1#ifndef BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED
2#define BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED
3
4// Copyright 2015-2017 Peter Dimov.
5//
6// Distributed under the Boost Software License, Version 1.0.
7//
8// See accompanying file LICENSE_1_0.txt or copy at
9// http://www.boost.org/LICENSE_1_0.txt
10
11#include <boost/mp11/detail/config.hpp>
12#include <boost/mp11/detail/mp_defer.hpp>
13
14namespace boost
15{
16namespace mp11
17{
18
19// mp_fold<L, V, F>
20namespace detail
21{
22
23template<class L, class V, template<class...> class F> struct mp_fold_impl
24{
25// An error "no type named 'type'" here means that the first argument to mp_fold is not a list
26};
27
28#if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, <= 1800 )
29
30template<template<class...> class L, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T...>, V, F>
31{
32 static_assert( sizeof...(T) == 0, "T... must be empty" );
33 using type = V;
34};
35
36#else
37
38template<template<class...> class L, class V, template<class...> class F> struct mp_fold_impl<L<>, V, F>
39{
40 using type = V;
41};
42
43#endif
44
45//
46
47template<class V, template<class...> class F> struct mp_fold_Q1
48{
49 template<class T1>
50 using fn = F<V, T1>;
51};
52
53template<class V, template<class...> class F> struct mp_fold_Q2
54{
55 template<class T1, class T2>
56 using fn = F<F<V, T1>, T2>;
57};
58
59template<class V, template<class...> class F> struct mp_fold_Q3
60{
61 template<class T1, class T2, class T3>
62 using fn = F<F<F<V, T1>, T2>, T3>;
63};
64
65template<class V, template<class...> class F> struct mp_fold_Q4
66{
67 template<class T1, class T2, class T3, class T4>
68 using fn = F<F<F<F<V, T1>, T2>, T3>, T4>;
69};
70
71template<class V, template<class...> class F> struct mp_fold_Q5
72{
73 template<class T1, class T2, class T3, class T4, class T5>
74 using fn = F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>;
75};
76
77template<class V, template<class...> class F> struct mp_fold_Q6
78{
79 template<class T1, class T2, class T3, class T4, class T5, class T6>
80 using fn = F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>;
81};
82
83template<class V, template<class...> class F> struct mp_fold_Q7
84{
85 template<class T1, class T2, class T3, class T4, class T5, class T6, class T7>
86 using fn = F<F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>, T7>;
87};
88
89template<class V, template<class...> class F> struct mp_fold_Q8
90{
91 template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8>
92 using fn = F<F<F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>, T7>, T8>;
93};
94
95template<class V, template<class...> class F> struct mp_fold_Q9
96{
97 template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9>
98 using fn = F<F<F<F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>, T7>, T8>, T9>;
99};
100
101//
102
103template<template<class...> class L, class T1, class V, template<class...> class F>
104struct mp_fold_impl<L<T1>, V, F>: mp_defer<mp_fold_Q1<V, F>::template fn, T1>
105{
106};
107
108template<template<class...> class L, class T1, class T2, class V, template<class...> class F>
109struct mp_fold_impl<L<T1, T2>, V, F>: mp_defer<mp_fold_Q2<V, F>::template fn, T1, T2>
110{
111};
112
113template<template<class...> class L, class T1, class T2, class T3, class V, template<class...> class F>
114struct mp_fold_impl<L<T1, T2, T3>, V, F>: mp_defer<mp_fold_Q3<V, F>::template fn, T1, T2, T3>
115{
116};
117
118template<template<class...> class L, class T1, class T2, class T3, class T4, class V, template<class...> class F>
119struct mp_fold_impl<L<T1, T2, T3, T4>, V, F>: mp_defer<mp_fold_Q4<V, F>::template fn, T1, T2, T3, T4>
120{
121};
122
123template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class V, template<class...> class F>
124struct mp_fold_impl<L<T1, T2, T3, T4, T5>, V, F>: mp_defer<mp_fold_Q5<V, F>::template fn, T1, T2, T3, T4, T5>
125{
126};
127
128template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class V, template<class...> class F>
129struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6>, V, F>: mp_defer<mp_fold_Q6<V, F>::template fn, T1, T2, T3, T4, T5, T6>
130{
131};
132
133template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class V, template<class...> class F>
134struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7>, V, F>: mp_defer<mp_fold_Q7<V, F>::template fn, T1, T2, T3, T4, T5, T6, T7>
135{
136};
137
138template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class V, template<class...> class F>
139struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7, T8>, V, F>: mp_defer<mp_fold_Q8<V, F>::template fn, T1, T2, T3, T4, T5, T6, T7, T8>
140{
141};
142
143template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class V, template<class...> class F>
144struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7, T8, T9>, V, F>: mp_defer<mp_fold_Q9<V, F>::template fn, T1, T2, T3, T4, T5, T6, T7, T8, T9>
145{
146};
147
148//
149
150template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class T10, class... T, class V, template<class...> class F>
151struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T...>, V, F>
152{
153 using type = typename mp_fold_impl<L<T...>, F<F<F<F<F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>, T7>, T8>, T9>, T10>, F>::type;
154};
155
156} // namespace detail
157
158template<class L, class V, template<class...> class F> using mp_fold = typename detail::mp_fold_impl<L, V, F>::type;
159template<class L, class V, class Q> using mp_fold_q = mp_fold<L, V, Q::template fn>;
160
161} // namespace mp11
162} // namespace boost
163
164#endif // #ifndef BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED
165