 | return tag-dispatched; | |
45 | }; | |
46 | #else | |
47 | template <typename T, typename U, typename = void> | |
48 | struct div_impl : div_impl<T, U, when<true>> { }; | |
49 | ||
50 | struct div_t { | |
51 | template <typename X, typename Y> | |
52 | constexpr decltype(auto) operator()(X&& x, Y&& y) const; | |
53 | }; | |
54 | ||
55 | constexpr div_t div{}; | |
56 | #endif | |
57 | BOOST_HANA_NAMESPACE_END | |
58 | ||
59 | #endif // !BOOST_HANA_FWD_DIV_HPP |