1#
2#   Copyright (C) 2002-2011, International Business Machines Corporation and others.
3#       All Rights Reserved.
4#
5#   file:  sent.txt
6#
7#   ICU Sentence Break Rules
8#      See Unicode Standard Annex #29.
9#      These rules are based on UAX #29 Revision 19 for Unicode Version 6.1
10#
11
12
13#
14# Character categories as defined in TR 29
15#
16$CR        = [\p{Sentence_Break = CR}];
17$LF        = [\p{Sentence_Break = LF}];
18$Extend    = [\p{Sentence_Break = Extend}];
19$Sep       = [\p{Sentence_Break = Sep}];
20$Format    = [\p{Sentence_Break = Format}];
21$Sp        = [\p{Sentence_Break = Sp}];
22$Lower     = [\p{Sentence_Break = Lower}];
23$Upper     = [\p{Sentence_Break = Upper}];
24$OLetter   = [\p{Sentence_Break = OLetter}];
25$Numeric   = [\p{Sentence_Break = Numeric}];
26$ATerm     = [\p{Sentence_Break = ATerm}];
27$SContinue = [\p{Sentence_Break = SContinue}];
28$STerm     = [\p{Sentence_Break = STerm}];
29$Close     = [\p{Sentence_Break = Close}];
30
31#
32# Define extended forms of the character classes,
33#   incorporate trailing Extend or Format chars.
34#   Rules 4 and 5.
35
36$SpEx       = $Sp      ($Extend | $Format)*;
37$LowerEx    = $Lower   ($Extend | $Format)*;
38$UpperEx    = $Upper   ($Extend | $Format)*;
39$OLetterEx  = $OLetter ($Extend | $Format)*;
40$NumericEx  = $Numeric ($Extend | $Format)*;
41$ATermEx    = $ATerm   ($Extend | $Format)*;
42$SContinueEx= $SContinue ($Extend | $Format)*;
43$STermEx    = $STerm   ($Extend | $Format)*;
44$CloseEx    = $Close   ($Extend | $Format)*;
45
46
47## -------------------------------------------------
48
49!!chain;
50!!forward;
51
52# Rule 3 - break after separators.  Keep CR/LF together.
53#
54$CR $LF;
55
56
57# Rule 4 - Break after $Sep.
58# Rule 5 - Ignore $Format and $Extend
59#
60[^$Sep $CR $LF]? ($Extend | $Format)*;
61
62
63# Rule 6
64$ATermEx $NumericEx;
65
66# Rule 7
67$UpperEx $ATermEx $UpperEx;
68
69#Rule 8
70$NotLettersEx = [^$OLetter $Upper $Lower $Sep $CR $LF $ATerm $STerm] ($Extend | $Format)*;
71$ATermEx $CloseEx* $SpEx* $NotLettersEx* $Lower;
72
73# Rule 8a
74($STermEx | $ATermEx) $CloseEx* $SpEx* ($SContinueEx | $STermEx | $ATermEx);
75
76#Rule 9, 10, 11
77($STermEx | $ATermEx) $CloseEx* $SpEx* ($Sep | $CR | $LF)?;
78
79#Rule 12
80[[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* .;
81[[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* ([$Sep $LF $CR {eof}] | $CR $LF){100};
82
83## -------------------------------------------------
84
85!!reverse;
86
87$SpEx_R       = ($Extend | $Format)* $Sp;
88$ATermEx_R    = ($Extend | $Format)* $ATerm;
89$STermEx_R    = ($Extend | $Format)* $STerm;
90$CloseEx_R    = ($Extend | $Format)* $Close;
91
92#
93#  Reverse rules.
94#     For now, use the old style inexact reverse rules, which are easier
95#     to write, but less efficient.
96#     TODO:  exact reverse rules.  It appears that exact reverse rules
97#            may require improving support for look-ahead breaks in the
98#            builder.  Needs more investigation.
99#
100
101[{bof}] (.? | $LF $CR) [^$Sep $CR $LF]* [$Sep $CR $LF {eof}] ($SpEx_R* $CloseEx_R* ($STermEx_R | $ATermEx_R))*;
102#.*;
103
104# Explanation for this rule:
105#
106#    It needs to back over
107#        The $Sep at which we probably begin
108#        All of the non $Sep chars leading to the preceding $Sep
109#        The preceding $Sep, which will be the second one that the rule matches.
110#        Any immediately preceding STerm or ATerm sequences.  We need to see these
111#              to get the correct rule status when moving forwards again.
112#
113# [{bof}]           inhibit rule chaining.  Without this, rule would loop on itself and match
114#                   the entire string.
115#
116# (.? | $LF $CR)    Match one $Sep instance.  Use .? rather than $Sep because position might be
117#                   at the beginning of the string at this point, and we don't want to fail.
118#                   Can only use {eof} once, and it is used later.
119#
120