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Revision 175 - (show annotations)
Mon Jun 11 13:38:38 2007 UTC (14 years, 3 months ago) by ph10
File size: 14906 byte(s)
Added the Perl 5.10 (?| "branch reset" feature.
1 News about PCRE releases
2 ------------------------
5 Release 7.2 30-Apr-07
6 ---------------------
8 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
9 recompiled for use with 7.2 (necessitated by the addition of \K).
11 Correction to the notes for 7.1: the note about shared libraries for Windows is
12 wrong. Previously, three libraries were built, but each could function
13 independently. For example, the pcreposix library also included all the
14 functions from the basic pcre library. The change is that the three libraries
15 are no longer independent. They are like the Unix libraries. To use the
16 pcreposix functions, for example, you need to link with both the pcreposix and
17 the basic pcre library.
19 Some more features from Perl 5.10 have been added:
21 (?-n) and (?+n) relative references for recursion and subroutines.
23 (Not sure if this one is actually in Perl 5.10)
24 (?(-n) and (?(+n) relative references as conditions.
26 \K to reset the start of the matched string; for example, (foo)\Kbar
27 matches bar preceded by foo, but only sets bar as the matched string.
29 (?| introduces a group where the capturing parentheses in each alternative
30 start from the same number; for example, (?|(abc)|(xyz)) sets capturing
31 parentheses number 1 in both cases.
34 Release 7.1 24-Apr-07
35 ---------------------
37 There is only one new feature in this release: a linebreak setting of
38 PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
39 recognizes only CRLF, CR, and LF as linebreaks.
41 A few bugs are fixed (see ChangeLog for details), but the major change is a
42 complete re-implementation of the build system. This now has full Autotools
43 support and so is now "standard" in some sense. It should help with compiling
44 PCRE in a wide variety of environments.
46 NOTE: when building shared libraries for Windows, three dlls are now built,
47 called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
48 included in a single dll.
50 Another important change is that the dftables auxiliary program is no longer
51 compiled and run at "make" time by default. Instead, a default set of character
52 tables (assuming ASCII coding) is used. If you want to use dftables to generate
53 the character tables as previously, add --enable-rebuild-chartables to the
54 "configure" command. You must do this if you are compiling PCRE to run on a
55 system that uses EBCDIC code.
57 There is a discussion about character tables in the README file. The default is
58 not to use dftables so that that there is no problem when cross-compiling.
61 Release 7.0 19-Dec-06
62 ---------------------
64 This release has a new major number because there have been some internal
65 upheavals to facilitate the addition of new optimizations and other facilities,
66 and to make subsequent maintenance and extension easier. Compilation is likely
67 to be a bit slower, but there should be no major effect on runtime performance.
68 Previously compiled patterns are NOT upwards compatible with this release. If
69 you have saved compiled patterns from a previous release, you will have to
70 re-compile them. Important changes that are visible to users are:
72 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
73 some more scripts.
75 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
76 sequence as a newline.
78 3. The \R escape matches a single Unicode newline sequence as a single unit.
80 4. New features that will appear in Perl 5.10 are now in PCRE. These include
81 alternative Perl syntax for named parentheses, and Perl syntax for
82 recursion.
84 5. The C++ wrapper interface has been extended by the addition of a
85 QuoteMeta function and the ability to allow copy construction and
86 assignment.
88 For a complete list of changes, see the ChangeLog file.
91 Release 6.7 04-Jul-06
92 ---------------------
94 The main additions to this release are the ability to use the same name for
95 multiple sets of parentheses, and support for CRLF line endings in both the
96 library and pcregrep (and in pcretest for testing).
98 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
99 significantly reduced for certain subject strings.
102 Release 6.5 01-Feb-06
103 ---------------------
105 Important changes in this release:
107 1. A number of new features have been added to pcregrep.
109 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
110 supported properties have been extended with script names such as "Arabic",
111 and the derived properties "Any" and "L&". This has necessitated a change to
112 the interal format of compiled patterns. Any saved compiled patterns that
113 use \p or \P must be recompiled.
115 3. The specification of recursion in patterns has been changed so that all
116 recursive subpatterns are automatically treated as atomic groups. Thus, for
117 example, (?R) is treated as if it were (?>(?R)). This is necessary because
118 otherwise there are situations where recursion does not work.
120 See the ChangeLog for a complete list of changes, which include a number of bug
121 fixes and tidies.
124 Release 6.0 07-Jun-05
125 ---------------------
127 The release number has been increased to 6.0 because of the addition of several
128 major new pieces of functionality.
130 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
131 algorithm, has been added. This has a number of advantages for certain cases,
132 though it does run more slowly, and lacks the ability to capture substrings. On
133 the other hand, it does find all matches, not just the first, and it works
134 better for partial matching. The pcrematching man page discusses the
135 differences.
137 The pcretest program has been enhanced so that it can make use of the new
138 pcre_dfa_exec() matching function and the extra features it provides.
140 The distribution now includes a C++ wrapper library. This is built
141 automatically if a C++ compiler is found. The pcrecpp man page discusses this
142 interface.
144 The code itself has been re-organized into many more files, one for each
145 function, so it no longer requires everything to be linked in when static
146 linkage is used. As a consequence, some internal functions have had to have
147 their names exposed. These functions all have names starting with _pcre_. They
148 are undocumented, and are not intended for use by outside callers.
150 The pcregrep program has been enhanced with new functionality such as
151 multiline-matching and options for output more matching context. See the
152 ChangeLog for a complete list of changes to the library and the utility
153 programs.
156 Release 5.0 13-Sep-04
157 ---------------------
159 The licence under which PCRE is released has been changed to the more
160 conventional "BSD" licence.
162 In the code, some bugs have been fixed, and there are also some major changes
163 in this release (which is why I've increased the number to 5.0). Some changes
164 are internal rearrangements, and some provide a number of new facilities. The
165 new features are:
167 1. There's an "automatic callout" feature that inserts callouts before every
168 item in the regex, and there's a new callout field that gives the position
169 in the pattern - useful for debugging and tracing.
171 2. The extra_data structure can now be used to pass in a set of character
172 tables at exec time. This is useful if compiled regex are saved and re-used
173 at a later time when the tables may not be at the same address. If the
174 default internal tables are used, the pointer saved with the compiled
175 pattern is now set to NULL, which means that you don't need to do anything
176 special unless you are using custom tables.
178 3. It is possible, with some restrictions on the content of the regex, to
179 request "partial" matching. A special return code is given if all of the
180 subject string matched part of the regex. This could be useful for testing
181 an input field as it is being typed.
183 4. There is now some optional support for Unicode character properties, which
184 means that the patterns items such as \p{Lu} and \X can now be used. Only
185 the general category properties are supported. If PCRE is compiled with this
186 support, an additional 90K data structure is include, which increases the
187 size of the library dramatically.
189 5. There is support for saving compiled patterns and re-using them later.
191 6. There is support for running regular expressions that were compiled on a
192 different host with the opposite endianness.
194 7. The pcretest program has been extended to accommodate the new features.
196 The main internal rearrangement is that sequences of literal characters are no
197 longer handled as strings. Instead, each character is handled on its own. This
198 makes some UTF-8 handling easier, and makes the support of partial matching
199 possible. Compiled patterns containing long literal strings will be larger as a
200 result of this change; I hope that performance will not be much affected.
203 Release 4.5 01-Dec-03
204 ---------------------
206 Again mainly a bug-fix and tidying release, with only a couple of new features:
208 1. It's possible now to compile PCRE so that it does not use recursive
209 function calls when matching. Instead it gets memory from the heap. This slows
210 things down, but may be necessary on systems with limited stacks.
212 2. UTF-8 string checking has been tightened to reject overlong sequences and to
213 check that a starting offset points to the start of a character. Failure of the
214 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
216 3. PCRE can now be compiled for systems that use EBCDIC code.
219 Release 4.4 21-Aug-03
220 ---------------------
222 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
223 checks UTF-8 strings for validity by default. There is an option to suppress
224 this, just in case anybody wants that teeny extra bit of performance.
227 Releases 4.1 - 4.3
228 ------------------
230 Sorry, I forgot about updating the NEWS file for these releases. Please take a
231 look at ChangeLog.
234 Release 4.0 17-Feb-03
235 ---------------------
237 There have been a lot of changes for the 4.0 release, adding additional
238 functionality and mending bugs. Below is a list of the highlights of the new
239 functionality. For full details of these features, please consult the
240 documentation. For a complete list of changes, see the ChangeLog file.
242 1. Support for Perl's \Q...\E escapes.
244 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
245 package. They provide some syntactic sugar for simple cases of "atomic
246 grouping".
248 3. Support for the \G assertion. It is true when the current matching position
249 is at the start point of the match.
251 4. A new feature that provides some of the functionality that Perl provides
252 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
253 is for the caller to provide an optional function, by setting pcre_callout to
254 its entry point. To get the function called, the regex must include (?C) at
255 appropriate points.
257 5. Support for recursive calls to individual subpatterns. This makes it really
258 easy to get totally confused.
260 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
261 name a group.
263 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
264 option for pcregrep to make it operate in UTF-8 mode.
266 8. The single man page has been split into a number of separate man pages.
267 These also give rise to individual HTML pages which are put in a separate
268 directory. There is an index.html page that lists them all. Some hyperlinking
269 between the pages has been installed.
272 Release 3.5 15-Aug-01
273 ---------------------
275 1. The configuring system has been upgraded to use later versions of autoconf
276 and libtool. By default it builds both a shared and a static library if the OS
277 supports it. You can use --disable-shared or --disable-static on the configure
278 command if you want only one of them.
280 2. The pcretest utility is now installed along with pcregrep because it is
281 useful for users (to test regexs) and by doing this, it automatically gets
282 relinked by libtool. The documentation has been turned into a man page, so
283 there are now .1, .txt, and .html versions in /doc.
285 3. Upgrades to pcregrep:
286 (i) Added long-form option names like gnu grep.
287 (ii) Added --help to list all options with an explanatory phrase.
288 (iii) Added -r, --recursive to recurse into sub-directories.
289 (iv) Added -f, --file to read patterns from a file.
291 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
292 script, to force use of CR or LF instead of \n in the source. On non-Unix
293 systems, the value can be set in config.h.
295 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
296 absolute limit. Changed the text of the error message to make this clear, and
297 likewise updated the man page.
299 6. The limit of 99 on the number of capturing subpatterns has been removed.
300 The new limit is 65535, which I hope will not be a "real" limit.
303 Release 3.3 01-Aug-00
304 ---------------------
306 There is some support for UTF-8 character strings. This is incomplete and
307 experimental. The documentation describes what is and what is not implemented.
308 Otherwise, this is just a bug-fixing release.
311 Release 3.0 01-Feb-00
312 ---------------------
314 1. A "configure" script is now used to configure PCRE for Unix systems. It
315 builds a Makefile, a config.h file, and the pcre-config script.
317 2. PCRE is built as a shared library by default.
319 3. There is support for POSIX classes such as [:alpha:].
321 5. There is an experimental recursion feature.
323 ----------------------------------------------------------------------------
326 Please note that there has been a change in the API such that a larger
327 ovector is required at matching time, to provide some additional workspace.
328 The new man page has details. This change was necessary in order to support
329 some of the new functionality in Perl 5.005.
333 Another (I hope this is the last!) change has been made to the API for the
334 pcre_compile() function. An additional argument has been added to make it
335 possible to pass over a pointer to character tables built in the current
336 locale by pcre_maketables(). To use the default tables, this new arguement
337 should be passed as NULL.
341 Yet another (and again I hope this really is the last) change has been made
342 to the API for the pcre_exec() function. An additional argument has been
343 added to make it possible to start the match other than at the start of the
344 subject string. This is important if there are lookbehinds. The new man
345 page has the details, but you just want to convert existing programs, all
346 you need to do is to stick in a new fifth argument to pcre_exec(), with a
347 value of zero. For example, change
349 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
350 to
351 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
353 ****


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