source/data/brkitr/rules/line_loose.txt - chromium/deps/icu.git - Git at Google

 # Copyright (C) 2016 and later: Unicode, Inc. and others.
 # License & terms of use: http://www.unicode.org/copyright.html
 #
 # Copyright (c) 2002-2016  International Business Machines Corporation and
 # others. All Rights Reserved.
 #
 #  file:  line_loose.txt
 #
 #         Line Breaking Rules
 #         Implement default line breaking as defined by
 #         Unicode Standard Annex #14 Revision 42 for Unicode 12.0
 #         http://www.unicode.org/reports/tr14/, with the following modification:
 #
 #         Boundaries between hyphens and following letters are suppressed when
 #         there is a boundary preceding the hyphen. See rule 20.9
 #
 #         This tailors the line break behavior to correspond to CSS
 #         line-break=loose (BCP47 -u-lb-loose) as defined for languages other than
 #         Chinese & Japanese.
 #         It sets characters of class CJ to behave like ID.
 #         In addition, it allows breaks:
 #         * before iteration marks 3005, 303B, 309D, 309E, 30FD, 30FE (all NS)
 #         * between characters of LineBreak class IN

 #
 #  Character Classes defined by TR 14.
 #

 !!chain;
 !!quoted_literals_only;

 $AI = [:LineBreak =  Ambiguous:];
 $AL = [:LineBreak =  Alphabetic:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
 $BK = [:LineBreak =  Mandatory_Break:];
 $B2 = [:LineBreak =  Break_Both:];
 $CB = [:LineBreak =  Contingent_Break:];
 $CJ = [:LineBreak =  Conditional_Japanese_Starter:];
 $CL = [:LineBreak =  Close_Punctuation:];
 # $CM = [:LineBreak =  Combining_Mark:];
 $CP = [:LineBreak =  Close_Parenthesis:];
 $CR = [:LineBreak =  Carriage_Return:];
 $EB = [:LineBreak =  EB:];
 $EM = [:LineBreak =  EM:];
 $EX = [:LineBreak =  Exclamation:];
 $GL = [:LineBreak =  Glue:];
 $HL = [:LineBreak =  Hebrew_Letter:];
 $HY = [:LineBreak =  Hyphen:];
 $H2 = [:LineBreak =  H2:];
 $H3 = [:LineBreak =  H3:];
 # CSS Loose tailoring: CJ resolves to ID
 $ID = [[:LineBreak =  Ideographic:] $CJ];
 $IN = [:LineBreak =  Inseperable:];
 $IS = [:LineBreak =  Infix_Numeric:];
 $JL = [:LineBreak =  JL:];
 $JV = [:LineBreak =  JV:];
 $JT = [:LineBreak =  JT:];
 $LF = [:LineBreak =  Line_Feed:];
 $NL = [:LineBreak =  Next_Line:];
 $NSX = [\u3005 \u303B \u309D \u309E \u30FD \u30FE];
 $NS = [[:LineBreak =  Nonstarter:] - $NSX];
 $NU = [:LineBreak =  Numeric:];
 $OP = [:LineBreak =  Open_Punctuation:];
 $PO = [:LineBreak =  Postfix_Numeric:];
 $PR = [:LineBreak =  Prefix_Numeric:];
 $QU = [:LineBreak =  Quotation:];
 $RI = [:LineBreak =  Regional_Indicator:];
 $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
 $ZWJ = [:LineBreak = ZWJ:];

 # By LB9, a ZWJ also behaves as a CM. Including it in the definition of CM avoids having to explicitly
 #         list it in the numerous rules that use CM.
 # By LB1, SA characters with general categor of Mn or Mc also resolve to CM.

 $CM = [[:LineBreak = Combining_Mark:] $ZWJ [$SA & [[:Mn:][:Mc:]]]];
 $CMX = [[$CM] - [$ZWJ]];

 #   Dictionary character set, for triggering language-based break engines. Currently
 #   limited to LineBreak=Complex_Context (SA).

 $dictionary = [$SA];

 #
 #  Rule LB1.  By default, treat AI  (characters with ambiguous east Asian width),
 #                               SA  (Dictionary chars, excluding Mn and Mc)
 #                               SG  (Unpaired Surrogates)
 #                               XX  (Unknown, unassigned)
 #                         as $AL  (Alphabetic)
 #
 $ALPlus = [$AL $AI $SG $XX [$SA-[[:Mn:][:Mc:]]]];


 ## -------------------------------------------------

 #
 # CAN_CM  is the set of characters that may combine with CM combining chars.
 #         Note that Linebreak UAX 14's concept of a combining char and the rules
 #         for what they can combine with are _very_ different from the rest of Unicode.
 #
 #         Note that $CM itself is left out of this set.  If CM is needed as a base
 #         it must be listed separately in the rule.
 #
 $CAN_CM  = [^$SP $BK $CR $LF $NL $ZW $CM];       # Bases that can   take CMs
 $CANT_CM = [ $SP $BK $CR $LF $NL $ZW $CM];       # Bases that can't take CMs

 #
 # AL_FOLLOW  set of chars that can unconditionally follow an AL
 #            Needed in rules where stand-alone $CM s are treated as AL.
 #
 $AL_FOLLOW      = [$BK $CR $LF $NL $ZW $SP $CL $CP $EX $HL $IS $SY $WJ $GL $OP $QU $BA $HY $NS $IN $NU $PR $PO $ALPlus];


 #
 #  Rule LB 4, 5    Mandatory (Hard) breaks.
 #
 $LB4Breaks    = [$BK $CR $LF $NL];
 $LB4NonBreaks = [^$BK $CR $LF $NL $CM];
 $CR $LF {100};

 #
 #  LB 6    Do not break before hard line breaks.
 #
 $LB4NonBreaks?  $LB4Breaks {100};    # LB 5  do not break before hard breaks.
 $CAN_CM $CM*    $LB4Breaks {100};
 ^$CM+           $LB4Breaks {100};

 # LB 7         x SP
 #              x ZW
 $LB4NonBreaks [$SP $ZW];
 $CAN_CM $CM*  [$SP $ZW];
 ^$CM+         [$SP $ZW];

 #
 # LB 8         Break after zero width space
 #              ZW SP* ÷
 #
 $LB8Breaks    = [$LB4Breaks $ZW];
 $LB8NonBreaks = [[$LB4NonBreaks] - [$ZW]];
 $ZW $SP* / [^$SP $ZW $LB4Breaks];

 # LB 8a        ZWJ x            Do not break Emoji ZWJ sequences.
 #
 $ZWJ [^$CM];

 # LB 9     Combining marks.      X   $CM needs to behave like X, where X is not $SP, $BK $CR $LF $NL
 #                                $CM not covered by the above needs to behave like $AL
 #                                See definition of $CAN_CM.

 $CAN_CM $CM+;                   #  Stick together any combining sequences that don't match other rules.
 ^$CM+;

 #
 # LB 11  Do not break before or after WORD JOINER & related characters.
 #
 $CAN_CM $CM*  $WJ;
 $LB8NonBreaks $WJ;
 ^$CM+         $WJ;

 $WJ $CM* .;

 #
 # LB 12  Do not break after NBSP and related characters.
 #         GL  x
 #
 $GL $CM* .;

 #
 # LB 12a  Do not break before NBSP and related characters ...
 #            [^SP BA HY] x GL
 #
 [[$LB8NonBreaks] - [$SP $BA $HY]] $CM* $GL;
 ^$CM+ $GL;


 # LB 13   Don't break before ']' or '!' or or '/', even after spaces.
 #
 $LB8NonBreaks $CL;
 $CAN_CM $CM*  $CL;
 ^$CM+         $CL;              # by rule 10, stand-alone CM behaves as AL

 $LB8NonBreaks $CP;
 $CAN_CM $CM*  $CP;
 ^$CM+         $CP;              # by rule 10, stand-alone CM behaves as AL

 $LB8NonBreaks $EX;
 $CAN_CM $CM*  $EX;
 ^$CM+         $EX;              # by rule 10, stand-alone CM behaves as AL

 $LB8NonBreaks $SY;
 $CAN_CM $CM*  $SY;
 ^$CM+         $SY;              # by rule 10, stand-alone CM behaves as AL


 #
 # LB 14  Do not break after OP, even after spaces
 #        Note subtle interaction with "SP IS /" rules in LB14a.
 #        This rule consumes the SP, chaining happens on the IS, effectivley overriding the  SP IS rules,
 #        which is the desired behavior.
 #
 $OP $CM* $SP* .;

 $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.


 # LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303


 $CanFollowIS = [$BK $CR $LF $NL $SP $ZW $WJ $GL $CL $CP $EX $IS $SY $QU $BA $HY $NS $ALPlus $HL];
 $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];

 #
 # LB 14b Do not break before numeric separators (IS), even after spaces.

 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
 $SP $IS $CM* $ZWJ [^$CM $NU];

 $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL


 # LB 15
 $QU $CM* $SP* $OP;

 # LB 16
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
 ($CL | $CP) $CM* $SP* $NS;

 # LB 17
 $B2 $CM* $SP* $B2;

 #
 # LB 18  Break after spaces.
 #
 $LB18NonBreaks = [$LB8NonBreaks - [$SP]];
 $LB18Breaks    = [$LB8Breaks $SP];


 # LB 19
 #         x QU
 $LB18NonBreaks $CM* $QU;
 ^$CM+               $QU;

 #         QU  x
 $QU $CM* .;

 # LB 20
 #        <break>  $CB
 #        $CB   <break>
 #
 $LB20NonBreaks = [$LB18NonBreaks - $CB];

 # LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
 #             Originally added as a Finnish tailoring, now promoted to default ICU behavior.
 #             Note: this is not default UAX-14 behaviour. See issue ICU-8151.
 #
 ^($HY | $HH) $CM* $ALPlus;

 # LB 21        x   (BA | HY | NS)
 #           BB x
 #
 # DO allow breaks here before NSX, so don't include it
 $LB20NonBreaks $CM* ($BA | $HY | $NS);


 ^$CM+ ($BA | $HY | $NS);

 $BB $CM* [^$CB];                                  #  $BB  x
 $BB $CM* $LB20NonBreaks;

 # LB 21a Don't break after Hebrew + Hyphen
 #   HL (HY | BA) x
 #
 $HL $CM* ($HY | $BA) $CM* [^$CB]?;

 # LB 21b (forward) Don't break between SY and HL
 # (break between HL and SY already disallowed by LB 13 above)
 $SY $CM* $HL;

 # LB 22
 ($ALPlus | $HL) $CM* $IN;
 ^$CM+    $IN;     #  by rule 10, any otherwise unattached CM behaves as AL
 $EX $CM*    $IN;
 ($ID | $EB | $EM) $CM*  $IN;
 # $IN $CM*    $IN;  # delete this rule for CSS loose
 $NU $CM*    $IN;


 # $LB 23
 #
 ($ALPlus | $HL) $CM* $NU;
 ^$CM+  $NU;       # Rule 10, any otherwise unattached CM behaves as AL
 $NU $CM* ($ALPlus | $HL);

 # LB 23a
 #
 $PR $CM* ($ID | $EB | $EM);
 ($ID | $EB | $EM) $CM*  $PO;


 #
 # LB 24
 #
 ($PR | $PO) $CM* ($ALPlus | $HL);
 ($ALPlus | $HL) $CM* ($PR | $PO);
 ^$CM+ ($PR | $PO);       # Rule 10, any otherwise unattached CM behaves as AL

 #
 # LB 25   Numbers.
 #
 (($PR | $PO) $CM*)? (($OP | $HY) $CM*)? ($IS $CM*)? $NU ($CM* ($NU | $SY | $IS))*
     ($CM* ($CL | $CP))? ($CM* ($PR | $PO))?;

 # LB 26  Do not break a Korean syllable
 #
 $JL $CM* ($JL | $JV | $H2 | $H3);
 ($JV | $H2) $CM* ($JV | $JT);
 ($JT | $H3) $CM* $JT;

 # LB 27  Treat korean Syllable Block the same as ID  (don't break it)
 ($JL | $JV | $JT | $H2 | $H3) $CM* $IN;
 ($JL | $JV | $JT | $H2 | $H3) $CM* $PO;
 $PR $CM* ($JL | $JV | $JT | $H2 | $H3);


 # LB 28   Do not break between alphabetics
 #
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL

 # LB 29
 $IS $CM* ($ALPlus | $HL);

 # LB 30
 ($ALPlus | $HL | $NU) $CM* $OP;
 ^$CM+ $OP;         # The $CM+ is from rule 10, an unattached CM is treated as AL.
 $CP $CM* ($ALPlus | $HL | $NU);

 # LB 30a  Do not break between regional indicators. Break after pairs of them.
 #         Tricky interaction with LB8a: ZWJ x .   together with ZWJ acting like a CM.
 $RI $CM* $RI                 / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM]];
 $RI $CM* $RI $CM* [$CM-$ZWJ] / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM]];
 $RI $CM* $RI $CM* [$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $ZWJ {eof}];
 # note: the preceding rule includes {eof} rather than having the last [set] term qualified with '?'
 #       because of the chain-out behavior difference. The rule must chain out only from the [set characters],
 #       not from the preceding $RI or $CM, which it would be able to do if the set were optional.

 # LB 30b Do not break between an Emoji Base and an Emoji Modifier
 $EB $CM* $EM;

 # LB 31 Break everywhere else.
 #       Match a single code point if no other rule applies.
 .;
	# Copyright (C) 2016 and later: Unicode, Inc. and others.
	# License & terms of use: http://www.unicode.org/copyright.html
	#
	# Copyright (c) 2002-2016 International Business Machines Corporation and
	# others. All Rights Reserved.
	#
	# file: line_loose.txt
	#
	# Line Breaking Rules
	# Implement default line breaking as defined by
	# Unicode Standard Annex #14 Revision 42 for Unicode 12.0
	# http://www.unicode.org/reports/tr14/, with the following modification:
	#
	# Boundaries between hyphens and following letters are suppressed when
	# there is a boundary preceding the hyphen. See rule 20.9
	#
	# This tailors the line break behavior to correspond to CSS
	# line-break=loose (BCP47 -u-lb-loose) as defined for languages other than
	# Chinese & Japanese.
	# It sets characters of class CJ to behave like ID.
	# In addition, it allows breaks:
	# * before iteration marks 3005, 303B, 309D, 309E, 30FD, 30FE (all NS)
	# * between characters of LineBreak class IN

	#
	# Character Classes defined by TR 14.
	#

	!!chain;
	!!quoted_literals_only;

	$AI = [:LineBreak = Ambiguous:];
	$AL = [:LineBreak = Alphabetic:];
	$BA = [:LineBreak = Break_After:];
	$HH = [\u2010]; # \u2010 is HYPHEN, default line break is BA.
	$BB = [:LineBreak = Break_Before:];
	$BK = [:LineBreak = Mandatory_Break:];
	$B2 = [:LineBreak = Break_Both:];
	$CB = [:LineBreak = Contingent_Break:];
	$CJ = [:LineBreak = Conditional_Japanese_Starter:];
	$CL = [:LineBreak = Close_Punctuation:];
	# $CM = [:LineBreak = Combining_Mark:];
	$CP = [:LineBreak = Close_Parenthesis:];
	$CR = [:LineBreak = Carriage_Return:];
	$EB = [:LineBreak = EB:];
	$EM = [:LineBreak = EM:];
	$EX = [:LineBreak = Exclamation:];
	$GL = [:LineBreak = Glue:];
	$HL = [:LineBreak = Hebrew_Letter:];
	$HY = [:LineBreak = Hyphen:];
	$H2 = [:LineBreak = H2:];
	$H3 = [:LineBreak = H3:];
	# CSS Loose tailoring: CJ resolves to ID
	$ID = [[:LineBreak = Ideographic:] $CJ];
	$IN = [:LineBreak = Inseperable:];
	$IS = [:LineBreak = Infix_Numeric:];
	$JL = [:LineBreak = JL:];
	$JV = [:LineBreak = JV:];
	$JT = [:LineBreak = JT:];
	$LF = [:LineBreak = Line_Feed:];
	$NL = [:LineBreak = Next_Line:];
	$NSX = [\u3005 \u303B \u309D \u309E \u30FD \u30FE];
	$NS = [[:LineBreak = Nonstarter:] - $NSX];
	$NU = [:LineBreak = Numeric:];
	$OP = [:LineBreak = Open_Punctuation:];
	$PO = [:LineBreak = Postfix_Numeric:];
	$PR = [:LineBreak = Prefix_Numeric:];
	$QU = [:LineBreak = Quotation:];
	$RI = [:LineBreak = Regional_Indicator:];
	$SA = [:LineBreak = Complex_Context:];
	$SG = [:LineBreak = Surrogate:];
	$SP = [:LineBreak = Space:];
	$SY = [:LineBreak = Break_Symbols:];
	$WJ = [:LineBreak = Word_Joiner:];
	$XX = [:LineBreak = Unknown:];
	$ZW = [:LineBreak = ZWSpace:];
	$ZWJ = [:LineBreak = ZWJ:];

	# By LB9, a ZWJ also behaves as a CM. Including it in the definition of CM avoids having to explicitly
	# list it in the numerous rules that use CM.
	# By LB1, SA characters with general categor of Mn or Mc also resolve to CM.

	$CM = [[:LineBreak = Combining_Mark:] $ZWJ [$SA & [[:Mn:][:Mc:]]]];
	$CMX = [[$CM] - [$ZWJ]];

	# Dictionary character set, for triggering language-based break engines. Currently
	# limited to LineBreak=Complex_Context (SA).

	$dictionary = [$SA];

	#
	# Rule LB1. By default, treat AI (characters with ambiguous east Asian width),
	# SA (Dictionary chars, excluding Mn and Mc)
	# SG (Unpaired Surrogates)
	# XX (Unknown, unassigned)
	# as $AL (Alphabetic)
	#
	$ALPlus = [$AL $AI $SG $XX [$SA-[[:Mn:][:Mc:]]]];


	## -------------------------------------------------

	#
	# CAN_CM is the set of characters that may combine with CM combining chars.
	# Note that Linebreak UAX 14's concept of a combining char and the rules
	# for what they can combine with are _very_ different from the rest of Unicode.
	#
	# Note that $CM itself is left out of this set. If CM is needed as a base
	# it must be listed separately in the rule.
	#
	$CAN_CM = [^$SP $BK $CR $LF $NL $ZW $CM]; # Bases that can take CMs
	$CANT_CM = [ $SP $BK $CR $LF $NL $ZW $CM]; # Bases that can't take CMs

	#
	# AL_FOLLOW set of chars that can unconditionally follow an AL
	# Needed in rules where stand-alone $CM s are treated as AL.
	#
	$AL_FOLLOW = [$BK $CR $LF $NL $ZW $SP $CL $CP $EX $HL $IS $SY $WJ $GL $OP $QU $BA $HY $NS $IN $NU $PR $PO $ALPlus];


	#
	# Rule LB 4, 5 Mandatory (Hard) breaks.
	#
	$LB4Breaks = [$BK $CR $LF $NL];
	$LB4NonBreaks = [^$BK $CR $LF $NL $CM];
	$CR $LF {100};

	#
	# LB 6 Do not break before hard line breaks.
	#
	$LB4NonBreaks? $LB4Breaks {100}; # LB 5 do not break before hard breaks.
	$CAN_CM $CM* $LB4Breaks {100};
	^$CM+ $LB4Breaks {100};

	# LB 7 x SP
	# x ZW
	$LB4NonBreaks [$SP $ZW];
	$CAN_CM $CM* [$SP $ZW];
	^$CM+ [$SP $ZW];

	#
	# LB 8 Break after zero width space
	# ZW SP* ÷
	#
	$LB8Breaks = [$LB4Breaks $ZW];
	$LB8NonBreaks = [[$LB4NonBreaks] - [$ZW]];
	$ZW $SP* / [^$SP $ZW $LB4Breaks];

	# LB 8a ZWJ x Do not break Emoji ZWJ sequences.
	#
	$ZWJ [^$CM];

	# LB 9 Combining marks. X $CM needs to behave like X, where X is not $SP, $BK $CR $LF $NL
	# $CM not covered by the above needs to behave like $AL
	# See definition of $CAN_CM.

	$CAN_CM $CM+; # Stick together any combining sequences that don't match other rules.
	^$CM+;

	#
	# LB 11 Do not break before or after WORD JOINER & related characters.
	#
	$CAN_CM $CM* $WJ;
	$LB8NonBreaks $WJ;
	^$CM+ $WJ;

	$WJ $CM* .;

	#
	# LB 12 Do not break after NBSP and related characters.
	# GL x
	#
	$GL $CM* .;

	#
	# LB 12a Do not break before NBSP and related characters ...
	# [^SP BA HY] x GL
	#
	[[$LB8NonBreaks] - [$SP $BA $HY]] $CM* $GL;
	^$CM+ $GL;




	# LB 13 Don't break before ']' or '!' or or '/', even after spaces.
	#
	$LB8NonBreaks $CL;
	$CAN_CM $CM* $CL;
	^$CM+ $CL; # by rule 10, stand-alone CM behaves as AL

	$LB8NonBreaks $CP;
	$CAN_CM $CM* $CP;
	^$CM+ $CP; # by rule 10, stand-alone CM behaves as AL

	$LB8NonBreaks $EX;
	$CAN_CM $CM* $EX;
	^$CM+ $EX; # by rule 10, stand-alone CM behaves as AL

	$LB8NonBreaks $SY;
	$CAN_CM $CM* $SY;
	^$CM+ $SY; # by rule 10, stand-alone CM behaves as AL


	#
	# LB 14 Do not break after OP, even after spaces
	# Note subtle interaction with "SP IS /" rules in LB14a.
	# This rule consumes the SP, chaining happens on the IS, effectivley overriding the SP IS rules,
	# which is the desired behavior.
	#
	$OP $CM* $SP* .;

	$OP $CM* $SP+ $CM+ $AL_FOLLOW?; # by rule 10, stand-alone CM behaves as AL
	# by rule 8, CM following a SP is stand-alone.


	# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
	# Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
	# See issue ICU-20303


	$CanFollowIS = [$BK $CR $LF $NL $SP $ZW $WJ $GL $CL $CP $EX $IS $SY $QU $BA $HY $NS $ALPlus $HL];
	$SP $IS / [^ $CanFollowIS $NU $CM];
	$SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];

	#
	# LB 14b Do not break before numeric separators (IS), even after spaces.

	[$LB8NonBreaks - $SP] $IS;
	$SP $IS $CM* [$CanFollowIS {eof}];
	$SP $IS $CM* $ZWJ [^$CM $NU];

	$CAN_CM $CM* $IS;
	^$CM+ $IS; # by rule 10, stand-alone CM behaves as AL


	# LB 15
	$QU $CM* $SP* $OP;

	# LB 16
	# Do not break between closing punctuation and $NS, even with intervening spaces
	# But DO allow a break between closing punctuation and $NSX, don't include it here
	($CL \| $CP) $CM* $SP* $NS;

	# LB 17
	$B2 $CM* $SP* $B2;

	#
	# LB 18 Break after spaces.
	#
	$LB18NonBreaks = [$LB8NonBreaks - [$SP]];
	$LB18Breaks = [$LB8Breaks $SP];


	# LB 19
	# x QU
	$LB18NonBreaks $CM* $QU;
	^$CM+ $QU;

	# QU x
	$QU $CM* .;

	# LB 20
	# <break> $CB
	# $CB <break>
	#
	$LB20NonBreaks = [$LB18NonBreaks - $CB];

	# LB 20.09 Don't break between Hyphens and Letters when there is a break preceding the hyphen.
	# Originally added as a Finnish tailoring, now promoted to default ICU behavior.
	# Note: this is not default UAX-14 behaviour. See issue ICU-8151.
	#
	^($HY \| $HH) $CM* $ALPlus;

	# LB 21 x (BA \| HY \| NS)
	# BB x
	#
	# DO allow breaks here before NSX, so don't include it
	$LB20NonBreaks $CM* ($BA \| $HY \| $NS);


	^$CM+ ($BA \| $HY \| $NS);

	$BB $CM* [^$CB]; # $BB x
	$BB $CM* $LB20NonBreaks;

	# LB 21a Don't break after Hebrew + Hyphen
	# HL (HY \| BA) x
	#
	$HL $CM* ($HY \| $BA) $CM* [^$CB]?;

	# LB 21b (forward) Don't break between SY and HL
	# (break between HL and SY already disallowed by LB 13 above)
	$SY $CM* $HL;

	# LB 22
	($ALPlus \| $HL) $CM* $IN;
	^$CM+ $IN; # by rule 10, any otherwise unattached CM behaves as AL
	$EX $CM* $IN;
	($ID \| $EB \| $EM) $CM* $IN;
	# $IN $CM* $IN; # delete this rule for CSS loose
	$NU $CM* $IN;


	# $LB 23
	#
	($ALPlus \| $HL) $CM* $NU;
	^$CM+ $NU; # Rule 10, any otherwise unattached CM behaves as AL
	$NU $CM* ($ALPlus \| $HL);

	# LB 23a
	#
	$PR $CM* ($ID \| $EB \| $EM);
	($ID \| $EB \| $EM) $CM* $PO;


	#
	# LB 24
	#
	($PR \| $PO) $CM* ($ALPlus \| $HL);
	($ALPlus \| $HL) $CM* ($PR \| $PO);
	^$CM+ ($PR \| $PO); # Rule 10, any otherwise unattached CM behaves as AL

	#
	# LB 25 Numbers.
	#
	(($PR \| $PO) $CM)? (($OP \| $HY) $CM)? ($IS $CM)? $NU ($CM ($NU \| $SY \| $IS))*
	($CM* ($CL \| $CP))? ($CM* ($PR \| $PO))?;

	# LB 26 Do not break a Korean syllable
	#
	$JL $CM* ($JL \| $JV \| $H2 \| $H3);
	($JV \| $H2) $CM* ($JV \| $JT);
	($JT \| $H3) $CM* $JT;

	# LB 27 Treat korean Syllable Block the same as ID (don't break it)
	($JL \| $JV \| $JT \| $H2 \| $H3) $CM* $IN;
	($JL \| $JV \| $JT \| $H2 \| $H3) $CM* $PO;
	$PR $CM* ($JL \| $JV \| $JT \| $H2 \| $H3);


	# LB 28 Do not break between alphabetics
	#
	($ALPlus \| $HL) $CM* ($ALPlus \| $HL);
	^$CM+ ($ALPlus \| $HL); # The $CM+ is from rule 10, an unattached CM is treated as AL

	# LB 29
	$IS $CM* ($ALPlus \| $HL);

	# LB 30
	($ALPlus \| $HL \| $NU) $CM* $OP;
	^$CM+ $OP; # The $CM+ is from rule 10, an unattached CM is treated as AL.
	$CP $CM* ($ALPlus \| $HL \| $NU);

	# LB 30a Do not break between regional indicators. Break after pairs of them.
	# Tricky interaction with LB8a: ZWJ x . together with ZWJ acting like a CM.
	$RI $CM* $RI / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM]];
	$RI $CM* $RI $CM* [$CM-$ZWJ] / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $CM]];
	$RI $CM* $RI $CM* [$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $ZWJ {eof}];
	# note: the preceding rule includes {eof} rather than having the last [set] term qualified with '?'
	# because of the chain-out behavior difference. The rule must chain out only from the [set characters],
	# not from the preceding $RI or $CM, which it would be able to do if the set were optional.

	# LB 30b Do not break between an Emoji Base and an Emoji Modifier
	$EB $CM* $EM;

	# LB 31 Break everywhere else.
	# Match a single code point if no other rule applies.
	.;