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
|
/*!
@file
Forward declares `boost::hana::suffix`.
@copyright Louis Dionne 2013-2017
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_SUFFIX_HPP
#define BOOST_HANA_FWD_SUFFIX_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Inserts a value after each element of a monadic structure.
//! @ingroup group-MonadPlus
//!
//! Given a monadic structure `xs` and a value `z` (called the suffix),
//! `suffix` returns a new monadic structure such that
//! @code
//! suffix(xs, z) == flatten(transform(xs, [](auto x) {
//! return concat(lift<M>(x), lift<M>(z));
//! }))
//! @endcode
//!
//! For sequences, this simply corresponds to inserting the suffix after
//! each element of the sequence. For example, given a sequence
//! `[x1, ..., xn]`, `suffix` will return
//! @code
//! [x1, z, x2, z, ..., xn, z]
//! @endcode
//! As explained above, this can be generalized to other MonadPlus models,
//! with various levels of interest.
//!
//!
//! Signature
//! ---------
//! Given a MonadPlus `M`, the signature is
//! @f$ \mathtt{suffix} : M(T) \times T \to M(T) @f$.
//!
//! @param xs
//! A monadic structure.
//!
//! @param sfx
//! A value (the suffix) to insert after each element of a monadic
//! structure.
//!
//!
//! Example
//! -------
//! @include example/suffix.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto suffix = [](auto&& xs, auto&& sfx) {
return tag-dispatched;
};
#else
template <typename M, typename = void>
struct suffix_impl : suffix_impl<M, when<true>> { };
struct suffix_t {
template <typename Xs, typename Sfx>
constexpr auto operator()(Xs&& xs, Sfx&& sfx) const;
};
constexpr suffix_t suffix{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_SUFFIX_HPP
|
