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Revision 489 - (hide annotations) (download)
Tue Jan 19 16:42:21 2010 UTC (5 years, 2 months ago) by ph10
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File tidies and documentation update for 8.01.

1 nigel 41 News about PCRE releases
2     ------------------------
4 ph10 489 Release 8.01 19-Jan-2010
5     ------------------------
7     This is a bug-fix release. Several bugs in the code itself and some bugs and
8     infelicities in the build system have been fixed.
11 ph10 469 Release 8.00 19-Oct-09
12 ph10 461 ----------------------
14     Bugs have been fixed in the library and in pcregrep. There are also some
15     enhancements. Restrictions on patterns used for partial matching have been
16     removed, extra information is given for partial matches, the partial matching
17     process has been improved, and an option to make a partial match override a
18     full match is available. The "study" process has been enhanced by finding a
19     lower bound matching length. Groups with duplicate numbers may now have
20     duplicated names without the use of PCRE_DUPNAMES. However, they may not have
21     different names. The documentation has been revised to reflect these changes.
22     The version number has been expanded to 3 digits as it is clear that the rate
23     of change is not slowing down.
26 ph10 415 Release 7.9 11-Apr-09
27 ph10 411 ---------------------
28 ph10 345
29 ph10 411 Mostly bugfixes and tidies with just a couple of minor functional additions.
32 ph10 374 Release 7.8 05-Sep-08
33 ph10 371 ---------------------
35     More bug fixes, plus a performance improvement in Unicode character property
36     lookup.
39 ph10 347 Release 7.7 07-May-08
40 ph10 345 ---------------------
42     This is once again mainly a bug-fix release, but there are a couple of new
43     features.
46 ph10 319 Release 7.6 28-Jan-08
47 ph10 309 ---------------------
49     The main reason for having this release so soon after 7.5 is because it fixes a
50     potential buffer overflow problem in pcre_compile() when run in UTF-8 mode. In
51     addition, the CMake configuration files have been brought up to date.
54 ph10 298 Release 7.5 10-Jan-08
55 ph10 289 ---------------------
56 ph10 122
57 ph10 289 This is mainly a bug-fix release. However the ability to link pcregrep with
58     libz or libbz2 and the ability to link pcretest with libreadline have been
59     added. Also the --line-offsets and --file-offsets options were added to
60     pcregrep.
63 ph10 260 Release 7.4 21-Sep-07
64 ph10 242 ---------------------
66 ph10 243 The only change of specification is the addition of options to control whether
67 ph10 242 \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
68 ph10 243 Otherwise, the changes are bug fixes and a refactoring to reduce the number of
69 ph10 261 relocations needed in a shared library. There have also been some documentation
70     updates, in particular, some more information about using CMake to build PCRE
71     has been added to the NON-UNIX-USE file.
72 ph10 242
74 ph10 228 Release 7.3 28-Aug-07
75 ph10 212 ---------------------
77     Most changes are bug fixes. Some that are not:
79     1. There is some support for Perl 5.10's experimental "backtracking control
80     verbs" such as (*PRUNE).
82     2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
83     restrictive in the strings it accepts.
85     3. Checking for potential integer overflow has been made more dynamic, and as a
86     consequence there is no longer a hard limit on the size of a subpattern that
87     has a limited repeat count.
88 ph10 227
89     4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
90     no longer advance by two characters instead of one when an unanchored match
91     fails at CRLF if there are explicit CR or LF matches within the pattern.
92 ph10 226 This gets rid of some anomalous effects that previously occurred.
93 ph10 212
94 ph10 227 5. Some PCRE-specific settings for varying the newline options at the start of
95     a pattern have been added.
96 ph10 212
97 ph10 227
98 ph10 184 Release 7.2 19-Jun-07
99 ph10 157 ---------------------
101 ph10 172 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
102 ph10 181 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
103     and \V).
104 ph10 168
105 ph10 159 Correction to the notes for 7.1: the note about shared libraries for Windows is
106     wrong. Previously, three libraries were built, but each could function
107     independently. For example, the pcreposix library also included all the
108     functions from the basic pcre library. The change is that the three libraries
109     are no longer independent. They are like the Unix libraries. To use the
110     pcreposix functions, for example, you need to link with both the pcreposix and
111 ph10 157 the basic pcre library.
113 ph10 166 Some more features from Perl 5.10 have been added:
114 ph10 157
115 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
116 ph10 172
117     (?(-n) and (?(+n) relative references as conditions.
118 ph10 182
119 ph10 181 \k{name} and \g{name} are synonyms for \k<name>.
120 ph10 172
121 ph10 168 \K to reset the start of the matched string; for example, (foo)\Kbar
122 ph10 175 matches bar preceded by foo, but only sets bar as the matched string.
123 ph10 182
124     (?| introduces a group where the capturing parentheses in each alternative
125     start from the same number; for example, (?|(abc)|(xyz)) sets capturing
126 ph10 175 parentheses number 1 in both cases.
127 ph10 166
128 ph10 182 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
129 ph10 166
130 ph10 182
131 ph10 155 Release 7.1 24-Apr-07
132 nigel 93 ---------------------
134 ph10 155 There is only one new feature in this release: a linebreak setting of
135     PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
136     recognizes only CRLF, CR, and LF as linebreaks.
137 ph10 122
138 ph10 155 A few bugs are fixed (see ChangeLog for details), but the major change is a
139     complete re-implementation of the build system. This now has full Autotools
140     support and so is now "standard" in some sense. It should help with compiling
141     PCRE in a wide variety of environments.
143 ph10 146 NOTE: when building shared libraries for Windows, three dlls are now built,
144     called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
145     included in a single dll.
147     Another important change is that the dftables auxiliary program is no longer
148 ph10 128 compiled and run at "make" time by default. Instead, a default set of character
149     tables (assuming ASCII coding) is used. If you want to use dftables to generate
150     the character tables as previously, add --enable-rebuild-chartables to the
151     "configure" command. You must do this if you are compiling PCRE to run on a
152     system that uses EBCDIC code.
153 ph10 122
154 ph10 128 There is a discussion about character tables in the README file. The default is
155     not to use dftables so that that there is no problem when cross-compiling.
158 ph10 122 Release 7.0 19-Dec-06
159     ---------------------
161 nigel 93 This release has a new major number because there have been some internal
162     upheavals to facilitate the addition of new optimizations and other facilities,
163     and to make subsequent maintenance and extension easier. Compilation is likely
164     to be a bit slower, but there should be no major effect on runtime performance.
165     Previously compiled patterns are NOT upwards compatible with this release. If
166     you have saved compiled patterns from a previous release, you will have to
167     re-compile them. Important changes that are visible to users are:
169     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
170     some more scripts.
172     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
173     sequence as a newline.
175     3. The \R escape matches a single Unicode newline sequence as a single unit.
177     4. New features that will appear in Perl 5.10 are now in PCRE. These include
178     alternative Perl syntax for named parentheses, and Perl syntax for
179     recursion.
181     5. The C++ wrapper interface has been extended by the addition of a
182     QuoteMeta function and the ability to allow copy construction and
183     assignment.
185     For a complete list of changes, see the ChangeLog file.
188 nigel 91 Release 6.7 04-Jul-06
189     ---------------------
191     The main additions to this release are the ability to use the same name for
192     multiple sets of parentheses, and support for CRLF line endings in both the
193     library and pcregrep (and in pcretest for testing).
195     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
196     significantly reduced for certain subject strings.
199 nigel 87 Release 6.5 01-Feb-06
200     ---------------------
202     Important changes in this release:
204     1. A number of new features have been added to pcregrep.
206     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
207     supported properties have been extended with script names such as "Arabic",
208     and the derived properties "Any" and "L&". This has necessitated a change to
209     the interal format of compiled patterns. Any saved compiled patterns that
210     use \p or \P must be recompiled.
212     3. The specification of recursion in patterns has been changed so that all
213     recursive subpatterns are automatically treated as atomic groups. Thus, for
214     example, (?R) is treated as if it were (?>(?R)). This is necessary because
215     otherwise there are situations where recursion does not work.
217     See the ChangeLog for a complete list of changes, which include a number of bug
218     fixes and tidies.
221 nigel 77 Release 6.0 07-Jun-05
222     ---------------------
224     The release number has been increased to 6.0 because of the addition of several
225     major new pieces of functionality.
227     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
228     algorithm, has been added. This has a number of advantages for certain cases,
229     though it does run more slowly, and lacks the ability to capture substrings. On
230     the other hand, it does find all matches, not just the first, and it works
231     better for partial matching. The pcrematching man page discusses the
232     differences.
234     The pcretest program has been enhanced so that it can make use of the new
235     pcre_dfa_exec() matching function and the extra features it provides.
237     The distribution now includes a C++ wrapper library. This is built
238     automatically if a C++ compiler is found. The pcrecpp man page discusses this
239     interface.
241     The code itself has been re-organized into many more files, one for each
242     function, so it no longer requires everything to be linked in when static
243     linkage is used. As a consequence, some internal functions have had to have
244     their names exposed. These functions all have names starting with _pcre_. They
245     are undocumented, and are not intended for use by outside callers.
247     The pcregrep program has been enhanced with new functionality such as
248     multiline-matching and options for output more matching context. See the
249     ChangeLog for a complete list of changes to the library and the utility
250     programs.
253 nigel 75 Release 5.0 13-Sep-04
254     ---------------------
256     The licence under which PCRE is released has been changed to the more
257     conventional "BSD" licence.
259     In the code, some bugs have been fixed, and there are also some major changes
260     in this release (which is why I've increased the number to 5.0). Some changes
261     are internal rearrangements, and some provide a number of new facilities. The
262     new features are:
264     1. There's an "automatic callout" feature that inserts callouts before every
265     item in the regex, and there's a new callout field that gives the position
266     in the pattern - useful for debugging and tracing.
268     2. The extra_data structure can now be used to pass in a set of character
269     tables at exec time. This is useful if compiled regex are saved and re-used
270     at a later time when the tables may not be at the same address. If the
271     default internal tables are used, the pointer saved with the compiled
272     pattern is now set to NULL, which means that you don't need to do anything
273     special unless you are using custom tables.
275     3. It is possible, with some restrictions on the content of the regex, to
276     request "partial" matching. A special return code is given if all of the
277     subject string matched part of the regex. This could be useful for testing
278     an input field as it is being typed.
280     4. There is now some optional support for Unicode character properties, which
281     means that the patterns items such as \p{Lu} and \X can now be used. Only
282     the general category properties are supported. If PCRE is compiled with this
283     support, an additional 90K data structure is include, which increases the
284     size of the library dramatically.
286     5. There is support for saving compiled patterns and re-using them later.
288     6. There is support for running regular expressions that were compiled on a
289     different host with the opposite endianness.
291     7. The pcretest program has been extended to accommodate the new features.
293     The main internal rearrangement is that sequences of literal characters are no
294     longer handled as strings. Instead, each character is handled on its own. This
295     makes some UTF-8 handling easier, and makes the support of partial matching
296     possible. Compiled patterns containing long literal strings will be larger as a
297     result of this change; I hope that performance will not be much affected.
300 nigel 73 Release 4.5 01-Dec-03
301     ---------------------
303     Again mainly a bug-fix and tidying release, with only a couple of new features:
305     1. It's possible now to compile PCRE so that it does not use recursive
306     function calls when matching. Instead it gets memory from the heap. This slows
307     things down, but may be necessary on systems with limited stacks.
309     2. UTF-8 string checking has been tightened to reject overlong sequences and to
310     check that a starting offset points to the start of a character. Failure of the
311     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
313     3. PCRE can now be compiled for systems that use EBCDIC code.
316 nigel 71 Release 4.4 21-Aug-03
317     ---------------------
319     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
320     checks UTF-8 strings for validity by default. There is an option to suppress
321     this, just in case anybody wants that teeny extra bit of performance.
324     Releases 4.1 - 4.3
325     ------------------
327     Sorry, I forgot about updating the NEWS file for these releases. Please take a
328     look at ChangeLog.
331 nigel 63 Release 4.0 17-Feb-03
332     ---------------------
334     There have been a lot of changes for the 4.0 release, adding additional
335     functionality and mending bugs. Below is a list of the highlights of the new
336     functionality. For full details of these features, please consult the
337     documentation. For a complete list of changes, see the ChangeLog file.
339     1. Support for Perl's \Q...\E escapes.
341     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
342     package. They provide some syntactic sugar for simple cases of "atomic
343     grouping".
345     3. Support for the \G assertion. It is true when the current matching position
346     is at the start point of the match.
348     4. A new feature that provides some of the functionality that Perl provides
349     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
350     is for the caller to provide an optional function, by setting pcre_callout to
351     its entry point. To get the function called, the regex must include (?C) at
352     appropriate points.
354     5. Support for recursive calls to individual subpatterns. This makes it really
355     easy to get totally confused.
357     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
358     name a group.
360     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
361     option for pcregrep to make it operate in UTF-8 mode.
363     8. The single man page has been split into a number of separate man pages.
364     These also give rise to individual HTML pages which are put in a separate
365     directory. There is an index.html page that lists them all. Some hyperlinking
366     between the pages has been installed.
369 nigel 53 Release 3.5 15-Aug-01
370     ---------------------
372     1. The configuring system has been upgraded to use later versions of autoconf
373     and libtool. By default it builds both a shared and a static library if the OS
374     supports it. You can use --disable-shared or --disable-static on the configure
375     command if you want only one of them.
377     2. The pcretest utility is now installed along with pcregrep because it is
378     useful for users (to test regexs) and by doing this, it automatically gets
379     relinked by libtool. The documentation has been turned into a man page, so
380     there are now .1, .txt, and .html versions in /doc.
382     3. Upgrades to pcregrep:
383     (i) Added long-form option names like gnu grep.
384     (ii) Added --help to list all options with an explanatory phrase.
385     (iii) Added -r, --recursive to recurse into sub-directories.
386     (iv) Added -f, --file to read patterns from a file.
388     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
389     script, to force use of CR or LF instead of \n in the source. On non-Unix
390     systems, the value can be set in config.h.
392     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
393     absolute limit. Changed the text of the error message to make this clear, and
394     likewise updated the man page.
396     6. The limit of 99 on the number of capturing subpatterns has been removed.
397     The new limit is 65535, which I hope will not be a "real" limit.
400 nigel 49 Release 3.3 01-Aug-00
401     ---------------------
403     There is some support for UTF-8 character strings. This is incomplete and
404     experimental. The documentation describes what is and what is not implemented.
405     Otherwise, this is just a bug-fixing release.
408 nigel 43 Release 3.0 01-Feb-00
409     ---------------------
410 nigel 41
411 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
412     builds a Makefile, a config.h file, and the pcre-config script.
414     2. PCRE is built as a shared library by default.
416     3. There is support for POSIX classes such as [:alpha:].
418     5. There is an experimental recursion feature.
420 nigel 41 ----------------------------------------------------------------------------
423     Please note that there has been a change in the API such that a larger
424     ovector is required at matching time, to provide some additional workspace.
425     The new man page has details. This change was necessary in order to support
426     some of the new functionality in Perl 5.005.
430     Another (I hope this is the last!) change has been made to the API for the
431     pcre_compile() function. An additional argument has been added to make it
432     possible to pass over a pointer to character tables built in the current
433     locale by pcre_maketables(). To use the default tables, this new arguement
434     should be passed as NULL.
438     Yet another (and again I hope this really is the last) change has been made
439     to the API for the pcre_exec() function. An additional argument has been
440     added to make it possible to start the match other than at the start of the
441     subject string. This is important if there are lookbehinds. The new man
442     page has the details, but you just want to convert existing programs, all
443     you need to do is to stick in a new fifth argument to pcre_exec(), with a
444     value of zero. For example, change
446     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
447     to
448     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
450     ****


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