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
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
|
//-----------------------------------------------------------------------------
// boost-libs variant/test/auto_visitors.cpp source file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2014-2015 Antony Polukhin
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#include "boost/config.hpp"
#include "boost/test/minimal.hpp"
#include "boost/variant.hpp"
#include "boost/variant/multivisitors.hpp"
#include "boost/lexical_cast.hpp"
struct lex_streamer_explicit: boost::static_visitor<std::string> {
template <class T>
const char* operator()(const T& ) {
return "10";
}
template <class T1, class T2>
const char* operator()(const T1& , const T2& ) {
return "100";
}
};
void run_explicit()
{
typedef boost::variant<int, std::string, double> variant_type;
variant_type v2("10"), v1("100");
lex_streamer_explicit visitor_ref;
// Must return instance of std::string
BOOST_CHECK(boost::apply_visitor(visitor_ref, v2).c_str() == std::string("10"));
BOOST_CHECK(boost::apply_visitor(visitor_ref, v2, v1).c_str() == std::string("100"));
}
// Most part of tests from this file require decltype(auto)
#ifdef BOOST_NO_CXX14_DECLTYPE_AUTO
void run()
{
BOOST_CHECK(true);
}
void run2()
{
BOOST_CHECK(true);
}
void run3()
{
BOOST_CHECK(true);
}
#else
#include <iostream>
struct lex_streamer {
template <class T>
std::string operator()(const T& val) const {
return boost::lexical_cast<std::string>(val);
}
};
struct lex_streamer_void {
template <class T>
void operator()(const T& val) const {
std::cout << val << std::endl;
}
template <class T1, class T2>
void operator()(const T1& val, const T2& val2) const {
std::cout << val << '+' << val2 << std::endl;
}
template <class T1, class T2, class T3>
void operator()(const T1& val, const T2& val2, const T3& val3) const {
std::cout << val << '+' << val2 << '+' << val3 << std::endl;
}
};
struct lex_streamer2 {
std::string res;
template <class T>
const char* operator()(const T& val) const {
return "fail";
}
template <class T1, class T2>
const char* operator()(const T1& v1, const T2& v2) const {
return "fail2";
}
template <class T1, class T2, class T3>
const char* operator()(const T1& v1, const T2& v2, const T3& v3) const {
return "fail3";
}
template <class T>
std::string& operator()(const T& val) {
res = boost::lexical_cast<std::string>(val);
return res;
}
template <class T1, class T2>
std::string& operator()(const T1& v1, const T2& v2) {
res = boost::lexical_cast<std::string>(v1) + "+" + boost::lexical_cast<std::string>(v2);
return res;
}
template <class T1, class T2, class T3>
std::string& operator()(const T1& v1, const T2& v2, const T3& v3) {
res = boost::lexical_cast<std::string>(v1) + "+" + boost::lexical_cast<std::string>(v2)
+ "+" + boost::lexical_cast<std::string>(v3);
return res;
}
};
#ifndef BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
# define BOOST_CHECK_IF_HAS_VARIADIC(x) BOOST_CHECK(x)
#else
# define BOOST_CHECK_IF_HAS_VARIADIC(x) /**/
#endif
void run()
{
typedef boost::variant<int, std::string, double> variant_type;
variant_type v1(1), v2("10"), v3(100.0);
lex_streamer lex_streamer_visitor;
BOOST_CHECK(boost::apply_visitor(lex_streamer(), v1) == "1");
BOOST_CHECK_IF_HAS_VARIADIC(boost::apply_visitor(lex_streamer_visitor)(v1) == "1");
BOOST_CHECK(boost::apply_visitor(lex_streamer(), v2) == "10");
BOOST_CHECK_IF_HAS_VARIADIC(boost::apply_visitor(lex_streamer_visitor)(v2) == "10");
#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
BOOST_CHECK(boost::apply_visitor([](auto v) { return boost::lexical_cast<std::string>(v); }, v1) == "1");
BOOST_CHECK(boost::apply_visitor([](auto v) { return boost::lexical_cast<std::string>(v); }, v2) == "10");
// Retun type must be the same in all instances, so this code does not compile
//boost::variant<int, short, unsigned> v_diff_types(1);
//BOOST_CHECK(boost::apply_visitor([](auto v) { return v; }, v_diff_types) == 1);
boost::apply_visitor([](auto v) { std::cout << v << std::endl; }, v1);
boost::apply_visitor([](auto v) { std::cout << v << std::endl; }, v2);
#endif
lex_streamer2 visitor_ref;
BOOST_CHECK(boost::apply_visitor(visitor_ref, v1) == "1");
BOOST_CHECK(boost::apply_visitor(visitor_ref, v2) == "10");
#ifndef BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
std::string& ref_to_string = boost::apply_visitor(visitor_ref, v1);
BOOST_CHECK(ref_to_string == "1");
#endif
lex_streamer_void lex_streamer_void_visitor;
boost::apply_visitor(lex_streamer_void(), v1);
boost::apply_visitor(lex_streamer_void(), v2);
#ifndef BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
boost::apply_visitor(lex_streamer_void_visitor)(v2);
#endif
}
struct lex_combine {
template <class T1, class T2>
std::string operator()(const T1& v1, const T2& v2) const {
return boost::lexical_cast<std::string>(v1) + "+" + boost::lexical_cast<std::string>(v2);
}
template <class T1, class T2, class T3>
std::string operator()(const T1& v1, const T2& v2, const T3& v3) const {
return boost::lexical_cast<std::string>(v1) + "+"
+ boost::lexical_cast<std::string>(v2) + '+'
+ boost::lexical_cast<std::string>(v3);
}
};
void run2()
{
typedef boost::variant<int, std::string, double> variant_type;
variant_type v1(1), v2("10"), v3(100.0);
lex_combine lex_combine_visitor;
BOOST_CHECK(boost::apply_visitor(lex_combine(), v1, v2) == "1+10");
BOOST_CHECK(boost::apply_visitor(lex_combine(), v2, v1) == "10+1");
BOOST_CHECK_IF_HAS_VARIADIC(boost::apply_visitor(lex_combine_visitor)(v2, v1) == "10+1");
#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
BOOST_CHECK(
boost::apply_visitor(
[](auto v1, auto v2) {
return boost::lexical_cast<std::string>(v1) + "+"
+ boost::lexical_cast<std::string>(v2);
}
, v1
, v2
) == "1+10"
);
BOOST_CHECK(
boost::apply_visitor(
[](auto v1, auto v2) {
return boost::lexical_cast<std::string>(v1) + "+"
+ boost::lexical_cast<std::string>(v2);
}
, v2
, v1
) == "10+1"
);
boost::apply_visitor([](auto v1, auto v2) { std::cout << v1 << '+' << v2 << std::endl; }, v1, v2);
boost::apply_visitor([](auto v1, auto v2) { std::cout << v1 << '+' << v2 << std::endl; }, v2, v1);
#endif
lex_streamer2 visitor_ref;
BOOST_CHECK(boost::apply_visitor(visitor_ref, v1, v2) == "1+10");
BOOST_CHECK(boost::apply_visitor(visitor_ref, v2, v1) == "10+1");
#ifndef BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
std::string& ref_to_string = boost::apply_visitor(visitor_ref)(v1, v2);
BOOST_CHECK(ref_to_string == "1+10");
#endif
boost::apply_visitor(lex_streamer_void(), v1, v2);
boost::apply_visitor(lex_streamer_void(), v2, v1);
}
#undef BOOST_CHECK_IF_HAS_VARIADIC
void run3()
{
#if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_HDR_TUPLE)
typedef boost::variant<int, std::string, double> variant_type;
variant_type v1(1), v2("10"), v3(100);
lex_combine lex_combine_visitor;
BOOST_CHECK(boost::apply_visitor(lex_combine(), v1, v2, v3) == "1+10+100");
BOOST_CHECK(boost::apply_visitor(lex_combine(), v2, v1, v3) == "10+1+100");
BOOST_CHECK(boost::apply_visitor(lex_combine_visitor)(v2, v1, v3) == "10+1+100");
#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
BOOST_CHECK(
boost::apply_visitor(
[](auto v1, auto v2, auto v3) {
return boost::lexical_cast<std::string>(v1) + "+"
+ boost::lexical_cast<std::string>(v2) + "+"
+ boost::lexical_cast<std::string>(v3);
}
, v1
, v2
, v3
) == "1+10+100"
);
BOOST_CHECK(
boost::apply_visitor(
[](auto v1, auto v2, auto v3) {
return boost::lexical_cast<std::string>(v1) + "+"
+ boost::lexical_cast<std::string>(v2) + "+"
+ boost::lexical_cast<std::string>(v3);
}
, v3
, v1
, v3
) == "100+1+100"
);
boost::apply_visitor(
[](auto v1, auto v2, auto v3) { std::cout << v1 << '+' << v2 << '+' << v3 << std::endl; },
v1, v2, v3
);
boost::apply_visitor(
[](auto v1, auto v2, auto v3) { std::cout << v1 << '+' << v2 << '+' << v3 << std::endl; },
v2, v1, v3
);
#endif
lex_streamer2 visitor_ref;
BOOST_CHECK(boost::apply_visitor(visitor_ref, v1, v2) == "1+10");
BOOST_CHECK(boost::apply_visitor(visitor_ref)(v2, v1) == "10+1");
std::string& ref_to_string = boost::apply_visitor(visitor_ref, v1, v2);
BOOST_CHECK(ref_to_string == "1+10");
lex_streamer_void lex_streamer_void_visitor;
boost::apply_visitor(lex_streamer_void(), v1, v2, v1);
boost::apply_visitor(lex_streamer_void(), v2, v1, v1);
boost::apply_visitor(lex_streamer_void_visitor)(v2, v1, v1);
#endif // !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_HDR_TUPLE)
}
#endif
int test_main(int , char* [])
{
run_explicit();
run();
run2();
run3();
return 0;
}
|
