# 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.txt
#
# Line Breaking Rules
# Implement default line breaking as defined by
# Unicode Standard Annex #14 Revision 44 for Unicode 13.0
# 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 corresponds to CSS line-break=strict (BCP47 -u-lb-strict).
# It sets characters of class CJ to behave like NS.
#
# 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:];
$ID = [:LineBreak = Ideographic:];
$IN = [:LineBreak = Inseperable:];
$IS = [:LineBreak = Infix_Numeric:];
$JL = [:LineBreak = JL:];
$JV = [:LineBreak = JV:];
$JT = [:LineBreak = JT:];
$LF = [:LineBreak = Line_Feed:];
$NL = [:LineBreak = Next_Line:];
# NS includes CJ for CSS strict line breaking.
$NS = [[:LineBreak = Nonstarter:] $CJ];
$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:];
# The following classes are no longer needed for ICU rules but may
# still be needed for WebKit rules in lineClasses.txt
# $EmojiNRK = [[\p{Emoji}] - [$RI \u002a\u00230-9©®™〰〽]];
# $Extended_Pict = [:ExtPict:];
# OP30 and CP30 are variants of OP and CP that appear in-line in rule LB30 from UAX 14,
# without a formal name. Because ICU rules require multiple uses of the expressions,
# give them a single definition with a name
$OP30 = [$OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
$CP30 = [$CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
# 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 $OP30 $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 $IN];
$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* $OP;
# LB 16
($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
#
$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 Do not break before ellipses
#
$LB20NonBreaks $CM* $IN;
^$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* $OP30;
^$CM+ $OP30; # The $CM+ is from rule 10, an unattached CM is treated as AL.
$CP30 $CM* ($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 $IN $CM]];
$RI $CM* $RI $CM* [$CM-$ZWJ] / [[^$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $IN $CM]];
$RI $CM* $RI $CM* [$BK $CR $LF $NL $SP $ZW $WJ $CL $CP $EX $IS $SY $GL $QU $BA $HY $NS $IN $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.
.;