1 # 2 # Copyright (C) 2016 and later: Unicode, Inc. and others. 3 # License & terms of use: http://www.unicode.org/copyright.html#License 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 16 # 17 # Character categories as defined in TR 29 18 # 19 $CR = [\p{Sentence_Break = CR}]; 20 $LF = [\p{Sentence_Break = LF}]; 21 $Extend = [\p{Sentence_Break = Extend}]; 22 $Sep = [\p{Sentence_Break = Sep}]; 23 $Format = [\p{Sentence_Break = Format}]; 24 $Sp = [\p{Sentence_Break = Sp}]; 25 $Lower = [\p{Sentence_Break = Lower}]; 26 $Upper = [\p{Sentence_Break = Upper}]; 27 $OLetter = [\p{Sentence_Break = OLetter}]; 28 $Numeric = [\p{Sentence_Break = Numeric}]; 29 $ATerm = [\p{Sentence_Break = ATerm}]; 30 $SContinue = [\p{Sentence_Break = SContinue}]; 31 $STerm = [\p{Sentence_Break = STerm} [\u003B \u037E]]; 32 $Close = [\p{Sentence_Break = Close}]; 33 34 # 35 # Define extended forms of the character classes, 36 # incorporate trailing Extend or Format chars. 37 # Rules 4 and 5. 38 39 $SpEx = $Sp ($Extend | $Format)*; 40 $LowerEx = $Lower ($Extend | $Format)*; 41 $UpperEx = $Upper ($Extend | $Format)*; 42 $OLetterEx = $OLetter ($Extend | $Format)*; 43 $NumericEx = $Numeric ($Extend | $Format)*; 44 $ATermEx = $ATerm ($Extend | $Format)*; 45 $SContinueEx= $SContinue ($Extend | $Format)*; 46 $STermEx = $STerm ($Extend | $Format)*; 47 $CloseEx = $Close ($Extend | $Format)*; 48 49 50 ## ------------------------------------------------- 51 52 !!chain; 53 !!forward; 54 55 # Rule 3 - break after separators. Keep CR/LF together. 56 # 57 $CR $LF; 58 59 60 # Rule 4 - Break after $Sep. 61 # Rule 5 - Ignore $Format and $Extend 62 # 63 [^$Sep $CR $LF]? ($Extend | $Format)*; 64 65 66 # Rule 6 67 $ATermEx $NumericEx; 68 69 # Rule 7 70 ($UpperEx | $LowerEx) $ATermEx $UpperEx; 71 72 #Rule 8 73 $NotLettersEx = [^$OLetter $Upper $Lower $Sep $CR $LF $ATerm $STerm] ($Extend | $Format)*; 74 $ATermEx $CloseEx* $SpEx* $NotLettersEx* $Lower; 75 76 # Rule 8a 77 ($STermEx | $ATermEx) $CloseEx* $SpEx* ($SContinueEx | $STermEx | $ATermEx); 78 79 #Rule 9, 10, 11 80 ($STermEx | $ATermEx) $CloseEx* $SpEx* ($Sep | $CR | $LF)?; 81 82 #Rule 12 83 [[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* .; 84 [[^$STerm $ATerm $Close $Sp $Sep $LF $CR $Format $Extend]{bof}] ($Extend | $Format | $Close | $Sp)* ([$Sep $LF $CR {eof}] | $CR $LF){100}; 85 86 ## ------------------------------------------------- 87 88 !!reverse; 89 90 $SpEx_R = ($Extend | $Format)* $Sp; 91 $ATermEx_R = ($Extend | $Format)* $ATerm; 92 $STermEx_R = ($Extend | $Format)* $STerm; 93 $CloseEx_R = ($Extend | $Format)* $Close; 94 95 # 96 # Reverse rules. 97 # For now, use the old style inexact reverse rules, which are easier 98 # to write, but less efficient. 99 # TODO: exact reverse rules. It appears that exact reverse rules 100 # may require improving support for look-ahead breaks in the 101 # builder. Needs more investigation. 102 # 103 104 [{bof}] (.? | $LF $CR) [^$Sep $CR $LF]* [$Sep $CR $LF {eof}] ($SpEx_R* $CloseEx_R* ($STermEx_R | $ATermEx_R))*; 105 #.*; 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
