icuSources/data/brkitr/line_normal_cj.txt

   1 # Copyright (c) 2002-2015  International Business Machines Corporation and
   2 # others. All Rights Reserved.
   3 #
   4 #  file:  line_normal_cj.txt
   5 #
   6 #         Line Breaking Rules
   7 #         Implement default line breaking as defined by
   8 #         Unicode Standard Annex #14 Revision 29 for Unicode 6.2
   9 #         http://www.unicode.org/reports/tr14/
  10 #         tailored as noted in 2nd paragraph below..
  11 #
  12 #         TODO:  Rule LB 8 remains as it was in Unicode 5.2
  13 #         This is only because of a limitation of ICU break engine implementation,
  14 #         not because the older behavior is desirable.
  15 #
  16 #         This tailors the line break behavior to correspond to CSS
  17 #         line-break=normal (BCP47 -u-lb-normal) as defined for Chinese & Japanese.
  18 #         It sets characters of class CJ to behave like ID.
  19 #         In addition, it allows breaks:
  20 #         * before hyphens 2010 & 2013 (both BA) and 301C, 30A0 (both NS)
  21
  22 #
  23 #  Character Classes defined by TR 14.
  24 #
  25
  26 !!chain;
  27 !!LBCMNoChain;
  28
  29
  30 !!lookAheadHardBreak;
  31 #
  32 #  !!lookAheadHardBreak    Described here because it is (as yet) undocumented elsewhere
  33 #                          and only used for the line break rules.
  34 #
  35 #           It is used in the implementation of rule LB 10
  36 #           which says to treat any combining mark that is not attached to a base
  37 #           character as if it were of class AL  (alphabetic).
  38 #
  39 #           The problem occurs in the reverse rules.
  40 #
  41 #           Consider a sequence like, with correct breaks as shown
  42 #               LF  ID  CM  AL  AL
  43 #                  ^       ^       ^
  44 #           Then consider the sequence without the initial ID (ideographic)
  45 #                 LF  CM  AL  AL
  46 #                    ^           ^
  47 #           Our CM, which in the first example was attached to the ideograph,
  48 #           is now unattached, becomes an alpha, and joins in with the other
  49 #           alphas.
  50 #
  51 #           When iterating forwards, these sequences do not present any problems
  52 #           When iterating backwards, we need to look ahead when encountering
  53 #           a CM to see whether it attaches to something further on or not.
  54 #           (Look-ahead in a reverse rule is looking towards the start)
  55 #
  56 #           If the CM is unattached, we need to force a break.
  57 #
  58 #           !!lookAheadHardBreak forces the run time state machine to
  59 #           stop immediately when a look ahead rule ( '/' operator) matches,
  60 #           and set the match position to that of the look-ahead operator,
  61 #           no matter what other rules may be in play at the time.
  62 #
  63 #           See rule LB 19 for an example.
  64 #
  65
  66 $AI = [:LineBreak =  Ambiguous:];
  67 $AL = [:LineBreak =  Alphabetic:];
  68 $BAX = [\u2010 \u2013];
  69 $BA = [[:LineBreak =  Break_After:] - $BAX];
  70 $BB = [:LineBreak =  Break_Before:];
  71 $BK = [:LineBreak =  Mandatory_Break:];
  72 $B2 = [:LineBreak =  Break_Both:];
  73 $CB = [:LineBreak =  Contingent_Break:];
  74 $CJ = [:LineBreak =  Conditional_Japanese_Starter:];
  75 $CL = [:LineBreak =  Close_Punctuation:];
  76 $CM = [:LineBreak =  Combining_Mark:];
  77 $CP = [:LineBreak =  Close_Parenthesis:];
  78 $CR = [:LineBreak =  Carriage_Return:];
  79 $EX = [:LineBreak =  Exclamation:];
  80 $GL = [:LineBreak =  Glue:];
  81 $HL = [:LineBreak =  Hebrew_Letter:];
  82 $HY = [:LineBreak =  Hyphen:];
  83 $H2 = [:LineBreak =  H2:];
  84 $H3 = [:LineBreak =  H3:];
  85 $ID = [[:LineBreak =  Ideographic:] $CJ];
  86 $IN = [:LineBreak =  Inseperable:];
  87 $IS = [:LineBreak =  Infix_Numeric:];
  88 $JL = [:LineBreak =  JL:];
  89 $JV = [:LineBreak =  JV:];
  90 $JT = [:LineBreak =  JT:];
  91 $LF = [:LineBreak =  Line_Feed:];
  92 $NL = [:LineBreak =  Next_Line:];
  93 $NSX = [\u301C \u30A0];
  94 $NS = [[:LineBreak =  Nonstarter:] - $NSX];
  95 $NU = [:LineBreak =  Numeric:];
  96 $OP = [:LineBreak =  Open_Punctuation:];
  97 $PO = [:LineBreak =  Postfix_Numeric:];
  98 $PR = [:LineBreak =  Prefix_Numeric:];
  99 $QU = [:LineBreak =  Quotation:];
 100 $RI = [:LineBreak =  Regional_Indicator:];
 101 $SA = [:LineBreak =  Complex_Context:];
 102 $SG = [:LineBreak =  Surrogate:];
 103 $SP = [:LineBreak =  Space:];
 104 $SY = [:LineBreak =  Break_Symbols:];
 105 $WJ = [:LineBreak =  Word_Joiner:];
 106 $XX = [:LineBreak =  Unknown:];
 107 $ZW = [:LineBreak =  ZWSpace:];
 108
 109 # Special character classes for people & body part emoji:
 110 # Subsets of $CM:
 111 $ZWJ = \u200D;
 112 $EmojiVar = \uFE0F;
 113 # The following are subsets of $ID
 114 $EmojiForSeqs = [\u2764 \U0001F466-\U0001F469 \U0001F48B];
 115 $EmojiForMods = [\u261D \u270A-\u270C \U0001F385 \U0001F3C3-\U0001F3C4 \U0001F3C7 \U0001F3CA \U0001F442-\U0001F443 \U0001F446-\U0001F450 \U0001F466-\U0001F469 \U0001F46E-\U0001F478 \U0001F47C \U0001F481-\U0001F483 \U0001F485-\U0001F487 \U0001F4AA \U0001F596 \U0001F645-\U0001F647 \U0001F64B-\U0001F64F \U0001F6A3 \U0001F6B4-\U0001F6B6 \U0001F6C0];
 116 $EmojiMods = [\U0001F3FB-\U0001F3FF];
 117
 118 #   Dictionary character set, for triggering language-based break engines. Currently
 119 #   limited to LineBreak=Complex_Context. Note that this set only works in Unicode
 120 #   5.0 or later as the definition of Complex_Context was corrected to include all
 121 #   characters requiring dictionary break.
 122
 123 $dictionary = [:LineBreak = Complex_Context:];
 124
 125 #
 126 #  Rule LB1.  By default, treat AI  (characters with ambiguous east Asian width),
 127 #                               SA  (South East Asian: Thai, Lao, Khmer)
 128 #                               SG  (Unpaired Surrogates)
 129 #                               XX  (Unknown, unassigned)
 130 #                         as $AL  (Alphabetic)
 131 #
 132 $ALPlus = [$AL $AI $SA $SG $XX];
 133
 134 #
 135 #  Combining Marks.   X $CM*  behaves as if it were X.  Rule LB6.
 136 #
 137 $ALcm = $ALPlus $CM*;
 138 $BAcm = $BA $CM*;
 139 $BAXcm = $BAX $CM*;
 140 $BBcm = $BB $CM*;
 141 $B2cm = $B2 $CM*;
 142 $CLcm = $CL $CM*;
 143 $CPcm = $CP $CM*;
 144 $EXcm = $EX $CM*;
 145 $GLcm = $GL $CM*;
 146 $HLcm = $HL $CM*;
 147 $HYcm = $HY $CM*;
 148 $H2cm = $H2 $CM*;
 149 $H3cm = $H3 $CM*;
 150 $IDcm = $ID $CM*;
 151 $INcm = $IN $CM*;
 152 $IScm = $IS $CM*;
 153 $JLcm = $JL $CM*;
 154 $JVcm = $JV $CM*;
 155 $JTcm = $JT $CM*;
 156 $NScm = $NS $CM*;
 157 $NSXcm = $NSX $CM*;
 158 $NUcm = $NU $CM*;
 159 $OPcm = $OP $CM*;
 160 $POcm = $PO $CM*;
 161 $PRcm = $PR $CM*;
 162 $QUcm = $QU $CM*;
 163 $RIcm = $RI $CM*;
 164 $SYcm = $SY $CM*;
 165 $WJcm = $WJ $CM*;
 166
 167 ## -------------------------------------------------
 168
 169 !!forward;
 170
 171 #
 172 #  Each class of character can stand by itself as an unbroken token, with trailing combining stuff
 173 #
 174 $ALPlus $CM+;
 175 $BA $CM+;
 176 $BAX $CM+;
 177 $BB $CM+;
 178 $B2 $CM+;
 179 $CL $CM+;
 180 $CP $CM+;
 181 $EX $CM+;
 182 $GL $CM+;
 183 $HL $CM+;
 184 $HY $CM+;
 185 $H2 $CM+;
 186 $H3 $CM+;
 187 $ID $CM+;
 188 $IN $CM+;
 189 $IS $CM+;
 190 $JL $CM+;
 191 $JV $CM+;
 192 $JT $CM+;
 193 $NS $CM+;
 194 $NSX $CM+;
 195 $NU $CM+;
 196 $OP $CM+;
 197 $PO $CM+;
 198 $PR $CM+;
 199 $QU $CM+;
 200 $RI $CM+;
 201 $SY $CM+;
 202 $WJ $CM+;
 203
 204 #
 205 # CAN_CM  is the set of characters that may combine with CM combining chars.
 206 #         Note that Linebreak UAX 14's concept of a combining char and the rules
 207 #         for what they can combine with are _very_ different from the rest of Unicode.
 208 #
 209 #         Note that $CM itself is left out of this set.  If CM is needed as a base
 210 #         it must be listed separately in the rule.
 211 #
 212 $CAN_CM  = [^$SP $BK $CR $LF $NL $ZW $CM];       # Bases that can   take CMs
 213 $CANT_CM = [ $SP $BK $CR $LF $NL $ZW $CM];       # Bases that can't take CMs
 214
 215 #
 216 # AL_FOLLOW  set of chars that can unconditionally follow an AL
 217 #            Needed in rules where stand-alone $CM s are treated as AL.
 218 #            Chaining is disabled with CM because it causes other failures,
 219 #            so for this one case we need to manually list out longer sequences.
 220 #
 221 $AL_FOLLOW_NOCM = [$BK $CR $LF $NL $ZW $SP];
 222 $AL_FOLLOW_CM   = [$CL $CP $EX $HL $IS $SY $WJ $GL $OP $QU $BA $BAX $HY $NS $NSX $IN $NU $ALPlus];
 223 $AL_FOLLOW      = [$AL_FOLLOW_NOCM $AL_FOLLOW_CM];
 224
 225
 226 #
 227 #  Rule LB 4, 5    Mandatory (Hard) breaks.
 228 #
 229 $LB4Breaks    = [$BK $CR $LF $NL];
 230 $LB4NonBreaks = [^$BK $CR $LF $NL];
 231 $CR $LF {100};
 232
 233 #
 234 #  LB 6    Do not break before hard line breaks.
 235 #
 236 $LB4NonBreaks?  $LB4Breaks {100};    # LB 5  do not break before hard breaks.
 237 $CAN_CM $CM*    $LB4Breaks {100};
 238 $CM+            $LB4Breaks {100};
 239
 240 # LB 7         x SP
 241 #              x ZW
 242 $LB4NonBreaks [$SP $ZW];
 243 $CAN_CM $CM*  [$SP $ZW];
 244 $CM+          [$SP $ZW];
 245
 246 #
 247 # LB 8         Break after zero width space
 248 #              TODO:  ZW SP* <break>
 249 #              An engine change is required to write the reverse rule for this.
 250 #              For now, leave the Unicode 5.2 rule, ZW <break>
 251 #
 252 $LB8Breaks    = [$LB4Breaks $ZW];
 253 $LB8NonBreaks = [[$LB4NonBreaks] - [$ZW]];
 254
 255
 256 # Special forward rule for people & body part emoji:
 257 # don't break $ZWJ from subsequent $EmojiForSeqs
 258 $EmojiForSeqs $EmojiVar? $EmojiMods? $ZWJ $EmojiForSeqs;
 259
 260 # LB 9     Combining marks.      X   $CM needs to behave like X, where X is not $SP, $BK $CR $LF $NL
 261 #                                $CM not covered by the above needs to behave like $AL
 262 #                                See definition of $CAN_CM.
 263
 264 $CAN_CM $CM+;                   #  Stick together any combining sequences that don't match other rules.
 265 $CM+;
 266
 267 #
 268 # LB 11  Do not break before or after WORD JOINER & related characters.
 269 #
 270 $CAN_CM $CM*  $WJcm;
 271 $LB8NonBreaks $WJcm;
 272 $CM+          $WJcm;
 273
 274 $WJcm $CANT_CM;
 275 $WJcm $CAN_CM $CM*;
 276
 277 #
 278 # LB 12  Do not break after NBSP and related characters.
 279 #         GL  x
 280 #
 281 $GLcm $CAN_CM $CM*;
 282 $GLcm $CANT_CM;
 283
 284 #
 285 # LB 12a  Do not break before NBSP and related characters ...
 286 #            [^SP BA HY] x GL
 287 #
 288 [[$LB8NonBreaks] - [$SP $BA $BAX $HY]] $CM* $GLcm;
 289 $CM+ GLcm;
 290
 291
 292
 293 #
 294 # LB 13   Don't break before ']' or '!' or ';' or '/', even after spaces.
 295 #
 296 $LB8NonBreaks $CL;
 297 $CAN_CM $CM*  $CL;
 298 $CM+          $CL;              # by rule 10, stand-alone CM behaves as AL
 299
 300 $LB8NonBreaks $CP;
 301 $CAN_CM $CM*  $CP;
 302 $CM+          $CP;              # by rule 10, stand-alone CM behaves as AL
 303
 304 $LB8NonBreaks $EX;
 305 $CAN_CM $CM*  $EX;
 306 $CM+          $EX;              # by rule 10, stand-alone CM behaves as AL
 307
 308 $LB8NonBreaks $IS;
 309 $CAN_CM $CM*  $IS;
 310 $CM+          $IS;              # by rule 10, stand-alone CM behaves as AL
 311
 312 $LB8NonBreaks $SY;
 313 $CAN_CM $CM*  $SY;
 314 $CM+          $SY;              # by rule 10, stand-alone CM behaves as AL
 315
 316
 317 #
 318 # LB 14  Do not break after OP, even after spaces
 319 #
 320 $OPcm $SP* $CAN_CM $CM*;
 321 $OPcm $SP* $CANT_CM;
 322
 323 $OPcm $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
 324
 325 # LB 15
 326 $QUcm $SP* $OPcm;
 327
 328 # LB 16
 329 # Do not break between closing punctuation and $NS, even with intervening spaces
 330 # But DO allow a break between closing punctuation and $NSX, don't include it here
 331 ($CLcm | $CPcm) $SP* $NScm;
 332
 333 # LB 17
 334 $B2cm $SP* $B2cm;
 335
 336 #
 337 # LB 18  Break after spaces.
 338 #
 339 $LB18NonBreaks = [$LB8NonBreaks - [$SP]];
 340 $LB18Breaks    = [$LB8Breaks $SP];
 341
 342
 343 # LB 19
 344 #         x QU
 345 $LB18NonBreaks $CM* $QUcm;
 346 $CM+                $QUcm;
 347
 348 #         QU  x
 349 $QUcm .?;
 350 $QUcm $LB18NonBreaks $CM*;    # Don't let a combining mark go onto $CR, $BK, etc.
 351                               #  TODO:  I don't think this rule is needed.
 352
 353
 354 # LB 20
 355 #        <break>  $CB
 356 #        $CB   <break>
 357
 358 $LB20NonBreaks = [$LB18NonBreaks - $CB];
 359
 360 # LB 21        x   (BA | HY | NS)
 361 #           BB x
 362 #
 363 # DO allow breaks here before $BAXcm and $NSXcm, so don't include them
 364 $LB20NonBreaks $CM* ($BAcm | $HYcm | $NScm);
 365
 366 $BBcm [^$CB];                                  #  $BB  x
 367 $BBcm $LB20NonBreaks $CM*;
 368
 369 # LB 21a Don't break after Hebrew + Hyphen
 370 #   HL (HY | BA) x
 371 #
 372 $HLcm ($HYcm | $BAcm | $BAXcm) [^$CB]?;
 373
 374 # LB 21b (forward) Don't break between SY and HL
 375 # (break between HL and SY already disallowed by LB 13 above)
 376 $SYcm $HLcm;
 377
 378 # LB 22
 379 ($ALcm | $HLcm) $INcm;
 380 $CM+     $INcm;     #  by rule 10, any otherwise unattached CM behaves as AL
 381 $IDcm    $INcm;
 382 $INcm    $INcm;
 383 $NUcm    $INcm;
 384
 385
 386 # $LB 23
 387 $IDcm  $POcm;
 388 $ALcm  $NUcm;       # includes $LB19
 389 $HLcm  $NUcm;
 390 $CM+   $NUcm;       # Rule 10, any otherwise unattached CM behaves as AL
 391 $NUcm  $ALcm;
 392 $NUcm  $HLcm;
 393
 394 #
 395 # LB 24
 396 #
 397 $PRcm $IDcm;
 398 $PRcm ($ALcm | $HLcm);
 399 $POcm ($ALcm | $HLcm);
 400
 401 #
 402 # LB 25   Numbers.
 403 #
 404 ($PRcm | $POcm)? ($OPcm | $HYcm)? $NUcm ($NUcm | $SYcm | $IScm)* ($CLcm | $CPcm)? ($PRcm | $POcm)?;
 405
 406 # LB 26  Do not break a Korean syllable
 407 #
 408 $JLcm ($JLcm | $JVcm | $H2cm | $H3cm);
 409 ($JVcm | $H2cm) ($JVcm | $JTcm);
 410 ($JTcm | $H3cm) $JTcm;
 411
 412 # LB 27  Treat korean Syllable Block the same as ID  (don't break it)
 413 ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $INcm;
 414 ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $POcm;
 415 $PRcm ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm);
 416
 417
 418 # LB 28   Do not break between alphabetics
 419 #
 420 ($ALcm | $HLcm) ($ALcm | $HLcm);
 421 $CM+ ($ALcm | $HLcm);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 422
 423 # LB 29
 424 $IScm ($ALcm | $HLcm);
 425
 426 # LB 30
 427 ($ALcm | $HLcm | $NUcm) $OPcm;
 428 $CM+ $OPcm;         # The $CM+ is from rule 10, an unattached CM is treated as AL.
 429 $CPcm ($ALcm | $HLcm | $NUcm);
 430
 431 # LB 30a  Do not break between regional indicators.
 432 $RIcm $RIcm;
 433
 434 # Special forward rule for people & body part emoji:
 435 # don't break between relevant emoji and $EmojiMods
 436 $EmojiForMods $EmojiVar? $EmojiMods;
 437
 438 #
 439 #  Reverse Rules.
 440 #
 441 ## -------------------------------------------------
 442
 443 !!reverse;
 444
 445 $CM+ $ALPlus;
 446 $CM+ $BA;
 447 $CM+ $BAX;
 448 $CM+ $BB;
 449 $CM+ $B2;
 450 $CM+ $CL;
 451 $CM+ $CP;
 452 $CM+ $EX;
 453 $CM+ $GL;
 454 $CM+ $HL;
 455 $CM+ $HY;
 456 $CM+ $H2;
 457 $CM+ $H3;
 458 $CM+ $ID;
 459 $CM+ $IN;
 460 $CM+ $IS;
 461 $CM+ $JL;
 462 $CM+ $JV;
 463 $CM+ $JT;
 464 $CM+ $NS;
 465 $CM+ $NSX;
 466 $CM+ $NU;
 467 $CM+ $OP;
 468 $CM+ $PO;
 469 $CM+ $PR;
 470 $CM+ $QU;
 471 $CM+ $RI;
 472 $CM+ $SY;
 473 $CM+ $WJ;
 474 $CM+;
 475
 476
 477 #
 478 #  Sequences of the form  (shown forwards)
 479 #      [CANT_CM]  <break>  [CM]  [whatever]
 480 #  The CM needs to behave as an AL
 481 #
 482 $AL_FOLLOW $CM+ / (
 483           [$BK $CR $LF $NL $ZW {eof}] |
 484           $SP+ $CM+ $SP |
 485           $SP+ $CM* ([^$OP $CM $SP] | [$AL {eof}]));   # if LB 14 will match, need to surpress this break.
 486                                                #  LB14 says    OP SP* x .
 487                                                #    becomes    OP SP* x AL
 488                                                #    becomes    OP SP* x CM+ AL_FOLLOW
 489                                                #
 490                                                # Further note:  the $AL in [$AL {eof}] is only to work around
 491                                                #                a rule compiler bug which complains about
 492                                                #                empty sets otherwise.
 493
 494 #
 495 #  Sequences of the form  (shown forwards)
 496 #      [CANT_CM]  <break> [CM]  <break>  [PR]
 497 #  The CM needs to behave as an AL
 498 #  This rule is concerned about getting the second of the two <breaks> in place.
 499 #
 500
 501 [$PR   ] / $CM+ [$BK $CR $LF $NL $ZW $SP {eof}];
 502
 503
 504
 505 # LB 4, 5, 5
 506
 507 $LB4Breaks [$LB4NonBreaks-$CM];
 508 $LB4Breaks $CM+ $CAN_CM;
 509 $LF $CR;
 510
 511
 512 # LB 7         x SP
 513 #              x ZW
 514 [$SP $ZW] [$LB4NonBreaks-$CM];
 515 [$SP $ZW] $CM+ $CAN_CM;
 516
 517 # LB 8 ZW SP* <break>
 518 #     TODO: to implement this, we need more than one look-ahead hard break in play at a time.
 519 #           Requires an engine enhancement.
 520 #   / $SP* $ZW
 521
 522 # Special reverse rule for people & body part emoji:
 523 # don't break $ZWJ from subsequent $EmojiForSeqs
 524 $EmojiForSeqs $ZWJ $EmojiMods? $EmojiVar? $EmojiForSeqs;
 525
 526 # LB 9,10  Combining marks.
 527 #    X   $CM needs to behave like X, where X is not $SP or controls.
 528 #    $CM not covered by the above needs to behave like $AL
 529 # Stick together any combining sequences that don't match other rules.
 530 $CM+ $CAN_CM;
 531
 532
 533 # LB 11
 534 $CM* $WJ $CM* $CAN_CM;
 535 $CM* $WJ      [$LB8NonBreaks-$CM];
 536
 537      $CANT_CM $CM* $WJ;
 538 $CM* $CAN_CM  $CM* $WJ;
 539
 540 # LB 12a
 541 #      [^SP BA HY] x GL
 542 #
 543 $CM* $GL $CM* [$LB8NonBreaks-[$CM $SP $BA $BAX $HY]];
 544
 545 # LB 12
 546 #     GL  x
 547 #
 548 $CANT_CM $CM* $GL;
 549 $CM* $CAN_CM $CM* $GL;
 550
 551
 552 # LB 13
 553 $CL $CM+ $CAN_CM;
 554 $CP $CM+ $CAN_CM;
 555 $EX $CM+ $CAN_CM;
 556 $IS $CM+ $CAN_CM;
 557 $SY $CM+ $CAN_CM;
 558
 559 $CL [$LB8NonBreaks-$CM];
 560 $CP [$LB8NonBreaks-$CM];
 561 $EX [$LB8NonBreaks-$CM];
 562 $IS [$LB8NonBreaks-$CM];
 563 $SY [$LB8NonBreaks-$CM];
 564
 565 # Rule 13 & 14 taken together for an edge case.
 566 #   Match this, shown forward
 567 #     OP SP+  ($CM+ behaving as $AL) (CL | CP | EX | IS | IY)
 568 #   This really wants to chain at the $CM+ (which is acting as an $AL)
 569 #   except for $CM chaining being disabled.
 570 [$CL $CP $EX $IS $SY] $CM+ $SP+ $CM* $OP;
 571
 572 # LB 14    OP SP* x
 573 #
 574 $CM* $CAN_CM    $SP* $CM* $OP;
 575      $CANT_CM   $SP* $CM* $OP;
 576 $AL_FOLLOW? $CM+  $SP $SP* $CM* $OP;     #  by LB 10, behaves like $AL_FOLLOW? $AL $SP* $CM* $OP
 577
 578      $AL_FOLLOW_NOCM $CM+ $SP+ $CM* $OP;
 579 $CM* $AL_FOLLOW_CM   $CM+ $SP+ $CM* $OP;
 580 $SY $CM $SP+ $OP;   # TODO:  Experiment.  Remove.
 581
 582
 583
 584 # LB 15
 585 $CM* $OP $SP* $CM* $QU;
 586
 587 # LB 16
 588 # Don't include $NSX here
 589 $CM* $NS $SP* $CM* ($CL | $CP);
 590
 591 # LB 17
 592 $CM* $B2 $SP* $CM* $B2;
 593
 594 # LB 18  break after spaces
 595 #        Nothing explicit needed here.
 596
 597
 598 #
 599 # LB 19
 600 #
 601 $CM* $QU $CM* $CAN_CM;                                #   . x QU
 602 $CM* $QU      $LB18NonBreaks;
 603
 604
 605 $CM* $CAN_CM  $CM* $QU;                               #   QU x .
 606      $CANT_CM $CM* $QU;
 607
 608 #
 609 #  LB 20  Break before and after CB.
 610 #         nothing needed here.
 611 #
 612
 613 # LB 21
 614 # Don't include $BAX or $NSX here
 615 $CM* ($BA | $HY | $NS) $CM* [$LB20NonBreaks-$CM];     #  . x (BA | HY | NS)
 616
 617 $CM* [$LB20NonBreaks-$CM] $CM* $BB;                   #  BB x .
 618 [^$CB] $CM* $BB;                                      #
 619
 620 # LB21a
 621 [^$CB] $CM* ($HY | $BA | $BAX) $CM* $HL;
 622
 623 # LB21b (reverse)
 624 $CM* $HL $CM* $SY;
 625
 626 # LB 22
 627 $CM* $IN $CM* ($ALPlus | $HL);
 628 $CM* $IN $CM* $ID;
 629 $CM* $IN $CM* $IN;
 630 $CM* $IN $CM* $NU;
 631
 632 # LB 23
 633 $CM* $PO $CM* $ID;
 634 $CM* $NU $CM* ($ALPlus | $HL);
 635 $CM* ($ALPlus | $HL) $CM* $NU;
 636
 637 # LB 24
 638 $CM* $ID $CM* $PR;
 639 $CM* ($ALPlus | $HL) $CM* $PR;
 640 $CM* ($ALPlus | $HL) $CM* $PO;
 641
 642
 643 # LB 25
 644 ($CM* ($PR | $PO))? ($CM* ($CL | $CP))? ($CM* ($NU | $IS | $SY))* $CM* $NU ($CM* ($OP | $HY))? ($CM* ($PR | $PO))?;
 645
 646 # LB 26
 647 $CM* ($H3 | $H2 | $JV | $JL) $CM* $JL;
 648 $CM* ($JT | $JV) $CM* ($H2 | $JV);
 649 $CM* $JT $CM* ($H3 | $JT);
 650
 651 # LB 27
 652 $CM* $IN $CM* ($H3 | $H2 | $JT | $JV | $JL);
 653 $CM* $PO $CM* ($H3 | $H2 | $JT | $JV | $JL);
 654 $CM* ($H3 | $H2 | $JT | $JV | $JL) $CM* $PR;
 655
 656 # LB 28
 657 $CM* ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 658
 659
 660 # LB 29
 661 $CM* ($ALPlus | $HL) $CM* $IS;
 662
 663 # LB 30
 664 $CM* $OP $CM* ($ALPlus | $HL | $NU);
 665 $CM* ($ALPlus | $HL | $NU) $CM* $CP;
 666
 667 # LB 30a
 668 $CM* $RI $CM* $RI;
 669
 670 # Special reverse rule for people & body part emoji:
 671 # don't break between relevant emoji and $EmojiMods
 672 $EmojiMods $EmojiVar? $EmojiForMods;
 673
 674 ## -------------------------------------------------
 675
 676 !!safe_reverse;
 677
 678 # LB 9
 679 $CM+ [^$CM $BK $CR $LF $NL $ZW $SP];
 680 $CM+ $SP / .;
 681
 682 # LB 14
 683 $SP+ $CM* $OP;
 684
 685 # LB 15
 686 $SP+ $CM* $QU;
 687
 688 # LB 16
 689 $SP+ $CM* ($CL | $CP);
 690
 691 # LB 17
 692 $SP+ $CM* $B2;
 693
 694 # LB 21
 695 $CM* ($HY | $BA) $CM* $HL;
 696
 697 # LB 25
 698 ($CM* ($IS | $SY))+ $CM* $NU;
 699 ($CL | $CP) $CM* ($NU | $IS | $SY);
 700
 701 # For dictionary-based break
 702 $dictionary $dictionary;
 703
 704 ## -------------------------------------------------
 705
 706 !!safe_forward;
 707
 708 # Skip forward over all character classes that are involved in
 709 #   rules containing patterns with possibly more than one char
 710 #   of context.
 711 #
 712 #  It might be slightly more efficient to have specific rules
 713 #  instead of one generic one, but only if we could
 714 #  turn off rule chaining.  We don't want to move more
 715 #  than necessary.
 716 #
 717 [$CM $OP $QU $CL $CP $B2 $PR $HY $BA $SP $dictionary]+ [^$CM $OP $QU $CL $CP $B2 $PR $HY $BA $dictionary];
 718 $dictionary $dictionary;
 719