/[pcre]/code/trunk/doc/pcrematching.3
ViewVC logotype

Diff of /code/trunk/doc/pcrematching.3

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 168 by ph10, Tue May 29 15:18:18 2007 UTC revision 426 by ph10, Wed Aug 26 15:38:32 2009 UTC
# Line 126  and not on others), is not supported. It Line 126  and not on others), is not supported. It
126  6. Callouts are supported, but the value of the \fIcapture_top\fP field is  6. Callouts are supported, but the value of the \fIcapture_top\fP field is
127  always 1, and the value of the \fIcapture_last\fP field is always -1.  always 1, and the value of the \fIcapture_last\fP field is always -1.
128  .P  .P
129  7.  7. The \eC escape sequence, which (in the standard algorithm) matches a single
 The \eC escape sequence, which (in the standard algorithm) matches a single  
130  byte, even in UTF-8 mode, is not supported because the alternative algorithm  byte, even in UTF-8 mode, is not supported because the alternative algorithm
131  moves through the subject string one character at a time, for all active paths  moves through the subject string one character at a time, for all active paths
132  through the tree.  through the tree.
133    .P
134    8. Except for (*FAIL), the backtracking control verbs such as (*PRUNE) are not
135    supported. (*FAIL) is supported, and behaves like a failing negative assertion.
136  .  .
137  .SH "ADVANTAGES OF THE ALTERNATIVE ALGORITHM"  .SH "ADVANTAGES OF THE ALTERNATIVE ALGORITHM"
138  .rs  .rs
# Line 142  found, and in particular, the longest ma Line 144  found, and in particular, the longest ma
144  match using the standard algorithm, you have to do kludgy things with  match using the standard algorithm, you have to do kludgy things with
145  callouts.  callouts.
146  .P  .P
147  2. There is much better support for partial matching. The restrictions on the  2. Because the alternative algorithm scans the subject string just once, and
 content of the pattern that apply when using the standard algorithm for partial  
 matching do not apply to the alternative algorithm. For non-anchored patterns,  
 the starting position of a partial match is available.  
 .P  
 3. Because the alternative algorithm scans the subject string just once, and  
148  never needs to backtrack, it is possible to pass very long subject strings to  never needs to backtrack, it is possible to pass very long subject strings to
149  the matching function in several pieces, checking for partial matching each  the matching function in several pieces, checking for partial matching each
150  time.  time.
# Line 181  Cambridge CB2 3QH, England. Line 178  Cambridge CB2 3QH, England.
178  .rs  .rs
179  .sp  .sp
180  .nf  .nf
181  Last updated: 29 May 2007  Last updated: 25 August 2009
182  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
183  .fi  .fi

Legend:
Removed from v.168  
changed lines
  Added in v.426

  ViewVC Help
Powered by ViewVC 1.1.5