skia / external / github.com / unicode-org / icu / refs/tags/icu-release-3-6-d02 / . / source / data / brkitr / line.txt

# Copyright (c) 2002-2006 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 version 5.0.0 | |

# http://www.unicode.org/reports/tr14/ | |

# | |

# Character Classes defined by TR 14. | |

# | |

!!chain; | |

!!LBCMNoChain; | |

!!lookAheadHardBreak; | |

# | |

# !!lookAheadHardBreak Described here because it is (as yet) undocumented elsewhere | |

# and only used for the line break rules. | |

# | |

# It is used in the implementation of the incredibly annoying rule LB 10 | |

# which says to treat any combining mark that is not attached to a base | |

# character as if it were of class AL (alphabetic). | |

# | |

# The problem occurs in the reverse rules. | |

# | |

# Consider a sequence like, with correct breaks as shown | |

# LF ID CM AL AL | |

# ^ ^ ^ | |

# Then consider the sequence without the initial ID (ideographic) | |

# LF CM AL AL | |

# ^ ^ | |

# Our CM, which in the first example was attached to the ideograph, | |

# is now unattached, becomes an alpha, and joins in with the other | |

# alphas. | |

# | |

# When iterating forwards, these sequences do not present any problems | |

# When iterating backwards, we need to look ahead when encountering | |

# a CM to see whether it attaches to something further on or not. | |

# (Look-ahead in a reverse rule is looking towards the start) | |

# | |

# If the CM is unattached, we need to force a break. | |

# | |

# !!lookAheadHardBreak forces the run time state machine to | |

# stop immediately when a look ahead rule ( '/' operator) matches, | |

# and set the match position to that of the look-ahead operator, | |

# no matter what other rules may be in play at the time. | |

# | |

# See rule LB 19 for an example. | |

# | |

$AI = [:LineBreak = Ambiguous:]; | |

$AL = [:LineBreak = Alphabetic:]; | |

$BA = [:LineBreak = Break_After:]; | |

$BB = [:LineBreak = Break_Before:]; | |

$BK = [:LineBreak = Mandatory_Break:]; | |

$B2 = [:LineBreak = Break_Both:]; | |

$CB = [:LineBreak = Contingent_Break:]; | |

$CL = [:LineBreak = Close_Punctuation:]; | |

$CM = [:LineBreak = Combining_Mark:]; | |

$CR = [:LineBreak = Carriage_Return:]; | |

$EX = [:LineBreak = Exclamation:]; | |

$GL = [:LineBreak = Glue:]; | |

$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 = [:LineBreak = Nonstarter:]; | |

$NU = [:LineBreak = Numeric:]; | |

$OP = [:LineBreak = Open_Punctuation:]; | |

$PO = [:LineBreak = Postfix_Numeric:]; | |

$PR = [:LineBreak = Prefix_Numeric:]; | |

$QU = [:LineBreak = Quotation:]; | |

$SA = [:LineBreak = Complex_Context:]; | |

$SG = [:LineBreak = Surrogate:]; | |

$SP = [:LineBreak = Space:]; | |

$SY = [:LineBreak = Break_Symbols:]; | |

$WJ = [:LineBreak = Word_Joiner:]; | |

$XX = [:LineBreak = Unknown:]; | |

$ZW = [:LineBreak = ZWSpace:]; | |

# Dictionary character set, for triggering language-based break engines. Currently | |

# limited to LineBreak=Complex_Context. Note that this set only works in Unicode | |

# 5.0 or later as the definition of Complex_Context was corrected to include all | |

# characters requiring dictionary break. | |

$dictionary = [:LineBreak = Complex_Context:]; | |

# | |

# Rule LB1. By default, treat AI (characters with ambiguous east Asian width), | |

# SA (South East Asian: Thai, Lao, Khmer) | |

# SG (Unpaired Surrogates) | |

# XX (Unknown, unassigned) | |

# as $AL (Alphabetic) | |

# | |

$ALPlus = [$AL $AI $SA $SG $XX]; | |

# | |

# Combining Marks. X $CM* behaves as if it were X. Rule LB6. | |

# | |

$ALcm = $ALPlus $CM*; | |

$BAcm = $BA $CM*; | |

$BBcm = $BB $CM*; | |

$B2cm = $B2 $CM*; | |

$CLcm = $CL $CM*; | |

$EXcm = $EX $CM*; | |

$GLcm = $GL $CM*; | |

$HYcm = $HY $CM*; | |

$H2cm = $H2 $CM*; | |

$H3cm = $H3 $CM*; | |

$IDcm = $ID $CM*; | |

$INcm = $IN $CM*; | |

$IScm = $IS $CM*; | |

$JLcm = $JL $CM*; | |

$JVcm = $JV $CM*; | |

$JTcm = $JT $CM*; | |

$NScm = $NS $CM*; | |

$NUcm = $NU $CM*; | |

$OPcm = $OP $CM*; | |

$POcm = $PO $CM*; | |

$PRcm = $PR $CM*; | |

$QUcm = $QU $CM*; | |

$SYcm = $SY $CM*; | |

$WJcm = $WJ $CM*; | |

## ------------------------------------------------- | |

!!forward; | |

# | |

# Each class of character can stand by itself as an unbroken token, with trailing combining stuff | |

# | |

$ALPlus $CM+; | |

$BA $CM+; | |

$BB $CM+; | |

$B2 $CM+; | |

$CL $CM+; | |

$EX $CM+; | |

$GL $CM+; | |

$HY $CM+; | |

$H2 $CM+; | |

$H3 $CM+; | |

$ID $CM+; | |

$IN $CM+; | |

$IS $CM+; | |

$JL $CM+; | |

$JV $CM+; | |

$JT $CM+; | |

$NS $CM+; | |

$NU $CM+; | |

$OP $CM+; | |

$PO $CM+; | |

$PR $CM+; | |

$QU $CM+; | |

$SY $CM+; | |

$WJ $CM+; | |

# | |

# 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. | |

# Chaining is disabled with CM because it causes other failures, | |

# so for this one case we need to manually list out longer sequences. | |

# | |

$AL_FOLLOW_NOCM = [$BK $CR $LF $NL $ZW $SP]; | |

$AL_FOLLOW_CM = [$CL $EX $IS $SY $WJ $GL $QU $BA $HY $NS $IN $NU $ALPlus $OP]; | |

$AL_FOLLOW = [$AL_FOLLOW_NOCM $AL_FOLLOW_CM]; | |

# | |

# Rule LB 4, 5 Mandatory (Hard) breaks. | |

# | |

$LB4Breaks = [$BK $CR $LF $NL]; | |

$LB4NonBreaks = [^$BK $CR $LF $NL]; | |

$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 | |

# | |

$LB8Breaks = [$LB4Breaks $ZW]; | |

$LB8NonBreaks = [[$LB4NonBreaks] - [$ZW]]; | |

# 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* $WJcm; | |

$LB8NonBreaks $WJcm; | |

$CM+ $WJcm; | |

$WJcm [^$CAN_CM]; | |

$WJcm $CAN_CM $CM*; | |

# | |

# LB 12 Do not break before or after NBSP and related characters. | |

# | |

# (!SP) x GL | |

[$LB8NonBreaks-$SP] $CM* $GLcm; | |

$CM+ $GLcm; | |

# GL x | |

$GLcm ($LB8Breaks | $SP); | |

$GLcm [$LB8NonBreaks-$SP] $CM*; # Don't let a combining mark go onto $CR, $BK, etc. | |

# TODO: I don't think we need this rule. | |

# All but $CM will chain off of preceding rule. | |

# $GLcm will pick up the CM case by itself. | |

# | |

# 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 $EX; | |

$CAN_CM $CM* $EX; | |

$CM+ $EX; # by rule 10, stand-alone CM behaves as AL | |

$LB8NonBreaks $IS; | |

$CAN_CM $CM* $IS; | |

$CM+ $IS; # 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 spaced | |

# | |

$OPcm $SP* $CAN_CM $CM*; | |

$OPcm $SP* $CANT_CM; | |

$OPcm $SP+ $CM+ $AL_FOLLOW?; # by rule 10, stand-alone CM behaves as AL | |

# LB 15 | |

$QUcm $SP* $OPcm; | |

# LB 16 | |

$CLcm $SP* $NScm; | |

# LB 17 | |

$B2cm $SP* $B2cm; | |

# | |

# LB 18 Break after spaces. | |

# | |

$LB18NonBreaks = [$LB8NonBreaks - [$SP]]; | |

$LB18Breaks = [$LB8Breaks $SP]; | |

# LB 19 | |

# x QU | |

$LB18NonBreaks $CM* $QUcm; | |

$CM+ $QUcm; | |

# QU x | |

$QUcm .?; | |

$QUcm $LB18NonBreaks $CM*; # Don't let a combining mark go onto $CR, $BK, etc. | |

# TODO: I don't think this rule is needed. | |

# LB 20 | |

# <break> $CB | |

# $CB <break> | |

$LB20NonBreaks = [$LB18NonBreaks - $CB]; | |

# LB 21 x (BA | HY | NS) | |

# BB x | |

# | |

$LB20NonBreaks $CM* ($BAcm | $HYcm | $NScm); | |

$BBcm [^$CB]; # $BB x | |

$BBcm $LB20NonBreaks $CM*; | |

# LB 22 | |

$ALcm $INcm; | |

$CM+ $INcm; # by rule 10, any otherwise unattached CM behaves as AL | |

$IDcm $INcm; | |

$INcm $INcm; | |

$NUcm $INcm; | |

# $LB 23 | |

$IDcm $POcm; | |

$ALcm $NUcm; # includes $LB19 | |

$CM+ $NUcm; # Rule 10, any otherwise unattached CM behaves as AL | |

$NUcm $ALcm; | |

# | |

# LB 24 | |

# | |

$PRcm $IDcm; | |

$PRcm $ALcm; | |

$POcm $ALcm; | |

# | |

# LB 25 Numbers. | |

# | |

($PRcm | $POcm)? ($OPcm | $HYcm)? $NUcm ($NUcm | $SYcm | $IScm)* $CLcm? ($PRcm | $POcm)?; | |

# LB 26 Do not break a Korean syllable | |

# | |

$JLcm ($JLcm | $JVcm | $H2cm | $H3cm); | |

($JVcm | $H2cm) ($JVcm | $JTcm); | |

($JTcm | $H3cm) $JTcm; | |

# LB 27 Treat korean Syllable Block the same as ID (don't break it) | |

($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $INcm; | |

($JLcm | $JVcm | $JTcm | $H2cm | $H3cm) $POcm; | |

$PRcm ($JLcm | $JVcm | $JTcm | $H2cm | $H3cm); | |

# LB 28 Do not break between alphabetics | |

# | |

$ALcm $ALcm; | |

$CM+ $ALcm; # The $CM+ is from rule 10, and unattached CM is treated as AL | |

# LB 29 | |

$IScm $ALcm; | |

# | |

# Rule 30 Do not break between letters, numbers or ordinary symbols | |

# and opening or closing punctuation | |

# | |

($ALcm | $NUcm) $OPcm; | |

$CM+ $OPcm; | |

$CLcm ($ALcm | $NUcm); | |

# | |

# Reverse Rules. | |

# | |

## ------------------------------------------------- | |

!!reverse; | |

$CM+ $ALPlus; | |

$CM+ $BA; | |

$CM+ $BB; | |

$CM+ $B2; | |

$CM+ $CL; | |

$CM+ $EX; | |

$CM+ $GL; | |

$CM+ $HY; | |

$CM+ $H2; | |

$CM+ $H3; | |

$CM+ $ID; | |

$CM+ $IN; | |

$CM+ $IS; | |

$CM+ $JL; | |

$CM+ $JV; | |

$CM+ $JT; | |

$CM+ $NS; | |

$CM+ $NU; | |

$CM+ $OP; | |

$CM+ $PO; | |

$CM+ $PR; | |

$CM+ $QU; | |

$CM+ $SY; | |

$CM+ $WJ; | |

$CM+; | |

# | |

# Sequences of the form (shown forwards) | |

# [CANT_CM] <break> [CM] [whatever] | |

# The CM needs to behave as an AL | |

# | |

$AL_FOLLOW $CM+ / ( | |

[$BK $CR $LF $NL $ZW {eof}] | | |

$SP+ $CM+ $SP | | |

$SP+ $CM* ([^$OP $CM $SP] | [$AL {eof}])); # if LB 14 will match, need to surpress this break. | |

# LB14 says OP SP* x . | |

# becomes OP SP* x AL | |

# becomes OP SP* x CM+ AL_FOLLOW | |

# | |

# Further note: the $AL in [$AL {eof}] is only to work around | |

# a rule compiler bug which complains about | |

# empty sets otherwise. | |

# | |

# Sequences of the form (shown forwards) | |

# [CANT_CM] <break> [CM] <break> [PR] | |

# The CM needs to behave as an AL | |

# This rule is concerned about getting the second of the two <breaks> in place. | |

# | |

[$PR ] / $CM+ [$BK $CR $LF $NL $ZW $SP {eof}]; | |

# LB 4, 5, 5 | |

$LB4Breaks [$LB4NonBreaks-$CM]; | |

$LB4Breaks $CM+ $CAN_CM; | |

$LF $CR; | |

# LB 7 x SP | |

# x ZW | |

[$SP $ZW] [$LB4NonBreaks-$CM]; | |

[$SP $ZW] $CM+ $CAN_CM; | |

# LB 8 Break after zero width space | |

# LB 9,10 Combining marks. | |

# X $CM needs to behave like X, where X is not $SP or controls. | |

# $CM not covered by the above needs to behave like $AL | |

# Stick together any combining sequences that don't match other rules. | |

$CM+ $CAN_CM; | |

# LB 11 | |

$CM* $WJ $CM* $CAN_CM; | |

$CM* $WJ [$LB8NonBreaks-$CM]; | |

$CANT_CM $CM* $WJ; | |

$CM* $CAN_CM $CM* $WJ; | |

# LB 12 | |

# x GL | |

# | |

$CM* $GL $CM* [$LB8NonBreaks-$CM-$SP]; | |

# | |

# GL x | |

# | |

$CANT_CM $CM* $GL; | |

$CM* $CAN_CM $CM* $GL; | |

# LB 13 | |

$CL $CM+ $CAN_CM; | |

$EX $CM+ $CAN_CM; | |

$IS $CM+ $CAN_CM; | |

$SY $CM+ $CAN_CM; | |

$CL [$LB8NonBreaks-$CM]; | |

$EX [$LB8NonBreaks-$CM]; | |

$IS [$LB8NonBreaks-$CM]; | |

$SY [$LB8NonBreaks-$CM]; | |

# Rule 13 & 14 taken together for an edge case. | |

# Match this, shown forward | |

# OP SP+ ($CM+ behaving as $AL) (CL | EX | IS | IY) | |

# This really wants to chain at the $CM+ (which is acting as an $AL) | |

# except for $CM chaining being disabled. | |

[$CL $EX $IS $SY] $CM+ $SP+ $CM* $OP; | |

# LB 14 OP SP* x | |

# | |

$CM* $CAN_CM $SP* $CM* $OP; | |

$CANT_CM $SP* $CM* $OP; | |

$AL_FOLLOW? $CM+ $SP $SP* $CM* $OP; # by LB 10, behaves like $AL_FOLLOW? $AL $SP* $CM* $OP | |

$AL_FOLLOW_NOCM $CM+ $SP+ $CM* $OP; | |

$CM* $AL_FOLLOW_CM $CM+ $SP+ $CM* $OP; | |

$SY $CM $SP+ $OP; # TODO: Experiment. Remove. | |

# LB 15 | |

$CM* $OP $SP* $CM* $QU; | |

# LB 16 | |

$CM* $NS $SP* $CM* $CL; | |

# LB 17 | |

$CM* $B2 $SP* $CM* $B2; | |

# LB 18 break after spaces | |

# Nothing explicit needed here. | |

# | |

# LB 19 | |

# | |

$CM* $QU $CM* $CAN_CM; # . x QU | |

$CM* $QU $LB18NonBreaks; | |

$CM* $CAN_CM $CM* $QU; # QU x . | |

$CANT_CM $CM* $QU; | |

# | |

# LB 20 Break before and after CB. | |

# nothing needed here. | |

# | |

# LB 21 | |

$CM* ($BA | $HY | $NS) $CM* [$LB20NonBreaks-$CM]; # . x (BA | HY | NS) | |

$CM* [$LB20NonBreaks-$CM] $CM* $BB; # BB x . | |

[^$CB] $CM* $BB; # | |

# LB 22 | |

$CM* $IN $CM* $ALPlus; | |

$CM* $IN $CM* $ID; | |

$CM* $IN $CM* $IN; | |

$CM* $IN $CM* $NU; | |

# LB 23 | |

$CM* $PO $CM* $ID; | |

$CM* $NU $CM* $ALPlus; | |

$CM* $ALPlus $CM* $NU; | |

# LB 24 | |

$CM* $ID $CM* $PR; | |

$CM* $ALPlus $CM* $PR; | |

$CM* $ALPlus $CM* $PO; | |

# LB 25 | |

($CM* ($PR | $PO))? ($CM* $CL)? ($CM* ($NU | $IS | $SY))* $CM* $NU ($CM* ($OP | $HY))? ($CM* ($PR | $PO))?; | |

# LB 26 | |

$CM* ($H3 | $H2 | $JV | $JL) $CM* $JL; | |

$CM* ($JT | $JV) $CM* ($H2 | $JV); | |

$CM* $JT $CM* ($H3 | $JT); | |

# LB 27 | |

$CM* $IN $CM* ($H3 | $H2 | $JT | $JV | $JL); | |

$CM* $PO $CM* ($H3 | $H2 | $JT | $JV | $JL); | |

$CM* ($H3 | $H2 | $JT | $JV | $JL) $CM* $PR; | |

# LB 28 | |

$CM* $ALPlus $CM* $ALPlus; | |

# LB 29 | |

$CM* $ALPlus $CM* $IS; | |

# LB 30 | |

$CM* $OP $CM* ($NU | $ALPlus); | |

$CM* ($NU | $ALPlus) $CM* $CL; | |

## ------------------------------------------------- | |

!!safe_reverse; | |

# LB 7 | |

$CM+ [^$CM $BK $CR $LF $NL $ZW $SP]; | |

$CM+ $SP / .; | |

# LB 9 | |

$SP+ $CM* $OP; | |

# LB 10 | |

$SP+ $CM* $QU; | |

# LB 11 | |

$SP+ $CM* $CL; | |

$SP+ $CM* $B2; | |

# LB 18 | |

($CM* ($IS | $SY))+ $CM* $NU; | |

$CL $CM* ($NU | $IS | $SY); | |

# For dictionary-based break | |

$dictionary $dictionary; | |

## ------------------------------------------------- | |

!!safe_forward; | |

# Skip forward over all character classes that are involved in | |

# rules containing patterns with possibly more than one char | |

# of context. | |

# | |

# It might be slightly more efficient to have specific rules | |

# instead of one generic one, but only if we could | |

# turn off rule chaining. We don't want to move more | |

# than necessary. | |

# | |

[$CM $OP $QU $CL $B2 $PR $HY $SP $dictionary]+ [^$CM $OP $QU $CL $B2 $PR $HY $dictionary]; | |

$dictionary $dictionary; | |