/[pcre]/code/trunk/doc/pcrepartial.3
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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC
# Line 81  PCRE_PARTIAL flag is used for the match. Line 81  PCRE_PARTIAL flag is used for the match.
81  uses the date example quoted above:  uses the date example quoted above:
82  .sp  .sp
83      re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/      re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
84    data> 25jun04\P    data> 25jun04\eP
85     0: 25jun04     0: 25jun04
86     1: jun     1: jun
87    data> 25dec3\P    data> 25dec3\eP
88    Partial match    Partial match
89    data> 3ju\P    data> 3ju\eP
90    Partial match    Partial match
91    data> 3juj\P    data> 3juj\eP
92    No match    No match
93    data> j\P    data> j\eP
94    No match    No match
95  .sp  .sp
96  The first data string is matched completely, so \fBpcretest\fP shows the  The first data string is matched completely, so \fBpcretest\fP shows the
# Line 175  hand, if "dogsbody" is presented as a si Line 175  hand, if "dogsbody" is presented as a si
175  .P  .P
176  Because of this phenomenon, it does not usually make sense to end a pattern  Because of this phenomenon, it does not usually make sense to end a pattern
177  that is going to be matched in this way with a variable repeat.  that is going to be matched in this way with a variable repeat.
178    .P
179    4. Patterns that contain alternatives at the top level which do not all
180    start with the same pattern item may not work as expected. For example,
181    consider this pattern:
182    .sp
183      1234|3789
184    .sp
185    If the first part of the subject is "ABC123", a partial match of the first
186    alternative is found at offset 3. There is no partial match for the second
187    alternative, because such a match does not start at the same point in the
188    subject string. Attempting to continue with the string "789" does not yield a
189    match because only those alternatives that match at one point in the subject
190    are remembered. The problem arises because the start of the second alternative
191    matches within the first alternative. There is no problem with anchored
192    patterns or patterns such as:
193    .sp
194      1234|ABCD
195    .sp
196    where no string can be a partial match for both alternatives.
197  .  .
198  .  .
199  .P  .P
200  .in 0  .in 0
201  Last updated: 28 February 2005  Last updated: 16 January 2006
202  .br  .br
203  Copyright (c) 1997-2005 University of Cambridge.  Copyright (c) 1997-2006 University of Cambridge.
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