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 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=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+     $INcm;     #  by rule 10, any otherwise unattached CM behaves as AL
358$EXcm    $INcm;
359$IDcm    $INcm;
360$INcm    $INcm;
361$NUcm    $INcm;
362
363
364# $LB 23
365$IDcm  $POcm;
366$ALcm  $NUcm;       # includes $LB19
367$HLcm  $NUcm;
368$CM+   $NUcm;       # Rule 10, any otherwise unattached CM behaves as AL
369$NUcm  $ALcm;
370$NUcm  $HLcm;
371
372#
373# LB 24
374#
375$PRcm $IDcm;
376$PRcm ($ALcm | $HLcm);
377$POcm ($ALcm | $HLcm);
378
379#
380# LB 25   Numbers.
381#
382($PRcm | $POcm)? ($OPcm | $HYcm)? $NUcm ($NUcm | $SYcm | $IScm)* ($CLcm | $CPcm)? ($PRcm | $POcm)?;
383
384# LB 26  Do not break a Korean syllable
385#
386$JLcm ($JLcm | $JVcm | $H2cm | $H3cm);
387($JVcm | $H2cm) ($JVcm | $JTcm);
388($JTcm | $H3cm) $JTcm;
389
390# LB 27  Treat korean Syllable Block the same as ID  (don't break it)
391($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $INcm;
392($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $POcm;
393$PRcm ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm);
394
395
396# LB 28   Do not break between alphabetics
397#
398($ALcm | $HLcm) ($ALcm | $HLcm);
399$CM+ ($ALcm | $HLcm);      # The $CM+ is from rule 10, an unattached CM is treated as AL
400
401# LB 29
402$IScm ($ALcm | $HLcm);
403
404# LB 30
405($ALcm | $HLcm | $NUcm) $OPcm;
406$CM+ $OPcm;         # The $CM+ is from rule 10, an unattached CM is treated as AL.
407$CPcm ($ALcm | $HLcm | $NUcm);
408
409# LB 30a  Do not break between regional indicators.
410$RIcm $RIcm;
411
412#
413#  Reverse Rules.
414#
415## -------------------------------------------------
416
417!!reverse;
418
419$CM+ $ALPlus;
420$CM+ $BA;
421$CM+ $BB;
422$CM+ $B2;
423$CM+ $CL;
424$CM+ $CP;
425$CM+ $EX;
426$CM+ $GL;
427$CM+ $HL;
428$CM+ $HY;
429$CM+ $H2;
430$CM+ $H3;
431$CM+ $ID;
432$CM+ $IN;
433$CM+ $IS;
434$CM+ $JL;
435$CM+ $JV;
436$CM+ $JT;
437$CM+ $NS;
438$CM+ $NU;
439$CM+ $OP;
440$CM+ $PO;
441$CM+ $PR;
442$CM+ $QU;
443$CM+ $RI;
444$CM+ $SY;
445$CM+ $WJ;
446$CM+;
447
448
449#
450#  Sequences of the form  (shown forwards)
451#      [CANT_CM]  <break>  [CM]  [whatever]
452#  The CM needs to behave as an AL
453#
454$AL_FOLLOW $CM+ / (
455          [$BK $CR $LF $NL $ZW {eof}] |
456          $SP+ $CM+ $SP |
457          $SP+ $CM* ([^$OP $CM $SP] | [$AL {eof}]));   # if LB 14 will match, need to surpress this break.
458                                               #  LB14 says    OP SP* x .
459                                               #    becomes    OP SP* x AL
460                                               #    becomes    OP SP* x CM+ AL_FOLLOW
461                                               #
462                                               # Further note:  the $AL in [$AL {eof}] is only to work around
463                                               #                a rule compiler bug which complains about
464                                               #                empty sets otherwise.
465
466#
467#  Sequences of the form  (shown forwards)
468#      [CANT_CM]  <break> [CM]  <break>  [PR]
469#  The CM needs to behave as an AL
470#  This rule is concerned about getting the second of the two <breaks> in place.
471#
472
473[$PR   ] / $CM+ [$BK $CR $LF $NL $ZW $SP {eof}];
474
475
476
477# LB 4, 5, 5
478
479$LB4Breaks [$LB4NonBreaks-$CM];
480$LB4Breaks $CM+ $CAN_CM;
481$LF $CR;
482
483
484# LB 7         x SP
485#              x ZW
486[$SP $ZW] [$LB4NonBreaks-$CM];
487[$SP $ZW] $CM+ $CAN_CM;
488
489# LB 8 ZW SP* <break>
490#     TODO: to implement this, we need more than one look-ahead hard break in play at a time.
491#           Requires an engine enhancement.
492#   / $SP* $ZW
493
494# LB 9,10  Combining marks.
495#    X   $CM needs to behave like X, where X is not $SP or controls.
496#    $CM not covered by the above needs to behave like $AL
497# Stick together any combining sequences that don't match other rules.
498$CM+ $CAN_CM;
499
500
501# LB 11
502$CM* $WJ $CM* $CAN_CM;
503$CM* $WJ      [$LB8NonBreaks-$CM];
504
505     $CANT_CM $CM* $WJ;
506$CM* $CAN_CM  $CM* $WJ;
507
508# LB 12a
509#      [^SP BA HY] x GL
510#
511$CM* $GL $CM* [$LB8NonBreaks-[$CM $SP $BA $HY]];
512
513# LB 12
514#     GL  x
515#
516$CANT_CM $CM* $GL;
517$CM* $CAN_CM $CM* $GL;
518
519
520# LB 13
521$CL $CM+ $CAN_CM;
522$CP $CM+ $CAN_CM;
523$EX $CM+ $CAN_CM;
524$IS $CM+ $CAN_CM;
525$SY $CM+ $CAN_CM;
526
527$CL [$LB8NonBreaks-$CM];
528$CP [$LB8NonBreaks-$CM];
529$EX [$LB8NonBreaks-$CM];
530$IS [$LB8NonBreaks-$CM];
531$SY [$LB8NonBreaks-$CM];
532
533# Rule 13 & 14 taken together for an edge case.
534#   Match this, shown forward
535#     OP SP+  ($CM+ behaving as $AL) (CL | CP | EX | IS | IY)
536#   This really wants to chain at the $CM+ (which is acting as an $AL)
537#   except for $CM chaining being disabled.
538[$CL $CP $EX $IS $SY] $CM+ $SP+ $CM* $OP;
539
540# LB 14    OP SP* x
541#
542$CM* $CAN_CM    $SP* $CM* $OP;
543     $CANT_CM   $SP* $CM* $OP;
544$AL_FOLLOW? $CM+  $SP $SP* $CM* $OP;     #  by LB 10, behaves like $AL_FOLLOW? $AL $SP* $CM* $OP
545
546     $AL_FOLLOW_NOCM $CM+ $SP+ $CM* $OP;
547$CM* $AL_FOLLOW_CM   $CM+ $SP+ $CM* $OP;
548$SY $CM $SP+ $OP;   # TODO:  Experiment.  Remove.
549
550
551
552# LB 15
553$CM* $OP $SP* $CM* $QU;
554
555# LB 16
556$CM* $NS $SP* $CM* ($CL | $CP);
557
558# LB 17
559$CM* $B2 $SP* $CM* $B2;
560
561# LB 18  break after spaces
562#        Nothing explicit needed here.
563
564
565#
566# LB 19
567#
568$CM* $QU $CM* $CAN_CM;                                #   . x QU
569$CM* $QU      $LB18NonBreaks;
570
571
572$CM* $CAN_CM  $CM* $QU;                               #   QU x .
573     $CANT_CM $CM* $QU;
574
575#
576#  LB 20  Break before and after CB.
577#         nothing needed here.
578#
579
580# LB 21
581$CM* ($BA | $HY | $NS) $CM* [$LB20NonBreaks-$CM];     #  . x (BA | HY | NS)
582
583$CM* [$LB20NonBreaks-$CM] $CM* $BB;                   #  BB x .
584[^$CB] $CM* $BB;                                      #
585
586# LB21a
587[^$CB] $CM* ($HY | $BA) $CM* $HL;
588
589# LB21b (reverse)
590$CM* $HL $CM* $SY;
591
592# LB 22
593$CM* $IN $CM* ($ALPlus | $HL);
594$CM* $IN $CM* $EX;
595$CM* $IN $CM* $ID;
596$CM* $IN $CM* $IN;
597$CM* $IN $CM* $NU;
598
599# LB 23
600$CM* $PO $CM* $ID;
601$CM* $NU $CM* ($ALPlus | $HL);
602$CM* ($ALPlus | $HL) $CM* $NU;
603
604# LB 24
605$CM* $ID $CM* $PR;
606$CM* ($ALPlus | $HL) $CM* $PR;
607$CM* ($ALPlus | $HL) $CM* $PO;
608
609
610# LB 25
611($CM* ($PR | $PO))? ($CM* ($CL | $CP))? ($CM* ($NU | $IS | $SY))* $CM* $NU ($CM* ($OP | $HY))? ($CM* ($PR | $PO))?;
612
613# LB 26
614$CM* ($H3 | $H2 | $JV | $JL) $CM* $JL;
615$CM* ($JT | $JV) $CM* ($H2 | $JV);
616$CM* $JT $CM* ($H3 | $JT);
617
618# LB 27
619$CM* $IN $CM* ($H3 | $H2 | $JT | $JV | $JL);
620$CM* $PO $CM* ($H3 | $H2 | $JT | $JV | $JL);
621$CM* ($H3 | $H2 | $JT | $JV | $JL) $CM* $PR;
622
623# LB 28
624$CM* ($ALPlus | $HL) $CM* ($ALPlus | $HL);
625
626
627# LB 29
628$CM* ($ALPlus | $HL) $CM* $IS;
629
630# LB 30
631$CM* $OP $CM* ($ALPlus | $HL | $NU);
632$CM* ($ALPlus | $HL | $NU) $CM* $CP;
633
634# LB 30a
635$CM* $RI $CM* $RI;
636
637## -------------------------------------------------
638
639!!safe_reverse;
640
641# LB 9
642$CM+ [^$CM $BK $CR $LF $NL $ZW $SP];
643$CM+ $SP / .;
644
645# LB 14
646$SP+ $CM* $OP;
647
648# LB 15
649$SP+ $CM* $QU;
650
651# LB 16
652$SP+ $CM* ($CL | $CP);
653
654# LB 17
655$SP+ $CM* $B2;
656
657# LB 21
658$CM* ($HY | $BA) $CM* $HL;
659
660# LB 25
661($CM* ($IS | $SY))+ $CM* $NU;
662($CL | $CP) $CM* ($NU | $IS | $SY);
663
664# For dictionary-based break
665$dictionary $dictionary;
666
667## -------------------------------------------------
668
669!!safe_forward;
670
671# Skip forward over all character classes that are involved in
672#   rules containing patterns with possibly more than one char
673#   of context.
674#
675#  It might be slightly more efficient to have specific rules
676#  instead of one generic one, but only if we could
677#  turn off rule chaining.  We don't want to move more
678#  than necessary.
679#
680[$CM $OP $QU $CL $CP $B2 $PR $HY $BA $SP $dictionary]+ [^$CM $OP $QU $CL $CP $B2 $PR $HY $BA $dictionary];
681$dictionary $dictionary;
682
683