1#ifndef BOOST_MP11_DETAIL_MP_MAP_FIND_HPP_INCLUDED
2#define BOOST_MP11_DETAIL_MP_MAP_FIND_HPP_INCLUDED
3
4// Copyright 2015 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/utility.hpp>
12#include <boost/mp11/detail/config.hpp>
13
14#if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
15
16// not exactly good practice, but...
17namespace std
18{
19 template<class... _Types> class tuple;
20}
21
22#endif
23
24namespace boost
25{
26namespace mp11
27{
28
29// mp_map_find
30namespace detail
31{
32
33#if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
34
35template<class T> using mpmf_wrap = mp_identity<T>;
36template<class T> using mpmf_unwrap = typename T::type;
37
38#else
39
40template<class... T> struct mpmf_tuple {};
41
42template<class T> struct mpmf_wrap_impl
43{
44 using type = mp_identity<T>;
45};
46
47template<class... T> struct mpmf_wrap_impl< std::tuple<T...> >
48{
49 using type = mp_identity< mpmf_tuple<T...> >;
50};
51
52template<class T> using mpmf_wrap = typename mpmf_wrap_impl<T>::type;
53
54template<class T> struct mpmf_unwrap_impl
55{
56 using type = typename T::type;
57};
58
59template<class... T> struct mpmf_unwrap_impl< mp_identity< mpmf_tuple<T...> > >
60{
61 using type = std::tuple<T...>;
62};
63
64template<class T> using mpmf_unwrap = typename mpmf_unwrap_impl<T>::type;
65
66#endif // #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
67
68template<class M, class K> struct mp_map_find_impl;
69
70template<template<class...> class M, class... T, class K> struct mp_map_find_impl<M<T...>, K>
71{
72 using U = mp_inherit<mpmf_wrap<T>...>;
73
74 template<template<class...> class L, class... U> static mp_identity<L<K, U...>> f( mp_identity<L<K, U...>>* );
75 static mp_identity<void> f( ... );
76
77 using type = mpmf_unwrap< decltype( f( static_cast<U*>(0) ) ) >;
78};
79
80} // namespace detail
81
82template<class M, class K> using mp_map_find = typename detail::mp_map_find_impl<M, K>::type;
83
84} // namespace mp11
85} // namespace boost
86
87#endif // #ifndef BOOST_MP11_DETAIL_MP_MAP_FIND_HPP_INCLUDED
88