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
13namespace boost
14{
15namespace mp11
16{
17
18// mp_fold<L, V, F>
19namespace detail
20{
21
22template<class L, class V, template<class...> class F> struct mp_fold_impl
23{
24// An error "no type named 'type'" here means that the first argument to mp_fold is not a list
25};
26
27#if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, <= 1800 )
28
29template<template<class...> class L, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T...>, V, F>
30{
31 static_assert( sizeof...(T) == 0, "T... must be empty" );
32 using type = V;
33};
34
35#else
36
37template<template<class...> class L, class V, template<class...> class F> struct mp_fold_impl<L<>, V, F>
38{
39 using type = V;
40};
41
42#endif
43
44template<template<class...> class L, class T1, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T1, T...>, V, F>
45{
46 using type = typename mp_fold_impl<L<T...>, F<V, T1>, F>::type;
47};
48
49template<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> struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T...>, V, F>
50{
51 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;
52};
53
54} // namespace detail
55
56template<class L, class V, template<class...> class F> using mp_fold = typename detail::mp_fold_impl<L, V, F>::type;
57template<class L, class V, class Q> using mp_fold_q = mp_fold<L, V, Q::template fn>;
58
59} // namespace mp11
60} // namespace boost
61
62#endif // #ifndef BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED
63

source code of include/boost/mp11/detail/mp_fold.hpp