summaryrefslogblamecommitdiffstats
path: root/vendor/gopkg.in/yaml.v2/parserc.go
blob: 0a7037ad1b2a6c352b7250278daf2feb9bb23a42 (plain) (tree)
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






































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                                                                                           
package yaml

import (
	"bytes"
)

// The parser implements the following grammar:
//
// stream               ::= STREAM-START implicit_document? explicit_document* STREAM-END
// implicit_document    ::= block_node DOCUMENT-END*
// explicit_document    ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
// block_node_or_indentless_sequence    ::=
//                          ALIAS
//                          | properties (block_content | indentless_block_sequence)?
//                          | block_content
//                          | indentless_block_sequence
// block_node           ::= ALIAS
//                          | properties block_content?
//                          | block_content
// flow_node            ::= ALIAS
//                          | properties flow_content?
//                          | flow_content
// properties           ::= TAG ANCHOR? | ANCHOR TAG?
// block_content        ::= block_collection | flow_collection | SCALAR
// flow_content         ::= flow_collection | SCALAR
// block_collection     ::= block_sequence | block_mapping
// flow_collection      ::= flow_sequence | flow_mapping
// block_sequence       ::= BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
// indentless_sequence  ::= (BLOCK-ENTRY block_node?)+
// block_mapping        ::= BLOCK-MAPPING_START
//                          ((KEY block_node_or_indentless_sequence?)?
//                          (VALUE block_node_or_indentless_sequence?)?)*
//                          BLOCK-END
// flow_sequence        ::= FLOW-SEQUENCE-START
//                          (flow_sequence_entry FLOW-ENTRY)*
//                          flow_sequence_entry?
//                          FLOW-SEQUENCE-END
// flow_sequence_entry  ::= flow_node | KEY flow_node? (VALUE flow_node?)?
// flow_mapping         ::= FLOW-MAPPING-START
//                          (flow_mapping_entry FLOW-ENTRY)*
//                          flow_mapping_entry?
//                          FLOW-MAPPING-END
// flow_mapping_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?

// Peek the next token in the token queue.
func peek_token(parser *yaml_parser_t) *yaml_token_t {
	if parser.token_available || yaml_parser_fetch_more_tokens(parser) {
		return &parser.tokens[parser.tokens_head]
	}
	return nil
}

// Remove the next token from the queue (must be called after peek_token).
func skip_token(parser *yaml_parser_t) {
	parser.token_available = false
	parser.tokens_parsed++
	parser.stream_end_produced = parser.tokens[parser.tokens_head].typ == yaml_STREAM_END_TOKEN
	parser.tokens_head++
}

// Get the next event.
func yaml_parser_parse(parser *yaml_parser_t, event *yaml_event_t) bool {
	// Erase the event object.
	*event = yaml_event_t{}

	// No events after the end of the stream or error.
	if parser.stream_end_produced || parser.error != yaml_NO_ERROR || parser.state == yaml_PARSE_END_STATE {
		return true
	}

	// Generate the next event.
	return yaml_parser_state_machine(parser, event)
}

// Set parser error.
func yaml_parser_set_parser_error(parser *yaml_parser_t, problem string, problem_mark yaml_mark_t) bool {
	parser.error = yaml_PARSER_ERROR
	parser.problem = problem
	parser.problem_mark = problem_mark
	return false
}

func yaml_parser_set_parser_error_context(parser *yaml_parser_t, context string, context_mark yaml_mark_t, problem string, problem_mark yaml_mark_t) bool {
	parser.error = yaml_PARSER_ERROR
	parser.context = context
	parser.context_mark = context_mark
	parser.problem = problem
	parser.problem_mark = problem_mark
	return false
}

// State dispatcher.
func yaml_parser_state_machine(parser *yaml_parser_t, event *yaml_event_t) bool {
	//trace("yaml_parser_state_machine", "state:", parser.state.String())

	switch parser.state {
	case yaml_PARSE_STREAM_START_STATE:
		return yaml_parser_parse_stream_start(parser, event)

	case yaml_PARSE_IMPLICIT_DOCUMENT_START_STATE:
		return yaml_parser_parse_document_start(parser, event, true)

	case yaml_PARSE_DOCUMENT_START_STATE:
		return yaml_parser_parse_document_start(parser, event, false)

	case yaml_PARSE_DOCUMENT_CONTENT_STATE:
		return yaml_parser_parse_document_content(parser, event)

	case yaml_PARSE_DOCUMENT_END_STATE:
		return yaml_parser_parse_document_end(parser, event)

	case yaml_PARSE_BLOCK_NODE_STATE:
		return yaml_parser_parse_node(parser, event, true, false)

	case yaml_PARSE_BLOCK_NODE_OR_INDENTLESS_SEQUENCE_STATE:
		return yaml_parser_parse_node(parser, event, true, true)

	case yaml_PARSE_FLOW_NODE_STATE:
		return yaml_parser_parse_node(parser, event, false, false)

	case yaml_PARSE_BLOCK_SEQUENCE_FIRST_ENTRY_STATE:
		return yaml_parser_parse_block_sequence_entry(parser, event, true)

	case yaml_PARSE_BLOCK_SEQUENCE_ENTRY_STATE:
		return yaml_parser_parse_block_sequence_entry(parser, event, false)

	case yaml_PARSE_INDENTLESS_SEQUENCE_ENTRY_STATE:
		return yaml_parser_parse_indentless_sequence_entry(parser, event)

	case yaml_PARSE_BLOCK_MAPPING_FIRST_KEY_STATE:
		return yaml_parser_parse_block_mapping_key(parser, event, true)

	case yaml_PARSE_BLOCK_MAPPING_KEY_STATE:
		return yaml_parser_parse_block_mapping_key(parser, event, false)

	case yaml_PARSE_BLOCK_MAPPING_VALUE_STATE:
		return yaml_parser_parse_block_mapping_value(parser, event)

	case yaml_PARSE_FLOW_SEQUENCE_FIRST_ENTRY_STATE:
		return yaml_parser_parse_flow_sequence_entry(parser, event, true)

	case yaml_PARSE_FLOW_SEQUENCE_ENTRY_STATE:
		return yaml_parser_parse_flow_sequence_entry(parser, event, false)

	case yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_KEY_STATE:
		return yaml_parser_parse_flow_sequence_entry_mapping_key(parser, event)

	case yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE_STATE:
		return yaml_parser_parse_flow_sequence_entry_mapping_value(parser, event)

	case yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_END_STATE:
		return yaml_parser_parse_flow_sequence_entry_mapping_end(parser, event)

	case yaml_PARSE_FLOW_MAPPING_FIRST_KEY_STATE:
		return yaml_parser_parse_flow_mapping_key(parser, event, true)

	case yaml_PARSE_FLOW_MAPPING_KEY_STATE:
		return yaml_parser_parse_flow_mapping_key(parser, event, false)

	case yaml_PARSE_FLOW_MAPPING_VALUE_STATE:
		return yaml_parser_parse_flow_mapping_value(parser, event, false)

	case yaml_PARSE_FLOW_MAPPING_EMPTY_VALUE_STATE:
		return yaml_parser_parse_flow_mapping_value(parser, event, true)

	default:
		panic("invalid parser state")
	}
	return false
}

// Parse the production:
// stream   ::= STREAM-START implicit_document? explicit_document* STREAM-END
//              ************
func yaml_parser_parse_stream_start(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if token.typ != yaml_STREAM_START_TOKEN {
		return yaml_parser_set_parser_error(parser, "did not find expected <stream-start>", token.start_mark)
	}
	parser.state = yaml_PARSE_IMPLICIT_DOCUMENT_START_STATE
	*event = yaml_event_t{
		typ:        yaml_STREAM_START_EVENT,
		start_mark: token.start_mark,
		end_mark:   token.end_mark,
		encoding:   token.encoding,
	}
	skip_token(parser)
	return true
}

// Parse the productions:
// implicit_document    ::= block_node DOCUMENT-END*
//                          *
// explicit_document    ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
//                          *************************
func yaml_parser_parse_document_start(parser *yaml_parser_t, event *yaml_event_t, implicit bool) bool {

	token := peek_token(parser)
	if token == nil {
		return false
	}

	// Parse extra document end indicators.
	if !implicit {
		for token.typ == yaml_DOCUMENT_END_TOKEN {
			skip_token(parser)
			token = peek_token(parser)
			if token == nil {
				return false
			}
		}
	}

	if implicit && token.typ != yaml_VERSION_DIRECTIVE_TOKEN &&
		token.typ != yaml_TAG_DIRECTIVE_TOKEN &&
		token.typ != yaml_DOCUMENT_START_TOKEN &&
		token.typ != yaml_STREAM_END_TOKEN {
		// Parse an implicit document.
		if !yaml_parser_process_directives(parser, nil, nil) {
			return false
		}
		parser.states = append(parser.states, yaml_PARSE_DOCUMENT_END_STATE)
		parser.state = yaml_PARSE_BLOCK_NODE_STATE

		*event = yaml_event_t{
			typ:        yaml_DOCUMENT_START_EVENT,
			start_mark: token.start_mark,
			end_mark:   token.end_mark,
		}

	} else if token.typ != yaml_STREAM_END_TOKEN {
		// Parse an explicit document.
		var version_directive *yaml_version_directive_t
		var tag_directives []yaml_tag_directive_t
		start_mark := token.start_mark
		if !yaml_parser_process_directives(parser, &version_directive, &tag_directives) {
			return false
		}
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_DOCUMENT_START_TOKEN {
			yaml_parser_set_parser_error(parser,
				"did not find expected <document start>", token.start_mark)
			return false
		}
		parser.states = append(parser.states, yaml_PARSE_DOCUMENT_END_STATE)
		parser.state = yaml_PARSE_DOCUMENT_CONTENT_STATE
		end_mark := token.end_mark

		*event = yaml_event_t{
			typ:               yaml_DOCUMENT_START_EVENT,
			start_mark:        start_mark,
			end_mark:          end_mark,
			version_directive: version_directive,
			tag_directives:    tag_directives,
			implicit:          false,
		}
		skip_token(parser)

	} else {
		// Parse the stream end.
		parser.state = yaml_PARSE_END_STATE
		*event = yaml_event_t{
			typ:        yaml_STREAM_END_EVENT,
			start_mark: token.start_mark,
			end_mark:   token.end_mark,
		}
		skip_token(parser)
	}

	return true
}

// Parse the productions:
// explicit_document    ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
//                                                    ***********
//
func yaml_parser_parse_document_content(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if token.typ == yaml_VERSION_DIRECTIVE_TOKEN ||
		token.typ == yaml_TAG_DIRECTIVE_TOKEN ||
		token.typ == yaml_DOCUMENT_START_TOKEN ||
		token.typ == yaml_DOCUMENT_END_TOKEN ||
		token.typ == yaml_STREAM_END_TOKEN {
		parser.state = parser.states[len(parser.states)-1]
		parser.states = parser.states[:len(parser.states)-1]
		return yaml_parser_process_empty_scalar(parser, event,
			token.start_mark)
	}
	return yaml_parser_parse_node(parser, event, true, false)
}

// Parse the productions:
// implicit_document    ::= block_node DOCUMENT-END*
//                                     *************
// explicit_document    ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
//
func yaml_parser_parse_document_end(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}

	start_mark := token.start_mark
	end_mark := token.start_mark

	implicit := true
	if token.typ == yaml_DOCUMENT_END_TOKEN {
		end_mark = token.end_mark
		skip_token(parser)
		implicit = false
	}

	parser.tag_directives = parser.tag_directives[:0]

	parser.state = yaml_PARSE_DOCUMENT_START_STATE
	*event = yaml_event_t{
		typ:        yaml_DOCUMENT_END_EVENT,
		start_mark: start_mark,
		end_mark:   end_mark,
		implicit:   implicit,
	}
	return true
}

// Parse the productions:
// block_node_or_indentless_sequence    ::=
//                          ALIAS
//                          *****
//                          | properties (block_content | indentless_block_sequence)?
//                            **********  *
//                          | block_content | indentless_block_sequence
//                            *
// block_node           ::= ALIAS
//                          *****
//                          | properties block_content?
//                            ********** *
//                          | block_content
//                            *
// flow_node            ::= ALIAS
//                          *****
//                          | properties flow_content?
//                            ********** *
//                          | flow_content
//                            *
// properties           ::= TAG ANCHOR? | ANCHOR TAG?
//                          *************************
// block_content        ::= block_collection | flow_collection | SCALAR
//                                                               ******
// flow_content         ::= flow_collection | SCALAR
//                                            ******
func yaml_parser_parse_node(parser *yaml_parser_t, event *yaml_event_t, block, indentless_sequence bool) bool {
	//defer trace("yaml_parser_parse_node", "block:", block, "indentless_sequence:", indentless_sequence)()

	token := peek_token(parser)
	if token == nil {
		return false
	}

	if token.typ == yaml_ALIAS_TOKEN {
		parser.state = parser.states[len(parser.states)-1]
		parser.states = parser.states[:len(parser.states)-1]
		*event = yaml_event_t{
			typ:        yaml_ALIAS_EVENT,
			start_mark: token.start_mark,
			end_mark:   token.end_mark,
			anchor:     token.value,
		}
		skip_token(parser)
		return true
	}

	start_mark := token.start_mark
	end_mark := token.start_mark

	var tag_token bool
	var tag_handle, tag_suffix, anchor []byte
	var tag_mark yaml_mark_t
	if token.typ == yaml_ANCHOR_TOKEN {
		anchor = token.value
		start_mark = token.start_mark
		end_mark = token.end_mark
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ == yaml_TAG_TOKEN {
			tag_token = true
			tag_handle = token.value
			tag_suffix = token.suffix
			tag_mark = token.start_mark
			end_mark = token.end_mark
			skip_token(parser)
			token = peek_token(parser)
			if token == nil {
				return false
			}
		}
	} else if token.typ == yaml_TAG_TOKEN {
		tag_token = true
		tag_handle = token.value
		tag_suffix = token.suffix
		start_mark = token.start_mark
		tag_mark = token.start_mark
		end_mark = token.end_mark
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ == yaml_ANCHOR_TOKEN {
			anchor = token.value
			end_mark = token.end_mark
			skip_token(parser)
			token = peek_token(parser)
			if token == nil {
				return false
			}
		}
	}

	var tag []byte
	if tag_token {
		if len(tag_handle) == 0 {
			tag = tag_suffix
			tag_suffix = nil
		} else {
			for i := range parser.tag_directives {
				if bytes.Equal(parser.tag_directives[i].handle, tag_handle) {
					tag = append([]byte(nil), parser.tag_directives[i].prefix...)
					tag = append(tag, tag_suffix...)
					break
				}
			}
			if len(tag) == 0 {
				yaml_parser_set_parser_error_context(parser,
					"while parsing a node", start_mark,
					"found undefined tag handle", tag_mark)
				return false
			}
		}
	}

	implicit := len(tag) == 0
	if indentless_sequence && token.typ == yaml_BLOCK_ENTRY_TOKEN {
		end_mark = token.end_mark
		parser.state = yaml_PARSE_INDENTLESS_SEQUENCE_ENTRY_STATE
		*event = yaml_event_t{
			typ:        yaml_SEQUENCE_START_EVENT,
			start_mark: start_mark,
			end_mark:   end_mark,
			anchor:     anchor,
			tag:        tag,
			implicit:   implicit,
			style:      yaml_style_t(yaml_BLOCK_SEQUENCE_STYLE),
		}
		return true
	}
	if token.typ == yaml_SCALAR_TOKEN {
		var plain_implicit, quoted_implicit bool
		end_mark = token.end_mark
		if (len(tag) == 0 && token.style == yaml_PLAIN_SCALAR_STYLE) || (len(tag) == 1 && tag[0] == '!') {
			plain_implicit = true
		} else if len(tag) == 0 {
			quoted_implicit = true
		}
		parser.state = parser.states[len(parser.states)-1]
		parser.states = parser.states[:len(parser.states)-1]

		*event = yaml_event_t{
			typ:             yaml_SCALAR_EVENT,
			start_mark:      start_mark,
			end_mark:        end_mark,
			anchor:          anchor,
			tag:             tag,
			value:           token.value,
			implicit:        plain_implicit,
			quoted_implicit: quoted_implicit,
			style:           yaml_style_t(token.style),
		}
		skip_token(parser)
		return true
	}
	if token.typ == yaml_FLOW_SEQUENCE_START_TOKEN {
		// [Go] Some of the events below can be merged as they differ only on style.
		end_mark = token.end_mark
		parser.state = yaml_PARSE_FLOW_SEQUENCE_FIRST_ENTRY_STATE
		*event = yaml_event_t{
			typ:        yaml_SEQUENCE_START_EVENT,
			start_mark: start_mark,
			end_mark:   end_mark,
			anchor:     anchor,
			tag:        tag,
			implicit:   implicit,
			style:      yaml_style_t(yaml_FLOW_SEQUENCE_STYLE),
		}
		return true
	}
	if token.typ == yaml_FLOW_MAPPING_START_TOKEN {
		end_mark = token.end_mark
		parser.state = yaml_PARSE_FLOW_MAPPING_FIRST_KEY_STATE
		*event = yaml_event_t{
			typ:        yaml_MAPPING_START_EVENT,
			start_mark: start_mark,
			end_mark:   end_mark,
			anchor:     anchor,
			tag:        tag,
			implicit:   implicit,
			style:      yaml_style_t(yaml_FLOW_MAPPING_STYLE),
		}
		return true
	}
	if block && token.typ == yaml_BLOCK_SEQUENCE_START_TOKEN {
		end_mark = token.end_mark
		parser.state = yaml_PARSE_BLOCK_SEQUENCE_FIRST_ENTRY_STATE
		*event = yaml_event_t{
			typ:        yaml_SEQUENCE_START_EVENT,
			start_mark: start_mark,
			end_mark:   end_mark,
			anchor:     anchor,
			tag:        tag,
			implicit:   implicit,
			style:      yaml_style_t(yaml_BLOCK_SEQUENCE_STYLE),
		}
		return true
	}
	if block && token.typ == yaml_BLOCK_MAPPING_START_TOKEN {
		end_mark = token.end_mark
		parser.state = yaml_PARSE_BLOCK_MAPPING_FIRST_KEY_STATE
		*event = yaml_event_t{
			typ:        yaml_MAPPING_START_EVENT,
			start_mark: start_mark,
			end_mark:   end_mark,
			anchor:     anchor,
			tag:        tag,
			implicit:   implicit,
			style:      yaml_style_t(yaml_BLOCK_MAPPING_STYLE),
		}
		return true
	}
	if len(anchor) > 0 || len(tag) > 0 {
		parser.state = parser.states[len(parser.states)-1]
		parser.states = parser.states[:len(parser.states)-1]

		*event = yaml_event_t{
			typ:             yaml_SCALAR_EVENT,
			start_mark:      start_mark,
			end_mark:        end_mark,
			anchor:          anchor,
			tag:             tag,
			implicit:        implicit,
			quoted_implicit: false,
			style:           yaml_style_t(yaml_PLAIN_SCALAR_STYLE),
		}
		return true
	}

	context := "while parsing a flow node"
	if block {
		context = "while parsing a block node"
	}
	yaml_parser_set_parser_error_context(parser, context, start_mark,
		"did not find expected node content", token.start_mark)
	return false
}

// Parse the productions:
// block_sequence ::= BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
//                    ********************  *********** *             *********
//
func yaml_parser_parse_block_sequence_entry(parser *yaml_parser_t, event *yaml_event_t, first bool) bool {
	if first {
		token := peek_token(parser)
		parser.marks = append(parser.marks, token.start_mark)
		skip_token(parser)
	}

	token := peek_token(parser)
	if token == nil {
		return false
	}

	if token.typ == yaml_BLOCK_ENTRY_TOKEN {
		mark := token.end_mark
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_BLOCK_ENTRY_TOKEN && token.typ != yaml_BLOCK_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_BLOCK_SEQUENCE_ENTRY_STATE)
			return yaml_parser_parse_node(parser, event, true, false)
		} else {
			parser.state = yaml_PARSE_BLOCK_SEQUENCE_ENTRY_STATE
			return yaml_parser_process_empty_scalar(parser, event, mark)
		}
	}
	if token.typ == yaml_BLOCK_END_TOKEN {
		parser.state = parser.states[len(parser.states)-1]
		parser.states = parser.states[:len(parser.states)-1]
		parser.marks = parser.marks[:len(parser.marks)-1]

		*event = yaml_event_t{
			typ:        yaml_SEQUENCE_END_EVENT,
			start_mark: token.start_mark,
			end_mark:   token.end_mark,
		}

		skip_token(parser)
		return true
	}

	context_mark := parser.marks[len(parser.marks)-1]
	parser.marks = parser.marks[:len(parser.marks)-1]
	return yaml_parser_set_parser_error_context(parser,
		"while parsing a block collection", context_mark,
		"did not find expected '-' indicator", token.start_mark)
}

// Parse the productions:
// indentless_sequence  ::= (BLOCK-ENTRY block_node?)+
//                           *********** *
func yaml_parser_parse_indentless_sequence_entry(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}

	if token.typ == yaml_BLOCK_ENTRY_TOKEN {
		mark := token.end_mark
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_BLOCK_ENTRY_TOKEN &&
			token.typ != yaml_KEY_TOKEN &&
			token.typ != yaml_VALUE_TOKEN &&
			token.typ != yaml_BLOCK_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_INDENTLESS_SEQUENCE_ENTRY_STATE)
			return yaml_parser_parse_node(parser, event, true, false)
		}
		parser.state = yaml_PARSE_INDENTLESS_SEQUENCE_ENTRY_STATE
		return yaml_parser_process_empty_scalar(parser, event, mark)
	}
	parser.state = parser.states[len(parser.states)-1]
	parser.states = parser.states[:len(parser.states)-1]

	*event = yaml_event_t{
		typ:        yaml_SEQUENCE_END_EVENT,
		start_mark: token.start_mark,
		end_mark:   token.start_mark, // [Go] Shouldn't this be token.end_mark?
	}
	return true
}

// Parse the productions:
// block_mapping        ::= BLOCK-MAPPING_START
//                          *******************
//                          ((KEY block_node_or_indentless_sequence?)?
//                            *** *
//                          (VALUE block_node_or_indentless_sequence?)?)*
//
//                          BLOCK-END
//                          *********
//
func yaml_parser_parse_block_mapping_key(parser *yaml_parser_t, event *yaml_event_t, first bool) bool {
	if first {
		token := peek_token(parser)
		parser.marks = append(parser.marks, token.start_mark)
		skip_token(parser)
	}

	token := peek_token(parser)
	if token == nil {
		return false
	}

	if token.typ == yaml_KEY_TOKEN {
		mark := token.end_mark
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_KEY_TOKEN &&
			token.typ != yaml_VALUE_TOKEN &&
			token.typ != yaml_BLOCK_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_BLOCK_MAPPING_VALUE_STATE)
			return yaml_parser_parse_node(parser, event, true, true)
		} else {
			parser.state = yaml_PARSE_BLOCK_MAPPING_VALUE_STATE
			return yaml_parser_process_empty_scalar(parser, event, mark)
		}
	} else if token.typ == yaml_BLOCK_END_TOKEN {
		parser.state = parser.states[len(parser.states)-1]
		parser.states = parser.states[:len(parser.states)-1]
		parser.marks = parser.marks[:len(parser.marks)-1]
		*event = yaml_event_t{
			typ:        yaml_MAPPING_END_EVENT,
			start_mark: token.start_mark,
			end_mark:   token.end_mark,
		}
		skip_token(parser)
		return true
	}

	context_mark := parser.marks[len(parser.marks)-1]
	parser.marks = parser.marks[:len(parser.marks)-1]
	return yaml_parser_set_parser_error_context(parser,
		"while parsing a block mapping", context_mark,
		"did not find expected key", token.start_mark)
}

// Parse the productions:
// block_mapping        ::= BLOCK-MAPPING_START
//
//                          ((KEY block_node_or_indentless_sequence?)?
//
//                          (VALUE block_node_or_indentless_sequence?)?)*
//                           ***** *
//                          BLOCK-END
//
//
func yaml_parser_parse_block_mapping_value(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if token.typ == yaml_VALUE_TOKEN {
		mark := token.end_mark
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_KEY_TOKEN &&
			token.typ != yaml_VALUE_TOKEN &&
			token.typ != yaml_BLOCK_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_BLOCK_MAPPING_KEY_STATE)
			return yaml_parser_parse_node(parser, event, true, true)
		}
		parser.state = yaml_PARSE_BLOCK_MAPPING_KEY_STATE
		return yaml_parser_process_empty_scalar(parser, event, mark)
	}
	parser.state = yaml_PARSE_BLOCK_MAPPING_KEY_STATE
	return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
}

// Parse the productions:
// flow_sequence        ::= FLOW-SEQUENCE-START
//                          *******************
//                          (flow_sequence_entry FLOW-ENTRY)*
//                           *                   **********
//                          flow_sequence_entry?
//                          *
//                          FLOW-SEQUENCE-END
//                          *****************
// flow_sequence_entry  ::= flow_node | KEY flow_node? (VALUE flow_node?)?
//                          *
//
func yaml_parser_parse_flow_sequence_entry(parser *yaml_parser_t, event *yaml_event_t, first bool) bool {
	if first {
		token := peek_token(parser)
		parser.marks = append(parser.marks, token.start_mark)
		skip_token(parser)
	}
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if token.typ != yaml_FLOW_SEQUENCE_END_TOKEN {
		if !first {
			if token.typ == yaml_FLOW_ENTRY_TOKEN {
				skip_token(parser)
				token = peek_token(parser)
				if token == nil {
					return false
				}
			} else {
				context_mark := parser.marks[len(parser.marks)-1]
				parser.marks = parser.marks[:len(parser.marks)-1]
				return yaml_parser_set_parser_error_context(parser,
					"while parsing a flow sequence", context_mark,
					"did not find expected ',' or ']'", token.start_mark)
			}
		}

		if token.typ == yaml_KEY_TOKEN {
			parser.state = yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_KEY_STATE
			*event = yaml_event_t{
				typ:        yaml_MAPPING_START_EVENT,
				start_mark: token.start_mark,
				end_mark:   token.end_mark,
				implicit:   true,
				style:      yaml_style_t(yaml_FLOW_MAPPING_STYLE),
			}
			skip_token(parser)
			return true
		} else if token.typ != yaml_FLOW_SEQUENCE_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_FLOW_SEQUENCE_ENTRY_STATE)
			return yaml_parser_parse_node(parser, event, false, false)
		}
	}

	parser.state = parser.states[len(parser.states)-1]
	parser.states = parser.states[:len(parser.states)-1]
	parser.marks = parser.marks[:len(parser.marks)-1]

	*event = yaml_event_t{
		typ:        yaml_SEQUENCE_END_EVENT,
		start_mark: token.start_mark,
		end_mark:   token.end_mark,
	}

	skip_token(parser)
	return true
}

//
// Parse the productions:
// flow_sequence_entry  ::= flow_node | KEY flow_node? (VALUE flow_node?)?
//                                      *** *
//
func yaml_parser_parse_flow_sequence_entry_mapping_key(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if token.typ != yaml_VALUE_TOKEN &&
		token.typ != yaml_FLOW_ENTRY_TOKEN &&
		token.typ != yaml_FLOW_SEQUENCE_END_TOKEN {
		parser.states = append(parser.states, yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE_STATE)
		return yaml_parser_parse_node(parser, event, false, false)
	}
	mark := token.end_mark
	skip_token(parser)
	parser.state = yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE_STATE
	return yaml_parser_process_empty_scalar(parser, event, mark)
}

// Parse the productions:
// flow_sequence_entry  ::= flow_node | KEY flow_node? (VALUE flow_node?)?
//                                                      ***** *
//
func yaml_parser_parse_flow_sequence_entry_mapping_value(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if token.typ == yaml_VALUE_TOKEN {
		skip_token(parser)
		token := peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_FLOW_ENTRY_TOKEN && token.typ != yaml_FLOW_SEQUENCE_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_END_STATE)
			return yaml_parser_parse_node(parser, event, false, false)
		}
	}
	parser.state = yaml_PARSE_FLOW_SEQUENCE_ENTRY_MAPPING_END_STATE
	return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
}

// Parse the productions:
// flow_sequence_entry  ::= flow_node | KEY flow_node? (VALUE flow_node?)?
//                                                                      *
//
func yaml_parser_parse_flow_sequence_entry_mapping_end(parser *yaml_parser_t, event *yaml_event_t) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	parser.state = yaml_PARSE_FLOW_SEQUENCE_ENTRY_STATE
	*event = yaml_event_t{
		typ:        yaml_MAPPING_END_EVENT,
		start_mark: token.start_mark,
		end_mark:   token.start_mark, // [Go] Shouldn't this be end_mark?
	}
	return true
}

// Parse the productions:
// flow_mapping         ::= FLOW-MAPPING-START
//                          ******************
//                          (flow_mapping_entry FLOW-ENTRY)*
//                           *                  **********
//                          flow_mapping_entry?
//                          ******************
//                          FLOW-MAPPING-END
//                          ****************
// flow_mapping_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
//                          *           *** *
//
func yaml_parser_parse_flow_mapping_key(parser *yaml_parser_t, event *yaml_event_t, first bool) bool {
	if first {
		token := peek_token(parser)
		parser.marks = append(parser.marks, token.start_mark)
		skip_token(parser)
	}

	token := peek_token(parser)
	if token == nil {
		return false
	}

	if token.typ != yaml_FLOW_MAPPING_END_TOKEN {
		if !first {
			if token.typ == yaml_FLOW_ENTRY_TOKEN {
				skip_token(parser)
				token = peek_token(parser)
				if token == nil {
					return false
				}
			} else {
				context_mark := parser.marks[len(parser.marks)-1]
				parser.marks = parser.marks[:len(parser.marks)-1]
				return yaml_parser_set_parser_error_context(parser,
					"while parsing a flow mapping", context_mark,
					"did not find expected ',' or '}'", token.start_mark)
			}
		}

		if token.typ == yaml_KEY_TOKEN {
			skip_token(parser)
			token = peek_token(parser)
			if token == nil {
				return false
			}
			if token.typ != yaml_VALUE_TOKEN &&
				token.typ != yaml_FLOW_ENTRY_TOKEN &&
				token.typ != yaml_FLOW_MAPPING_END_TOKEN {
				parser.states = append(parser.states, yaml_PARSE_FLOW_MAPPING_VALUE_STATE)
				return yaml_parser_parse_node(parser, event, false, false)
			} else {
				parser.state = yaml_PARSE_FLOW_MAPPING_VALUE_STATE
				return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
			}
		} else if token.typ != yaml_FLOW_MAPPING_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_FLOW_MAPPING_EMPTY_VALUE_STATE)
			return yaml_parser_parse_node(parser, event, false, false)
		}
	}

	parser.state = parser.states[len(parser.states)-1]
	parser.states = parser.states[:len(parser.states)-1]
	parser.marks = parser.marks[:len(parser.marks)-1]
	*event = yaml_event_t{
		typ:        yaml_MAPPING_END_EVENT,
		start_mark: token.start_mark,
		end_mark:   token.end_mark,
	}
	skip_token(parser)
	return true
}

// Parse the productions:
// flow_mapping_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
//                                   *                  ***** *
//
func yaml_parser_parse_flow_mapping_value(parser *yaml_parser_t, event *yaml_event_t, empty bool) bool {
	token := peek_token(parser)
	if token == nil {
		return false
	}
	if empty {
		parser.state = yaml_PARSE_FLOW_MAPPING_KEY_STATE
		return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
	}
	if token.typ == yaml_VALUE_TOKEN {
		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
		if token.typ != yaml_FLOW_ENTRY_TOKEN && token.typ != yaml_FLOW_MAPPING_END_TOKEN {
			parser.states = append(parser.states, yaml_PARSE_FLOW_MAPPING_KEY_STATE)
			return yaml_parser_parse_node(parser, event, false, false)
		}
	}
	parser.state = yaml_PARSE_FLOW_MAPPING_KEY_STATE
	return yaml_parser_process_empty_scalar(parser, event, token.start_mark)
}

// Generate an empty scalar event.
func yaml_parser_process_empty_scalar(parser *yaml_parser_t, event *yaml_event_t, mark yaml_mark_t) bool {
	*event = yaml_event_t{
		typ:        yaml_SCALAR_EVENT,
		start_mark: mark,
		end_mark:   mark,
		value:      nil, // Empty
		implicit:   true,
		style:      yaml_style_t(yaml_PLAIN_SCALAR_STYLE),
	}
	return true
}

var default_tag_directives = []yaml_tag_directive_t{
	{[]byte("!"), []byte("!")},
	{[]byte("!!"), []byte("tag:yaml.org,2002:")},
}

// Parse directives.
func yaml_parser_process_directives(parser *yaml_parser_t,
	version_directive_ref **yaml_version_directive_t,
	tag_directives_ref *[]yaml_tag_directive_t) bool {

	var version_directive *yaml_version_directive_t
	var tag_directives []yaml_tag_directive_t

	token := peek_token(parser)
	if token == nil {
		return false
	}

	for token.typ == yaml_VERSION_DIRECTIVE_TOKEN || token.typ == yaml_TAG_DIRECTIVE_TOKEN {
		if token.typ == yaml_VERSION_DIRECTIVE_TOKEN {
			if version_directive != nil {
				yaml_parser_set_parser_error(parser,
					"found duplicate %YAML directive", token.start_mark)
				return false
			}
			if token.major != 1 || token.minor != 1 {
				yaml_parser_set_parser_error(parser,
					"found incompatible YAML document", token.start_mark)
				return false
			}
			version_directive = &yaml_version_directive_t{
				major: token.major,
				minor: token.minor,
			}
		} else if token.typ == yaml_TAG_DIRECTIVE_TOKEN {
			value := yaml_tag_directive_t{
				handle: token.value,
				prefix: token.prefix,
			}
			if !yaml_parser_append_tag_directive(parser, value, false, token.start_mark) {
				return false
			}
			tag_directives = append(tag_directives, value)
		}

		skip_token(parser)
		token = peek_token(parser)
		if token == nil {
			return false
		}
	}

	for i := range default_tag_directives {
		if !yaml_parser_append_tag_directive(parser, default_tag_directives[i], true, token.start_mark) {
			return false
		}
	}

	if version_directive_ref != nil {
		*version_directive_ref = version_directive
	}
	if tag_directives_ref != nil {
		*tag_directives_ref = tag_directives
	}
	return true
}

// Append a tag directive to the directives stack.
func yaml_parser_append_tag_directive(parser *yaml_parser_t, value yaml_tag_directive_t, allow_duplicates bool, mark yaml_mark_t) bool {
	for i := range parser.tag_directives {
		if bytes.Equal(value.handle, parser.tag_directives[i].handle) {
			if allow_duplicates {
				return true
			}
			return yaml_parser_set_parser_error(parser, "found duplicate %TAG directive", mark)
		}
	}

	// [Go] I suspect the copy is unnecessary. This was likely done
	// because there was no way to track ownership of the data.
	value_copy := yaml_tag_directive_t{
		handle: make([]byte, len(value.handle)),
		prefix: make([]byte, len(value.prefix)),
	}
	copy(value_copy.handle, value.handle)
	copy(value_copy.prefix, value.prefix)
	parser.tag_directives = append(parser.tag_directives, value_copy)
	return true
}