File: reference.qbk

package info (click to toggle)
boost1.83 1.83.0-5
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 545,632 kB
  • sloc: cpp: 3,857,086; xml: 125,552; ansic: 34,414; python: 25,887; asm: 5,276; sh: 4,799; ada: 1,681; makefile: 1,629; perl: 1,212; pascal: 1,139; sql: 810; yacc: 478; ruby: 102; lisp: 24; csh: 6
file content (1517 lines) | stat: -rw-r--r-- 60,519 bytes parent folder | download | duplicates (6)
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
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
[/
  Copyright 2016-2017 Joaquin M Lopez Munoz.
  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)
]

[def _AllocatorAwareContainer_ [@http://en.cppreference.com/w/cpp/named_req/AllocatorAwareContainer [* `AllocatorAwareContainer`]]]
[def _Callable_ [@http://en.cppreference.com/w/cpp/named_req/Callable [* `Callable`]]]
[def _Container_ [@http://en.cppreference.com/w/cpp/named_req/Container [* `Container`]]]
[def _CopyAssignable_ [@http://en.cppreference.com/w/cpp/named_req/CopyAssignable [* `CopyAssignable`]]]
[def _CopyInsertable_ [@http://en.cppreference.com/w/cpp/named_req/CopyInsertable [* `CopyInsertable`]]]
[def _DefaultConstructible_ [@http://en.cppreference.com/w/cpp/named_req/DefaultConstructible [* `DefaultConstructible`]]]
[def _InputIterator_ [@http://en.cppreference.com/w/cpp/named_req/InputIterator [* `InputIterator`]]]
[def _INVOKE_ [@http://en.cppreference.com/w/cpp/utility/functional/invoke ['[* `INVOKE`]]]]
[def _MoveAssignable_ [@http://en.cppreference.com/w/cpp/named_req/MoveAssignable [* `MoveAssignable`]]]
[def _MoveInsertable_ [@http://en.cppreference.com/w/cpp/named_req/MoveInsertable [* `MoveInsertable`]]]

[section Reference]

[section Polymorphism models]

[def _polymorphism_model_ [link poly_collection.reference.polymorphism_models polymorphism model]]

The key aspect of dynamic polymorphism is the ability for a value of type `T`
to internally use another value of a possibily different type `U` for the
implementation of a given interface. Base/derived polymorphism is the classic
model of dynamic polymorphism in C++, but not the only possible one.

Formally, a /polymorphism model/ is defined by

* A family *Interface* of permissible interface types and, for each
`I` \u2208 *Interface*, the family *Implementation*(`I`) of types satisfying
`I`.
* For a given interface type `I`, an operation *subobject*(`x`) that maps each
value of an implementation type to its internally used value `y` of a possibly
different implementation type
[footnote This is a metalinguistic definition not directly expressible in C++.
There are equivalent formulations that can indeed be realized in C++, but
they add little to the comprehension of the concepts.].

Static polymorphism is the trivial case where *subobject*(`x`) = `x` for all
`x`. Base/derived polymorphism is characterized by:

* *Interface* = { `Base` : `std::is_polymorphic_v<Base>` }.
* *Implementation*(`Base`) = { `Derived` : `std::is_base_of_v<Base,Derived>` }.
* *subobject*(`x`) = `static_cast<Derived&>(x)` with `typeid(x)==typeid(Derived)`.

[endsect]

[section Polymorphic containers]

[def _PolymorphicContainer_ [link poly_collection.reference.polymorphic_containers [* `PolymorphicContainer`]]]

A /polymorphic container/ is an object that stores objects of some type `T`
implementing a given interface `I` under an implicitly associated polymorphism
model. Polymorphic containers satisfy the requirements for _Container_ and
_AllocatorAwareContainer_ with the following modifications:

* Where it occurs, replace the requirement that `T` be _CopyInsertable_,
_CopyAssignable_, _MoveInsertable_,  _MoveAssignable_ or
_EqualityComparable_,  with the following semantic clause: may throw if
some subobject in the container is not
_CopyConstructible_ (respectively, _CopyAssignable_, _MoveConstructible_, 
_MoveAssignable_, _EqualityComparable_).
* Replace [container.requirements.general]/3 with:
`allocator_type` must have the property that for any type `U`
implementing `I` and the associated type `A` =
`std::allocator_traits<allocator_type>::rebind_alloc<U>`, `U` is
_CopyInsertable_ (respectively _MoveInsertable_) with respect to `A` if and
only if `U` is  _CopyConstructible_ (respectively _MoveConstructible_);
all subobjects of type `U` stored in these containers shall be constructed
using the `std::allocator_traits<A>::construct` function and
destroyed using the `std::allocator_traits<A>::destroy` function;
these functions (or their equivalents for a rebound allocator) are called
only for the types of the stored subobjects, not for
any other type (internal or public) used by the container.

[section Polymorphic collections]

[def _PolymorphicCollection_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections [* `PolymorphicCollection`]]]

/Polymorphic collections/ store their objects of type `value_type` in
/segments/ dedicated to each of the types of the contained subojects.
Only objects whose subobjects are of an /acceptable/ type are allowed,
where a type `U` is said to be acceptable if

* it implements the interface associated to the container,
* it is _MoveConstructible_,
* it is _MoveAssignable_ or
[@http://en.cppreference.com/w/cpp/types/is_move_constructible
`std::is_nothrow_move_constructible<U>::value`] is `true`.

Polymorphic collections conform
to the requirements of _PolymorphicContainer_ with the following
modfications and extra guarantees:

* The complexity of `empty()` and `size()` is linear on the number of
segments of the collection.
* `max_size()` is not provided.
* `a==b` evaluates to `true` iff for each non-empty segment of subojects
of type `U` in `a` there is a segment of `U` in `b` with the same size
and equal elements in the same order, and vice versa.
* No exceptions are thrown associated to some subobject type not being
_CopyAssignable_, _MoveConstructible_ or _MoveAssignable_.

A type `U` is said to be /registered/ into the collection if a
(possibly empty) segment for `U` has been created. Registered types
continue to stay so for the duration of the container except if it is
moved from, assigned to, or swapped.

Each segment has an associated capacity indicating the maximum size
that it can attain without reallocation. When the limit
is exceeded (or explicitly through `reserve`) new storage space is
allocated with greater capacity and elements are moved.

Collection traversal goes through the elements of the first segment,
then the second, etc. The order in which segments are visited is
unspecified but remains stable until a new segment is created.

Besides `iterator` and `const_iterator`, there are iterator types
`local_base_iterator` and `local_iterator<U>` (and their `const_`
counterparts) whose objects can be used to iterate over the segment
for `U` (in the same order followed by global traversal).
Local base iterators refer to `value_type`, whereas
(`const_`)`local_iterator<U>` refers to `U`. All local iterators model
_RandomAccessIterator_. Local base iterators may not be used
to iterate across segments, and comparing local base iterators
associated to different segments is undefined behavior. A (const)
local base iterator to a segment for `U` can be explicitly converted
to (`const_`)`local_iterator<U>` pointing to the same position,
and vice versa.

Insertion and erasure do not invalidate iterators (global or local)
except those from the insertion/erasure point to the end of the
affected segment, if its capacity is not exceeded, or all
iterators/references to the segment otherwise
[footnote The global `end()` iterator lies outside any segment, hence
it always remain valid.].

For the description of the remaining requirements of polymorphic collections,
we use the following notation:

* `C` is a polymorphic collection type,
* `c` is an object of type `C`, `cc` is a possibly `const` object of type `C`,
* `al` is a value of type `C::allocator_type`,
* `info` is a `const std::type_info&`,
* `U` is an acceptable type, `Us...` is a template parameter pack of
acceptable types, 
* `n` is a value of `size_type`,
* `x` is a value of a type `T` implementing the interface associated to the
collection,
* `args...` is a function parameter pack of types `Args&&...`,
* `it` is a possibly const global iterator of `c`,
* `it1` and `it2` are (same-typed) possibly const global iterators of a `C`
collection other than `c` such that \[`it1`, `it2`) is a valid range.
* `lbit` is a possibly const local base iterator of `c`,
* `lbit1` and `lbit2` are (same-typed) possibly const local base iterators of
a `C` collection other than `c` such that \[`lbit1`, `lbit2`) is a valid range.
* `lit` is a (`const_`)`local_iterator<U>` of `c`,
* `lit1` and `lit2` are (same-typed) (`const_`)`local_iterator<U>`s of
a `C` collection other than `c` such that \[`lit1`, `lit2`) is a valid range,
* `i1` and `i2` are iterators external to `c` referring to `T` such that
\[`i1`, `i2`) is a valid range,
* `j1` and `j2` are iterators external to `c` such that
\[`j1`, `j2`) is a valid range,
* `xit1` and `xit2` are (same-typed) possibly const iterators (global or
local) of `c` such that \[`xit1`, `xit2`) is a valid range.

[section Types]

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.local_base_iterator]
[def _local_base_iterator_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.local_base_iterator `local_base_iterator`]]

`C::local_base_iterator`

_RandomAccessIterator_ with same value type, difference type and pointer and
reference types as `C::iterator`, valid for accessing elements of a given
segment. Implicily convertible to `C::const_local_base_iterator`, explicitly
convertible to `C::local_iterator<U>` if the segment it points to is actually
that for `U`.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_local_base_iterator]
[def _const_local_base_iterator_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_local_base_iterator `const_local_base_iterator`]]

`C::const_local_base_iterator`

_RandomAccessIterator_ with same value type, difference type and pointer and
reference types as `C::const_iterator`, valid for accessing elements of a given
segment. Explicitly convertible to `C::const_local_iterator<U>` if the segment
it points to is actually that for `U`.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.local_iterator]
[def _local_iterator_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.local_iterator `local_iterator`]]

`C::local_iterator<U>`

_RandomAccessIterator_ with value type `U`, reference type `U&`, pointer type
`U*` and the same difference type as `C::iterator`, valid for accessing elements
of the segment for `U`. Implicily convertible to `C::const_local_iterator<U>`,
explicitly convertible to `C::local_base_iterator`.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_local_iterator]
[def _const_local_iterator_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_local_iterator `const_local_iterator`]]

`C::const_local_iterator<U>`

_RandomAccessIterator_ with value type `U`, reference type `const U&`, pointer
type `const U*` and the same difference type as `C::iterator`, valid for
accessing elements of the segment for `U`. Explicitly convertible to
`C::const_local_base_iterator`.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_base_segment_info]
[def _const_base_segment_info_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_base_segment_info `const_base_segment_info`]]

`C::const_base_segment_info`

_CopyConstructible_ and _CopyAssignable_ type with information about a given
segment of a collection. If `ci` is a possibly `const` object of type
`C::const_base_segment_info` associated to the segment of `c` for `U`, then

* `ci.begin()==c.cbegin(typeid(U))`
* `ci.cbegin()==c.cbegin(typeid(U))`
* `ci.begin<U>()==c.cbegin<U>()`
* `ci.cbegin<U>()==c.cbegin<U>()`
* `ci.end()==c.cend(typeid(U))`
* `ci.cend()==c.cend(typeid(U))`
* `ci.end<U>()==c.cend<U>()`
* `ci.cend<U>()==c.cend<U>()`
* `ci.type_info()==typeid(U)`

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.base_segment_info]
[def _base_segment_info_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.base_segment_info `base_segment_info`]]

`C::base_segment_info`

_CopyConstructible_ and _CopyAssignable_ type publicly derived from 
`C::const_base_segment_info` and exposing its public interface. Additionally,
if `i` is an object of type `C::base_segment_info` associated to the
segment of `c` for `U`, then

* `i.begin()==c.begin(typeid(U))`
* `i.begin<U>()==c.begin<U>()`
* `i.end()==c.end(typeid(U))`
* `i.end<U>()==c.end<U>()`

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_segment_info]
[def _const_segment_info_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_segment_info `const_segment_info`]]

`C::const_segment_info<U>`

_CopyConstructible_ and _CopyAssignable_ type with information about the segment
for `U`. If `ci` is a possibly `const` object of type `C::const_segment_info<U>`
associated to the collection `c`, then

* `ci.begin()==c.cbegin<U>()`
* `ci.cbegin()==c.cbegin<U>()`
* `ci.end()==c.cend<U>()`
* `ci.cend()==c.cend<U>()`

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.segment_info]
[def _segment_info_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.segment_info `segment_info`]]

`C::segment_info<U>`

_CopyConstructible_ and _CopyAssignable_ type publicly derived from 
`C::const_segment_info<U>` and exposing its public interface. Additionally,
if `i` is an object of type `C::segment_info<U>` associated to the collection
`c`, then

* `i.begin()==c.begin<U>()`
* `i.end()==c.end<U>()`

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.base_segment_info_iterator]
[def _base_segment_info_iterator_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.base_segment_info_iterator `base_segment_info_iterator`]]

`C::base_segment_info_iterator`

_InputIterator_ with value type and reference type `C::base_segment_info`.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_base_segment_info_iterator]
[def _const_base_segment_info_iterator_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_base_segment_info_iterator `const_base_segment_info_iterator`]]

`C::const_base_segment_info_iterator`

_InputIterator_ with value type and reference type `C::const_base_segment_info`.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_segment_traversal_info]
[def _const_segment_traversal_info_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.const_segment_traversal_info `const_segment_traversal_info`]]

`C::const_segment_traversal_info`

_CopyConstructible_ and _CopyAssignable_ type with `const` member
functions `begin`/`cbegin` and `end`/`cend` returning
`C::const_base_segment_info_iterator` objects that span over a range
of `C::const_base_segment_info` objects.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.types.segment_traversal_info]
[def _segment_traversal_info_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.types.segment_traversal_info `segment_traversal_info`]]

`C::segment_traversal_info`

_CopyConstructible_ and _CopyAssignable_ type publicly derived
from with `C::const_segment_traversal_info` and exposing its
public interface. Additionally, provides non-const member
functions `begin` and `end` returning
`C::base_segment_info_iterator` objects that span over an equivalent range
of `C::base_segment_info` objects.

[endsect]

[section Construct/copy/destroy]

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.construct_copy_destroy.range_construction]

`C(j1,j2)`[br]
`C d(j1,j2)`

[*Requires:] `C::allocator_type` is _DefaultConstructible_. \[`j1`, `j2`) can be
inserted into `C`.[br]
[*Effects:] Copy constructs the internal allocator from `C::allocator_type()`.
Internally calls `this->insert(j1,j2)` on construction.

`C(j1,j2,al)`[br]
`C d(j1,j2,al)`

[*Requires:] \[`j1`, `j2`) can be inserted into `C`.[br]
[*Effects:] Copy constructs the internal allocator from `al`.
Internally calls `this->insert(j1,j2)` on construction.

[endsect]

[section Type registration]

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.type_registration.register_types]
[def _register_types_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.type_registration.register_types `register_types`]]

`c.register_types<Us...>()`

[*Effects:] Registers (if needed) each of the indicated types in the
collection.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.type_registration.is_registered]
[def _is_registered_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.type_registration.is_registered `is_registered`]]

`cc.is_registered(info)`[br]
`cc.is_registered<U>()`

[*Returns:] `true` iff the indicated type is registered in the collection.

[endsect]

[section Iterators]

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.begin]
[def _begin_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.begin `begin`]]
[def _cbegin_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.begin `cbegin`]]

(1) `c.begin(info)`[br]
(2) `c.begin<U>()`[br]
(3) `const_cast<const C&>(c).begin(info)`[br]
(4) `cc.cbegin(info)`[br]
(5) `const_cast<const C&>(c).begin<U>()`[br]
(6) `cc.cbegin<U>()`

[*Returns:] A `local_base_iterator` (1) or `local_iterator<U>` (2) or
`const_local_base_iterator` (3,4) or `const_local_iterator<U>` (5,6) to the
beginning of the segment for the indicated type.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.end]
[def _end_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.end `end`]]
[def _cend_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.end `cend`]]

(1) `c.end(info)`[br]
(2) `c.end<U>()`[br]
(3) `const_cast<const C&>(c).end(info)`[br]
(4) `cc.cend(info)`[br]
(5) `const_cast<const C&>(c).end<U>()`[br]
(6) `cc.cend<U>()`

[*Returns:] A `local_base_iterator` (1) or `local_iterator<U>` (2) or
`const_local_base_iterator` (3,4) or `const_local_iterator<U>` (5,6) to the
end of the segment for the indicated type.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.segment]
[def _segment_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.segment `segment`]]

(1) `c.segment(info)`[br]
(2) `c.segment<U>()`[br]
(3) `const_cast<const C&>(c).segment(info)`[br]
(4) `const_cast<const C&>(c).segment<U>()`[br]

[*Returns:] A `base_segment_info` (1) or `segment_info<U>` (2) or
`const_base_segment_info` (3) or `const_segment_info<U>` (4) object
referring to the segment for the indicated type.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.segment_traversal]
[def _segment_traversal_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.iterators.segment_traversal `segment_traversal`]]

(1) `c.segment_traversal()`[br]
(2) `const_cast<const C&>(c).segment_traversal()`

[*Returns:] A `segment_traversal_info` (1) or `const_segment_traversal_info`
(2) object spanning over a range of segment descriptors for the collection.
The order in which segments are visited matches that of
\[`c.begin()`, `c.end()`).

[endsect]

[section Capacity]

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.empty]
[def _empty_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.empty `empty`]]

`cc.empty(info)`[br]
`cc.empty<U>()`

[*Returns:] `true` iff the segment for the indicated type exists and
is empty.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.size]
[def _size_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.size `size`]]

`cc.size(info)`[br]
`cc.size<U>()`

[*Returns:] The size of the segment for the indicated type.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.max_size]
[def _max_size_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.max_size `max_size`]]

`cc.max_size(info)`[br]
`cc.max_size<U>()`

[*Returns:] The maximum size attainable by the segment for
the indicated type.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.capacity]
[def _capacity_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.capacity `capacity`]]

`cc.capacity(info)`[br]
`cc.capacity<U>()`[br]

[*Returns:] The maximum size that the segment for the indicated type can
attain without requiring reallocation.[br]
[*Throws:] If the indicated type is not registered.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.reserve]
[def _reserve_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.reserve `reserve`]]

`c.reserve(n)`

[*Effects:] Calls `reserve` with `n` for each of the segments of the
collection.

(1) `c.reserve(info,n)`[br]
(2) `c.reserve<U>(n)`

[*Effects:] Throws if the type indicated by `info` is not registered (1)
or registers `U` if needed (2). If `n` is greater than the current
capacity of the segment for the indicated type, new storage space is allocated
with a capacity of at least `n` and elements are moved there.[br]
[*Complexity:] Linear in the size of the segment if reallocation happens,
constant otherwise.[br]
[*Throws:] `std::length_error` if `n` is greater than the return value of
`max_size` for the segment.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.shrink_to_fit]
[def _shrink_to_fit_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.capacity.shrink_to_fit `shrink_to_fit`]]

`c.shrink_to_fit()`

[*Effects:] Calls `shrink_to_fit` for each of the segments of the
collection.

`c.shrink_to_fit(info)`[br]
`c.shrink_to_fit<U>()`

[*Effects:] Non-binding request to reduce memory usage while preserving the
sequence of elements of the segment for the indicated type. May invalidate
all iterators and references to the segment.[br]
[*Throws:] If the indicated type is not registered.

[endsect]

[section Modifiers]

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.emplace]
[def _emplace_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.emplace `emplace`]]
[def _emplace_hint_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.emplace `emplace_hint`]]

(1) `c.emplace<U>(args...)`[br]
(2) `c.emplace_hint<U>(it,args...)`

[*Requires:] `U` is constructible from `std::forward<Args>(args)...`.[br]
[*Effects:] Registers `U` (if needed) and inserts a new element with
a subobject constructed from `std::forward<Args>(args)...`: (1) at the end of
the segment for `U`; (2) just before the
position indicated by `it`, if it points to the segment for `U`, or at the
end of the segment for `U` otherwise.[br]
[*Returns:] An `iterator` to the newly inserted element.[br]
[*Complexity:] Amortized constant time plus linear in the distance from the
insertion position to the end of the segment.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.emplace_pos]
[def _emplace_pos_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.emplace_pos `emplace_pos`]]

(1) `c.emplace_pos<U>(lbit,args...)`[br]
(2) `c.emplace_pos(lit,args...)`

[*Requires:] `U` is constructible from `std::forward<Args>(args)...`.
(1) `lbit` points to the segment for `U`.[br]
[*Effects:] Inserts a new element with
a subobject constructed from `std::forward<Args>(args)...` just before the
position indicated.[br]
[*Returns:] A `local_base_iterator` (1) or `local_iterator<U>` (2) to the
newly inserted element.[br]
[*Complexity:] Amortized constant time plus linear in the distance from
the insertion position to the end of the segment.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert]
[def _insert_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert `insert`]]
[def _insert_hint_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert `insert`]]

(1) `c.insert(x)`[br]
(2) `c.insert(it,x)`

[*Effects:] Let `Q` be the type of the subobject of `x`. If
`Q` = `T` and `T` is acceptable, registers `T` if needed.
If `Q` = `T` and `T` is not acceptable, throws.
If `Q` \u2260 `T` and `Q` is not registered, throws.
If `x` is not a non-const rvalue expression and `Q` is not _CopyConstructible_, throws.
Inserts an element with a subobject move constructed or copy constructed
from the subobject of `x`: (1) at the end of the corresponding segment;
(2) just before the position indicated by `it`, if it points to the
corresponding segment, or at the end of the segment otherwise.[br]
[*Returns:] An `iterator` to the newly inserted element.[br]
[*Complexity:] Amortized constant time plus linear in the distance
from the insertion position to the end of the segment.

(1) `c.insert(lbit,x)`[br]
(2) `c.insert(lit,x)`

[*Requires:] The type of the subobject of `x` corresponds to the indicated
segment.[br]
[*Effects:] Inserts an element with a subobject move constructed or copy
constructed from the subobject of `x` just before the
position indicated.[br]
[*Returns:] A `local_base_iterator` (1) or `local_iterator<U>` (2) to the
newly inserted element.[br]
[*Complexity:] Amortized constant time plus linear in the distance
from the insertion position to the end of the segment.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert_range]
[def _insert_range_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert_range `insert`]]

`c.insert(i1,i2)`

[*Effects:] Equivalent to `while(i1!=i2)c.insert(*i1++)`.

`c.insert(it1,it2)`[br]
`c.insert(lbit1,lbit2)`[br]
`c.insert(lit1,lit2)`

[*Effects:] For each of the elements of the range in succession, registers the
type of its subobject if needed and inserts it into the collection
[footnote Note that, unlike `c.insert(i1,i2)`, these versions do not throw
due to type registration problems.].

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert_hint_range]
[def _insert_hint_range_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.insert_hint_range `insert`]]

`c.insert(it,i1,i2)`

[*Effects:] If `it==c.end()`, equivalent to `while(i1!=i2)c.insert(it,*i1++)`,
otherwise inserts each of the elements in \[`i1`, `i2`) in succession with a hint
pointing to `*it`
[footnote That is, the hint remains stable even if `it` may become invalid due
to reallocations.].

`c.insert(it,it1,it2)`[br]
`c.insert(it,lbit1,lbit2)`[br]
`c.insert(it,lit1,lit2)`

[*Effects:] If `it==c.end()`, equivalent to the corresponding hint-less version,
otherwise for each of the elements in \[`i1`, `i2`) in succession registers the
type of its subobject if needed and inserts it into the collection with a hint
pointing to `*it`
[footnote The two previous notes apply here.].

`c.insert(lbit,i1,i2)`

[*Requires:] The subojects of elements in  \[`i1`, `i2`) are all of the type
corresponding to the indicated segment.[br]
[*Effects:] Inserts a range of elements with subobjects copy constructed from
those in \[`i1`, `i2`) just before `lbit`.[br]
[*Returns:] A `local_base_iterator` to the beginning of the inserted range.

`c.insert(lit,j1,j2)`

[*Requires:] For each value `x` in \[`j1`, `j2`) either (a) `x` is of a type
implementing the interface associated to the collection and the subobject of
`x` is of type `U` or (b) `U` is constructible from `x`.[br]
[*Effects:] Inserts a range of elements with subobjects copy
constructed (a) or constructed (b) from the values in \[`j1`, `j2`)
just before `lit`.[br]
[*Returns:] A `local_iterator<U>` to the beginning of the inserted range.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.erase]
[def _erase_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.erase `erase`]]

`c.erase(xit1)`[br]
`c.erase(xit1,xit2)`

[*Effects:] Erases the indicated element(s).[br]
[*Returns:] A non-const iterator of the same category as `xit` pointing
to the position just after the erased element(s).[br]
[*Complexity:] Linear on the number of elements erased plus the distance
from the last one to the end of its segment.

[#poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.clear]
[def _clear_ [link poly_collection.reference.polymorphic_containers.polymorphic_collections.modifiers.clear `clear`]]

`c.clear()`

[*Effects:] Erases all the elements of the container.[br]
[*Complexity:] Linear.

`c.clear(info)`[br]
`c.clear<U>()`

[*Effects:] Erases all the elements of the segment for the indicated type.[br]
[*Complexity:] Linear in the size of the segment.[br]
[*Throws:] If the indicated type is not registered.

[endsect]

[endsect]

[endsect]

[import poly_collection_synopsis.qbk] [/ template poly_collection_synopsis]

[section Header `"boost/poly_collection/exception.hpp"` synopsis]

All the collections in Boost.PolyCollection use the following exceptions
(and only these) to signal various run-time problems with contained types:

  namespace boost{

  namespace poly_collection{

  struct ``[link poly_collection.reference.header_boost_poly_collection_exc.class_unregistered_type unregistered_type]``;
  struct ``[link poly_collection.reference.header_boost_poly_collection_exc.class_not_copy_constructible not_copy_constructible]``;
  struct ``[link poly_collection.reference.header_boost_poly_collection_exc.class_not_equality_comparable not_equality_comparable]``;

  } /* namespace poly_collection */

  } /* namespace boost */

[section Class `unregistered_type`]

  struct unregistered_type:std::logic_error
  {
    unregistered_type(const std::type_info& info);

    const std::type_info* pinfo;
  };

`unregistered_type` is thrown when an operation is requested on a type which
does not yet have an associated segment.

`unregistered_type(const std::type_info& info);`

[*Effects:] Constructs an `unregistered_type` object with the specified type
information.

[endsect]

[section Class `not_copy_constructible`]

  struct not_copy_constructible:std::logic_error
  {
    not_copy_constructible(const std::type_info& info);

    const std::type_info* pinfo;
  };

`not_copy_constructible` is thrown when a copy operation is tried that
involves a non-_CopyConstructible_ type.

`not_copy_constructible(const std::type_info& info);`

[*Effects:] Constructs a `not_copy_constructible` object with the specified
type information.

[endsect]

[section Class `not_equality_comparable`]

  struct not_equality_comparable:std::logic_error
  {
    not_equality_comparable(const std::type_info& info);

    const std::type_info* pinfo;
  };

`not_equality_comparable` is thrown when comparing two collections
for (in)equality involves a non-_EqualityComparable_ type.

`not_equality_comparable(const std::type_info& info);`

[*Effects:] Constructs a `not_equality_comparable` object with the specified
type information.

[endsect]

[endsect]

[section Header `"boost/poly_collection/base_collection_fwd.hpp"` synopsis]

[def _base_collection_ [link poly_collection.reference.header_boost_poly_collection_ba0.class_template_base_collection `base_collection`]]

  #include <memory>

  namespace boost{

  namespace poly_collection{

  template<typename Base,typename Allocator=std::allocator<Base>>
  class _base_collection_;

  template<typename Base,typename Allocator>
  bool operator==(
    const base_collection<Base,Allocator>& x,
    const base_collection<Base,Allocator>& y);

  template<typename Base,typename Allocator>
  bool operator!=(
    const base_collection<Base,Allocator>& x,
    const base_collection<Base,Allocator>& y);

  template<typename Base,typename Allocator>
  void swap(
    base_collection<Base,Allocator>& x,base_collection<Base,Allocator>& y);

  } /* namespace poly_collection */

  using poly_collection::base_collection;

  } /* namespace boost */

Forward declares the class template _base_collection_
and specifies its default template arguments. Forward declares associated free
functions and brings `boost::poly_collection::base_collection` to the `boost`
namespace.

[endsect]

[section Header `"boost/poly_collection/base_collection.hpp"` synopsis]

  #include <boost/poly_collection/base_collection_fwd.hpp>

  namespace boost{

  namespace poly_collection{

  template<typename Base,typename Allocator>
  class _base_collection_;

  template<typename Base,typename Allocator>
  bool operator==(
    const base_collection<Base,Allocator>& x,
    const base_collection<Base,Allocator>& y);

  template<typename Base,typename Allocator>
  bool operator!=(
    const base_collection<Base,Allocator>& x,
    const base_collection<Base,Allocator>& y);

  template<typename Base,typename Allocator>
  void swap(
    base_collection<Base,Allocator>& x,base_collection<Base,Allocator>& y);

  } /* namespace poly_collection */

  } /* namespace boost */

[section Class template `base_collection`]

`base_collection<Base,Allocator>` is a _PolymorphicCollection_ associated to
the classic base/derived _polymorphism_model_:

* *Interface* = { `Base` : `std::is_polymorphic_v<Base>` }.
* *Implementation*(`Base`) = { `Derived` : `std::is_base_of_v<Base,Derived>` }.
* *subobject*(`x`) = `static_cast<Derived&>(x)` with `typeid(x)==typeid(Derived)`.

[poly_collection_synopsis `base_collection`..`template<typename Base,typename Allocator>`..`Base`]

[endsect]

[endsect]

[section Header `"boost/poly_collection/function_collection_fwd.hpp"` synopsis]

[def _function_collection_ [link poly_collection.reference.header_boost_poly_collection_fu0.class_template_function_collecti `function_collection`]]
[def _function_collection_value_type_ [link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti `function_collection_value_type`]]

  #include <memory>

  namespace boost{

  namespace poly_collection{

  template<typename Signature>
  using _function_collection_value_type_=``/implementation-defined/``;

  template<
    typename Signature,
    typename Allocator=std::allocator<function_collection_value_type<Signature>>
  >
  class _function_collection_;

  template<typename Signature,typename Allocator>
  bool operator==(
    const function_collection<Signature,Allocator>& x,
    const function_collection<Signature,Allocator>& y);

  template<typename Signature,typename Allocator>
  bool operator!=(
    const function_collection<Signature,Allocator>& x,
    const function_collection<Signature,Allocator>& y);

  template<typename Signature,typename Allocator>
  void swap(
    function_collection<Signature,Allocator>& x,
    function_collection<Signature,Allocator>& y);

  } /* namespace poly_collection */

  using poly_collection::function_collection;

  } /* namespace boost */

Defines the alias template _function_collection_value_type_ (the actual type
it refers to, though, is merely forward declared).
Forward declares the class template _function_collection_
and specifies its default template arguments. Forward declares associated free
functions and brings `boost::poly_collection::function_collection` to the
`boost` namespace.

[endsect]

[section Header `"boost/poly_collection/function_collection.hpp"` synopsis]

  #include <boost/poly_collection/function_collection_fwd.hpp>

  namespace boost{

  namespace poly_collection{

  // defines the type ``_function_collection_value_type_`` refers to

  template<typename Signature,typename Allocator>
  class _function_collection_;

  template<typename Signature,typename Allocator>
  bool operator==(
    const function_collection<Signature,Allocator>& x,
    const function_collection<Signature,Allocator>& y);

  template<typename Signature,typename Allocator>
  bool operator!=(
    const function_collection<Signature,Allocator>& x,
    const function_collection<Signature,Allocator>& y);

  template<typename Signature,typename Allocator>
  void swap(
    function_collection<Signature,Allocator>& x,
    function_collection<Signature,Allocator>& y);

  } /* namespace poly_collection */

  } /* namespace boost */

[section Alias template `function_collection_value_type`]

`function_collection_value_type<Signature>` is the `value_type` of
`boost::function_collection<Signature,Allocator>`, where `Signature` must be a type
of the form `R(Args...)`. `function_collection_value_type<Signature>` wraps a
reference to an object modeling _Callable_ for the given `Signature`. The
interface provided partially replicates that of _std::function_ and adds some
extra facilities.

In what follows, the name [' `function_collection_value_type_impl`]
is used just for explanatory purposes in place of the actual
class template name, which is implementation defined.

  template<typename Signature>
  using function_collection_value_type=
    ``/function_collection_value_type_impl/``<Signature>;

  template<typename Signature>
  class ``/function_collection_value_type_impl/``;

  template<typename R,typename... Args>
  class ``/function_collection_value_type_impl/``<R(Args...)>
  {
  public:
    explicit ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.operator_bool operator bool]``()const noexcept;

    R ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.operator_call operator()]``(Args... args)const;

    const std::type_info& ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.target_type target_type]``()const noexcept;
    template<typename T> T* ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.target target]``()noexcept;
    template<typename T> const T* ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.target target]``()const noexcept;

    operator ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.operator_std_function std::function<R(Args...)>]``()const noexcept;

    void*       ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.data data]``()noexcept;
    const void* ``[link poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.data data]``()const noexcept;
  };

[#poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.operator_bool]

`explicit operator bool()const noexcept;`

[*Returns:] `true`.

[#poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.operator_call]

`R operator()(Args... args)const;`

[*Effects:] `_INVOKE_(f,std::forward<Args>(args)...,R)`, where f is the wrapped
callable object.[br]
[*Returns:] Nothing if `R` is `void`, otherwise the return value of
`_INVOKE_(f,std::forward<Args>(args)...,R)`.

[#poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.target_type]

`const std::type_info& target_type()const noexcept;`

[*Returns:] `typeid(T)` where `T` is the type of the wrapped callable object.

[#poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.target]

`template<typename T> T* target()noexcept;`[br]
`template<typename T> const T* target()const noexcept;`

[*Returns:] If `target_type()==typeid(T)` a pointer to the wrapped callable
object, otherwise `nullptr`.

[#poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.operator_std_function]

`operator std::function<R(Args...)>()const noexcept;`

[*Returns:] A `std::function<R(Args...)>` object holding a reference to the
wrapped callable object.

[#poly_collection.reference.header_boost_poly_collection_fu0.alias_template_function_collecti.data]

`void* data()noexcept;`[br]
`const void* data()const noexcept;`

[*Returns:] The address of the wrapped callable object.

[endsect]

[section Class template `function_collection`]

`function_collection<Signature,Allocator>` is a _PolymorphicCollection_ associated to
a dynamic _polymorphism_model_ based on call signature compatibility:

[itemized_list
  [*Interface* = { `Signature` : `Signature` = `R(Args...)` }.]
  [*Implementation*(`Signature`) = { `Callable` : `std::is_invocable_r_v<R,Callable,Args...>` }.]
  [*subobject*(`x`) =[br]
    `x.target<T>()` with `typeid(T)==x.target_type()`, if `x` is an instantiation of _function_collection_value_type_,[br]
    `x`, otherwise.
  ]
]

[poly_collection_synopsis `function_collection`..`template<typename Signature,typename Allocator>`..`_function_collection_value_type_<Signature>`]

[endsect]

[endsect]

[section Header `"boost/poly_collection/any_collection_fwd.hpp"` synopsis]

[def _any_collection_ [link poly_collection.reference.header_boost_poly_collection_an0.class_template_any_collection `any_collection`]]
[def _any_collection_value_type_ [link poly_collection.reference.header_boost_poly_collection_an0.alias_template_any_collection_va `any_collection_value_type`]]

  #include <memory>

  namespace boost{

  namespace poly_collection{

  template<typename Concept>
  using _any_collection_value_type_=``/implementation-defined/``;

  template<
    typename Concept,
    typename Allocator=std::allocator<any_collection_value_type<Concept>>
  >
  class _any_collection_;

  template<typename Concept,typename Allocator>
  bool operator==(
    const any_collection<Concept,Allocator>& x,
    const any_collection<Concept,Allocator>& y);

  template<typename Concept,typename Allocator>
  bool operator!=(
    const any_collection<Concept,Allocator>& x,
    const any_collection<Concept,Allocator>& y);

  template<typename Concept,typename Allocator>
  void swap(
    any_collection<Concept,Allocator>& x,any_collection<Concept,Allocator>& y);

  } /* namespace poly_collection */

  using poly_collection::any_collection;

  } /* namespace boost */

Defines the alias template _any_collection_value_type_ (the actual type
it refers to, though, is merely forward declared).
Forward declares the class template _any_collection_
and specifies its default template arguments. Forward declares associated free
functions and brings `boost::poly_collection::any_collection` to the
`boost` namespace.

[endsect]

[section Header `"boost/poly_collection/any_collection.hpp"` synopsis]

  #include <boost/poly_collection/any_collection_fwd.hpp>

  namespace boost{

  namespace poly_collection{

  // defines the type ``_any_collection_value_type_`` refers to

  template<typename Concept,typename Allocator>
  class _any_collection_;

  template<typename Concept,typename Allocator>
  bool operator==(
    const any_collection<Concept,Allocator>& x,
    const any_collection<Concept,Allocator>& y);

  template<typename Concept,typename Allocator>
  bool operator!=(
    const any_collection<Concept,Allocator>& x,
    const any_collection<Concept,Allocator>& y);

  template<typename Concept,typename Allocator>
  void swap(
    any_collection<Concept,Allocator>& x,any_collection<Concept,Allocator>& y);

  } /* namespace poly_collection */

  } /* namespace boost */

[section Alias template `any_collection_value_type`]

`any_collection_value_type<Concept>` is the `value_type` of
`boost::any_collection<Concept,Allocator>`, where `Concept` is defined according to
the [@boost:/doc/html/boost_typeerasure/conceptdef.html requisites]
of _Boost.TypeErasure_ using
[@boost:/doc/html/boost/type_erasure/_self.html `_self`]
as its [@boost:/doc/html/boost/type_erasure/placeholder.html placeholder].
The alias template definition has the form

  template<typename Concept>
  using any_collection_value_type=
    boost::type_erasure::``[@boost:/doc/html/boost/type_erasure/any.html any]``<Concept2,boost::type_erasure::_self&>;

with `boost::type_erasure::`[@boost:/doc/html/boost/type_erasure/is_subconcept.html `is_subconcept`]`<Concept,Concept2>::value==true`.
The exact definition of `Concept2` is implementation defined.

[endsect]

[section Class template `any_collection`]

`any_collection<Concept,Allocator>` is a _PolymorphicCollection_ associated to
a dynamic _polymorphism_model_ based on _duck_typing_ as implemented by
_Boost.TypeErasure_:

[itemized_list
  [*Interface* = { `Concept` :
    as [@boost:/doc/html/boost_typeerasure/conceptdef.html specified] by _Boost.TypeErasure_,
    using the [@boost:/doc/html/boost/type_erasure/_self.html `_self`]
    [@boost:/doc/html/boost/type_erasure/placeholder.html placeholder] }.]
  [*Implementation*(`Concept`) = { `Concrete` : `Concrete` satisfies `Concept` }.]
  [*subobject*(`x`) =[br]
    `boost::type_erasure::`[@boost:/doc/html/boost/type_erasure/any_cast.html `any_cast`]`<T&>(x)`
    with `typeid(T)==boost::type_erasure::`[@boost:/doc/html/boost/type_erasure/typeid_of.html `typeid_of`]`(x)`,
    if `x` is an instantiation of `boost::type_erasure::`[@boost:/doc/html/boost/type_erasure/any.html `any`]
    including [@boost:/doc/html/boost/type_erasure/typeid_.html `typeid_`]`<>`,[br]
    `x`, otherwise.
  ]
]

[poly_collection_synopsis `any_collection`..`template<typename Concept,typename Allocator>`..`_any_collection_value_type_<Concept>`]

[endsect]

[endsect]

[section Header `"boost/poly_collection/algorithm.hpp"` synopsis]

  namespace boost{

  namespace poly_collection{

  ``['`// non-modifying sequence operations:`]``

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  bool all_of(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  bool any_of(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  bool none_of(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<typename... Ts,typename PolyCollectionIterator,typename Function>
  Function for_each(
    PolyCollectionIterator first,PolyCollectionIterator last,Function f);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename Size,typename Function
  >
  Iterator for_each_n(
    PolyCollectionIterator first,Size n,Function f);

  template<typename... Ts,typename PolyCollectionIterator,typename T>
  PolyCollectionIterator find(
    PolyCollectionIterator first,PolyCollectionIterator last,const T& x);

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  PolyCollectionIterator find_if(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  PolyCollectionIterator find_if_not(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename ForwardIterator
  >
  PolyCollectionIterator find_end(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename ForwardIterator,typename BinaryPredicate
  >
  PolyCollectionIterator find_end(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename ForwardIterator
  >
  PolyCollectionIterator find_first_of(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename ForwardIterator,typename BinaryPredicate
  >
  PolyCollectionIterator find_first_of(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2,BinaryPredicate pred);

  template<typename... Ts,typename PolyCollectionIterator>
  PolyCollectionIterator adjacent_find(
    PolyCollectionIterator first,PolyCollectionIterator last);

  template<
    typename... Ts,typename PolyCollectionIterator,typename BinaryPredicate
  >
  PolyCollectionIterator adjacent_find(
    PolyCollectionIterator first,PolyCollectionIterator last,
    BinaryPredicate pred);

  template<typename... Ts,typename PolyCollectionIterator,typename T>
  std::ptrdiff_t count(
    PolyCollectionIterator first,PolyCollectionIterator last,const T& x);

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  std::ptrdiff_t count_if(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename InputIterator
  >
  std::pair<PolyCollectionIterator,InputIterator> mismatch(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename InputIterator,typename BinaryPredicate
  >
  std::pair<PolyCollectionIterator,InputIterator> mismatch(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename InputIterator
  >
  std::pair<PolyCollectionIterator,InputIterator> mismatch(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,InputIterator last2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename InputIterator,typename BinaryPredicate
  >
  std::pair<PolyCollectionIterator,InputIterator> mismatch(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,InputIterator last2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename InputIterator
  >
  bool equal(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename InputIterator,typename BinaryPredicate
  >
  bool equal(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename InputIterator
  >
  bool equal(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,InputIterator last2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename InputIterator,typename BinaryPredicate
  >
  bool equal(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,InputIterator last2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename ForwardIterator
  >
  bool is_permutation(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename ForwardIterator,typename BinaryPredicate
  >
  bool is_permutation(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename ForwardIterator
  >
  bool is_permutation(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename ForwardIterator,typename BinaryPredicate
  >
  bool is_permutation(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename ForwardIterator
  >
  PolyCollectionIterator search(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename ForwardIterator,typename BinaryPredicate
  >
  PolyCollectionIterator search(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    ForwardIterator first2,ForwardIterator last2,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename Size,typename T
  >
  PolyCollectionIterator search_n(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    Size count,const T& x);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename Size,typename T,typename BinaryPredicate
  >
  PolyCollectionIterator search_n(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    Size count,const T& x,BinaryPredicate pred);

  ``['`// modifying sequence operations:`]``

  template<
    typename... Ts,typename PolyCollectionIterator,typename OutputIterator
  >
  OutputIterator copy(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename Size,typename OutputIterator
  >
  OutputIterator copy_n(
    PolyCollectionIterator first,Size count,OutputIterator res);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename Predicate
  >
  OutputIterator copy_if(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,Predicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename OutputIterator
  >
  OutputIterator move(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename UnaryOperation
  >
  OutputIterator transform(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,UnaryOperation op);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename InputIterator,typename OutputIterator,typename BinaryOperation
  >
  OutputIterator transform(
    PolyCollectionIterator first1,PolyCollectionIterator last1,
    InputIterator first2,OutputIterator res,BinaryOperation op);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename T
  >
  OutputIterator replace_copy(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,const T& old_x,const T& new_x);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename Predicate,typename T
  >
  OutputIterator replace_copy_if(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,Predicate pred,const T& new_x);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename T
  >
  OutputIterator remove_copy(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,const T& x);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename Predicate
  >
  OutputIterator remove_copy_if(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,Predicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename OutputIterator
  >
  OutputIterator unique_copy(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator,typename BinaryPredicate
  >
  OutputIterator unique_copy(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,BinaryPredicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,typename OutputIterator
  >
  OutputIterator rotate_copy(
    PolyCollectionIterator first,PolyCollectionIterator middle,
    PolyCollectionIterator last,OutputIterator res);

  template<
    typename... Ts,typename PolyCollectionIterator,typename OutputIterator,
    typename Distance,typename UniformRandomBitGenerator
  >
  OutputIterator sample(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator res,Distance n,UniformRandomBitGenerator&& g);
  
  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  bool is_partitioned(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  template<
    typename... Ts,typename PolyCollectionIterator,
    typename OutputIterator1,typename OutputIterator2,typename Predicate
  >
  std::pair<OutputIterator1,OutputIterator2> partition_copy(
    PolyCollectionIterator first,PolyCollectionIterator last,
    OutputIterator1 rest,OutputIterator2 resf,Predicate pred);

  template<typename... Ts,typename PolyCollectionIterator,typename Predicate>
  PolyCollectionIterator partition_point(
    PolyCollectionIterator first,PolyCollectionIterator last,Predicate pred);

  } /* namespace poly_collection */

  } /* namespace boost */

The algorithms provided mimic the functionality of their homonyms in
[@http://en.cppreference.com/w/cpp/algorithm `<algorithm>`] but take advantage
of the segmented nature of Boost.PolyCollection (global) iterators to
deliver better performance. Additionally, concrete types can be passed to
these algorithms for /type restitution/.

For the description of the algorithms we use the following notation:

* [' `alg`] is the (unqualified) name of any of the algorithms in
`"boost/poly_collection/algorithm.hpp"` except `copy_n` and `rotate_copy`.
* `first`, `middle` and `last` are (same-typed) possibly const global iterators
of a collection of Boost.PolyCollection such that \[`first`, `middle`) and
\[`middle`, `last`) are valid ranges.
* `args...` is a function parameter pack of types `Args&&...`,
* `Ts...` is a template parameter pack of arbitrary types. 

(1) [' `alg`]`(first,last,args...)`[br]
(2) `for_each_n(first,args...)`[br]
(3) `copy_n(first,args...)`[br]
(4) `rotate_copy(first,middle,last,args...)`

[*Requires:] The expression `expr` is well-formed, where `expr` is defined
as:[br]
(1) `std::`[' `alg`]`(first,last,args...)`,[br]
(2) `std::for_each_n(first,args...)`,[br]
(3) `std::copy_n(first,args...)`,[br]
(4) `std::rotate_copy(first,middle,last,args...)`.[br]
[*Effects:] Equivalent to `expr`.[br]
[*Returns:] `expr`.[br]
[*Complexity:] That of `expr`.

(1) [' `alg`]`<Ts...>(first,last,args...)`[br]
(2) `for_each_n<Ts...>(first,args...)`[br]
(3) `copy_n<Ts...>(first,args...)`[br]
(4) `rotate_copy<Ts...>(first,middle,last,args...)`

[*Requires:] The expression `expr` is well-formed, where `expr` is defined
as:[br]
(1) `std::`[' `alg`]`(rfirst,rlast,args...)`,[br]
(2) `std::for_each_n(rfirst,args...)`,[br]
(3) `std::copy_n(rfirst,args...)`,[br]
(4) `std::rotate_copy(rfirst,rmiddle,rlast,args...)`,[br]
and `rfirst`, `rmiddle` and `rlast` are iterator-like objects behaving like
their `first`, `middle` and `last` counterparts except that they
dereference to the corresponding subobject (`const`) `T&` if pointing to a
segment for `T` and `T` is in `Ts...`
[footnote Strictly speaking a proper _ForwardIterator_ cannot behave
like this as dereferencing must yield /exactly/ a (`const`) `value_type&`
value, which disallows this type of polymorphism.].[br]
[*Effects:] Equivalent to `expr`.[br]
[*Returns:] `expr`.[br]
[*Complexity:] That of `expr`.

[endsect]

[endsect]