blob: 38df48e941c340af0bf80095355f3f5152f6e659 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
/*!
@file
Forward declares `boost::hana::union_`.
@copyright Louis Dionne 2013-2016
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
*/
#ifndef BOOST_HANA_FWD_UNION_HPP
#define BOOST_HANA_FWD_UNION_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Returns the union of two sets.
//! @relates hana::set
//!
//! Given two sets `xs` and `ys`, `union_(xs, ys)` is a new set containing
//! all the elements of `xs` and all the elements of `ys`, without
//! duplicates. For any object `x`, the following holds:
//! @code
//! x ^in^ union_(xs, ys) if and only if x ^in^ xs || x ^in^ ys
//! @endcode
//!
//!
//! @param xs, ys
//! Two sets to compute the union of.
//!
//!
//! Example
//! -------
//! @include example/union.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto union_ = [](auto&& xs, auto&& ys) {
return tag-dispatched;
};
#else
template <typename S, typename = void>
struct union_impl : union_impl<S, when<true>> { };
struct union_t {
template <typename Xs, typename Ys>
constexpr auto operator()(Xs&& xs, Ys&& ys) const;
};
constexpr union_t union_{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_UNION_HPP
|
