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Revision 166 - (show annotations) (download)
Wed May 9 14:48:28 2007 UTC (7 years, 2 months ago) by ph10
File size: 14316 byte(s)
Add (?-n) and (?+n) relative references.

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

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