#
# Copyright (C) 2002-2011, International Business Machines Corporation and others.
# All Rights Reserved.
#
# file: sent.txt
#
# ICU Sentence Break Rules
# See Unicode Standard Annex #29.
# These rules are based on UAX #29 Revision 19 for Unicode Version 6.1
#
#
# Character categories as defined in TR 29
#
$CR = [\p{Sentence_Break = CR}];
$LF = [\p{Sentence_Break = LF}];
$Extend = [\p{Sentence_Break = Extend}];
$Sep = [\p{Sentence_Break = Sep}];
$Format = [\p{Sentence_Break = Format}];
$Sp = [\p{Sentence_Break = Sp}];
$Lower = [\p{Sentence_Break = Lower}];
$Upper = [\p{Sentence_Break = Upper}];
$OLetter = [\p{Sentence_Break = OLetter}];
$Numeric = [\p{Sentence_Break = Numeric}];
$ATerm = [\p{Sentence_Break = ATerm}];
$SContinue = [\p{Sentence_Break = SContinue}];
$STerm = [\p{Sentence_Break = STerm}];
$Close = [\p{Sentence_Break = Close}];
#
# Define extended forms of the character classes,
# incorporate trailing Extend or Format chars.
# Rules 4 and 5.
$SpEx = $Sp ($Extend | $Format)*;
$LowerEx = $Lower ($Extend | $Format)*;
$UpperEx = $Upper ($Extend | $Format)*;
$OLetterEx = $OLetter ($Extend | $Format)*;
$NumericEx = $Numeric ($Extend | $Format)*;
$ATermEx = $ATerm ($Extend | $Format)*;
$SContinueEx= $SContinue ($Extend | $Format)*;
$STermEx = $STerm ($Extend | $Format)*;
$CloseEx = $Close ($Extend | $Format)*;
## -------------------------------------------------
!!chain;
!!forward;
# Rule 3 - break after separators. Keep CR/LF together.
#
$CR $LF;
# Rule 4 - Break after $Sep.
# Rule 5 - Ignore $Format and $Extend
#
[^$Sep $CR $LF]? ($Extend | $Format)*;
# Rule 6
$ATermEx $NumericEx;
# Rule 7
$UpperEx $ATermEx $UpperEx;
#Rule 8
$NotLettersEx = [^$OLetter $Upper $Lower $Sep $CR $LF $ATerm $STerm] ($Extend | $Format)*;
$ATermEx $CloseEx* $SpEx* $NotLettersEx* $Lower;
# Rule 8a
($STermEx | $ATermEx) $CloseEx* $SpEx* ($SContinueEx | $STermEx | $ATermEx);
#Rule 9, 10, 11
($STermEx | $ATermEx) $CloseEx* $SpEx* ($Sep | $CR | $LF)?;
#Rule 12
[[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* .;
[[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* ([$Sep $LF $CR {eof}] | $CR $LF){100};
## -------------------------------------------------
!!reverse;
$SpEx_R = ($Extend | $Format)* $Sp;
$ATermEx_R = ($Extend | $Format)* $ATerm;
$STermEx_R = ($Extend | $Format)* $STerm;
$CloseEx_R = ($Extend | $Format)* $Close;
#
# Reverse rules.
# For now, use the old style inexact reverse rules, which are easier
# to write, but less efficient.
# TODO: exact reverse rules. It appears that exact reverse rules
# may require improving support for look-ahead breaks in the
# builder. Needs more investigation.
#
[{bof}] (.? | $LF $CR) [^$Sep $CR $LF]* [$Sep $CR $LF {eof}] ($SpEx_R* $CloseEx_R* ($STermEx_R | $ATermEx_R))*;
#.*;
# Explanation for this rule:
#
# It needs to back over
# The $Sep at which we probably begin
# All of the non $Sep chars leading to the preceding $Sep
# The preceding $Sep, which will be the second one that the rule matches.
# Any immediately preceding STerm or ATerm sequences. We need to see these
# to get the correct rule status when moving forwards again.
#
# [{bof}] inhibit rule chaining. Without this, rule would loop on itself and match
# the entire string.
#
# (.? | $LF $CR) Match one $Sep instance. Use .? rather than $Sep because position might be
# at the beginning of the string at this point, and we don't want to fail.
# Can only use {eof} once, and it is used later.
#