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
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// UNSUPPORTED: libcpp-no-concepts
// UNSUPPORTED: gcc-10
// UNSUPPORTED: libcpp-has-no-incomplete-ranges
// template<class R>
// concept viewable_range;
#include <ranges>
#include <type_traits>
#include "test_iterators.h"
#include "test_range.h"
// The constraints we have in viewable_range are:
// range<T>
// view<remove_cvref_t<T>>
// constructible_from<remove_cvref_t<T>, T>
// borrowed_range<T>
//
// We test all the relevant combinations of satisfying/not satisfying those constraints.
// viewable_range<T> is not satisfied for (range=false, view=*, constructible_from=*, borrowed_range=*)
struct T1 { };
static_assert(!std::ranges::range<T1>);
static_assert(!std::ranges::viewable_range<T1>);
static_assert(!std::ranges::viewable_range<T1&>);
static_assert(!std::ranges::viewable_range<T1 const>);
static_assert(!std::ranges::viewable_range<T1 const&>);
// viewable_range<T> is satisfied for (range=true, view=true, constructible_from=true, borrowed_range=true)
struct T2 : test_range<cpp20_input_iterator>, std::ranges::view_base {
T2(T2 const&) = default;
};
template<> constexpr bool std::ranges::enable_borrowed_range<T2> = true;
static_assert(std::ranges::range<T2>);
static_assert(std::ranges::view<T2>);
static_assert(std::constructible_from<T2, T2>);
static_assert(std::ranges::borrowed_range<T2>);
static_assert(std::ranges::viewable_range<T2>);
static_assert(std::ranges::viewable_range<T2&>);
static_assert(std::ranges::viewable_range<T2 const>);
static_assert(std::ranges::viewable_range<T2 const&>);
// viewable_range<T> is satisfied for (range=true, view=true, constructible_from=true, borrowed_range=false)
struct T3 : test_range<cpp20_input_iterator>, std::ranges::view_base {
T3(T3 const&) = default;
};
template<> constexpr bool std::ranges::enable_borrowed_range<T3> = false;
static_assert(std::ranges::range<T3>);
static_assert(std::ranges::view<T3>);
static_assert(std::constructible_from<T3, T3>);
static_assert(!std::ranges::borrowed_range<T3>);
static_assert(std::ranges::viewable_range<T3>);
static_assert(std::ranges::viewable_range<T3&>);
static_assert(std::ranges::viewable_range<T3 const>);
static_assert(std::ranges::viewable_range<T3 const&>);
// viewable_range<T> is not satisfied for (range=true, view=true, constructible_from=false, borrowed_range=true)
struct T4 : test_range<cpp20_input_iterator>, std::ranges::view_base {
T4(T4 const&) = delete;
T4(T4&&) = default; // necessary to model view
T4& operator=(T4&&) = default; // necessary to model view
};
static_assert(std::ranges::range<T4 const&>);
static_assert(std::ranges::view<std::remove_cvref_t<T4 const&>>);
static_assert(!std::constructible_from<std::remove_cvref_t<T4 const&>, T4 const&>);
static_assert(std::ranges::borrowed_range<T4 const&>);
static_assert(!std::ranges::viewable_range<T4 const&>);
// A type that satisfies (range=true, view=true, constructible_from=false, borrowed_range=false) can't be formed
// viewable_range<T> is satisfied for (range=true, view=false, constructible_from=true, borrowed_range=true)
struct T5 : test_range<cpp20_input_iterator> { };
template<> constexpr bool std::ranges::enable_borrowed_range<T5> = true;
static_assert(std::ranges::range<T5>);
static_assert(!std::ranges::view<T5>);
static_assert(std::constructible_from<T5, T5>);
static_assert(std::ranges::borrowed_range<T5>);
static_assert(std::ranges::viewable_range<T5>);
// viewable_range<T> is not satisfied for (range=true, view=false, constructible_from=true, borrowed_range=false)
struct T6 : test_range<cpp20_input_iterator> { };
template<> constexpr bool std::ranges::enable_borrowed_range<T6> = false;
static_assert(std::ranges::range<T6>);
static_assert(!std::ranges::view<T6>);
static_assert(std::constructible_from<T6, T6>);
static_assert(!std::ranges::borrowed_range<T6>);
static_assert(!std::ranges::viewable_range<T6>);
// viewable_range<T> is satisfied for (range=true, view=false, constructible_from=false, borrowed_range=true)
struct T7 : test_range<cpp20_input_iterator> {
T7(T7 const&) = delete;
};
static_assert(std::ranges::range<T7&>);
static_assert(!std::ranges::view<std::remove_cvref_t<T7&>>);
static_assert(!std::constructible_from<std::remove_cvref_t<T7&>, T7&>);
static_assert(std::ranges::borrowed_range<T7&>);
static_assert(std::ranges::viewable_range<T7&>);
// A type that satisfies (range=true, view=false, constructible_from=false, borrowed_range=false) can't be formed
struct T8 : test_range<cpp20_input_iterator> {
T8(T8 const&) = delete;
};
static_assert(std::ranges::range<T8>);
static_assert(!std::ranges::view<T8>);
static_assert(!std::constructible_from<T8, T8>);
static_assert(!std::ranges::borrowed_range<T8>);
static_assert(!std::ranges::viewable_range<T8>);
// Test with a few degenerate types
static_assert(!std::ranges::viewable_range<void>);
static_assert(!std::ranges::viewable_range<int>);
static_assert(!std::ranges::viewable_range<int (*)(char)>);
static_assert(!std::ranges::viewable_range<int[]>);
static_assert(!std::ranges::viewable_range<int[10]>);
static_assert(!std::ranges::viewable_range<int(&)[]>); // unbounded array is not a range
static_assert( std::ranges::viewable_range<int(&)[10]>);
|
