1# Copyright (C) 2016 and later: Unicode, Inc. and others.
2# License & terms of use: http://www.unicode.org/copyright.html
3#
4#
5#   Copyright (C) 2002-2015, International Business Machines Corporation and others.
6#       All Rights Reserved.
7#
8#   file:  sent_el.txt
9#
10#   ICU Sentence Break Rules
11#      See Unicode Standard Annex #29.
12#      These rules are based on UAX #29 Revision 26 for Unicode Version 8.0
13#
14
15!!quoted_literals_only;
16
17#
18# Character categories as defined in TR 29
19#
20$CR        = [\p{Sentence_Break = CR}];
21$LF        = [\p{Sentence_Break = LF}];
22$Extend    = [\p{Sentence_Break = Extend}];
23$Sep       = [\p{Sentence_Break = Sep}];
24$Format    = [\p{Sentence_Break = Format}];
25$Sp        = [\p{Sentence_Break = Sp}];
26$Lower     = [\p{Sentence_Break = Lower}];
27$Upper     = [\p{Sentence_Break = Upper}];
28$OLetter   = [\p{Sentence_Break = OLetter}];
29$Numeric   = [\p{Sentence_Break = Numeric}];
30$ATerm     = [\p{Sentence_Break = ATerm}];
31$SContinue = [\p{Sentence_Break = SContinue}];
32$STerm     = [\p{Sentence_Break = STerm} [\u003B \u037E]];
33$Close     = [\p{Sentence_Break = Close}];
34
35#
36# Define extended forms of the character classes,
37#   incorporate trailing Extend or Format chars.
38#   Rules 4 and 5.
39
40$SpEx       = $Sp      ($Extend | $Format)*;
41$LowerEx    = $Lower   ($Extend | $Format)*;
42$UpperEx    = $Upper   ($Extend | $Format)*;
43$OLetterEx  = $OLetter ($Extend | $Format)*;
44$NumericEx  = $Numeric ($Extend | $Format)*;
45$ATermEx    = $ATerm   ($Extend | $Format)*;
46$SContinueEx= $SContinue ($Extend | $Format)*;
47$STermEx    = $STerm   ($Extend | $Format)*;
48$CloseEx    = $Close   ($Extend | $Format)*;
49
50
51## -------------------------------------------------
52
53!!chain;
54!!forward;
55
56# Rule 3 - break after separators.  Keep CR/LF together.
57#
58$CR $LF;
59
60
61# Rule 4 - Break after $Sep.
62# Rule 5 - Ignore $Format and $Extend
63#
64[^$Sep $CR $LF]? ($Extend | $Format)*;
65
66
67# Rule 6
68$ATermEx $NumericEx;
69
70# Rule 7
71($UpperEx | $LowerEx) $ATermEx $UpperEx;
72
73#Rule 8
74$NotLettersEx = [^$OLetter $Upper $Lower $Sep $CR $LF $ATerm $STerm] ($Extend | $Format)*;
75$ATermEx $CloseEx* $SpEx* $NotLettersEx* $Lower;
76
77# Rule 8a
78($STermEx | $ATermEx) $CloseEx* $SpEx* ($SContinueEx | $STermEx | $ATermEx);
79
80#Rule 9, 10, 11
81($STermEx | $ATermEx) $CloseEx* $SpEx* ($Sep | $CR | $LF)?;
82
83#Rule 12
84[[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* .;
85[[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* ([$Sep $LF $CR {eof}] | $CR $LF){100};
86
87## -------------------------------------------------
88
89!!safe_reverse;
90
91$SpEx_R       = ($Extend | $Format)* $Sp;
92$ATermEx_R    = ($Extend | $Format)* $ATerm;
93$STermEx_R    = ($Extend | $Format)* $STerm;
94$CloseEx_R    = ($Extend | $Format)* $Close;
95
96#
97#  Reverse rules.
98#     For now, use the old style inexact reverse rules, which are easier
99#     to write, but less efficient.
100#     TODO:  exact reverse rules.  It appears that exact reverse rules
101#            may require improving support for look-ahead breaks in the
102#            builder.  Needs more investigation.
103#
104
105[{bof}] (.? | $LF $CR) [^$Sep $CR $LF]* [$Sep $CR $LF {eof}] ($SpEx_R* $CloseEx_R* ($STermEx_R | $ATermEx_R))*;
106
107# Explanation for this rule:
108#
109#    It needs to back over
110#        The $Sep at which we probably begin
111#        All of the non $Sep chars leading to the preceding $Sep
112#        The preceding $Sep, which will be the second one that the rule matches.
113#        Any immediately preceding STerm or ATerm sequences.  We need to see these
114#              to get the correct rule status when moving forwards again.
115#
116# [{bof}]           inhibit rule chaining.  Without this, rule would loop on itself and match
117#                   the entire string.
118#
119# (.? | $LF $CR)    Match one $Sep instance.  Use .? rather than $Sep because position might be
120#                   at the beginning of the string at this point, and we don't want to fail.
121#                   Can only use {eof} once, and it is used later.
122#
123