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Revision 261 - (show annotations)
Fri Sep 21 08:37:48 2007 UTC (8 years ago) by ph10
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Final doc updates and file tidies for 7.4.
1 News about PCRE releases
2 ------------------------
5 Release 7.4 21-Sep-07
6 ---------------------
8 The only change of specification is the addition of options to control whether
9 \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
10 Otherwise, the changes are bug fixes and a refactoring to reduce the number of
11 relocations needed in a shared library. There have also been some documentation
12 updates, in particular, some more information about using CMake to build PCRE
13 has been added to the NON-UNIX-USE file.
16 Release 7.3 28-Aug-07
17 ---------------------
19 Most changes are bug fixes. Some that are not:
21 1. There is some support for Perl 5.10's experimental "backtracking control
22 verbs" such as (*PRUNE).
24 2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
25 restrictive in the strings it accepts.
27 3. Checking for potential integer overflow has been made more dynamic, and as a
28 consequence there is no longer a hard limit on the size of a subpattern that
29 has a limited repeat count.
31 4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
32 no longer advance by two characters instead of one when an unanchored match
33 fails at CRLF if there are explicit CR or LF matches within the pattern.
34 This gets rid of some anomalous effects that previously occurred.
36 5. Some PCRE-specific settings for varying the newline options at the start of
37 a pattern have been added.
40 Release 7.2 19-Jun-07
41 ---------------------
43 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
44 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
45 and \V).
47 Correction to the notes for 7.1: the note about shared libraries for Windows is
48 wrong. Previously, three libraries were built, but each could function
49 independently. For example, the pcreposix library also included all the
50 functions from the basic pcre library. The change is that the three libraries
51 are no longer independent. They are like the Unix libraries. To use the
52 pcreposix functions, for example, you need to link with both the pcreposix and
53 the basic pcre library.
55 Some more features from Perl 5.10 have been added:
57 (?-n) and (?+n) relative references for recursion and subroutines.
59 (?(-n) and (?(+n) relative references as conditions.
61 \k{name} and \g{name} are synonyms for \k<name>.
63 \K to reset the start of the matched string; for example, (foo)\Kbar
64 matches bar preceded by foo, but only sets bar as the matched string.
66 (?| introduces a group where the capturing parentheses in each alternative
67 start from the same number; for example, (?|(abc)|(xyz)) sets capturing
68 parentheses number 1 in both cases.
70 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
73 Release 7.1 24-Apr-07
74 ---------------------
76 There is only one new feature in this release: a linebreak setting of
77 PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
78 recognizes only CRLF, CR, and LF as linebreaks.
80 A few bugs are fixed (see ChangeLog for details), but the major change is a
81 complete re-implementation of the build system. This now has full Autotools
82 support and so is now "standard" in some sense. It should help with compiling
83 PCRE in a wide variety of environments.
85 NOTE: when building shared libraries for Windows, three dlls are now built,
86 called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
87 included in a single dll.
89 Another important change is that the dftables auxiliary program is no longer
90 compiled and run at "make" time by default. Instead, a default set of character
91 tables (assuming ASCII coding) is used. If you want to use dftables to generate
92 the character tables as previously, add --enable-rebuild-chartables to the
93 "configure" command. You must do this if you are compiling PCRE to run on a
94 system that uses EBCDIC code.
96 There is a discussion about character tables in the README file. The default is
97 not to use dftables so that that there is no problem when cross-compiling.
100 Release 7.0 19-Dec-06
101 ---------------------
103 This release has a new major number because there have been some internal
104 upheavals to facilitate the addition of new optimizations and other facilities,
105 and to make subsequent maintenance and extension easier. Compilation is likely
106 to be a bit slower, but there should be no major effect on runtime performance.
107 Previously compiled patterns are NOT upwards compatible with this release. If
108 you have saved compiled patterns from a previous release, you will have to
109 re-compile them. Important changes that are visible to users are:
111 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
112 some more scripts.
114 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
115 sequence as a newline.
117 3. The \R escape matches a single Unicode newline sequence as a single unit.
119 4. New features that will appear in Perl 5.10 are now in PCRE. These include
120 alternative Perl syntax for named parentheses, and Perl syntax for
121 recursion.
123 5. The C++ wrapper interface has been extended by the addition of a
124 QuoteMeta function and the ability to allow copy construction and
125 assignment.
127 For a complete list of changes, see the ChangeLog file.
130 Release 6.7 04-Jul-06
131 ---------------------
133 The main additions to this release are the ability to use the same name for
134 multiple sets of parentheses, and support for CRLF line endings in both the
135 library and pcregrep (and in pcretest for testing).
137 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
138 significantly reduced for certain subject strings.
141 Release 6.5 01-Feb-06
142 ---------------------
144 Important changes in this release:
146 1. A number of new features have been added to pcregrep.
148 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
149 supported properties have been extended with script names such as "Arabic",
150 and the derived properties "Any" and "L&". This has necessitated a change to
151 the interal format of compiled patterns. Any saved compiled patterns that
152 use \p or \P must be recompiled.
154 3. The specification of recursion in patterns has been changed so that all
155 recursive subpatterns are automatically treated as atomic groups. Thus, for
156 example, (?R) is treated as if it were (?>(?R)). This is necessary because
157 otherwise there are situations where recursion does not work.
159 See the ChangeLog for a complete list of changes, which include a number of bug
160 fixes and tidies.
163 Release 6.0 07-Jun-05
164 ---------------------
166 The release number has been increased to 6.0 because of the addition of several
167 major new pieces of functionality.
169 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
170 algorithm, has been added. This has a number of advantages for certain cases,
171 though it does run more slowly, and lacks the ability to capture substrings. On
172 the other hand, it does find all matches, not just the first, and it works
173 better for partial matching. The pcrematching man page discusses the
174 differences.
176 The pcretest program has been enhanced so that it can make use of the new
177 pcre_dfa_exec() matching function and the extra features it provides.
179 The distribution now includes a C++ wrapper library. This is built
180 automatically if a C++ compiler is found. The pcrecpp man page discusses this
181 interface.
183 The code itself has been re-organized into many more files, one for each
184 function, so it no longer requires everything to be linked in when static
185 linkage is used. As a consequence, some internal functions have had to have
186 their names exposed. These functions all have names starting with _pcre_. They
187 are undocumented, and are not intended for use by outside callers.
189 The pcregrep program has been enhanced with new functionality such as
190 multiline-matching and options for output more matching context. See the
191 ChangeLog for a complete list of changes to the library and the utility
192 programs.
195 Release 5.0 13-Sep-04
196 ---------------------
198 The licence under which PCRE is released has been changed to the more
199 conventional "BSD" licence.
201 In the code, some bugs have been fixed, and there are also some major changes
202 in this release (which is why I've increased the number to 5.0). Some changes
203 are internal rearrangements, and some provide a number of new facilities. The
204 new features are:
206 1. There's an "automatic callout" feature that inserts callouts before every
207 item in the regex, and there's a new callout field that gives the position
208 in the pattern - useful for debugging and tracing.
210 2. The extra_data structure can now be used to pass in a set of character
211 tables at exec time. This is useful if compiled regex are saved and re-used
212 at a later time when the tables may not be at the same address. If the
213 default internal tables are used, the pointer saved with the compiled
214 pattern is now set to NULL, which means that you don't need to do anything
215 special unless you are using custom tables.
217 3. It is possible, with some restrictions on the content of the regex, to
218 request "partial" matching. A special return code is given if all of the
219 subject string matched part of the regex. This could be useful for testing
220 an input field as it is being typed.
222 4. There is now some optional support for Unicode character properties, which
223 means that the patterns items such as \p{Lu} and \X can now be used. Only
224 the general category properties are supported. If PCRE is compiled with this
225 support, an additional 90K data structure is include, which increases the
226 size of the library dramatically.
228 5. There is support for saving compiled patterns and re-using them later.
230 6. There is support for running regular expressions that were compiled on a
231 different host with the opposite endianness.
233 7. The pcretest program has been extended to accommodate the new features.
235 The main internal rearrangement is that sequences of literal characters are no
236 longer handled as strings. Instead, each character is handled on its own. This
237 makes some UTF-8 handling easier, and makes the support of partial matching
238 possible. Compiled patterns containing long literal strings will be larger as a
239 result of this change; I hope that performance will not be much affected.
242 Release 4.5 01-Dec-03
243 ---------------------
245 Again mainly a bug-fix and tidying release, with only a couple of new features:
247 1. It's possible now to compile PCRE so that it does not use recursive
248 function calls when matching. Instead it gets memory from the heap. This slows
249 things down, but may be necessary on systems with limited stacks.
251 2. UTF-8 string checking has been tightened to reject overlong sequences and to
252 check that a starting offset points to the start of a character. Failure of the
253 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
255 3. PCRE can now be compiled for systems that use EBCDIC code.
258 Release 4.4 21-Aug-03
259 ---------------------
261 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
262 checks UTF-8 strings for validity by default. There is an option to suppress
263 this, just in case anybody wants that teeny extra bit of performance.
266 Releases 4.1 - 4.3
267 ------------------
269 Sorry, I forgot about updating the NEWS file for these releases. Please take a
270 look at ChangeLog.
273 Release 4.0 17-Feb-03
274 ---------------------
276 There have been a lot of changes for the 4.0 release, adding additional
277 functionality and mending bugs. Below is a list of the highlights of the new
278 functionality. For full details of these features, please consult the
279 documentation. For a complete list of changes, see the ChangeLog file.
281 1. Support for Perl's \Q...\E escapes.
283 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
284 package. They provide some syntactic sugar for simple cases of "atomic
285 grouping".
287 3. Support for the \G assertion. It is true when the current matching position
288 is at the start point of the match.
290 4. A new feature that provides some of the functionality that Perl provides
291 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
292 is for the caller to provide an optional function, by setting pcre_callout to
293 its entry point. To get the function called, the regex must include (?C) at
294 appropriate points.
296 5. Support for recursive calls to individual subpatterns. This makes it really
297 easy to get totally confused.
299 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
300 name a group.
302 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
303 option for pcregrep to make it operate in UTF-8 mode.
305 8. The single man page has been split into a number of separate man pages.
306 These also give rise to individual HTML pages which are put in a separate
307 directory. There is an index.html page that lists them all. Some hyperlinking
308 between the pages has been installed.
311 Release 3.5 15-Aug-01
312 ---------------------
314 1. The configuring system has been upgraded to use later versions of autoconf
315 and libtool. By default it builds both a shared and a static library if the OS
316 supports it. You can use --disable-shared or --disable-static on the configure
317 command if you want only one of them.
319 2. The pcretest utility is now installed along with pcregrep because it is
320 useful for users (to test regexs) and by doing this, it automatically gets
321 relinked by libtool. The documentation has been turned into a man page, so
322 there are now .1, .txt, and .html versions in /doc.
324 3. Upgrades to pcregrep:
325 (i) Added long-form option names like gnu grep.
326 (ii) Added --help to list all options with an explanatory phrase.
327 (iii) Added -r, --recursive to recurse into sub-directories.
328 (iv) Added -f, --file to read patterns from a file.
330 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
331 script, to force use of CR or LF instead of \n in the source. On non-Unix
332 systems, the value can be set in config.h.
334 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
335 absolute limit. Changed the text of the error message to make this clear, and
336 likewise updated the man page.
338 6. The limit of 99 on the number of capturing subpatterns has been removed.
339 The new limit is 65535, which I hope will not be a "real" limit.
342 Release 3.3 01-Aug-00
343 ---------------------
345 There is some support for UTF-8 character strings. This is incomplete and
346 experimental. The documentation describes what is and what is not implemented.
347 Otherwise, this is just a bug-fixing release.
350 Release 3.0 01-Feb-00
351 ---------------------
353 1. A "configure" script is now used to configure PCRE for Unix systems. It
354 builds a Makefile, a config.h file, and the pcre-config script.
356 2. PCRE is built as a shared library by default.
358 3. There is support for POSIX classes such as [:alpha:].
360 5. There is an experimental recursion feature.
362 ----------------------------------------------------------------------------
365 Please note that there has been a change in the API such that a larger
366 ovector is required at matching time, to provide some additional workspace.
367 The new man page has details. This change was necessary in order to support
368 some of the new functionality in Perl 5.005.
372 Another (I hope this is the last!) change has been made to the API for the
373 pcre_compile() function. An additional argument has been added to make it
374 possible to pass over a pointer to character tables built in the current
375 locale by pcre_maketables(). To use the default tables, this new arguement
376 should be passed as NULL.
380 Yet another (and again I hope this really is the last) change has been made
381 to the API for the pcre_exec() function. An additional argument has been
382 added to make it possible to start the match other than at the start of the
383 subject string. This is important if there are lookbehinds. The new man
384 page has the details, but you just want to convert existing programs, all
385 you need to do is to stick in a new fifth argument to pcre_exec(), with a
386 value of zero. For example, change
388 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
389 to
390 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
392 ****


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