598bfd3f
 Hu Chunming
提交_GLIBCXX_USE_CX...
|
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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
/*!
@file
Defines `boost::hana::append`.
Copyright Louis Dionne 2013-2022
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_APPEND_HPP
#define BOOST_HANA_APPEND_HPP
#include <boost/hana/fwd/append.hpp>
#include <boost/hana/at.hpp>
#include <boost/hana/concat.hpp>
#include <boost/hana/concept/monad_plus.hpp>
#include <boost/hana/concept/sequence.hpp>
#include <boost/hana/config.hpp>
#include <boost/hana/core/dispatch.hpp>
#include <boost/hana/core/make.hpp>
#include <boost/hana/length.hpp>
#include <boost/hana/lift.hpp>
#include <cstddef>
#include <utility>
namespace boost { namespace hana {
//! @cond
template <typename Xs, typename X>
constexpr auto append_t::operator()(Xs&& xs, X&& x) const {
using M = typename hana::tag_of<Xs>::type;
using Append = BOOST_HANA_DISPATCH_IF(append_impl<M>,
hana::MonadPlus<M>::value
);
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
static_assert(hana::MonadPlus<M>::value,
"hana::append(xs, x) requires 'xs' to be a MonadPlus");
#endif
return Append::apply(static_cast<Xs&&>(xs), static_cast<X&&>(x));
}
//! @endcond
template <typename M, bool condition>
struct append_impl<M, when<condition>> : default_ {
template <typename Xs, typename X>
static constexpr auto apply(Xs&& xs, X&& x) {
return hana::concat(static_cast<Xs&&>(xs),
hana::lift<M>(static_cast<X&&>(x)));
}
};
template <typename S>
struct append_impl<S, when<Sequence<S>::value>> {
template <typename Xs, typename X, std::size_t ...i>
static constexpr auto append_helper(Xs&& xs, X&& x, std::index_sequence<i...>) {
return hana::make<S>(
hana::at_c<i>(static_cast<Xs&&>(xs))..., static_cast<X&&>(x)
);
}
template <typename Xs, typename X>
static constexpr auto apply(Xs&& xs, X&& x) {
constexpr std::size_t N = decltype(hana::length(xs))::value;
return append_helper(static_cast<Xs&&>(xs), static_cast<X&&>(x),
std::make_index_sequence<N>{});
}
};
}} // end namespace boost::hana
#endif // !BOOST_HANA_APPEND_HPP
|
