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Revision 228 - (show annotations) (download)
Tue Aug 28 13:37:37 2007 UTC (6 years, 11 months ago) by ph10
File size: 15920 byte(s)
Final version number changes for the 7.3 release.

1 News about PCRE releases
2 ------------------------
3
4
5 Release 7.3 28-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 5. Some PCRE-specific settings for varying the newline options at the start of
26 a pattern have been added.
27
28
29 Release 7.2 19-Jun-07
30 ---------------------
31
32 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
33 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
34 and \V).
35
36 Correction to the notes for 7.1: the note about shared libraries for Windows is
37 wrong. Previously, three libraries were built, but each could function
38 independently. For example, the pcreposix library also included all the
39 functions from the basic pcre library. The change is that the three libraries
40 are no longer independent. They are like the Unix libraries. To use the
41 pcreposix functions, for example, you need to link with both the pcreposix and
42 the basic pcre library.
43
44 Some more features from Perl 5.10 have been added:
45
46 (?-n) and (?+n) relative references for recursion and subroutines.
47
48 (?(-n) and (?(+n) relative references as conditions.
49
50 \k{name} and \g{name} are synonyms for \k<name>.
51
52 \K to reset the start of the matched string; for example, (foo)\Kbar
53 matches bar preceded by foo, but only sets bar as the matched string.
54
55 (?| introduces a group where the capturing parentheses in each alternative
56 start from the same number; for example, (?|(abc)|(xyz)) sets capturing
57 parentheses number 1 in both cases.
58
59 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
60
61
62 Release 7.1 24-Apr-07
63 ---------------------
64
65 There is only one new feature in this release: a linebreak setting of
66 PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
67 recognizes only CRLF, CR, and LF as linebreaks.
68
69 A few bugs are fixed (see ChangeLog for details), but the major change is a
70 complete re-implementation of the build system. This now has full Autotools
71 support and so is now "standard" in some sense. It should help with compiling
72 PCRE in a wide variety of environments.
73
74 NOTE: when building shared libraries for Windows, three dlls are now built,
75 called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
76 included in a single dll.
77
78 Another important change is that the dftables auxiliary program is no longer
79 compiled and run at "make" time by default. Instead, a default set of character
80 tables (assuming ASCII coding) is used. If you want to use dftables to generate
81 the character tables as previously, add --enable-rebuild-chartables to the
82 "configure" command. You must do this if you are compiling PCRE to run on a
83 system that uses EBCDIC code.
84
85 There is a discussion about character tables in the README file. The default is
86 not to use dftables so that that there is no problem when cross-compiling.
87
88
89 Release 7.0 19-Dec-06
90 ---------------------
91
92 This release has a new major number because there have been some internal
93 upheavals to facilitate the addition of new optimizations and other facilities,
94 and to make subsequent maintenance and extension easier. Compilation is likely
95 to be a bit slower, but there should be no major effect on runtime performance.
96 Previously compiled patterns are NOT upwards compatible with this release. If
97 you have saved compiled patterns from a previous release, you will have to
98 re-compile them. Important changes that are visible to users are:
99
100 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
101 some more scripts.
102
103 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
104 sequence as a newline.
105
106 3. The \R escape matches a single Unicode newline sequence as a single unit.
107
108 4. New features that will appear in Perl 5.10 are now in PCRE. These include
109 alternative Perl syntax for named parentheses, and Perl syntax for
110 recursion.
111
112 5. The C++ wrapper interface has been extended by the addition of a
113 QuoteMeta function and the ability to allow copy construction and
114 assignment.
115
116 For a complete list of changes, see the ChangeLog file.
117
118
119 Release 6.7 04-Jul-06
120 ---------------------
121
122 The main additions to this release are the ability to use the same name for
123 multiple sets of parentheses, and support for CRLF line endings in both the
124 library and pcregrep (and in pcretest for testing).
125
126 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
127 significantly reduced for certain subject strings.
128
129
130 Release 6.5 01-Feb-06
131 ---------------------
132
133 Important changes in this release:
134
135 1. A number of new features have been added to pcregrep.
136
137 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
138 supported properties have been extended with script names such as "Arabic",
139 and the derived properties "Any" and "L&". This has necessitated a change to
140 the interal format of compiled patterns. Any saved compiled patterns that
141 use \p or \P must be recompiled.
142
143 3. The specification of recursion in patterns has been changed so that all
144 recursive subpatterns are automatically treated as atomic groups. Thus, for
145 example, (?R) is treated as if it were (?>(?R)). This is necessary because
146 otherwise there are situations where recursion does not work.
147
148 See the ChangeLog for a complete list of changes, which include a number of bug
149 fixes and tidies.
150
151
152 Release 6.0 07-Jun-05
153 ---------------------
154
155 The release number has been increased to 6.0 because of the addition of several
156 major new pieces of functionality.
157
158 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
159 algorithm, has been added. This has a number of advantages for certain cases,
160 though it does run more slowly, and lacks the ability to capture substrings. On
161 the other hand, it does find all matches, not just the first, and it works
162 better for partial matching. The pcrematching man page discusses the
163 differences.
164
165 The pcretest program has been enhanced so that it can make use of the new
166 pcre_dfa_exec() matching function and the extra features it provides.
167
168 The distribution now includes a C++ wrapper library. This is built
169 automatically if a C++ compiler is found. The pcrecpp man page discusses this
170 interface.
171
172 The code itself has been re-organized into many more files, one for each
173 function, so it no longer requires everything to be linked in when static
174 linkage is used. As a consequence, some internal functions have had to have
175 their names exposed. These functions all have names starting with _pcre_. They
176 are undocumented, and are not intended for use by outside callers.
177
178 The pcregrep program has been enhanced with new functionality such as
179 multiline-matching and options for output more matching context. See the
180 ChangeLog for a complete list of changes to the library and the utility
181 programs.
182
183
184 Release 5.0 13-Sep-04
185 ---------------------
186
187 The licence under which PCRE is released has been changed to the more
188 conventional "BSD" licence.
189
190 In the code, some bugs have been fixed, and there are also some major changes
191 in this release (which is why I've increased the number to 5.0). Some changes
192 are internal rearrangements, and some provide a number of new facilities. The
193 new features are:
194
195 1. There's an "automatic callout" feature that inserts callouts before every
196 item in the regex, and there's a new callout field that gives the position
197 in the pattern - useful for debugging and tracing.
198
199 2. The extra_data structure can now be used to pass in a set of character
200 tables at exec time. This is useful if compiled regex are saved and re-used
201 at a later time when the tables may not be at the same address. If the
202 default internal tables are used, the pointer saved with the compiled
203 pattern is now set to NULL, which means that you don't need to do anything
204 special unless you are using custom tables.
205
206 3. It is possible, with some restrictions on the content of the regex, to
207 request "partial" matching. A special return code is given if all of the
208 subject string matched part of the regex. This could be useful for testing
209 an input field as it is being typed.
210
211 4. There is now some optional support for Unicode character properties, which
212 means that the patterns items such as \p{Lu} and \X can now be used. Only
213 the general category properties are supported. If PCRE is compiled with this
214 support, an additional 90K data structure is include, which increases the
215 size of the library dramatically.
216
217 5. There is support for saving compiled patterns and re-using them later.
218
219 6. There is support for running regular expressions that were compiled on a
220 different host with the opposite endianness.
221
222 7. The pcretest program has been extended to accommodate the new features.
223
224 The main internal rearrangement is that sequences of literal characters are no
225 longer handled as strings. Instead, each character is handled on its own. This
226 makes some UTF-8 handling easier, and makes the support of partial matching
227 possible. Compiled patterns containing long literal strings will be larger as a
228 result of this change; I hope that performance will not be much affected.
229
230
231 Release 4.5 01-Dec-03
232 ---------------------
233
234 Again mainly a bug-fix and tidying release, with only a couple of new features:
235
236 1. It's possible now to compile PCRE so that it does not use recursive
237 function calls when matching. Instead it gets memory from the heap. This slows
238 things down, but may be necessary on systems with limited stacks.
239
240 2. UTF-8 string checking has been tightened to reject overlong sequences and to
241 check that a starting offset points to the start of a character. Failure of the
242 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
243
244 3. PCRE can now be compiled for systems that use EBCDIC code.
245
246
247 Release 4.4 21-Aug-03
248 ---------------------
249
250 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
251 checks UTF-8 strings for validity by default. There is an option to suppress
252 this, just in case anybody wants that teeny extra bit of performance.
253
254
255 Releases 4.1 - 4.3
256 ------------------
257
258 Sorry, I forgot about updating the NEWS file for these releases. Please take a
259 look at ChangeLog.
260
261
262 Release 4.0 17-Feb-03
263 ---------------------
264
265 There have been a lot of changes for the 4.0 release, adding additional
266 functionality and mending bugs. Below is a list of the highlights of the new
267 functionality. For full details of these features, please consult the
268 documentation. For a complete list of changes, see the ChangeLog file.
269
270 1. Support for Perl's \Q...\E escapes.
271
272 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
273 package. They provide some syntactic sugar for simple cases of "atomic
274 grouping".
275
276 3. Support for the \G assertion. It is true when the current matching position
277 is at the start point of the match.
278
279 4. A new feature that provides some of the functionality that Perl provides
280 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
281 is for the caller to provide an optional function, by setting pcre_callout to
282 its entry point. To get the function called, the regex must include (?C) at
283 appropriate points.
284
285 5. Support for recursive calls to individual subpatterns. This makes it really
286 easy to get totally confused.
287
288 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
289 name a group.
290
291 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
292 option for pcregrep to make it operate in UTF-8 mode.
293
294 8. The single man page has been split into a number of separate man pages.
295 These also give rise to individual HTML pages which are put in a separate
296 directory. There is an index.html page that lists them all. Some hyperlinking
297 between the pages has been installed.
298
299
300 Release 3.5 15-Aug-01
301 ---------------------
302
303 1. The configuring system has been upgraded to use later versions of autoconf
304 and libtool. By default it builds both a shared and a static library if the OS
305 supports it. You can use --disable-shared or --disable-static on the configure
306 command if you want only one of them.
307
308 2. The pcretest utility is now installed along with pcregrep because it is
309 useful for users (to test regexs) and by doing this, it automatically gets
310 relinked by libtool. The documentation has been turned into a man page, so
311 there are now .1, .txt, and .html versions in /doc.
312
313 3. Upgrades to pcregrep:
314 (i) Added long-form option names like gnu grep.
315 (ii) Added --help to list all options with an explanatory phrase.
316 (iii) Added -r, --recursive to recurse into sub-directories.
317 (iv) Added -f, --file to read patterns from a file.
318
319 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
320 script, to force use of CR or LF instead of \n in the source. On non-Unix
321 systems, the value can be set in config.h.
322
323 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
324 absolute limit. Changed the text of the error message to make this clear, and
325 likewise updated the man page.
326
327 6. The limit of 99 on the number of capturing subpatterns has been removed.
328 The new limit is 65535, which I hope will not be a "real" limit.
329
330
331 Release 3.3 01-Aug-00
332 ---------------------
333
334 There is some support for UTF-8 character strings. This is incomplete and
335 experimental. The documentation describes what is and what is not implemented.
336 Otherwise, this is just a bug-fixing release.
337
338
339 Release 3.0 01-Feb-00
340 ---------------------
341
342 1. A "configure" script is now used to configure PCRE for Unix systems. It
343 builds a Makefile, a config.h file, and the pcre-config script.
344
345 2. PCRE is built as a shared library by default.
346
347 3. There is support for POSIX classes such as [:alpha:].
348
349 5. There is an experimental recursion feature.
350
351 ----------------------------------------------------------------------------
352 IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
353
354 Please note that there has been a change in the API such that a larger
355 ovector is required at matching time, to provide some additional workspace.
356 The new man page has details. This change was necessary in order to support
357 some of the new functionality in Perl 5.005.
358
359 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
360
361 Another (I hope this is the last!) change has been made to the API for the
362 pcre_compile() function. An additional argument has been added to make it
363 possible to pass over a pointer to character tables built in the current
364 locale by pcre_maketables(). To use the default tables, this new arguement
365 should be passed as NULL.
366
367 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
368
369 Yet another (and again I hope this really is the last) change has been made
370 to the API for the pcre_exec() function. An additional argument has been
371 added to make it possible to start the match other than at the start of the
372 subject string. This is important if there are lookbehinds. The new man
373 page has the details, but you just want to convert existing programs, all
374 you need to do is to stick in a new fifth argument to pcre_exec(), with a
375 value of zero. For example, change
376
377 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
378 to
379 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
380
381 ****

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