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
|
// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++
// | | |__ | | | | | | version 3.11.2
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2022 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT
#pragma once
#include <type_traits>
#include <nlohmann/detail/meta/void_t.hpp>
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{
// https://en.cppreference.com/w/cpp/experimental/is_detected
struct nonesuch
{
nonesuch() = delete;
~nonesuch() = delete;
nonesuch(nonesuch const&) = delete;
nonesuch(nonesuch const&&) = delete;
void operator=(nonesuch const&) = delete;
void operator=(nonesuch&&) = delete;
};
template<class Default,
class AlwaysVoid,
template<class...> class Op,
class... Args>
struct detector
{
using value_t = std::false_type;
using type = Default;
};
template<class Default, template<class...> class Op, class... Args>
struct detector<Default, void_t<Op<Args...>>, Op, Args...>
{
using value_t = std::true_type;
using type = Op<Args...>;
};
template<template<class...> class Op, class... Args>
using is_detected = typename detector<nonesuch, void, Op, Args...>::value_t;
template<template<class...> class Op, class... Args>
struct is_detected_lazy : is_detected<Op, Args...> { };
template<template<class...> class Op, class... Args>
using detected_t = typename detector<nonesuch, void, Op, Args...>::type;
template<class Default, template<class...> class Op, class... Args>
using detected_or = detector<Default, void, Op, Args...>;
template<class Default, template<class...> class Op, class... Args>
using detected_or_t = typename detected_or<Default, Op, Args...>::type;
template<class Expected, template<class...> class Op, class... Args>
using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
template<class To, template<class...> class Op, class... Args>
using is_detected_convertible =
std::is_convertible<detected_t<Op, Args...>, To>;
} // namespace detail
NLOHMANN_JSON_NAMESPACE_END
|
