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      1 # Copyright (c) 2002-2015  International Business Machines Corporation and
      2 # others. All Rights Reserved.
      3 #
      4 #  file:  line_loose_cj.txt
      5 #
      6 #         Line Breaking Rules
      7 #         Implement default line breaking as defined by 
      8 #         Unicode Standard Annex #14 Revision 34 for Unicode 8.0
      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=loose (BCP47 -u-lb-loose) 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 #         * before iteration marks 3005, 303B, 309D, 309E, 30FD, 30FE (all NS)
     22 #         * between characters of LineBreak class IN such as 2026
     23 #         * before some centered punct 203C, 2047, 2048, 2049, 30FB, FF1A, FF1B,
     24 #           FF65 (all NS) and FF01, FF1F (both EX).
     25 #         * before suffix characters with LineBreak class PO and EastAsianWidth A,F,W;
     26 #           this includes: 00B0 2030 2032 2033 2035 2103 2109 FE6A FF05 FFE0
     27 #         * after prefix characters with LineBreak class PR and EastAsianWidth A,F,W;
     28 #           this includes: 00A4 00B1 20AC 2116 FE69 FF04 FFE1 FFE5 FFE6
     29 
     30 
     31 #
     32 #  Character Classes defined by TR 14.
     33 #
     34 
     35 !!chain;
     36 !!LBCMNoChain;
     37 
     38 
     39 !!lookAheadHardBreak;
     40 #
     41 #  !!lookAheadHardBreak    Described here because it is (as yet) undocumented elsewhere
     42 #                          and only used for the line break rules.
     43 #
     44 #           It is used in the implementation of rule LB 10
     45 #           which says to treat any combining mark that is not attached to a base
     46 #           character as if it were of class AL  (alphabetic).
     47 #
     48 #           The problem occurs in the reverse rules.
     49 #
     50 #           Consider a sequence like, with correct breaks as shown
     51 #               LF  ID  CM  AL  AL
     52 #                  ^       ^       ^
     53 #           Then consider the sequence without the initial ID (ideographic)
     54 #                 LF  CM  AL  AL
     55 #                    ^           ^
     56 #           Our CM, which in the first example was attached to the ideograph,
     57 #           is now unattached, becomes an alpha, and joins in with the other
     58 #           alphas.
     59 #
     60 #           When iterating forwards, these sequences do not present any problems
     61 #           When iterating backwards, we need to look ahead when encountering
     62 #           a CM to see whether it attaches to something further on or not.
     63 #           (Look-ahead in a reverse rule is looking towards the start)
     64 #
     65 #           If the CM is unattached, we need to force a break.
     66 #
     67 #           !!lookAheadHardBreak forces the run time state machine to
     68 #           stop immediately when a look ahead rule ( '/' operator) matches,
     69 #           and set the match position to that of the look-ahead operator,
     70 #           no matter what other rules may be in play at the time.
     71 #
     72 #           See rule LB 19 for an example.
     73 #
     74 
     75 $AI = [:LineBreak =  Ambiguous:];
     76 $AL = [:LineBreak =  Alphabetic:];
     77 $BAX = [\u2010 \u2013];
     78 $BA = [[:LineBreak =  Break_After:] - $BAX];
     79 $BB = [:LineBreak =  Break_Before:];
     80 $BK = [:LineBreak =  Mandatory_Break:];
     81 $B2 = [:LineBreak =  Break_Both:];
     82 $CB = [:LineBreak =  Contingent_Break:];
     83 $CJ = [:LineBreak =  Conditional_Japanese_Starter:];
     84 $CL = [:LineBreak =  Close_Punctuation:];
     85 $CM = [:LineBreak =  Combining_Mark:];
     86 $CP = [:LineBreak =  Close_Parenthesis:];
     87 $CR = [:LineBreak =  Carriage_Return:];
     88 $EXX = [\uFF01 \uFF1F];
     89 $EX = [[:LineBreak =  Exclamation:] - $EXX];
     90 $GL = [:LineBreak =  Glue:];
     91 $HL = [:LineBreak =  Hebrew_Letter:];
     92 $HY = [:LineBreak =  Hyphen:];
     93 $H2 = [:LineBreak =  H2:];
     94 $H3 = [:LineBreak =  H3:];
     95 $ID = [[:LineBreak =  Ideographic:] $CJ];
     96 $IN = [:LineBreak =  Inseperable:];
     97 $IS = [:LineBreak =  Infix_Numeric:];
     98 $JL = [:LineBreak =  JL:];
     99 $JV = [:LineBreak =  JV:];
    100 $JT = [:LineBreak =  JT:];
    101 $LF = [:LineBreak =  Line_Feed:];
    102 $NL = [:LineBreak =  Next_Line:];
    103 $NSX = [\u301C \u30A0 \u3005 \u303B \u309D \u309E \u30FD \u30FE \u203C \u2047 \u2048 \u2049 \u30FB \uFF1A \uFF1B \uFF65];
    104 $NS = [[:LineBreak =  Nonstarter:] - $NSX];
    105 $NU = [:LineBreak =  Numeric:];
    106 $OP = [:LineBreak =  Open_Punctuation:];
    107 $POX = [\u00B0 \u2030 \u2032 \u2033 \u2035 \u2103 \u2109 \uFE6A \uFF05 \uFFE0];
    108 $PO = [[:LineBreak =  Postfix_Numeric:] - $POX];
    109 $PRX = [\u00A4 \u00B1 \u20AC \u2116 \uFE69 \uFF04 \uFFE1 \uFFE5 \uFFE6];
    110 $PR = [[:LineBreak =  Prefix_Numeric:] - $PRX];
    111 $QU = [:LineBreak =  Quotation:];
    112 $RI = [:LineBreak =  Regional_Indicator:];
    113 $SA = [:LineBreak =  Complex_Context:];
    114 $SG = [:LineBreak =  Surrogate:];
    115 $SP = [:LineBreak =  Space:];
    116 $SY = [:LineBreak =  Break_Symbols:];
    117 $WJ = [:LineBreak =  Word_Joiner:];
    118 $XX = [:LineBreak =  Unknown:];
    119 $ZW = [:LineBreak =  ZWSpace:];
    120 
    121 #   Dictionary character set, for triggering language-based break engines. Currently
    122 #   limited to LineBreak=Complex_Context. Note that this set only works in Unicode
    123 #   5.0 or later as the definition of Complex_Context was corrected to include all
    124 #   characters requiring dictionary break.
    125 
    126 $dictionary = [:LineBreak = Complex_Context:];
    127 
    128 #
    129 #  Rule LB1.  By default, treat AI  (characters with ambiguous east Asian width),
    130 #                               SA  (South East Asian: Thai, Lao, Khmer)
    131 #                               SG  (Unpaired Surrogates)
    132 #                               XX  (Unknown, unassigned)
    133 #                         as $AL  (Alphabetic)
    134 #
    135 $ALPlus = [$AL $AI $SA $SG $XX];
    136 
    137 #
    138 #  Combining Marks.   X $CM*  behaves as if it were X.  Rule LB6.
    139 #
    140 $ALcm = $ALPlus $CM*;
    141 $BAcm = $BA $CM*;
    142 $BAXcm = $BAX $CM*;
    143 $BBcm = $BB $CM*;
    144 $B2cm = $B2 $CM*;
    145 $CLcm = $CL $CM*;
    146 $CPcm = $CP $CM*;
    147 $EXcm = $EX $CM*;
    148 $EXXcm = $EXX $CM*;
    149 $GLcm = $GL $CM*;
    150 $HLcm = $HL $CM*;
    151 $HYcm = $HY $CM*;
    152 $H2cm = $H2 $CM*;
    153 $H3cm = $H3 $CM*;
    154 $IDcm = $ID $CM*;
    155 $INcm = $IN $CM*;
    156 $IScm = $IS $CM*;
    157 $JLcm = $JL $CM*;
    158 $JVcm = $JV $CM*;
    159 $JTcm = $JT $CM*;
    160 $NScm = $NS $CM*;
    161 $NSXcm = $NSX $CM*;
    162 $NUcm = $NU $CM*;
    163 $OPcm = $OP $CM*;
    164 $POcm = $PO $CM*;
    165 $POXcm = $POX $CM*;
    166 $PRcm = $PR $CM*;
    167 $PRXcm = $PRX $CM*;
    168 $QUcm = $QU $CM*;
    169 $RIcm = $RI $CM*;
    170 $SYcm = $SY $CM*;
    171 $WJcm = $WJ $CM*;
    172 
    173 ## -------------------------------------------------
    174 
    175 !!forward;
    176 
    177 #
    178 #  Each class of character can stand by itself as an unbroken token, with trailing combining stuff
    179 #
    180 $ALPlus $CM+;
    181 $BA $CM+;
    182 $BAX $CM+;
    183 $BB $CM+;
    184 $B2 $CM+;
    185 $CL $CM+;
    186 $CP $CM+;
    187 $EX $CM+;
    188 $EXX $CM+;
    189 $GL $CM+;
    190 $HL $CM+;
    191 $HY $CM+;
    192 $H2 $CM+;
    193 $H3 $CM+;
    194 $ID $CM+;
    195 $IN $CM+;
    196 $IS $CM+;
    197 $JL $CM+;
    198 $JV $CM+;
    199 $JT $CM+;
    200 $NS $CM+;
    201 $NSX $CM+;
    202 $NU $CM+;
    203 $OP $CM+;
    204 $PO $CM+;
    205 $POX $CM+;
    206 $PR $CM+;
    207 $PRX $CM+;
    208 $QU $CM+;
    209 $RI $CM+;
    210 $SY $CM+;
    211 $WJ $CM+;
    212 
    213 #
    214 # CAN_CM  is the set of characters that may combine with CM combining chars.
    215 #         Note that Linebreak UAX 14's concept of a combining char and the rules
    216 #         for what they can combine with are _very_ different from the rest of Unicode.
    217 #
    218 #         Note that $CM itself is left out of this set.  If CM is needed as a base
    219 #         it must be listed separately in the rule.
    220 #
    221 $CAN_CM  = [^$SP $BK $CR $LF $NL $ZW $CM];       # Bases that can   take CMs
    222 $CANT_CM = [ $SP $BK $CR $LF $NL $ZW $CM];       # Bases that can't take CMs
    223 
    224 #
    225 # AL_FOLLOW  set of chars that can unconditionally follow an AL
    226 #            Needed in rules where stand-alone $CM s are treated as AL.
    227 #            Chaining is disabled with CM because it causes other failures,
    228 #            so for this one case we need to manually list out longer sequences.
    229 #
    230 $AL_FOLLOW_NOCM = [$BK $CR $LF $NL $ZW $SP];
    231 $AL_FOLLOW_CM   = [$CL $CP $EX $HL $IS $SY $WJ $GL $OP $QU $BA $HY $NS $IN $NU $ALPlus];
    232 $AL_FOLLOW      = [$AL_FOLLOW_NOCM $AL_FOLLOW_CM];
    233 
    234 
    235 #
    236 #  Rule LB 4, 5    Mandatory (Hard) breaks.
    237 #
    238 $LB4Breaks    = [$BK $CR $LF $NL];
    239 $LB4NonBreaks = [^$BK $CR $LF $NL];
    240 $CR $LF {100};
    241 
    242 #
    243 #  LB 6    Do not break before hard line breaks.
    244 #
    245 $LB4NonBreaks?  $LB4Breaks {100};    # LB 5  do not break before hard breaks.
    246 $CAN_CM $CM*    $LB4Breaks {100};
    247 $CM+            $LB4Breaks {100};
    248 
    249 # LB 7         x SP
    250 #              x ZW
    251 $LB4NonBreaks [$SP $ZW];
    252 $CAN_CM $CM*  [$SP $ZW];
    253 $CM+          [$SP $ZW];
    254 
    255 #
    256 # LB 8         Break after zero width space
    257 #              TODO:  ZW SP* <break>
    258 #              An engine change is required to write the reverse rule for this.
    259 #              For now, leave the Unicode 5.2 rule, ZW <break>
    260 #
    261 $LB8Breaks    = [$LB4Breaks $ZW];
    262 $LB8NonBreaks = [[$LB4NonBreaks] - [$ZW]];
    263 
    264 
    265 # LB 9     Combining marks.      X   $CM needs to behave like X, where X is not $SP, $BK $CR $LF $NL 
    266 #                                $CM not covered by the above needs to behave like $AL   
    267 #                                See definition of $CAN_CM.
    268 
    269 $CAN_CM $CM+;                   #  Stick together any combining sequences that don't match other rules.
    270 $CM+;
    271 
    272 #
    273 # LB 11  Do not break before or after WORD JOINER & related characters.
    274 #
    275 $CAN_CM $CM*  $WJcm;
    276 $LB8NonBreaks $WJcm;
    277 $CM+          $WJcm;
    278 
    279 $WJcm $CANT_CM;
    280 $WJcm $CAN_CM $CM*;
    281 
    282 #
    283 # LB 12  Do not break after NBSP and related characters.
    284 #         GL  x
    285 #
    286 $GLcm $CAN_CM $CM*;
    287 $GLcm $CANT_CM;
    288  
    289 #
    290 # LB 12a  Do not break before NBSP and related characters ...
    291 #            [^SP BA HY] x GL
    292 #
    293 [[$LB8NonBreaks] - [$SP $BA $BAX $HY]] $CM* $GLcm;
    294 $CM+ GLcm;
    295 
    296 
    297 
    298 #
    299 # LB 13   Don't break before ']' or '!' or ';' or '/', even after spaces.
    300 #
    301 # Do not include $EXX here
    302 $LB8NonBreaks $CL;
    303 $CAN_CM $CM*  $CL;
    304 $CM+          $CL;              # by rule 10, stand-alone CM behaves as AL
    305 
    306 $LB8NonBreaks $CP;
    307 $CAN_CM $CM*  $CP;
    308 $CM+          $CP;              # by rule 10, stand-alone CM behaves as AL
    309 
    310 $LB8NonBreaks $EX;
    311 $CAN_CM $CM*  $EX;
    312 $CM+          $EX;              # by rule 10, stand-alone CM behaves as AL
    313 
    314 $LB8NonBreaks $IS;
    315 $CAN_CM $CM*  $IS;
    316 $CM+          $IS;              # by rule 10, stand-alone CM behaves as AL
    317 
    318 $LB8NonBreaks $SY;
    319 $CAN_CM $CM*  $SY;
    320 $CM+          $SY;              # by rule 10, stand-alone CM behaves as AL
    321 
    322 
    323 #
    324 # LB 14  Do not break after OP, even after spaces
    325 #
    326 $OPcm $SP* $CAN_CM $CM*;
    327 $OPcm $SP* $CANT_CM;
    328 
    329 $OPcm $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
    330 
    331 # LB 15
    332 $QUcm $SP* $OPcm;
    333 
    334 # LB 16
    335 # Do not break between closing punctuation and $NS, even with intervening spaces
    336 # But DO allow a break between closing punctuation and $NSX, don't include it here
    337 ($CLcm | $CPcm) $SP* $NScm;
    338 
    339 # LB 17
    340 $B2cm $SP* $B2cm;
    341 
    342 #
    343 # LB 18  Break after spaces.
    344 #
    345 $LB18NonBreaks = [$LB8NonBreaks - [$SP]];
    346 $LB18Breaks    = [$LB8Breaks $SP];
    347 
    348 
    349 # LB 19
    350 #         x QU
    351 $LB18NonBreaks $CM* $QUcm;
    352 $CM+                $QUcm;
    353 
    354 #         QU  x
    355 $QUcm .?;
    356 $QUcm $LB18NonBreaks $CM*;    # Don't let a combining mark go onto $CR, $BK, etc.
    357                               #  TODO:  I don't think this rule is needed.
    358 
    359 
    360 # LB 20
    361 #        <break>  $CB
    362 #        $CB   <break>
    363 
    364 $LB20NonBreaks = [$LB18NonBreaks - $CB];
    365 
    366 # LB 21        x   (BA | HY | NS)
    367 #           BB x
    368 #
    369 # DO allow breaks here before $BAXcm and $NSXcm, so don't include them
    370 $LB20NonBreaks $CM* ($BAcm | $HYcm | $NScm); 
    371 
    372 $BBcm [^$CB];                                  #  $BB  x
    373 $BBcm $LB20NonBreaks $CM*;
    374 
    375 # LB 21a Don't break after Hebrew + Hyphen
    376 #   HL (HY | BA) x
    377 #  
    378 $HLcm ($HYcm | $BAcm | $BAXcm) [^$CB]?;
    379 
    380 # LB 21b (forward) Don't break between SY and HL
    381 # (break between HL and SY already disallowed by LB 13 above)
    382 $SYcm $HLcm;
    383 
    384 # LB 22
    385 ($ALcm | $HLcm) $INcm;
    386 $CM+     $INcm;     #  by rule 10, any otherwise unattached CM behaves as AL
    387 $EXcm    $INcm;
    388 $IDcm    $INcm;
    389 # $INcm  $INcm; # delete this rule for CSS loose
    390 $NUcm    $INcm;
    391 
    392 
    393 # LB 23
    394 # Do not include $POX here
    395 $IDcm  $POcm;
    396 $ALcm  $NUcm;       # includes $LB19
    397 $HLcm  $NUcm;
    398 $CM+   $NUcm;       # Rule 10, any otherwise unattached CM behaves as AL
    399 $NUcm  $ALcm;
    400 $NUcm  $HLcm;
    401 
    402 #
    403 # LB 24
    404 #
    405 # Do not include $PRX here
    406 $PRcm $IDcm;
    407 $PRcm ($ALcm | $HLcm);
    408 ($POcm | $POXcm) ($ALcm | $HLcm);
    409 
    410 #
    411 # LB 25   Numbers.
    412 #
    413 # Here do not include $PRX at the beginning or $POX at the end
    414 ($PRcm | $POcm | $POXcm)? ($OPcm | $HYcm)? $NUcm ($NUcm | $SYcm | $IScm)* ($CLcm | $CPcm)? ($PRcm | $PRXcm | $POcm)?;
    415 
    416 # LB 26  Do not break a Korean syllable
    417 #
    418 $JLcm ($JLcm | $JVcm | $H2cm | $H3cm);
    419 ($JVcm | $H2cm) ($JVcm | $JTcm);
    420 ($JTcm | $H3cm) $JTcm;
    421 
    422 # LB 27  Treat korean Syllable Block the same as ID  (don't break it)
    423 # Do not include $POX or $PRX here
    424 ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $INcm;
    425 ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $POcm;
    426 $PRcm ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm);
    427 
    428 
    429 # LB 28   Do not break between alphabetics
    430 #
    431 ($ALcm | $HLcm) ($ALcm | $HLcm);
    432 $CM+ ($ALcm | $HLcm);      # The $CM+ is from rule 10, an unattached CM is treated as AL
    433 
    434 # LB 29
    435 $IScm ($ALcm | $HLcm);
    436 
    437 # LB 30
    438 ($ALcm | $HLcm | $NUcm) $OPcm;
    439 $CM+ $OPcm;         # The $CM+ is from rule 10, an unattached CM is treated as AL.          
    440 $CPcm ($ALcm | $HLcm | $NUcm);
    441 
    442 # LB 30a  Do not break between regional indicators.
    443 $RIcm $RIcm;
    444 
    445 #
    446 #  Reverse Rules.
    447 #
    448 ## -------------------------------------------------
    449 
    450 !!reverse;
    451 
    452 $CM+ $ALPlus;
    453 $CM+ $BA;
    454 $CM+ $BAX;
    455 $CM+ $BB;
    456 $CM+ $B2;
    457 $CM+ $CL;
    458 $CM+ $CP;
    459 $CM+ $EX;
    460 $CM+ $EXX;
    461 $CM+ $GL;
    462 $CM+ $HL;
    463 $CM+ $HY;
    464 $CM+ $H2;
    465 $CM+ $H3;
    466 $CM+ $ID;
    467 $CM+ $IN;
    468 $CM+ $IS;
    469 $CM+ $JL;
    470 $CM+ $JV;
    471 $CM+ $JT;
    472 $CM+ $NS;
    473 $CM+ $NSX;
    474 $CM+ $NU;
    475 $CM+ $OP;
    476 $CM+ $PO;
    477 $CM+ $POX;
    478 $CM+ $PR;
    479 $CM+ $PRX;
    480 $CM+ $QU;
    481 $CM+ $RI;
    482 $CM+ $SY;
    483 $CM+ $WJ;
    484 $CM+;
    485 
    486 
    487 #
    488 #  Sequences of the form  (shown forwards)
    489 #      [CANT_CM]  <break>  [CM]  [whatever]
    490 #  The CM needs to behave as an AL
    491 #
    492 $AL_FOLLOW $CM+ / (
    493           [$BK $CR $LF $NL $ZW {eof}] |
    494           $SP+ $CM+ $SP |
    495           $SP+ $CM* ([^$OP $CM $SP] | [$AL {eof}]));   # if LB 14 will match, need to surpress this break.
    496                                                #  LB14 says    OP SP* x .        
    497                                                #    becomes    OP SP* x AL
    498                                                #    becomes    OP SP* x CM+ AL_FOLLOW
    499                                                #
    500                                                # Further note:  the $AL in [$AL {eof}] is only to work around
    501                                                #                a rule compiler bug which complains about
    502                                                #                empty sets otherwise.
    503           
    504 #
    505 #  Sequences of the form  (shown forwards)
    506 #      [CANT_CM]  <break> [CM]  <break>  [PR]
    507 #  The CM needs to behave as an AL
    508 #  This rule is concerned about getting the second of the two <breaks> in place.
    509 #
    510 
    511 [$PR $PRX  ] / $CM+ [$BK $CR $LF $NL $ZW $SP {eof}];
    512 
    513 
    514 
    515 # LB 4, 5, 5
    516 
    517 $LB4Breaks [$LB4NonBreaks-$CM];
    518 $LB4Breaks $CM+ $CAN_CM;
    519 $LF $CR;
    520 
    521 
    522 # LB 7         x SP
    523 #              x ZW
    524 [$SP $ZW] [$LB4NonBreaks-$CM];
    525 [$SP $ZW] $CM+ $CAN_CM;
    526 
    527 # LB 8 ZW SP* <break>
    528 #     TODO: to implement this, we need more than one look-ahead hard break in play at a time.
    529 #           Requires an engine enhancement.
    530 #   / $SP* $ZW
    531 
    532 # LB 9,10  Combining marks.
    533 #    X   $CM needs to behave like X, where X is not $SP or controls.
    534 #    $CM not covered by the above needs to behave like $AL
    535 # Stick together any combining sequences that don't match other rules.
    536 $CM+ $CAN_CM;
    537 
    538 
    539 # LB 11
    540 $CM* $WJ $CM* $CAN_CM;
    541 $CM* $WJ      [$LB8NonBreaks-$CM];
    542 
    543      $CANT_CM $CM* $WJ;
    544 $CM* $CAN_CM  $CM* $WJ;
    545 
    546 # LB 12a
    547 #      [^SP BA HY] x GL
    548 #
    549 $CM* $GL $CM* [$LB8NonBreaks-[$CM $SP $BA $BAX $HY]];
    550 
    551 # LB 12
    552 #     GL  x
    553 #
    554 $CANT_CM $CM* $GL;
    555 $CM* $CAN_CM $CM* $GL;
    556 
    557 
    558 # LB 13
    559 # Do not include $EXX here
    560 $CL $CM+ $CAN_CM;
    561 $CP $CM+ $CAN_CM;
    562 $EX $CM+ $CAN_CM;
    563 $IS $CM+ $CAN_CM;
    564 $SY $CM+ $CAN_CM;
    565 
    566 $CL [$LB8NonBreaks-$CM];
    567 $CP [$LB8NonBreaks-$CM];
    568 $EX [$LB8NonBreaks-$CM];
    569 $IS [$LB8NonBreaks-$CM];
    570 $SY [$LB8NonBreaks-$CM];
    571 
    572 # Rule 13 & 14 taken together for an edge case.
    573 #   Match this, shown forward
    574 #     OP SP+  ($CM+ behaving as $AL) (CL | CP | EX | IS | IY)
    575 #   This really wants to chain at the $CM+ (which is acting as an $AL)
    576 #   except for $CM chaining being disabled.
    577 [$CL $CP $EX $IS $SY] $CM+ $SP+ $CM* $OP;  
    578 
    579 # LB 14    OP SP* x
    580 #
    581 $CM* $CAN_CM    $SP* $CM* $OP;
    582      $CANT_CM   $SP* $CM* $OP;
    583 $AL_FOLLOW? $CM+  $SP $SP* $CM* $OP;     #  by LB 10, behaves like $AL_FOLLOW? $AL $SP* $CM* $OP
    584      
    585      $AL_FOLLOW_NOCM $CM+ $SP+ $CM* $OP;
    586 $CM* $AL_FOLLOW_CM   $CM+ $SP+ $CM* $OP;
    587 $SY $CM $SP+ $OP;   # TODO:  Experiment.  Remove.
    588 
    589 
    590 
    591 # LB 15
    592 $CM* $OP $SP* $CM* $QU;
    593 
    594 # LB 16
    595 # Don't include $NSX here
    596 $CM* $NS $SP* $CM* ($CL | $CP);
    597 
    598 # LB 17
    599 $CM* $B2 $SP* $CM* $B2;
    600 
    601 # LB 18  break after spaces
    602 #        Nothing explicit needed here.
    603 
    604 
    605 #
    606 # LB 19
    607 #
    608 $CM* $QU $CM* $CAN_CM;                                #   . x QU
    609 $CM* $QU      $LB18NonBreaks;
    610 
    611 
    612 $CM* $CAN_CM  $CM* $QU;                               #   QU x .
    613      $CANT_CM $CM* $QU;
    614      
    615 #
    616 #  LB 20  Break before and after CB.
    617 #         nothing needed here.
    618 #
    619 
    620 # LB 21
    621 # Don't include $BAX or $NSX here
    622 $CM* ($BA | $HY | $NS) $CM* [$LB20NonBreaks-$CM];     #  . x (BA | HY | NS)
    623 
    624 $CM* [$LB20NonBreaks-$CM] $CM* $BB;                   #  BB x .
    625 [^$CB] $CM* $BB;                                      # 
    626 
    627 # LB21a
    628 [^$CB]? $CM* ($HY | $BA | $BAX) $CM* $HL;
    629 
    630 # LB21b (reverse)
    631 $CM* $HL $CM* $SY;
    632 
    633 # LB 22
    634 $CM* $IN $CM* ($ALPlus | $HL);
    635 $CM* $IN $CM* $EX;
    636 $CM* $IN $CM* $ID;
    637 # $CM* $IN $CM* $IN; # delete this rule for CSS loose
    638 $CM* $IN $CM* $NU;
    639 
    640 # LB 23
    641 # Do not include $POX here
    642 $CM* $PO $CM* $ID;
    643 $CM* $NU $CM* ($ALPlus | $HL);
    644 $CM* ($ALPlus | $HL) $CM* $NU;
    645 
    646 # LB 24
    647 # Do not include $PRX here
    648 $CM* $ID $CM* $PR;
    649 $CM* ($ALPlus | $HL) $CM* $PR;
    650 $CM* ($ALPlus | $HL) $CM* ($PO | $POX);
    651 
    652 
    653 # LB 25
    654 # Here do not include $POX at the beginning or $PRX at the end
    655 ($CM* ($PR | $PRX | $PO))? ($CM* ($CL | $CP))? ($CM* ($NU | $IS | $SY))* $CM* $NU ($CM* ($OP | $HY))? ($CM* ($PR | $PO | $POX))?;
    656 
    657 # LB 26
    658 $CM* ($H3 | $H2 | $JV | $JL) $CM* $JL;
    659 $CM* ($JT | $JV) $CM* ($H2 | $JV);
    660 $CM* $JT $CM* ($H3 | $JT);
    661 
    662 # LB 27
    663 # Do not include $POX or $PRX here
    664 $CM* $IN $CM* ($H3 | $H2 | $JT | $JV | $JL);
    665 $CM* $PO $CM* ($H3 | $H2 | $JT | $JV | $JL);
    666 $CM* ($H3 | $H2 | $JT | $JV | $JL) $CM* $PR;
    667 
    668 # LB 28
    669 $CM* ($ALPlus | $HL) $CM* ($ALPlus | $HL);
    670 
    671 
    672 # LB 29
    673 $CM* ($ALPlus | $HL) $CM* $IS;
    674 
    675 # LB 30
    676 $CM* $OP $CM* ($ALPlus | $HL | $NU);
    677 $CM* ($ALPlus | $HL | $NU) $CM* $CP;
    678 
    679 # LB 30a
    680 $CM* $RI $CM* $RI;
    681 
    682 ## -------------------------------------------------
    683 
    684 !!safe_reverse;
    685 
    686 # LB 9
    687 $CM+ [^$CM $BK $CR $LF $NL $ZW $SP];
    688 $CM+ $SP / .;
    689 
    690 # LB 14
    691 $SP+ $CM* $OP;
    692 
    693 # LB 15
    694 $SP+ $CM* $QU;
    695 
    696 # LB 16
    697 $SP+ $CM* ($CL | $CP);
    698 
    699 # LB 17
    700 $SP+ $CM* $B2;
    701 
    702 # LB 21
    703 $CM* ($HY | $BA | $BAX) $CM* $HL;
    704 
    705 # LB 25
    706 ($CM* ($IS | $SY))+ $CM* $NU;
    707 ($CL | $CP) $CM* ($NU | $IS | $SY);
    708 
    709 # For dictionary-based break
    710 $dictionary $dictionary;
    711 
    712 ## -------------------------------------------------
    713 
    714 !!safe_forward;
    715 
    716 # Skip forward over all character classes that are involved in
    717 #   rules containing patterns with possibly more than one char
    718 #   of context.
    719 #
    720 #  It might be slightly more efficient to have specific rules
    721 #  instead of one generic one, but only if we could
    722 #  turn off rule chaining.  We don't want to move more
    723 #  than necessary.
    724 #
    725 [$CM $OP $QU $CL $CP $B2 $PR $PRX $HY $BA $BAX $SP $dictionary]+ [^$CM $OP $QU $CL $CP $B2 $PR $PRX $HY $BA $BAX $dictionary];
    726 $dictionary $dictionary;
    727 
    728