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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// REQUIRES: std-at-least-c++23
// <ranges>
// constexpr auto begin();
// constexpr auto begin() const
// requires forward_range<const V> &&
// forward_range<const Pattern> &&
// is_reference_v<range_reference_t<const V>> &&
// input_range<range_reference_t<const V>>;
#include <ranges>
#include <algorithm>
#include <array>
#include <string>
#include <vector>
#include "../types.h"
#include "test_iterators.h"
template <bool Simple>
using MaybeSimpleForwardView = BasicView<std::vector<std::string>, ViewProperties{.simple = Simple}, forward_iterator>;
template <bool Simple>
using MaybeSimpleForwardRvalueView =
BasicView<RvalueVector<std::string>, ViewProperties{.simple = Simple}, forward_iterator>;
template <bool Simple>
using MaybeSimplePattern = BasicView<std::string, ViewProperties{.simple = Simple}, forward_iterator>;
template <class V, class Pattern>
concept JoinWithViewHasConstBegin = requires(const std::ranges::join_with_view<V, Pattern> jwv) {
{ jwv.begin() } -> std::input_iterator;
};
constexpr void test_begin() {
using Str = std::string;
using Vec = std::vector<Str>;
{ // `V` models simple-view
// `is_reference_v<InnerRng>` is true
// `Pattern` models simple-view
// `V` and `Pattern` contain some elements
using V = MaybeSimpleForwardView<true>;
using Pattern = MaybeSimplePattern<true>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"A", "B", "C"}), Pattern(Str{">>"}));
auto it = jwv.begin();
assert(std::ranges::equal(std::views::counted(it, 7), Str{"A>>B>>C"}));
}
{ // `V` does not model simple-view
// `is_reference_v<InnerRng>` is true
// `Pattern` models simple-view
// `V` and `Pattern` are empty
using V = MaybeSimpleForwardView<false>;
using Pattern = MaybeSimplePattern<true>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{}), Pattern(Str{}));
auto it = jwv.begin();
assert(it == jwv.end());
}
{ // `V` models simple-view
// `is_reference_v<InnerRng>` is false
// `Pattern` models simple-view
// `V` contains two elements, `Pattern` is empty
using V = MaybeSimpleForwardRvalueView<true>;
using Pattern = MaybeSimplePattern<true>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"1", "2"}), Pattern(Str{""}));
auto it = jwv.begin();
assert(*it == '1');
assert(*++it == '2');
}
{ // `V` models simple-view
// `is_reference_v<InnerRng>` is true
// `Pattern` does not model simple-view
// `V` contains one element, `Pattern` is empty
using V = MaybeSimpleForwardView<true>;
using Pattern = MaybeSimplePattern<false>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"07"}), Pattern(Str{}));
auto it = jwv.begin();
assert(*it++ == '0');
assert(*it == '7');
}
{ // `V` does not model simple-view
// `is_reference_v<InnerRng>` is false
// `Pattern` models simple-view
// `V` contains three elements (2nd is empty), `Pattern` is not empty
using V = MaybeSimpleForwardRvalueView<false>;
using Pattern = MaybeSimplePattern<true>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"A", "", "C"}), Pattern(Str{"--"}));
auto it = jwv.begin();
assert(std::ranges::equal(std::views::counted(it, 6), Str("A----C")));
}
{ // `V` does not model simple-view
// `is_reference_v<InnerRng>` is true
// `Pattern` does not model simple-view
// `V` contains some empty elements, `Pattern` is not empty
using V = MaybeSimpleForwardView<false>;
using Pattern = MaybeSimplePattern<false>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"", "", ""}), Pattern(Str{"-"}));
auto it = jwv.begin();
assert(*it++ == '-');
assert(*it == '-');
}
{ // `V` models simple-view
// `is_reference_v<InnerRng>` is false
// `Pattern` does not model simple-view
// `V` contains two elements, `Pattern` is not empty
using V = MaybeSimpleForwardRvalueView<true>;
using Pattern = MaybeSimplePattern<false>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"X", "Z"}), Pattern(Str{"Y"}));
auto it = jwv.begin();
assert(*it == 'X');
assert(*++it == 'Y');
assert(*++it == 'Z');
}
{ // `V` does not model simple-view
// `is_reference_v<InnerRng>` is false
// `Pattern` does not model simple-view
// `V` contains two empty elements, `Pattern` is not empty
using V = MaybeSimpleForwardRvalueView<false>;
using Pattern = MaybeSimplePattern<false>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"", ""}), Pattern(Str{"?"}));
auto it = jwv.begin();
assert(*it == '?');
assert(++it == jwv.end());
}
{ // `V` does not model forward range
// `V` contains some empty elements, `Pattern` is empty
using V = BasicView<Vec, ViewProperties{.common = false}, cpp20_input_iterator>;
using Pattern = MaybeSimplePattern<false>;
std::ranges::join_with_view<V, Pattern> jwv(V(Vec{"", "", ""}), Pattern(Str{""}));
auto it = jwv.begin();
assert(it == jwv.end());
}
}
constexpr void test_const_begin() {
using Vec = std::vector<std::array<int, 2>>;
using Pat = std::array<int, 2>;
{ // `const V` models forward range
// `const Pattern` models forward range
// `is_reference_v<range_reference_t<const V>>` is true
// `range_reference_t<const V>` models input range
using V = BasicView<Vec, ViewProperties{}, forward_iterator>;
using Pattern = BasicView<Pat, ViewProperties{}, forward_iterator>;
const std::ranges::join_with_view<V, Pattern> jwv{V{Vec{std::array{1, 2}, std::array{3, 4}}}, Pattern{Pat{0, 0}}};
auto it = jwv.begin();
assert(std::ranges::equal(std::views::counted(it, 6), std::array{1, 2, 0, 0, 3, 4}));
}
// `const V` does not model forward range
// `const Pattern` models forward range
// `is_reference_v<range_reference_t<const V>>` is true
// `range_reference_t<const V>` models input range
static_assert(!JoinWithViewHasConstBegin<BasicView<Vec, ViewProperties{.common = false}, cpp20_input_iterator>,
BasicView<Pat, ViewProperties{}, forward_iterator>>);
// `const V` models forward range
// `const Pattern` does not model forward range
// `is_reference_v<range_reference_t<const V>>` is true
// `range_reference_t<const V>` models input range
static_assert(!JoinWithViewHasConstBegin<BasicView<Vec, ViewProperties{}, forward_iterator>,
BasicView<Pat, ViewProperties{.common = false}, cpp20_input_iterator>>);
// `const V` models forward range
// `const Pattern` models forward range
// `is_reference_v<range_reference_t<const V>>` is false
// `range_reference_t<const V>` models input range
static_assert(
!JoinWithViewHasConstBegin<BasicView<RvalueVector<std::vector<int>>, ViewProperties{}, forward_iterator>,
BasicView<Pat, ViewProperties{}, forward_iterator>>);
// `const V` models forward range
// `const Pattern` models forward range
// `is_reference_v<range_reference_t<const V>>` is true
// `range_reference_t<const V>` does not model input range
static_assert(!JoinWithViewHasConstBegin<
BasicView<std::vector<InputRangeButOutputWhenConst<int>>, ViewProperties{}, forward_iterator>,
BasicView<Pat, ViewProperties{}, forward_iterator>>);
// `concatable<range_reference_t<const V>, const Pattern>` is not satisfied
// See also LWG-4074: compatible-joinable-ranges is underconstrained
static_assert(!JoinWithViewHasConstBegin<BasicVectorView<int, ViewProperties{}, forward_iterator>,
lwg4074::PatternWithProxyConstAccess>);
// Check situation when iterators returned by `begin()` and `begin() const` are the same
using JWV = std::ranges::join_with_view<MaybeSimpleForwardView<true>, MaybeSimplePattern<true>>;
static_assert(std::same_as<std::ranges::iterator_t<JWV&>, std::ranges::iterator_t<const JWV&>>);
}
constexpr bool test() {
test_begin();
test_const_begin();
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
|
