1#ifndef BOOST_MP11_UTILITY_HPP_INCLUDED
2#define BOOST_MP11_UTILITY_HPP_INCLUDED
3
4// Copyright 2015-2020 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/integral.hpp>
12#include <boost/mp11/detail/mp_list.hpp>
13#include <boost/mp11/detail/mp_fold.hpp>
14#include <boost/mp11/detail/mp_front.hpp>
15#include <boost/mp11/detail/mp_rename.hpp>
16#include <boost/mp11/detail/mp_defer.hpp>
17#include <boost/mp11/detail/config.hpp>
18
19namespace boost
20{
21namespace mp11
22{
23
24// mp_identity
25template<class T> struct mp_identity
26{
27 using type = T;
28};
29
30// mp_identity_t
31template<class T> using mp_identity_t = typename mp_identity<T>::type;
32
33// mp_inherit
34template<class... T> struct mp_inherit: T... {};
35
36// mp_if, mp_if_c
37// mp_valid
38// mp_defer
39// moved to detail/mp_defer.hpp
40
41// mp_eval_if, mp_eval_if_c
42namespace detail
43{
44
45template<bool C, class T, template<class...> class F, class... U> struct mp_eval_if_c_impl;
46
47template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<true, T, F, U...>
48{
49 using type = T;
50};
51
52template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<false, T, F, U...>: mp_defer<F, U...>
53{
54};
55
56} // namespace detail
57
58template<bool C, class T, template<class...> class F, class... U> using mp_eval_if_c = typename detail::mp_eval_if_c_impl<C, T, F, U...>::type;
59template<class C, class T, template<class...> class F, class... U> using mp_eval_if = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, F, U...>::type;
60template<class C, class T, class Q, class... U> using mp_eval_if_q = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, Q::template fn, U...>::type;
61
62// mp_eval_if_not
63template<class C, class T, template<class...> class F, class... U> using mp_eval_if_not = mp_eval_if<mp_not<C>, T, F, U...>;
64template<class C, class T, class Q, class... U> using mp_eval_if_not_q = mp_eval_if<mp_not<C>, T, Q::template fn, U...>;
65
66// mp_eval_or
67template<class T, template<class...> class F, class... U> using mp_eval_or = mp_eval_if_not<mp_valid<F, U...>, T, F, U...>;
68template<class T, class Q, class... U> using mp_eval_or_q = mp_eval_or<T, Q::template fn, U...>;
69
70// mp_valid_and_true
71template<template<class...> class F, class... T> using mp_valid_and_true = mp_eval_or<mp_false, F, T...>;
72template<class Q, class... T> using mp_valid_and_true_q = mp_valid_and_true<Q::template fn, T...>;
73
74// mp_cond
75
76// so elegant; so doesn't work
77// template<class C, class T, class... E> using mp_cond = mp_eval_if<C, T, mp_cond, E...>;
78
79namespace detail
80{
81
82template<class C, class T, class... E> struct mp_cond_impl;
83
84} // namespace detail
85
86template<class C, class T, class... E> using mp_cond = typename detail::mp_cond_impl<C, T, E...>::type;
87
88namespace detail
89{
90
91template<class C, class T, class... E> using mp_cond_ = mp_eval_if<C, T, mp_cond, E...>;
92
93template<class C, class T, class... E> struct mp_cond_impl: mp_defer<mp_cond_, C, T, E...>
94{
95};
96
97} // namespace detail
98
99// mp_quote
100template<template<class...> class F> struct mp_quote
101{
102 // the indirection through mp_defer works around the language inability
103 // to expand T... into a fixed parameter list of an alias template
104
105 template<class... T> using fn = typename mp_defer<F, T...>::type;
106};
107
108// mp_quote_trait
109template<template<class...> class F> struct mp_quote_trait
110{
111 template<class... T> using fn = typename F<T...>::type;
112};
113
114// mp_invoke_q
115#if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 )
116
117namespace detail
118{
119
120template<class Q, class... T> struct mp_invoke_q_impl: mp_defer<Q::template fn, T...> {};
121
122} // namespace detail
123
124template<class Q, class... T> using mp_invoke_q = typename detail::mp_invoke_q_impl<Q, T...>::type;
125
126#elif BOOST_MP11_WORKAROUND( BOOST_MP11_GCC, < 50000 )
127
128template<class Q, class... T> using mp_invoke_q = typename mp_defer<Q::template fn, T...>::type;
129
130#else
131
132template<class Q, class... T> using mp_invoke_q = typename Q::template fn<T...>;
133
134#endif
135
136// mp_not_fn<P>
137template<template<class...> class P> struct mp_not_fn
138{
139 template<class... T> using fn = mp_not< mp_invoke_q<mp_quote<P>, T...> >;
140};
141
142template<class Q> using mp_not_fn_q = mp_not_fn<Q::template fn>;
143
144// mp_compose
145namespace detail
146{
147
148template<class L, class Q> using mp_compose_helper = mp_list< mp_apply_q<Q, L> >;
149
150} // namespace detail
151
152#if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 )
153
154template<template<class...> class... F> struct mp_compose
155{
156 template<class... T> using fn = mp_front< mp_fold<mp_list<mp_quote<F>...>, mp_list<T...>, detail::mp_compose_helper> >;
157};
158
159#endif
160
161template<class... Q> struct mp_compose_q
162{
163 template<class... T> using fn = mp_front< mp_fold<mp_list<Q...>, mp_list<T...>, detail::mp_compose_helper> >;
164};
165
166} // namespace mp11
167} // namespace boost
168
169#endif // #ifndef BOOST_MP11_UTILITY_HPP_INCLUDED
170