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Contents of /code/tags/pcre-7.8/NEWS

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Revision 226 - (show annotations) (download)
Tue Aug 21 11:46:08 2007 UTC (7 years, 1 month ago) by ph10
Original Path: code/trunk/NEWS
File size: 15816 byte(s)
Don't advance by 2 if explicit \r or \n in the pattern. Add 
PCRE_INFO_HASCRORLF.

1 News about PCRE releases
2 ------------------------
3
4
5 Release 7.3 20-Aug-07
6 ---------------------
7
8 Most changes are bug fixes. Some that are not:
9
10 1. There is some support for Perl 5.10's experimental "backtracking control
11 verbs" such as (*PRUNE).
12
13 2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
14 restrictive in the strings it accepts.
15
16 3. Checking for potential integer overflow has been made more dynamic, and as a
17 consequence there is no longer a hard limit on the size of a subpattern that
18 has a limited repeat count.
19
20 4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
21 no longer advance by two characters instead of one when an unanchored match
22 fails at CRLF if there are explicit CR or LF matches within the pattern.
23 This gets rid of some anomalous effects that previously occurred.
24
25
26 Release 7.2 19-Jun-07
27 ---------------------
28
29 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
30 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
31 and \V).
32
33 Correction to the notes for 7.1: the note about shared libraries for Windows is
34 wrong. Previously, three libraries were built, but each could function
35 independently. For example, the pcreposix library also included all the
36 functions from the basic pcre library. The change is that the three libraries
37 are no longer independent. They are like the Unix libraries. To use the
38 pcreposix functions, for example, you need to link with both the pcreposix and
39 the basic pcre library.
40
41 Some more features from Perl 5.10 have been added:
42
43 (?-n) and (?+n) relative references for recursion and subroutines.
44
45 (?(-n) and (?(+n) relative references as conditions.
46
47 \k{name} and \g{name} are synonyms for \k<name>.
48
49 \K to reset the start of the matched string; for example, (foo)\Kbar
50 matches bar preceded by foo, but only sets bar as the matched string.
51
52 (?| introduces a group where the capturing parentheses in each alternative
53 start from the same number; for example, (?|(abc)|(xyz)) sets capturing
54 parentheses number 1 in both cases.
55
56 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
57
58
59 Release 7.1 24-Apr-07
60 ---------------------
61
62 There is only one new feature in this release: a linebreak setting of
63 PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
64 recognizes only CRLF, CR, and LF as linebreaks.
65
66 A few bugs are fixed (see ChangeLog for details), but the major change is a
67 complete re-implementation of the build system. This now has full Autotools
68 support and so is now "standard" in some sense. It should help with compiling
69 PCRE in a wide variety of environments.
70
71 NOTE: when building shared libraries for Windows, three dlls are now built,
72 called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
73 included in a single dll.
74
75 Another important change is that the dftables auxiliary program is no longer
76 compiled and run at "make" time by default. Instead, a default set of character
77 tables (assuming ASCII coding) is used. If you want to use dftables to generate
78 the character tables as previously, add --enable-rebuild-chartables to the
79 "configure" command. You must do this if you are compiling PCRE to run on a
80 system that uses EBCDIC code.
81
82 There is a discussion about character tables in the README file. The default is
83 not to use dftables so that that there is no problem when cross-compiling.
84
85
86 Release 7.0 19-Dec-06
87 ---------------------
88
89 This release has a new major number because there have been some internal
90 upheavals to facilitate the addition of new optimizations and other facilities,
91 and to make subsequent maintenance and extension easier. Compilation is likely
92 to be a bit slower, but there should be no major effect on runtime performance.
93 Previously compiled patterns are NOT upwards compatible with this release. If
94 you have saved compiled patterns from a previous release, you will have to
95 re-compile them. Important changes that are visible to users are:
96
97 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
98 some more scripts.
99
100 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
101 sequence as a newline.
102
103 3. The \R escape matches a single Unicode newline sequence as a single unit.
104
105 4. New features that will appear in Perl 5.10 are now in PCRE. These include
106 alternative Perl syntax for named parentheses, and Perl syntax for
107 recursion.
108
109 5. The C++ wrapper interface has been extended by the addition of a
110 QuoteMeta function and the ability to allow copy construction and
111 assignment.
112
113 For a complete list of changes, see the ChangeLog file.
114
115
116 Release 6.7 04-Jul-06
117 ---------------------
118
119 The main additions to this release are the ability to use the same name for
120 multiple sets of parentheses, and support for CRLF line endings in both the
121 library and pcregrep (and in pcretest for testing).
122
123 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
124 significantly reduced for certain subject strings.
125
126
127 Release 6.5 01-Feb-06
128 ---------------------
129
130 Important changes in this release:
131
132 1. A number of new features have been added to pcregrep.
133
134 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
135 supported properties have been extended with script names such as "Arabic",
136 and the derived properties "Any" and "L&". This has necessitated a change to
137 the interal format of compiled patterns. Any saved compiled patterns that
138 use \p or \P must be recompiled.
139
140 3. The specification of recursion in patterns has been changed so that all
141 recursive subpatterns are automatically treated as atomic groups. Thus, for
142 example, (?R) is treated as if it were (?>(?R)). This is necessary because
143 otherwise there are situations where recursion does not work.
144
145 See the ChangeLog for a complete list of changes, which include a number of bug
146 fixes and tidies.
147
148
149 Release 6.0 07-Jun-05
150 ---------------------
151
152 The release number has been increased to 6.0 because of the addition of several
153 major new pieces of functionality.
154
155 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
156 algorithm, has been added. This has a number of advantages for certain cases,
157 though it does run more slowly, and lacks the ability to capture substrings. On
158 the other hand, it does find all matches, not just the first, and it works
159 better for partial matching. The pcrematching man page discusses the
160 differences.
161
162 The pcretest program has been enhanced so that it can make use of the new
163 pcre_dfa_exec() matching function and the extra features it provides.
164
165 The distribution now includes a C++ wrapper library. This is built
166 automatically if a C++ compiler is found. The pcrecpp man page discusses this
167 interface.
168
169 The code itself has been re-organized into many more files, one for each
170 function, so it no longer requires everything to be linked in when static
171 linkage is used. As a consequence, some internal functions have had to have
172 their names exposed. These functions all have names starting with _pcre_. They
173 are undocumented, and are not intended for use by outside callers.
174
175 The pcregrep program has been enhanced with new functionality such as
176 multiline-matching and options for output more matching context. See the
177 ChangeLog for a complete list of changes to the library and the utility
178 programs.
179
180
181 Release 5.0 13-Sep-04
182 ---------------------
183
184 The licence under which PCRE is released has been changed to the more
185 conventional "BSD" licence.
186
187 In the code, some bugs have been fixed, and there are also some major changes
188 in this release (which is why I've increased the number to 5.0). Some changes
189 are internal rearrangements, and some provide a number of new facilities. The
190 new features are:
191
192 1. There's an "automatic callout" feature that inserts callouts before every
193 item in the regex, and there's a new callout field that gives the position
194 in the pattern - useful for debugging and tracing.
195
196 2. The extra_data structure can now be used to pass in a set of character
197 tables at exec time. This is useful if compiled regex are saved and re-used
198 at a later time when the tables may not be at the same address. If the
199 default internal tables are used, the pointer saved with the compiled
200 pattern is now set to NULL, which means that you don't need to do anything
201 special unless you are using custom tables.
202
203 3. It is possible, with some restrictions on the content of the regex, to
204 request "partial" matching. A special return code is given if all of the
205 subject string matched part of the regex. This could be useful for testing
206 an input field as it is being typed.
207
208 4. There is now some optional support for Unicode character properties, which
209 means that the patterns items such as \p{Lu} and \X can now be used. Only
210 the general category properties are supported. If PCRE is compiled with this
211 support, an additional 90K data structure is include, which increases the
212 size of the library dramatically.
213
214 5. There is support for saving compiled patterns and re-using them later.
215
216 6. There is support for running regular expressions that were compiled on a
217 different host with the opposite endianness.
218
219 7. The pcretest program has been extended to accommodate the new features.
220
221 The main internal rearrangement is that sequences of literal characters are no
222 longer handled as strings. Instead, each character is handled on its own. This
223 makes some UTF-8 handling easier, and makes the support of partial matching
224 possible. Compiled patterns containing long literal strings will be larger as a
225 result of this change; I hope that performance will not be much affected.
226
227
228 Release 4.5 01-Dec-03
229 ---------------------
230
231 Again mainly a bug-fix and tidying release, with only a couple of new features:
232
233 1. It's possible now to compile PCRE so that it does not use recursive
234 function calls when matching. Instead it gets memory from the heap. This slows
235 things down, but may be necessary on systems with limited stacks.
236
237 2. UTF-8 string checking has been tightened to reject overlong sequences and to
238 check that a starting offset points to the start of a character. Failure of the
239 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
240
241 3. PCRE can now be compiled for systems that use EBCDIC code.
242
243
244 Release 4.4 21-Aug-03
245 ---------------------
246
247 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
248 checks UTF-8 strings for validity by default. There is an option to suppress
249 this, just in case anybody wants that teeny extra bit of performance.
250
251
252 Releases 4.1 - 4.3
253 ------------------
254
255 Sorry, I forgot about updating the NEWS file for these releases. Please take a
256 look at ChangeLog.
257
258
259 Release 4.0 17-Feb-03
260 ---------------------
261
262 There have been a lot of changes for the 4.0 release, adding additional
263 functionality and mending bugs. Below is a list of the highlights of the new
264 functionality. For full details of these features, please consult the
265 documentation. For a complete list of changes, see the ChangeLog file.
266
267 1. Support for Perl's \Q...\E escapes.
268
269 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
270 package. They provide some syntactic sugar for simple cases of "atomic
271 grouping".
272
273 3. Support for the \G assertion. It is true when the current matching position
274 is at the start point of the match.
275
276 4. A new feature that provides some of the functionality that Perl provides
277 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
278 is for the caller to provide an optional function, by setting pcre_callout to
279 its entry point. To get the function called, the regex must include (?C) at
280 appropriate points.
281
282 5. Support for recursive calls to individual subpatterns. This makes it really
283 easy to get totally confused.
284
285 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
286 name a group.
287
288 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
289 option for pcregrep to make it operate in UTF-8 mode.
290
291 8. The single man page has been split into a number of separate man pages.
292 These also give rise to individual HTML pages which are put in a separate
293 directory. There is an index.html page that lists them all. Some hyperlinking
294 between the pages has been installed.
295
296
297 Release 3.5 15-Aug-01
298 ---------------------
299
300 1. The configuring system has been upgraded to use later versions of autoconf
301 and libtool. By default it builds both a shared and a static library if the OS
302 supports it. You can use --disable-shared or --disable-static on the configure
303 command if you want only one of them.
304
305 2. The pcretest utility is now installed along with pcregrep because it is
306 useful for users (to test regexs) and by doing this, it automatically gets
307 relinked by libtool. The documentation has been turned into a man page, so
308 there are now .1, .txt, and .html versions in /doc.
309
310 3. Upgrades to pcregrep:
311 (i) Added long-form option names like gnu grep.
312 (ii) Added --help to list all options with an explanatory phrase.
313 (iii) Added -r, --recursive to recurse into sub-directories.
314 (iv) Added -f, --file to read patterns from a file.
315
316 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
317 script, to force use of CR or LF instead of \n in the source. On non-Unix
318 systems, the value can be set in config.h.
319
320 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
321 absolute limit. Changed the text of the error message to make this clear, and
322 likewise updated the man page.
323
324 6. The limit of 99 on the number of capturing subpatterns has been removed.
325 The new limit is 65535, which I hope will not be a "real" limit.
326
327
328 Release 3.3 01-Aug-00
329 ---------------------
330
331 There is some support for UTF-8 character strings. This is incomplete and
332 experimental. The documentation describes what is and what is not implemented.
333 Otherwise, this is just a bug-fixing release.
334
335
336 Release 3.0 01-Feb-00
337 ---------------------
338
339 1. A "configure" script is now used to configure PCRE for Unix systems. It
340 builds a Makefile, a config.h file, and the pcre-config script.
341
342 2. PCRE is built as a shared library by default.
343
344 3. There is support for POSIX classes such as [:alpha:].
345
346 5. There is an experimental recursion feature.
347
348 ----------------------------------------------------------------------------
349 IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
350
351 Please note that there has been a change in the API such that a larger
352 ovector is required at matching time, to provide some additional workspace.
353 The new man page has details. This change was necessary in order to support
354 some of the new functionality in Perl 5.005.
355
356 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
357
358 Another (I hope this is the last!) change has been made to the API for the
359 pcre_compile() function. An additional argument has been added to make it
360 possible to pass over a pointer to character tables built in the current
361 locale by pcre_maketables(). To use the default tables, this new arguement
362 should be passed as NULL.
363
364 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
365
366 Yet another (and again I hope this really is the last) change has been made
367 to the API for the pcre_exec() function. An additional argument has been
368 added to make it possible to start the match other than at the start of the
369 subject string. This is important if there are lookbehinds. The new man
370 page has the details, but you just want to convert existing programs, all
371 you need to do is to stick in a new fifth argument to pcre_exec(), with a
372 value of zero. For example, change
373
374 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
375 to
376 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
377
378 ****

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