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