• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# Copyright (C) 2016 and later: Unicode, Inc. and others.
2# License & terms of use: http://www.unicode.org/copyright.html
3# Copyright (c) 2002-2016  International Business Machines Corporation and
4# others. All Rights Reserved.
5#
6#  file:  line_loose_fi.txt
7#
8#         Line Breaking Rules
9#         Implement default line breaking as defined by
10#         Unicode Standard Annex #14 Revision 37 for Unicode 9.0
11#         http://www.unicode.org/reports/tr14/
12#         tailored as noted in 3rd paragraph below.
13#
14#         Includes extensions to the handling of emoji ZWJ sequences from
15#         https://goo.gl/cluFCn
16#
17#         TODO:  Rule LB 8 remains as it was in Unicode 5.2
18#         This is only because of a limitation of ICU break engine implementation,
19#         not because the older behavior is desirable.
20#
21#         This tailors the line break behavior both for Finnish and to correpond to CSS
22#         line-break=loose (BCP47 -u-lb-loose) as defined for languages other than
23#         Chinese & Japanese.
24#         It sets characters of class CJ to behave like ID.
25#         In addition, it allows breaks before 3005, 303B, 309D, 309E, 30FD, 30FE (all NS).
26#
27#  Character Classes defined by TR 14.
28#
29
30!!chain;
31
32$AI = [:LineBreak =  Ambiguous:];
33$AL = [:LineBreak =  Alphabetic:];
34$BA = [:LineBreak =  Break_After:];
35$HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
36$BB = [:LineBreak =  Break_Before:];
37$BK = [:LineBreak =  Mandatory_Break:];
38$B2 = [:LineBreak =  Break_Both:];
39$CB = [:LineBreak =  Contingent_Break:];
40$CJ = [:LineBreak =  Conditional_Japanese_Starter:];
41$CL = [:LineBreak =  Close_Punctuation:];
42# $CM = [:LineBreak =  Combining_Mark:];
43$CP = [:LineBreak =  Close_Parenthesis:];
44$CR = [:LineBreak =  Carriage_Return:];
45$EB = [[:LineBreak =  EB:]\U0001F3C2\U0001F3C7\U0001F3CC\U0001F46A-\U0001F46D\U0001F46F\U0001F574\U0001F6CC];
46$EM = [:LineBreak =  EM:];
47$EX = [:LineBreak =  Exclamation:];
48$GL = [:LineBreak =  Glue:];
49$HL = [:LineBreak =  Hebrew_Letter:];
50$HY = [:LineBreak =  Hyphen:];
51$H2 = [:LineBreak =  H2:];
52$H3 = [:LineBreak =  H3:];
53# CSS Loose tailoring: CJ resolves to ID
54$ID = [[:LineBreak =  Ideographic:] $CJ];
55$IN = [:LineBreak =  Inseperable:];
56$IS = [:LineBreak =  Infix_Numeric:];
57$JL = [:LineBreak =  JL:];
58$JV = [:LineBreak =  JV:];
59$JT = [:LineBreak =  JT:];
60$LF = [:LineBreak =  Line_Feed:];
61$NL = [:LineBreak =  Next_Line:];
62$NSX = [\u3005 \u303B \u309D \u309E \u30FD \u30FE];
63$NS = [[:LineBreak =  Nonstarter:] - $NSX];
64$NU = [:LineBreak =  Numeric:];
65$OP = [:LineBreak =  Open_Punctuation:];
66$PO = [:LineBreak =  Postfix_Numeric:];
67$PR = [:LineBreak =  Prefix_Numeric:];
68$QU = [:LineBreak =  Quotation:];
69$RI = [:LineBreak =  Regional_Indicator:];
70$SA = [:LineBreak =  Complex_Context:];
71$SG = [:LineBreak =  Surrogate:];
72$SP = [:LineBreak =  Space:];
73$SY = [:LineBreak =  Break_Symbols:];
74$WJ = [:LineBreak =  Word_Joiner:];
75$XX = [:LineBreak =  Unknown:];
76$ZW = [:LineBreak =  ZWSpace:];
77$ZWJ = [:LineBreak = ZWJ:];
78
79$EmojiNRK = [[\p{Emoji}] - [$RI \u002a\u00230-9©®™〰〽]];
80# Data for Extended Pictographic scraped from CLDR common/properties/ExtendedPictographic.txt, r12773
81$Extended_Pict = [\U0001F774-\U0001F77F\u2700-\u2701\u2703-\u2704\u270E\u2710-\u2711\u2765-\u2767\U0001F030-\U0001F093\U0001F094-\U0001F09F\U0001F10D-\U0001F10F\U0001F12F\U0001F16C-\U0001F16F\U0001F1AD-\U0001F1E5\U0001F203-\U0001F20F\U0001F23C-\U0001F23F\U0001F249-\U0001F24F\U0001F252-\U0001F2FF\U0001F7D5-\U0001F7FF\U0001F000-\U0001F003\U0001F005-\U0001F02B\U0001F02C-\U0001F02F\U0001F322-\U0001F323\U0001F394-\U0001F395\U0001F398\U0001F39C-\U0001F39D\U0001F3F1-\U0001F3F2\U0001F3F6\U0001F4FE\U0001F53E-\U0001F548\U0001F54F\U0001F568-\U0001F56E\U0001F571-\U0001F572\U0001F57B-\U0001F586\U0001F588-\U0001F589\U0001F58E-\U0001F58F\U0001F591-\U0001F594\U0001F597-\U0001F5A3\U0001F5A6-\U0001F5A7\U0001F5A9-\U0001F5B0\U0001F5B3-\U0001F5BB\U0001F5BD-\U0001F5C1\U0001F5C5-\U0001F5D0\U0001F5D4-\U0001F5DB\U0001F5DF-\U0001F5E0\U0001F5E2\U0001F5E4-\U0001F5E7\U0001F5E9-\U0001F5EE\U0001F5F0-\U0001F5F2\U0001F5F4-\U0001F5F9\u2605\u2607-\u260D\u260F-\u2610\u2612\u2616-\u2617\u2619-\u261C\u261E-\u261F\u2621\u2624-\u2625\u2627-\u2629\u262B-\u262D\u2630-\u2637\u263B-\u2647\u2654-\u265F\u2661-\u2662\u2664\u2667\u2669-\u267A\u267C-\u267E\u2680-\u2691\u2695\u2698\u269A\u269D-\u269F\u26A2-\u26A9\u26AC-\u26AF\u26B2-\u26BC\u26BF-\u26C3\u26C6-\u26C7\u26C9-\u26CD\u26D0\u26D2\u26D5-\u26E8\u26EB-\u26EF\u26F6\u26FB-\u26FC\u26FE-\u26FF\u2388\U0001FA00-\U0001FFFD\U0001F0A0-\U0001F0AE\U0001F0B1-\U0001F0BF\U0001F0C1-\U0001F0CF\U0001F0D1-\U0001F0F5\U0001F0AF-\U0001F0B0\U0001F0C0\U0001F0D0\U0001F0F6-\U0001F0FF\U0001F80C-\U0001F80F\U0001F848-\U0001F84F\U0001F85A-\U0001F85F\U0001F888-\U0001F88F\U0001F8AE-\U0001F8FF\U0001F900-\U0001F90F\U0001F91F\U0001F928-\U0001F92F\U0001F931-\U0001F932\U0001F93F\U0001F94C-\U0001F94F\U0001F95F-\U0001F97F\U0001F992-\U0001F9BF\U0001F9C1-\U0001F9FF\U0001F6C6-\U0001F6CA\U0001F6E6-\U0001F6E8\U0001F6EA\U0001F6F1-\U0001F6F2\U0001F6D3-\U0001F6DF\U0001F6ED-\U0001F6EF\U0001F6F7-\U0001F6FF];
82
83# By LB9, a ZWJ also behaves as a CM. Including it in the definition of CM avoids having to explicitly
84#         list it in the numerous rules that use CM.
85# By LB1, SA characters with general categor of Mn or Mc also resolve to CM.
86
87$CM = [[:LineBreak = Combining_Mark:] $ZWJ [$SA & [[:Mn:][:Mc:]]]];
88
89#   Dictionary character set, for triggering language-based break engines. Currently
90#   limited to LineBreak=Complex_Context (SA).
91
92$dictionary = [$SA];
93
94#
95#  Rule LB1.  By default, treat AI  (characters with ambiguous east Asian width),
96#                               SA  (Dictionary chars, excluding Mn and Mc)
97#                               SG  (Unpaired Surrogates)
98#                               XX  (Unknown, unassigned)
99#                         as $AL  (Alphabetic)
100#
101$ALPlus = [$AL $AI $SG $XX [$SA-[[:Mn:][:Mc:]]]];
102
103
104## -------------------------------------------------
105
106!!forward;
107
108#
109# CAN_CM  is the set of characters that may combine with CM combining chars.
110#         Note that Linebreak UAX 14's concept of a combining char and the rules
111#         for what they can combine with are _very_ different from the rest of Unicode.
112#
113#         Note that $CM itself is left out of this set.  If CM is needed as a base
114#         it must be listed separately in the rule.
115#
116$CAN_CM  = [^$SP $BK $CR $LF $NL $ZW $CM];       # Bases that can   take CMs
117$CANT_CM = [ $SP $BK $CR $LF $NL $ZW $CM];       # Bases that can't take CMs
118
119#
120# AL_FOLLOW  set of chars that can unconditionally follow an AL
121#            Needed in rules where stand-alone $CM s are treated as AL.
122#
123$AL_FOLLOW      = [$BK $CR $LF $NL $ZW $SP $CL $CP $EX $HL $IS $SY $WJ $GL $OP $QU $BA $HH $HY $NS $IN $NU $PR $PO $ALPlus];
124
125
126#
127#  Rule LB 4, 5    Mandatory (Hard) breaks.
128#
129$LB4Breaks    = [$BK $CR $LF $NL];
130$LB4NonBreaks = [^$BK $CR $LF $NL $CM];
131$CR $LF {100};
132
133#
134#  LB 6    Do not break before hard line breaks.
135#
136$LB4NonBreaks?  $LB4Breaks {100};    # LB 5  do not break before hard breaks.
137$CAN_CM $CM*    $LB4Breaks {100};
138^$CM+           $LB4Breaks {100};
139
140# LB 7         x SP
141#              x ZW
142$LB4NonBreaks [$SP $ZW];
143$CAN_CM $CM*  [$SP $ZW];
144^$CM+         [$SP $ZW];
145
146#
147# LB 8         Break after zero width space
148#              TODO:  ZW SP* <break>
149#              An engine change is required to write the reverse rule for this.
150#              For now, leave the Unicode 5.2 rule, ZW <break>
151#
152$LB8Breaks    = [$LB4Breaks $ZW];
153$LB8NonBreaks = [[$LB4NonBreaks] - [$ZW]];
154
155# LB 8a        ZWJ x (ID | Extended_Pict | EmojiNRK)   Emoji ZWJ sequences.
156#
157$ZWJ ($ID | $Extended_Pict | $EmojiNRK);
158
159# LB 9     Combining marks.      X   $CM needs to behave like X, where X is not $SP, $BK $CR $LF $NL
160#                                $CM not covered by the above needs to behave like $AL
161#                                See definition of $CAN_CM.
162
163$CAN_CM $CM+;                   #  Stick together any combining sequences that don't match other rules.
164^$CM+;
165
166#
167# LB 11  Do not break before or after WORD JOINER & related characters.
168#
169$CAN_CM $CM*  $WJ;
170$LB8NonBreaks $WJ;
171^$CM+         $WJ;
172
173$WJ $CM* .;
174
175#
176# LB 12  Do not break after NBSP and related characters.
177#         GL  x
178#
179$GL $CM* .;
180
181#
182# LB 12a  Do not break before NBSP and related characters ...
183#            [^SP BA HY] x GL
184#
185[[$LB8NonBreaks] - [$SP $BA $HH $HY]] $CM* $GL;
186^$CM+ $GL;
187
188
189
190#
191# LB 13   Don't break before ']' or '!' or ';' or '/', even after spaces.
192#
193$LB8NonBreaks $CL;
194$CAN_CM $CM*  $CL;
195^$CM+         $CL;              # by rule 10, stand-alone CM behaves as AL
196
197$LB8NonBreaks $CP;
198$CAN_CM $CM*  $CP;
199^$CM+         $CP;              # by rule 10, stand-alone CM behaves as AL
200
201$LB8NonBreaks $EX;
202$CAN_CM $CM*  $EX;
203^$CM+         $EX;              # by rule 10, stand-alone CM behaves as AL
204
205$LB8NonBreaks $IS;
206$CAN_CM $CM*  $IS;
207^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
208
209$LB8NonBreaks $SY;
210$CAN_CM $CM*  $SY;
211^$CM+         $SY;              # by rule 10, stand-alone CM behaves as AL
212
213
214#
215# LB 14  Do not break after OP, even after spaces
216#
217$OP $CM* $SP* .;
218
219$OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
220                                   # by rule 8, CM following a SP is stand-alone.
221
222# LB 15
223$QU $CM* $SP* $OP;
224
225# LB 16
226# Do not break between closing punctuation and $NS, even with intervening spaces
227# But DO allow a break between closing punctuation and $NSX, don't include it here
228($CL | $CP) $CM* $SP* $NS;
229
230# LB 17
231$B2 $CM* $SP* $B2;
232
233#
234# LB 18  Break after spaces.
235#
236$LB18NonBreaks = [$LB8NonBreaks - [$SP]];
237$LB18Breaks    = [$LB8Breaks $SP];
238
239
240# LB 19
241#         x QU
242$LB18NonBreaks $CM* $QU;
243^$CM+               $QU;
244
245#         QU  x
246$QU $CM* .;
247
248
249# LB 20
250#        <break>  $CB
251#        $CB   <break>
252
253$LB20NonBreaks = [$LB18NonBreaks - $CB];
254
255# LB 20.09 added rule for Finnish tailoring
256# LB 21        x   (BA | HY | NS)
257#           BB x
258#
259# DO allow breaks here before NSX, so don't include it
260$LB20NonBreaks $CM* ($BA | $HH | $HY | $NS) $CM* / $AL;
261$LB20NonBreaks $CM* ($BA | $HH | $HY | $NS);
262($HY | $HH) $AL;
263^$CM+ ($BA | $HY | $HH | $NS);
264
265$BB $CM* [^$CB];                                  #  $BB  x
266$BB $CM* $LB20NonBreaks;
267
268# LB 21a Don't break after Hebrew + Hyphen
269#   HL (HY | BA) x
270#
271$HL $CM* ($HY | $BA | $HH) $CM* [^$CB]?;
272
273# LB 21b (forward) Don't break between SY and HL
274# (break between HL and SY already disallowed by LB 13 above)
275$SY $CM* $HL;
276
277# LB 22
278($ALPlus | $HL) $CM* $IN;
279^$CM+    $IN;     #  by rule 10, any otherwise unattached CM behaves as AL
280$EX $CM*    $IN;
281($ID | $EB | $EM) $CM*  $IN;
282# $IN $CM*    $IN;  # delete this rule for CSS loose
283$NU $CM*    $IN;
284
285
286# $LB 23
287#
288($ALPlus | $HL) $CM* $NU;
289^$CM+  $NU;       # Rule 10, any otherwise unattached CM behaves as AL
290$NU $CM* ($ALPlus | $HL);
291
292# LB 23a
293#
294$PR $CM* ($ID | $EB | $EM);
295($ID | $EB | $EM) $CM*  $PO;
296
297
298#
299# LB 24
300#
301($PR | $PO) $CM* ($ALPlus | $HL);
302($ALPlus | $HL) $CM* ($PR | $PO);
303^$CM+ ($PR | $PO);       # Rule 10, any otherwise unattached CM behaves as AL
304
305#
306# LB 25   Numbers.
307#
308(($PR | $PO) $CM*)? (($OP | $HY) $CM*)? $NU ($CM* ($NU | $SY | $IS))*
309    ($CM* ($CL | $CP))? ($CM* ($PR | $PO))?;
310
311# LB 26  Do not break a Korean syllable
312#
313$JL $CM* ($JL | $JV | $H2 | $H3);
314($JV | $H2) $CM* ($JV | $JT);
315($JT | $H3) $CM* $JT;
316
317# LB 27  Treat korean Syllable Block the same as ID  (don't break it)
318($JL | $JV | $JT | $H2 | $H3) $CM* $IN;
319($JL | $JV | $JT | $H2 | $H3) $CM* $PO;
320$PR $CM* ($JL | $JV | $JT | $H2 | $H3);
321
322
323# LB 28   Do not break between alphabetics
324#
325($ALPlus | $HL) $CM* ($ALPlus | $HL);
326^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
327
328# LB 29
329$IS $CM* ($ALPlus | $HL);
330
331# LB 30
332($ALPlus | $HL | $NU) $CM* $OP;
333^$CM+ $OP;         # The $CM+ is from rule 10, an unattached CM is treated as AL.
334$CP $CM* ($ALPlus | $HL | $NU);
335
336# LB 30a  Do not break between regional indicators. Break after pairs of them.
337#         Tricky interaction with LB8a: ZWJ x ID
338$RI $CM* $RI                / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM] {eof}];
339$RI $CM* $RI $CM*  $ZWJ     / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM $ID $Extended_Pict $EmojiNRK] {eof}];
340$RI $CM* $RI $CM* [$CM-$ZWJ] / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM] {eof}];
341
342$RI $CM* $RI $CM* [$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS {eof}];
343$RI $CM* $RI $CM* $ZWJ ($ID | $Extended_Pict | $EmojiNRK);
344
345# LB 30b Do not break between an Emoji Base and an Emoji Modifier
346$EB $CM* $EM;
347
348#
349#  Reverse Rules.
350#
351## -------------------------------------------------
352
353!!reverse;
354
355#  LB 9 Combining Marks.
356#  Stick together any combining sequences that don't match other rules.
357
358^$CM+ $CAN_CM?;
359
360#
361#  Sequences of the form  (shown forwards)
362#      [CANT_CM]  <break>  [CM]  [whatever]
363#  The CM needs to behave as an AL
364#
365$AL_FOLLOW $CM+ / (
366          [$BK $CR $LF $NL $ZW {eof}] |
367          $SP+ $CM+ $SP |
368          $SP+ $CM* ([^$OP $CM $SP] | [$AL {eof}]));   # if LB 14 will match, need to surpress this break.
369                                               #  LB14 says    OP SP* x .
370                                               #    becomes    OP SP* x AL
371                                               #    becomes    OP SP* x CM+ AL_FOLLOW
372                                               #
373                                               # Further note:  the $AL in [$AL {eof}] is only to work around
374                                               #                a rule compiler bug which complains about
375                                               #                empty sets otherwise.
376
377
378# LB 4, 5, 6
379
380$LB4Breaks [$LB4NonBreaks-$CM];
381$LB4Breaks $CM+ $CAN_CM;
382$LF $CR;
383
384
385# LB 7         x SP
386#              x ZW
387[$SP $ZW] [$LB4NonBreaks-$CM];
388[$SP $ZW] $CM+ $CAN_CM;
389
390# LB 8 ZW SP* <break>
391#     TODO: to implement this, we need more than one look-ahead hard break in play at a time.
392#           Requires an engine enhancement.
393#   / $SP* $ZW
394
395# LB 8a        ZWJ x (ID | Extended_Pict | EmojiNRK)
396#
397($ID | $Extended_Pict | $EmojiNRK) $ZWJ $CM* $CAN_CM?;
398
399
400# LB 9,10  Combining marks.
401#    X   $CM needs to behave like X, where X is not $SP or controls.
402#    $CM not covered by the above needs to behave like $AL
403# Stick together any combining sequences that don't match other rules.
404^$CM+ $CAN_CM;
405
406
407# LB 11
408#
409$WJ $CM* $CAN_CM;
410$WJ      [$LB8NonBreaks-$CM];
411
412     $CANT_CM $CM* $WJ;
413$CAN_CM  $CM* $WJ;
414
415# LB 12a
416#      [^SP BA HY] x GL
417#
418$GL $CM* [$LB8NonBreaks-[$CM $SP $BA $HH $HY]];
419
420# LB 12
421#     GL  x
422#
423$CANT_CM $CM* $GL;
424$CAN_CM $CM* $GL;
425
426
427# LB 13
428$CL $CM+ $CAN_CM;
429$CP $CM+ $CAN_CM;
430$EX $CM+ $CAN_CM;
431$IS $CM+ $CAN_CM;
432$SY $CM+ $CAN_CM;
433
434$CL [$LB8NonBreaks-$CM];
435$CP [$LB8NonBreaks-$CM];
436$EX [$LB8NonBreaks-$CM];
437$IS [$LB8NonBreaks-$CM];
438$SY [$LB8NonBreaks-$CM];
439
440
441# LB 14    OP SP* x
442#
443.   $SP* $CM* $OP;
444$AL_FOLLOW? $CM+ $SP+ $CM* $OP;     #  by LB 10, behaves like $AL_FOLLOW? $AL $SP+ $CM* $OP
445
446
447# LB 15
448$OP $SP* $CM* $QU;
449
450# LB 16
451# Don't include $NSX here
452$NS $SP* $CM* ($CL | $CP);
453
454# LB 17
455$B2 $SP* $CM* $B2;
456
457# LB 18  break after spaces
458#        Nothing explicit needed here.
459
460
461#
462# LB 19
463#
464$QU $CM* $CAN_CM;                                #   . x QU
465$QU      $LB18NonBreaks;
466
467
468$CAN_CM  $CM* $QU;                               #   QU x .
469     $CANT_CM $CM* $QU;
470
471#
472#  LB 20  Break before and after CB.
473#         nothing needed here.
474#
475
476# LB 20.09 added rule for Finnish tailoring
477$AL ($HY | $HH) / $SP;
478
479# LB 21
480# Don't include $NSX here
481($BA | $HH | $HY | $NS) $CM* [$LB20NonBreaks-$CM];     #  . x (BA | HY | NS)
482
483[$LB20NonBreaks-$CM] $CM* $BB;                   #  BB x .
484[^$CB] $CM* $BB;                                      #
485
486# LB21a
487[^$CB] $CM* ($HY | $BA | $HH) $CM* $HL;
488
489# LB21b (reverse)
490$HL $CM* $SY;
491
492# LB 22
493$IN $CM* ($ALPlus | $HL);
494$IN $CM* $EX;
495$IN $CM* ($ID | $EB | $EM);
496# $IN $CM* $IN; # delete this rule for CSS loose
497$IN $CM* $NU;
498
499# LB 23
500$NU $CM* ($ALPlus | $HL);
501($ALPlus | $HL) $CM* $NU;
502
503# LB23a
504($ID | $EB | $EM) $CM* $PR;
505$PO $CM* ($ID | $EB | $EM);
506
507# LB 24
508($ALPlus | $HL) $CM* ($PR | $PO);
509($PR | $PO) $CM* ($ALPlus | $HL);
510
511
512# LB 25
513($CM* ($PR | $PO))? ($CM* ($CL | $CP))? ($CM* ($NU | $IS | $SY))* $CM* $NU ($CM* ($OP | $HY))? ($CM* ($PR | $PO))?;
514
515# LB 26
516($H3 | $H2 | $JV | $JL) $CM* $JL;
517($JT | $JV) $CM* ($H2 | $JV);
518$JT $CM* ($H3 | $JT);
519
520# LB 27
521$IN $CM* ($H3 | $H2 | $JT | $JV | $JL);
522$PO $CM* ($H3 | $H2 | $JT | $JV | $JL);
523 ($H3 | $H2 | $JT | $JV | $JL) $CM* $PR;
524
525# LB 28
526($ALPlus | $HL) $CM* ($ALPlus | $HL);
527
528
529# LB 29
530($ALPlus | $HL) $CM* $IS;
531
532# LB 30
533$OP $CM* ($ALPlus | $HL | $NU);
534($ALPlus | $HL | $NU) $CM* $CP;
535
536# LB 30a
537#    Pairs of Regional Indicators.
538#    The following two rules are nearly identical. The first matches only sequences with an odd number of adjacent RIs,
539#    the second with an even number. Stripping away the cruft they look like
540#         [^RI] RI / (RI RI)+ ^RI;
541#         [^RI] RI RI / (RI RI)+ ^RI;
542#
543# Line Loose tailoring: Don't include NSX here.
544[{bof} $NS $HY $BA $QU $CL $CP $EX $IS $SY $WJ $GL $ZW $SP $BK $CR $LF $NL $ZWJ] $CM* $RI / ($CM* $RI $CM* $RI)+ $CM* [{eof}[^$RI $CM]];
545[{bof} $NS $HY $BA $QU $CL $CP $EX $IS $SY $WJ $GL $ZW $SP $BK $CR $LF $NL $ZWJ] $CM* $RI $CM* $RI / ($CM* $RI $CM* $RI)+ $CM* [{eof}[^$RI $CM]];
546
547# In general, adjacent RIs stay together. The hard-break rules, above, overide this, forcing in the boundaries between pairs.
548$RI $CM* $RI;
549
550#    WJ, GL, QU, etc. are classes with rules like "WJ x "   which includes "WJ x RI".
551$RI $CM* ([$WJ $GL $QU $BB] |  (($HY | $BA)$CM* $HL));
552
553
554# LB 30b Do not break between an Emoji Base and an Emoji Modifier
555$EM $CM* $EB;
556
557
558## -------------------------------------------------
559
560!!safe_reverse;
561
562# LB 9
563^$CM+ [^$CM $BK $CR $LF $NL $ZW $SP];
564^$CM+ $SP / .;
565
566# LB 14
567$SP+ $CM* $OP;
568
569# LB 15
570$SP+ $CM* $QU;
571
572# LB 16
573$SP+ $CM* ($CL | $CP);
574
575# LB 17
576$SP+ $CM* $B2;
577
578# LB 21
579$CM* ($HY | $BA | $HH) $CM* $HL;
580
581# LB 25
582($CM* ($IS | $SY))+ $CM* $NU;
583($CL | $CP) $CM* ($NU | $IS | $SY);
584
585#  LB 30
586($CM* $RI)+;
587
588# For dictionary-based break
589$dictionary $dictionary;
590
591## -------------------------------------------------
592
593!!safe_forward;
594
595# Skip forward over all character classes that are involved in
596#   rules containing patterns with possibly more than one char
597#   of context.
598#
599#  It might be slightly more efficient to have specific rules
600#  instead of one generic one, but only if we could
601#  turn off rule chaining.  We don't want to move more
602#  than necessary.
603#
604^[$CM $OP $QU $CL $CP $B2 $PR $HY $BA $SP $RI $ZWJ $dictionary]+ [^$CM $OP $QU $CL $CP $B2 $PR $HY $BA $RI $ZWJ $dictionary];
605$dictionary $dictionary;
606
607