File: ruby_lexer.rb

package info (click to toggle)
ruby-parser 3.11.0-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 3,144 kB
  • sloc: ruby: 50,524; yacc: 18,916; makefile: 11
file content (1346 lines) | stat: -rw-r--r-- 34,344 bytes parent folder | download | duplicates (3)
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
# encoding: UTF-8

$DEBUG = true if ENV["DEBUG"]

class RubyLexer

  # :stopdoc:
  HAS_ENC = "".respond_to? :encoding

  IDENT_CHAR = if HAS_ENC then
                 /[\w\u0080-\u{10ffff}]/u
               else
                 /[\w\x80-\xFF]/n
               end

  EOF = :eof_haha!

  # ruby constants for strings (should this be moved somewhere else?)

  STR_FUNC_BORING = 0x00
  STR_FUNC_ESCAPE = 0x01 # TODO: remove and replace with REGEXP
  STR_FUNC_EXPAND = 0x02
  STR_FUNC_REGEXP = 0x04
  STR_FUNC_QWORDS = 0x08
  STR_FUNC_SYMBOL = 0x10
  STR_FUNC_INDENT = 0x20 # <<-HEREDOC
  STR_FUNC_ICNTNT = 0x40 # <<~HEREDOC

  STR_SQUOTE = STR_FUNC_BORING
  STR_DQUOTE = STR_FUNC_BORING | STR_FUNC_EXPAND
  STR_XQUOTE = STR_FUNC_BORING | STR_FUNC_EXPAND
  STR_REGEXP = STR_FUNC_REGEXP | STR_FUNC_ESCAPE | STR_FUNC_EXPAND
  STR_SSYM   = STR_FUNC_SYMBOL
  STR_DSYM   = STR_FUNC_SYMBOL | STR_FUNC_EXPAND

  ESCAPES = {
    "a"    => "\007",
    "b"    => "\010",
    "e"    => "\033",
    "f"    => "\f",
    "n"    => "\n",
    "r"    => "\r",
    "s"    => " ",
    "t"    => "\t",
    "v"    => "\13",
    "\\"   => '\\',
    "\n"   => "",
    "C-\?" => 127.chr,
    "c\?"  => 127.chr,
  }

  TOKENS = {
    "!"   => :tBANG,
    "!="  => :tNEQ,
    # "!@"  => :tUBANG,
    "!~"  => :tNMATCH,
    ","   => :tCOMMA,
    ".."  => :tDOT2,
    "..." => :tDOT3,
    "="   => :tEQL,
    "=="  => :tEQ,
    "===" => :tEQQ,
    "=>"  => :tASSOC,
    "=~"  => :tMATCH,
    "->"  => :tLAMBDA,
  }

  TAB_WIDTH = 8

  @@regexp_cache = Hash.new { |h,k| h[k] = Regexp.new(Regexp.escape(k)) }
  @@regexp_cache[nil] = nil

  # :startdoc:

  attr_accessor :lineno # we're bypassing oedipus' lineno handling.
  attr_accessor :brace_nest
  attr_accessor :cmdarg
  attr_accessor :command_start
  attr_accessor :command_state
  attr_accessor :last_state
  attr_accessor :cond
  attr_accessor :extra_lineno

  ##
  # Additional context surrounding tokens that both the lexer and
  # grammar use.

  attr_accessor :lex_state
  attr_accessor :lex_strterm
  attr_accessor :lpar_beg
  attr_accessor :paren_nest
  attr_accessor :parser # HACK for very end of lexer... *sigh*
  attr_accessor :space_seen
  attr_accessor :string_buffer
  attr_accessor :string_nest

  if $DEBUG then
    alias lex_state= lex_state=
    def lex_state=o
      return if @lex_state == o
      c = caller.first
      c = caller[1] if c =~ /\bresult\b/
      warn "lex_state: %p -> %p from %s" % [@lex_state, o, c.clean_caller]
      @lex_state = o
    end
  end

  # Last token read via next_token.
  attr_accessor :token

  ##
  # What version of ruby to parse. 18 and 19 are the only valid values
  # currently supported.

  attr_accessor :version

  attr_writer :comments

  def initialize v = 18
    self.version = v
    @lex_state = :expr_none

    self.cmdarg = RubyParserStuff::StackState.new(:cmdarg, $DEBUG)
    self.cond   = RubyParserStuff::StackState.new(:cond, $DEBUG)

    reset
  end

  def arg_ambiguous
    self.warning("Ambiguous first argument. make sure.")
  end

  def arg_state
    in_arg_state? ? :expr_arg : :expr_beg
  end

  def beginning_of_line?
    ss.bol?
  end
  alias :bol? :beginning_of_line? # to make .rex file more readable

  def comments # TODO: remove this... maybe comment_string + attr_accessor
    c = @comments.join
    @comments.clear
    c
  end

  def end_of_stream?
    ss.eos?
  end

  def expr_dot?
    lex_state == :expr_dot
  end

  def expr_fname?
    lex_state == :expr_fname
  end

  def expr_result token, text
    cond.push false
    cmdarg.push false
    result :expr_beg, token, text
  end

  def heredoc here # TODO: rewrite / remove
    _, eos, func, last_line = here

    indent         = (func & STR_FUNC_INDENT) != 0 ? "[ \t]*" : nil
    content_indent = (func & STR_FUNC_ICNTNT) != 0
    expand         = (func & STR_FUNC_EXPAND) != 0
    eos_re         = /#{indent}#{Regexp.escape eos}(\r*\n|\z)/
    err_msg        = "can't match #{eos_re.inspect} anywhere in "

    rb_compile_error err_msg if end_of_stream?

    if beginning_of_line? && scan(eos_re) then
      self.lineno += 1
      ss.unread_many last_line # TODO: figure out how to remove this
      return :tSTRING_END, eos
    end

    self.string_buffer = []

    if expand then
      case
      when scan(/#[$@]/) then
        ss.pos -= 1 # FIX omg stupid
        return :tSTRING_DVAR, matched
      when scan(/#[{]/) then
        return :tSTRING_DBEG, matched
      when scan(/#/) then
        string_buffer << '#'
      end

      begin
        c = tokadd_string func, "\n", nil

        rb_compile_error err_msg if
          c == RubyLexer::EOF

        if c != "\n" then
          return :tSTRING_CONTENT, string_buffer.join.delete("\r")
        else
          string_buffer << scan(/\n/)
        end

        rb_compile_error err_msg if end_of_stream?
      end until check(eos_re)
    else
      until check(eos_re) do
        string_buffer << scan(/.*(\n|\z)/)
        rb_compile_error err_msg if end_of_stream?
      end
    end

    self.lex_strterm = [:heredoc, eos, func, last_line]

    string_content = string_buffer.join.delete("\r")

    string_content = heredoc_dedent(string_content) if content_indent && ruby23plus?

    return :tSTRING_CONTENT, string_content
  end

  def heredoc_dedent(string_content)
    width = string_content.scan(/^[ \t]*(?=\S)/).map do |whitespace|
      heredoc_whitespace_indent_size whitespace
    end.min || 0

    string_content.split("\n", -1).map do |line|
      dedent_string line, width
    end.join "\n"
  end

  def dedent_string(string, width)
    characters_skipped = 0
    indentation_skipped = 0

    string.chars.each do |char|
      break if indentation_skipped >= width
      if char == ' '
        characters_skipped += 1
        indentation_skipped += 1
      elsif char == "\t"
        proposed = TAB_WIDTH * (indentation_skipped / TAB_WIDTH + 1)
        break if (proposed > width)
        characters_skipped += 1
        indentation_skipped = proposed
      end
    end
    string[characters_skipped..-1]
  end

  def heredoc_whitespace_indent_size(whitespace)
    whitespace.chars.inject 0 do |size, char|
      if char == "\t"
        size + TAB_WIDTH
      else
        size + 1
      end
    end
  end

  def heredoc_identifier # TODO: remove / rewrite
    term, func = nil, STR_FUNC_BORING
    self.string_buffer = []

    heredoc_indent_mods = '-'
    heredoc_indent_mods += '\~' if ruby23plus?

    case
    when scan(/([#{heredoc_indent_mods}]?)([\'\"\`])(.*?)\2/) then
      term = ss[2]
      func |= STR_FUNC_INDENT unless ss[1].empty?
      func |= STR_FUNC_ICNTNT if ss[1] == '~'
      func |= case term
              when "\'" then
                STR_SQUOTE
              when '"' then
                STR_DQUOTE
              else
                STR_XQUOTE
              end
      string_buffer << ss[3]
    when scan(/[#{heredoc_indent_mods}]?([\'\"\`])(?!\1*\Z)/) then
      rb_compile_error "unterminated here document identifier"
    when scan(/([#{heredoc_indent_mods}]?)(#{IDENT_CHAR}+)/) then
      term = '"'
      func |= STR_DQUOTE
      unless ss[1].empty? then
        func |= STR_FUNC_INDENT
        func |= STR_FUNC_ICNTNT if ss[1] == '~'
      end
      string_buffer << ss[2]
    else
      return nil
    end

    if scan(/.*\n/) then
      # TODO: think about storing off the char range instead
      line = matched
    else
      line = nil
    end

    self.lex_strterm = [:heredoc, string_buffer.join, func, line]

    if term == '`' then
      result nil, :tXSTRING_BEG, "`"
    else
      result nil, :tSTRING_BEG, "\""
    end
  end

  def in_fname?
    in_lex_state? :expr_fname
  end

  def in_arg_state? # TODO: rename is_after_operator?
    in_lex_state? :expr_fname, :expr_dot
  end

  def in_lex_state?(*states)
    states.include? lex_state
  end

  def int_with_base base
    rb_compile_error "Invalid numeric format" if matched =~ /__/

    text = matched
    case
    when text.end_with?('ri')
      return result(:expr_end, :tIMAGINARY, Complex(0, Rational(text.chop.chop.to_i(base))))
    when text.end_with?('r')
      return result(:expr_end, :tRATIONAL, Rational(text.chop.to_i(base)))
    when text.end_with?('i')
      return result(:expr_end, :tIMAGINARY, Complex(0, text.chop.to_i(base)))
    else
      return result(:expr_end, :tINTEGER, text.to_i(base))
    end
  end

  def is_arg?
    in_lex_state? :expr_arg, :expr_cmdarg
  end

  def is_beg?
    in_lex_state? :expr_beg, :expr_value, :expr_mid, :expr_class, :expr_labelarg
  end

  def is_end?
    in_lex_state? :expr_end, :expr_endarg, :expr_endfn
  end

  def ruby22_label?
    ruby22plus? and is_label_possible?
  end

  def is_label_possible?
    (in_lex_state?(:expr_beg, :expr_endfn) && !command_state) || is_arg?
  end

  def is_label_suffix?
    check(/:(?!:)/)
  end

  def is_space_arg? c = "x"
    is_arg? and space_seen and c !~ /\s/
  end

  def matched
    ss.matched
  end

  def not_end?
    not is_end?
  end

  def process_amper text
    token = if is_arg? && space_seen && !check(/\s/) then
               warning("`&' interpreted as argument prefix")
               :tAMPER
             elsif in_lex_state? :expr_beg, :expr_mid then
               :tAMPER
             else
               :tAMPER2
             end

    return result(:arg_state, token, "&")
  end

  def process_backref text
    token = ss[1].to_sym
    # TODO: can't do lineno hack w/ symbol
    result :expr_end, :tBACK_REF, token
  end

  def process_begin text
    @comments << matched

    unless scan(/.*?\n=end( |\t|\f)*[^\n]*(\n|\z)/m) then
      @comments.clear
      rb_compile_error("embedded document meets end of file")
    end

    @comments << matched
    self.lineno += matched.count("\n")

    nil # TODO
  end

  def process_bracing text
    cond.lexpop
    cmdarg.lexpop

    case matched
    when "}" then
      self.brace_nest -= 1
      self.lex_state   = :expr_endarg

      # TODO
      # if (c == '}') {
      #     if (!brace_nest--) c = tSTRING_DEND;
      # }

      return :tRCURLY, matched
    when "]" then
      self.paren_nest -= 1
      self.lex_state   = :expr_endarg
      return :tRBRACK, matched
    when ")" then
      self.paren_nest -= 1
      self.lex_state   = :expr_endfn
      return :tRPAREN, matched
    else
      raise "Unknown bracing: #{matched.inspect}"
    end
  end

  def process_colon1 text
    # ?: / then / when
    if is_end? || check(/\s/) then
      return result :expr_beg, :tCOLON, text
    end

    case
    when scan(/\'/) then
      string STR_SSYM
    when scan(/\"/) then
      string STR_DSYM
    end

    result :expr_fname, :tSYMBEG, text
  end

  def process_colon2 text
    if is_beg? || in_lex_state?(:expr_class) || is_space_arg? then
      result :expr_beg, :tCOLON3, text
    else
      result :expr_dot, :tCOLON2, text
    end
  end

  def process_curly_brace text
    self.brace_nest += 1
    if lpar_beg && lpar_beg == paren_nest then
      self.lpar_beg = nil
      self.paren_nest -= 1

      return expr_result(:tLAMBEG, "{")
    end

    token = if is_arg? || in_lex_state?(:expr_end, :expr_endfn) then
               :tLCURLY      #  block (primary)
             elsif in_lex_state?(:expr_endarg) then
               :tLBRACE_ARG  #  block (expr)
             else
               :tLBRACE      #  hash
             end

    self.command_start = true unless token == :tLBRACE

    return expr_result(token, "{")
  end

  def process_float text
    rb_compile_error "Invalid numeric format" if text =~ /__/

    case
    when text.end_with?('ri')
      return result(:expr_end, :tIMAGINARY, Complex(0, Rational(text.chop.chop)))
    when text.end_with?('r')
      return result(:expr_end, :tRATIONAL, Rational(text.chop))
    when text.end_with?('i')
      return result(:expr_end, :tIMAGINARY, Complex(0, text.chop.to_f))
    else
      return result(:expr_end, :tFLOAT, text.to_f)
    end
  end

  def process_gvar text
    text.lineno = self.lineno
    result(:expr_end, :tGVAR, text)
  end

  def process_gvar_oddity text
    return result :expr_end, "$", "$" if text == "$" # TODO: wtf is this?
    rb_compile_error "#{text.inspect} is not allowed as a global variable name"
  end

  def process_ivar text
    tok_id = text =~ /^@@/ ? :tCVAR : :tIVAR
    text.lineno = self.lineno
    return result(:expr_end, tok_id, text)
  end

  def process_lchevron text
    if (!in_lex_state?(:expr_dot, :expr_class) &&
        !is_end? &&
        (!is_arg? || space_seen)) then
      tok = self.heredoc_identifier
      return tok if tok
    end

    return result(:arg_state, :tLSHFT, "\<\<")
  end

  def process_newline_or_comment text
    c = matched
    hit = false

    if c == '#' then
      ss.pos -= 1

      while scan(/\s*\#.*(\n+|\z)/) do
        hit = true
        self.lineno += matched.lines.to_a.size
        @comments << matched.gsub(/^ +#/, '#').gsub(/^ +$/, '')
      end

      return nil if end_of_stream?
    end

    self.lineno += 1 unless hit

    # Replace a string of newlines with a single one
    self.lineno += matched.lines.to_a.size if scan(/\n+/)

    return if in_lex_state?(:expr_beg, :expr_value, :expr_class,
                            :expr_fname, :expr_dot)

    if scan(/([\ \t\r\f\v]*)(\.|&)/) then
      self.space_seen = true unless ss[1].empty?

      ss.pos -= 1
      return unless check(/\.\./)
    end

    self.command_start = true

    return result(:expr_beg, :tNL, nil)
  end

  def process_nthref text
    # TODO: can't do lineno hack w/ number
    result :expr_end, :tNTH_REF, ss[1].to_i
  end

  def process_paren text
    token = if ruby18 then
              process_paren18
            else
              process_paren19
            end

    self.paren_nest += 1

    # TODO: add :expr_label to :expr_beg (set in expr_result below)
    return expr_result(token, "(")
  end

  def process_paren18
    self.command_start = true
    token = :tLPAREN2

    if in_lex_state? :expr_beg, :expr_mid then
      token = :tLPAREN
    elsif space_seen then
      if in_lex_state? :expr_cmdarg then
        token = :tLPAREN_ARG
      elsif in_lex_state? :expr_arg then
        warning "don't put space before argument parentheses"
      end
    else
      # not a ternary -- do nothing?
    end

    token
  end

  def process_paren19
    if is_beg? then
      :tLPAREN
    elsif is_space_arg? then
      :tLPAREN_ARG
    else
      :tLPAREN2 # plain '(' in parse.y
    end
  end

  def process_percent text
    return parse_quote if is_beg?

    return result(:expr_beg, :tOP_ASGN, "%") if scan(/\=/)

    return parse_quote if is_arg? && space_seen && ! check(/\s/)

    return result(:arg_state, :tPERCENT, "%")
  end

  def process_plus_minus text
    sign = matched
    utype, type = if sign == "+" then
                    [:tUPLUS, :tPLUS]
                  else
                    [:tUMINUS, :tMINUS]
                  end

    if in_arg_state? then
      if scan(/@/) then
        return result(:expr_arg, utype, "#{sign}@")
      else
        return result(:expr_arg, type, sign)
      end
    end

    return result(:expr_beg, :tOP_ASGN, sign) if scan(/\=/)

    if (is_beg? || (is_arg? && space_seen && !check(/\s/))) then
      arg_ambiguous if is_arg?

      if check(/\d/) then
        return nil if utype == :tUPLUS
        return result(:expr_beg, :tUMINUS_NUM, sign)
      end

      return result(:expr_beg, utype, sign)
    end

    return result(:expr_beg, type, sign)
  end

  def process_questionmark text
    if is_end? then
      state = ruby18 ? :expr_beg : :expr_value # HACK?
      return result(state, :tEH, "?")
    end

    if end_of_stream? then
      rb_compile_error "incomplete character syntax: parsed #{text.inspect}"
    end

    if check(/\s|\v/) then
      unless is_arg? then
        c2 = { " " => 's',
              "\n" => 'n',
              "\t" => 't',
              "\v" => 'v',
              "\r" => 'r',
              "\f" => 'f' }[matched]

        if c2 then
          warning("invalid character syntax; use ?\\" + c2)
        end
      end

      # ternary
      state = ruby18 ? :expr_beg : :expr_value # HACK?
      return result(state, :tEH, "?")
    elsif check(/\w(?=\w)/) then # ternary, also
      return result(:expr_beg, :tEH, "?")
    end

    c = if scan(/\\/) then
          self.read_escape
        else
          ss.getch
        end

    if version == 18 then
      return result(:expr_end, :tINTEGER, c[0].ord & 0xff)
    else
      return result(:expr_end, :tSTRING, c)
    end
  end

  def process_slash text
    if is_beg? then
      string STR_REGEXP

      return result(nil, :tREGEXP_BEG, "/")
    end

    if scan(/\=/) then
      return result(:expr_beg, :tOP_ASGN, "/")
    end

    if is_arg? && space_seen then
      unless scan(/\s/) then
        arg_ambiguous
        string STR_REGEXP, "/"
        return result(nil, :tREGEXP_BEG, "/")
      end
    end

    return result(:arg_state, :tDIVIDE, "/")
  end

  def process_square_bracket text
    self.paren_nest += 1

    token = nil

    if in_arg_state? then
      case
      when scan(/\]\=/) then
        self.paren_nest -= 1 # HACK? I dunno, or bug in MRI
        return result(:expr_arg, :tASET, "[]=")
      when scan(/\]/) then
        self.paren_nest -= 1 # HACK? I dunno, or bug in MRI
        return result(:expr_arg, :tAREF, "[]")
      else
        rb_compile_error "unexpected '['"
      end
    elsif is_beg? then
      token = :tLBRACK
    elsif is_arg? && space_seen then
      token = :tLBRACK
    else
      token = :tLBRACK2
    end

    return expr_result(token, "[")
  end

  def process_symbol text
    symbol = match[1].gsub(ESC) { unescape $1 }

    rb_compile_error "symbol cannot contain '\\0'" if
      ruby18 && symbol =~ /\0/

    return result(:expr_end, :tSYMBOL, symbol)
  end

  def was_label?
    @was_label = ruby22_label?
    true
  end

  def process_label_or_string text
    if @was_label && text =~ /:\Z/ then
      @was_label = nil
      return process_label text
    elsif text =~ /:\Z/ then
      ss.pos -= 1 # put back ":"
      text = text[0..-2]
    end

    result :expr_end, :tSTRING, text[1..-2].gsub(/\\\\/, "\\").gsub(/\\'/, "'")
  end

  def process_label text
    symbol = text[1..-3].gsub(ESC) { unescape $1 }

    result(:expr_labelarg, :tLABEL, [symbol, self.lineno])
  end

  def process_token text
    # TODO: make this always return [token, lineno]
    token = self.token = text
    token << matched if scan(/[\!\?](?!=)/)

    tok_id =
      case
      when token =~ /[!?]$/ then
        :tFID
      when in_lex_state?(:expr_fname) && scan(/=(?:(?![~>=])|(?==>))/) then
        # ident=, not =~ => == or followed by =>
        # TODO test lexing of a=>b vs a==>b
        token << matched
        :tIDENTIFIER
      when token =~ /^[A-Z]/ then
        :tCONSTANT
      else
        :tIDENTIFIER
      end

    if !ruby18 and is_label_possible? and is_label_suffix? then
      scan(/:/)
      return result(:expr_labelarg, :tLABEL, [token, self.lineno])
    end

    unless in_lex_state? :expr_dot then
      # See if it is a reserved word.
      keyword = if ruby18 then # REFACTOR need 18/19 lexer subclasses
                  RubyParserStuff::Keyword.keyword18 token
                else
                  RubyParserStuff::Keyword.keyword19 token
                end

      return process_token_keyword keyword if keyword
    end # unless in_lex_state? :expr_dot

    # TODO:
    # if (mb == ENC_CODERANGE_7BIT && lex_state != EXPR_DOT) {

    state = if is_beg? or is_arg? or in_lex_state? :expr_dot then
              command_state ? :expr_cmdarg : :expr_arg
            elsif not ruby18 and in_lex_state? :expr_fname then
              :expr_endfn
            else
              :expr_end
            end

    if not [:expr_dot, :expr_fname].include? last_state and
        self.parser.env[token.to_sym] == :lvar then
      state = :expr_end
    end

    token.lineno = self.lineno # yes, on a string. I know... I know...

    return result(state, tok_id, token)
  end

  def process_token_keyword keyword
    state = keyword.state

    value = [token, self.lineno]

    self.command_start = true if state == :expr_beg and lex_state != :expr_fname

    case
    when lex_state == :expr_fname then
      result(state, keyword.id0, keyword.name)
    when keyword.id0 == :kDO then
      case
      when lpar_beg && lpar_beg == paren_nest then
        self.lpar_beg = nil
        self.paren_nest -= 1
        expr_result(:kDO_LAMBDA, value)
      when cond.is_in_state then
        result(state, :kDO_COND, value)
      when cmdarg.is_in_state && lex_state != :expr_cmdarg then
        result(state, :kDO_BLOCK, value)
      when in_lex_state?(:expr_beg, :expr_endarg) then
        result(state, :kDO_BLOCK, value)
      else
        result(state, :kDO, value)
      end
    when in_lex_state?(:expr_beg, :expr_value, :expr_labelarg) then
      result(state, keyword.id0, value)
    when keyword.id0 != keyword.id1 then
      result(:expr_beg, keyword.id1, value)
    else
      result(state, keyword.id1, value)
    end
  end

  def process_underscore text
    ss.unscan # put back "_"

    if beginning_of_line? && scan(/\__END__(\r?\n|\Z)/) then
      return [RubyLexer::EOF, RubyLexer::EOF]
    elsif scan(/\_\w*/) then
      return process_token matched
    end
  end

  def rb_compile_error msg
    msg += ". near line #{self.lineno}: #{ss.rest[/^.*/].inspect}"
    raise RubyParser::SyntaxError, msg
  end

  def read_escape # TODO: remove / rewrite
    case
    when scan(/\\/) then                  # Backslash
      '\\'
    when scan(/n/) then                   # newline
      self.extra_lineno -= 1
      "\n"
    when scan(/t/) then                   # horizontal tab
      "\t"
    when scan(/r/) then                   # carriage-return
      "\r"
    when scan(/f/) then                   # form-feed
      "\f"
    when scan(/v/) then                   # vertical tab
      "\13"
    when scan(/a/) then                   # alarm(bell)
      "\007"
    when scan(/e/) then                   # escape
      "\033"
    when scan(/b/) then                   # backspace
      "\010"
    when scan(/s/) then                   # space
      " "
    when scan(/[0-7]{1,3}/) then          # octal constant
      (matched.to_i(8) & 0xFF).chr
    when scan(/x([0-9a-fA-F]{1,2})/) then # hex constant
      ss[1].to_i(16).chr
    when check(/M-\\[\\MCc]/) then
      scan(/M-\\/) # eat it
      c = self.read_escape
      c[0] = (c[0].ord | 0x80).chr
      c
    when scan(/M-(.)/) then
      c = ss[1]
      c[0] = (c[0].ord | 0x80).chr
      c
    when check(/(C-|c)\\[\\MCc]/) then
      scan(/(C-|c)\\/) # eat it
      c = self.read_escape
      c[0] = (c[0].ord & 0x9f).chr
      c
    when scan(/C-\?|c\?/) then
      127.chr
    when scan(/(C-|c)(.)/) then
      c = ss[2]
      c[0] = (c[0].ord & 0x9f).chr
      c
    when scan(/^[89]/i) then # bad octal or hex... MRI ignores them :(
      matched
    when scan(/u([0-9a-fA-F]{2,4}|\{[0-9a-fA-F]{2,6}\})/) then
      [ss[1].delete("{}").to_i(16)].pack("U")
    when scan(/[McCx0-9]/) || end_of_stream? then
      rb_compile_error("Invalid escape character syntax")
    else
      ss.getch
    end
  end

  def regx_options # TODO: rewrite / remove
    good, bad = [], []

    if scan(/[a-z]+/) then
      good, bad = matched.split(//).partition { |s| s =~ /^[ixmonesu]$/ }
    end

    unless bad.empty? then
      rb_compile_error("unknown regexp option%s - %s" %
                       [(bad.size > 1 ? "s" : ""), bad.join.inspect])
    end

    return good.join
  end

  def reset
    self.brace_nest    = 0
    self.command_start = true
    self.comments      = []
    self.lex_state     = :expr_none
    self.lex_strterm   = nil
    self.lineno        = 1
    self.lpar_beg      = nil
    self.paren_nest    = 0
    self.space_seen    = false
    self.string_nest   = 0
    self.token         = nil
    self.extra_lineno  = 0

    self.cmdarg.reset
    self.cond.reset
  end

  def result lex_state, token, text # :nodoc:
    lex_state = self.arg_state if lex_state == :arg_state
    self.lex_state = lex_state if lex_state
    [token, text]
  end

  def ruby18
    RubyParser::V18 === parser
  end

  def scan re
    ss.scan re
  end

  def check re
    ss.check re
  end

  def eat_whitespace
    r = scan(/\s+/)
    self.extra_lineno += r.count("\n") if r
    r
  end

  def fixup_lineno extra = 0
    self.lineno += self.extra_lineno + extra
    self.extra_lineno = 0
  end

  def scanner_class # TODO: design this out of oedipus_lex. or something.
    RPStringScanner
  end

  def space_vs_beginning space_type, beg_type, fallback
    if is_space_arg? check(/./m) then
      warning "`**' interpreted as argument prefix"
      space_type
    elsif is_beg? then
      beg_type
    else
      # TODO: warn_balanced("**", "argument prefix");
      fallback
    end
  end

  def string type, beg = matched, nnd = "\0"
    self.lex_strterm = [:strterm, type, beg, nnd]
  end

  # TODO: consider
  # def src= src
  #   raise "bad src: #{src.inspect}" unless String === src
  #   @src = RPStringScanner.new(src)
  # end

  def tokadd_escape term # TODO: rewrite / remove
    case
    when scan(/\\\n/) then
      # just ignore
    when scan(/\\([0-7]{1,3}|x[0-9a-fA-F]{1,2})/) then
      self.string_buffer << matched
    when scan(/\\([MC]-|c)(?=\\)/) then
      self.string_buffer << matched
      self.tokadd_escape term
    when scan(/\\([MC]-|c)(.)/) then
      self.string_buffer << matched
    when scan(/\\[McCx]/) then
      rb_compile_error "Invalid escape character syntax"
    when scan(/\\(.)/m) then
      chr = ss[1]
      prev = self.string_buffer.last
      if term == chr && prev && prev.end_with?("(?") then
        self.string_buffer << chr
      else
        self.string_buffer << matched
      end
    else
      rb_compile_error "Invalid escape character syntax"
    end
  end

  def tokadd_string(func, term, paren) # TODO: rewrite / remove
    qwords = (func & STR_FUNC_QWORDS) != 0
    escape = (func & STR_FUNC_ESCAPE) != 0
    expand = (func & STR_FUNC_EXPAND) != 0
    regexp = (func & STR_FUNC_REGEXP) != 0
    symbol = (func & STR_FUNC_SYMBOL) != 0

    paren_re = @@regexp_cache[paren]
    term_re  = @@regexp_cache[term]

    until end_of_stream? do
      c = nil
      handled = true

      case
      when paren_re && scan(paren_re) then
        self.string_nest += 1
      when scan(term_re) then
        if self.string_nest == 0 then
          ss.pos -= 1
          break
        else
          self.string_nest -= 1
        end
      when expand && scan(/#(?=[\$\@\{])/) then
        ss.pos -= 1
        break
      when qwords && scan(/\s/) then
        ss.pos -= 1
        break
      when expand && scan(/#(?!\n)/) then
        # do nothing
      when check(/\\/) then
        case
        when qwords && scan(/\\\n/) then
          string_buffer << "\n"
          next
        when qwords && scan(/\\\s/) then
          c = ' '
        when expand && scan(/\\\n/) then
          next
        when regexp && check(/\\/) then
          self.tokadd_escape term
          next
        when expand && scan(/\\/) then
          c = self.read_escape
        when scan(/\\\n/) then
          # do nothing
        when scan(/\\\\/) then
          string_buffer << '\\' if escape
          c = '\\'
        when scan(/\\/) then
          unless scan(term_re) || paren.nil? || scan(paren_re) then
            string_buffer << "\\"
          end
        else
          handled = false
        end # inner /\\/ case
      else
        handled = false
      end # top case

      unless handled then
        t = Regexp.escape term
        x = Regexp.escape(paren) if paren && paren != "\000"
        re = if qwords then
               if HAS_ENC then
                 /[^#{t}#{x}\#\0\\\s]+|./ # |. to pick up whatever
               else
                 /[^#{t}#{x}\#\0\\\s\v]+|./ # argh. 1.8's \s doesn't pick up \v
               end
             else
               /[^#{t}#{x}\#\0\\]+|./
             end

        scan re
        c = matched

        rb_compile_error "symbol cannot contain '\\0'" if symbol && c =~ /\0/
      end # unless handled

      c ||= matched
      string_buffer << c
    end # until

    c ||= matched
    c = RubyLexer::EOF if end_of_stream?

    return c
  end

  def unescape s
    r = ESCAPES[s]

    self.extra_lineno += 1 if s == "\n"     # eg backslash newline strings
    self.extra_lineno -= 1 if r && s == "n" # literal \n, not newline

    return r if r

    x = case s
        when /^[0-7]{1,3}/ then
          ($&.to_i(8) & 0xFF).chr
        when /^x([0-9a-fA-F]{1,2})/ then
          $1.to_i(16).chr
        when /^M-(.)/ then
          ($1[0].ord | 0x80).chr
        when /^(C-|c)(.)/ then
          ($2[0].ord & 0x9f).chr
        when /^[89a-f]/i then # bad octal or hex... ignore? that's what MRI does :(
          s
        when /^[McCx0-9]/ then
          rb_compile_error("Invalid escape character syntax")
        when /u([0-9a-fA-F]{2,4}|\{[0-9a-fA-F]{2,6}\})/ then
          [$1.delete("{}").to_i(16)].pack("U")
        else
          s
        end
    x.force_encoding "UTF-8" if HAS_ENC
    x
  end

  def warning s
    # do nothing for now
  end

  def ruby22plus?
    parser.class.version >= 22
  end

  def ruby23plus?
    parser.class.version >= 23
  end

  def process_string # TODO: rewrite / remove
    token = if lex_strterm[0] == :heredoc then
              self.heredoc lex_strterm
            else
              self.parse_string lex_strterm
            end

    token_type, c = token

    if ruby22plus? && token_type == :tSTRING_END && ["'", '"'].include?(c) then
      if (([:expr_beg, :expr_endfn].include?(lex_state) &&
           !cond.is_in_state) || is_arg?) &&
          is_label_suffix? then
        scan(/:/)
        token_type = token[0] = :tLABEL_END
      end
    end

    if [:tSTRING_END, :tREGEXP_END, :tLABEL_END].include? token_type then
      self.lex_strterm = nil
      self.lex_state   = (token_type == :tLABEL_END) ? :expr_labelarg : :expr_end
    end

    return token
  end

  def parse_quote # TODO: remove / rewrite
    beg, nnd, short_hand, c = nil, nil, false, nil

    if scan(/[a-z0-9]{1,2}/i) then # Long-hand (e.g. %Q{}).
      rb_compile_error "unknown type of %string" if ss.matched_size == 2
      c, beg, short_hand = matched, ss.getch, false
    else                               # Short-hand (e.g. %{, %., %!, etc)
      c, beg, short_hand = 'Q', ss.getch, true
    end

    if end_of_stream? or c == RubyLexer::EOF or beg == RubyLexer::EOF then
      rb_compile_error "unterminated quoted string meets end of file"
    end

    # Figure nnd-char.  "\0" is special to indicate beg=nnd and that no nesting?
    nnd = { "(" => ")", "[" => "]", "{" => "}", "<" => ">" }[beg]
    nnd, beg = beg, "\0" if nnd.nil?

    token_type, text = nil, "%#{c}#{beg}"
    token_type, string_type = case c
                              when 'Q' then
                                ch = short_hand ? nnd : c + beg
                                text = "%#{ch}"
                                [:tSTRING_BEG,   STR_DQUOTE]
                              when 'q' then
                                [:tSTRING_BEG,   STR_SQUOTE]
                              when 'W' then
                                eat_whitespace
                                [:tWORDS_BEG,    STR_DQUOTE | STR_FUNC_QWORDS]
                              when 'w' then
                                eat_whitespace
                                [:tQWORDS_BEG,   STR_SQUOTE | STR_FUNC_QWORDS]
                              when 'x' then
                                [:tXSTRING_BEG,  STR_XQUOTE]
                              when 'r' then
                                [:tREGEXP_BEG,   STR_REGEXP]
                              when 's' then
                                self.lex_state  = :expr_fname
                                [:tSYMBEG,       STR_SSYM]
                              when 'I' then
                                eat_whitespace
                                [:tSYMBOLS_BEG, STR_DQUOTE | STR_FUNC_QWORDS]
                              when 'i' then
                                eat_whitespace
                                [:tQSYMBOLS_BEG, STR_SQUOTE | STR_FUNC_QWORDS]
                              end

    rb_compile_error "Bad %string type. Expected [QqWwIixrs], found '#{c}'." if
      token_type.nil?

    raise "huh" unless string_type

    string string_type, nnd, beg

    return token_type, text
  end

  def parse_string quote # TODO: rewrite / remove
    _, string_type, term, open = quote

    space = false # FIX: remove these
    func = string_type
    paren = open
    term_re = @@regexp_cache[term]

    qwords = (func & STR_FUNC_QWORDS) != 0
    regexp = (func & STR_FUNC_REGEXP) != 0
    expand = (func & STR_FUNC_EXPAND) != 0

    unless func then # nil'ed from qwords below. *sigh*
      return :tSTRING_END, nil
    end

    space = true if qwords and eat_whitespace

    if self.string_nest == 0 && scan(/#{term_re}/) then
      if qwords then
        quote[1] = nil
        return :tSPACE, nil
      elsif regexp then
        return :tREGEXP_END, self.regx_options
      else
        return :tSTRING_END, term
      end
    end

    return :tSPACE, nil if space

    self.string_buffer = []

    if expand
      case
      when scan(/#(?=\$(-.|[a-zA-Z_0-9~\*\$\?!@\/\\;,\.=:<>\"\&\`\'+]))/) then
        # TODO: !ISASCII
        # ?! see parser_peek_variable_name
        return :tSTRING_DVAR, nil
      when scan(/#(?=\@\@?[a-zA-Z_])/) then
        # TODO: !ISASCII
        return :tSTRING_DVAR, nil
      when scan(/#[{]/) then
        return :tSTRING_DBEG, nil
      when scan(/#/) then
        string_buffer << '#'
      end
    end

    if tokadd_string(func, term, paren) == RubyLexer::EOF then
      rb_compile_error "unterminated string meets end of file"
    end

    return :tSTRING_CONTENT, string_buffer.join
  end
end

require "ruby_lexer.rex"

if ENV["RP_LINENO_DEBUG"] then
  class RubyLexer
    alias :old_lineno= :lineno=

    def d o
      $stderr.puts o.inspect
    end

    def lineno= n
      self.old_lineno= n
      where = caller.first.split(/:/).first(2).join(":")
      d :lineno => [n, where, ss && ss.rest[0,40]]
    end
  end
end