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Revision 469 - (hide annotations) (download)
Mon Oct 19 14:38:48 2009 UTC (5 years, 6 months ago) by ph10
File size: 18106 byte(s)
Final doc and source tidies for 8.00

1 nigel 41 News about PCRE releases
2     ------------------------
4 ph10 469 Release 8.00 19-Oct-09
5 ph10 461 ----------------------
7     Bugs have been fixed in the library and in pcregrep. There are also some
8     enhancements. Restrictions on patterns used for partial matching have been
9     removed, extra information is given for partial matches, the partial matching
10     process has been improved, and an option to make a partial match override a
11     full match is available. The "study" process has been enhanced by finding a
12     lower bound matching length. Groups with duplicate numbers may now have
13     duplicated names without the use of PCRE_DUPNAMES. However, they may not have
14     different names. The documentation has been revised to reflect these changes.
15     The version number has been expanded to 3 digits as it is clear that the rate
16     of change is not slowing down.
19 ph10 415 Release 7.9 11-Apr-09
20 ph10 411 ---------------------
21 ph10 345
22 ph10 411 Mostly bugfixes and tidies with just a couple of minor functional additions.
25 ph10 374 Release 7.8 05-Sep-08
26 ph10 371 ---------------------
28     More bug fixes, plus a performance improvement in Unicode character property
29     lookup.
32 ph10 347 Release 7.7 07-May-08
33 ph10 345 ---------------------
35     This is once again mainly a bug-fix release, but there are a couple of new
36     features.
39 ph10 319 Release 7.6 28-Jan-08
40 ph10 309 ---------------------
42     The main reason for having this release so soon after 7.5 is because it fixes a
43     potential buffer overflow problem in pcre_compile() when run in UTF-8 mode. In
44     addition, the CMake configuration files have been brought up to date.
47 ph10 298 Release 7.5 10-Jan-08
48 ph10 289 ---------------------
49 ph10 122
50 ph10 289 This is mainly a bug-fix release. However the ability to link pcregrep with
51     libz or libbz2 and the ability to link pcretest with libreadline have been
52     added. Also the --line-offsets and --file-offsets options were added to
53     pcregrep.
56 ph10 260 Release 7.4 21-Sep-07
57 ph10 242 ---------------------
59 ph10 243 The only change of specification is the addition of options to control whether
60 ph10 242 \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
61 ph10 243 Otherwise, the changes are bug fixes and a refactoring to reduce the number of
62 ph10 261 relocations needed in a shared library. There have also been some documentation
63     updates, in particular, some more information about using CMake to build PCRE
64     has been added to the NON-UNIX-USE file.
65 ph10 242
67 ph10 228 Release 7.3 28-Aug-07
68 ph10 212 ---------------------
70     Most changes are bug fixes. Some that are not:
72     1. There is some support for Perl 5.10's experimental "backtracking control
73     verbs" such as (*PRUNE).
75     2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
76     restrictive in the strings it accepts.
78     3. Checking for potential integer overflow has been made more dynamic, and as a
79     consequence there is no longer a hard limit on the size of a subpattern that
80     has a limited repeat count.
81 ph10 227
82     4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
83     no longer advance by two characters instead of one when an unanchored match
84     fails at CRLF if there are explicit CR or LF matches within the pattern.
85 ph10 226 This gets rid of some anomalous effects that previously occurred.
86 ph10 212
87 ph10 227 5. Some PCRE-specific settings for varying the newline options at the start of
88     a pattern have been added.
89 ph10 212
90 ph10 227
91 ph10 184 Release 7.2 19-Jun-07
92 ph10 157 ---------------------
94 ph10 172 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
95 ph10 181 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
96     and \V).
97 ph10 168
98 ph10 159 Correction to the notes for 7.1: the note about shared libraries for Windows is
99     wrong. Previously, three libraries were built, but each could function
100     independently. For example, the pcreposix library also included all the
101     functions from the basic pcre library. The change is that the three libraries
102     are no longer independent. They are like the Unix libraries. To use the
103     pcreposix functions, for example, you need to link with both the pcreposix and
104 ph10 157 the basic pcre library.
106 ph10 166 Some more features from Perl 5.10 have been added:
107 ph10 157
108 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
109 ph10 172
110     (?(-n) and (?(+n) relative references as conditions.
111 ph10 182
112 ph10 181 \k{name} and \g{name} are synonyms for \k<name>.
113 ph10 172
114 ph10 168 \K to reset the start of the matched string; for example, (foo)\Kbar
115 ph10 175 matches bar preceded by foo, but only sets bar as the matched string.
116 ph10 182
117     (?| introduces a group where the capturing parentheses in each alternative
118     start from the same number; for example, (?|(abc)|(xyz)) sets capturing
119 ph10 175 parentheses number 1 in both cases.
120 ph10 166
121 ph10 182 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
122 ph10 166
123 ph10 182
124 ph10 155 Release 7.1 24-Apr-07
125 nigel 93 ---------------------
127 ph10 155 There is only one new feature in this release: a linebreak setting of
128     PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
129     recognizes only CRLF, CR, and LF as linebreaks.
130 ph10 122
131 ph10 155 A few bugs are fixed (see ChangeLog for details), but the major change is a
132     complete re-implementation of the build system. This now has full Autotools
133     support and so is now "standard" in some sense. It should help with compiling
134     PCRE in a wide variety of environments.
136 ph10 146 NOTE: when building shared libraries for Windows, three dlls are now built,
137     called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
138     included in a single dll.
140     Another important change is that the dftables auxiliary program is no longer
141 ph10 128 compiled and run at "make" time by default. Instead, a default set of character
142     tables (assuming ASCII coding) is used. If you want to use dftables to generate
143     the character tables as previously, add --enable-rebuild-chartables to the
144     "configure" command. You must do this if you are compiling PCRE to run on a
145     system that uses EBCDIC code.
146 ph10 122
147 ph10 128 There is a discussion about character tables in the README file. The default is
148     not to use dftables so that that there is no problem when cross-compiling.
151 ph10 122 Release 7.0 19-Dec-06
152     ---------------------
154 nigel 93 This release has a new major number because there have been some internal
155     upheavals to facilitate the addition of new optimizations and other facilities,
156     and to make subsequent maintenance and extension easier. Compilation is likely
157     to be a bit slower, but there should be no major effect on runtime performance.
158     Previously compiled patterns are NOT upwards compatible with this release. If
159     you have saved compiled patterns from a previous release, you will have to
160     re-compile them. Important changes that are visible to users are:
162     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
163     some more scripts.
165     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
166     sequence as a newline.
168     3. The \R escape matches a single Unicode newline sequence as a single unit.
170     4. New features that will appear in Perl 5.10 are now in PCRE. These include
171     alternative Perl syntax for named parentheses, and Perl syntax for
172     recursion.
174     5. The C++ wrapper interface has been extended by the addition of a
175     QuoteMeta function and the ability to allow copy construction and
176     assignment.
178     For a complete list of changes, see the ChangeLog file.
181 nigel 91 Release 6.7 04-Jul-06
182     ---------------------
184     The main additions to this release are the ability to use the same name for
185     multiple sets of parentheses, and support for CRLF line endings in both the
186     library and pcregrep (and in pcretest for testing).
188     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
189     significantly reduced for certain subject strings.
192 nigel 87 Release 6.5 01-Feb-06
193     ---------------------
195     Important changes in this release:
197     1. A number of new features have been added to pcregrep.
199     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
200     supported properties have been extended with script names such as "Arabic",
201     and the derived properties "Any" and "L&". This has necessitated a change to
202     the interal format of compiled patterns. Any saved compiled patterns that
203     use \p or \P must be recompiled.
205     3. The specification of recursion in patterns has been changed so that all
206     recursive subpatterns are automatically treated as atomic groups. Thus, for
207     example, (?R) is treated as if it were (?>(?R)). This is necessary because
208     otherwise there are situations where recursion does not work.
210     See the ChangeLog for a complete list of changes, which include a number of bug
211     fixes and tidies.
214 nigel 77 Release 6.0 07-Jun-05
215     ---------------------
217     The release number has been increased to 6.0 because of the addition of several
218     major new pieces of functionality.
220     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
221     algorithm, has been added. This has a number of advantages for certain cases,
222     though it does run more slowly, and lacks the ability to capture substrings. On
223     the other hand, it does find all matches, not just the first, and it works
224     better for partial matching. The pcrematching man page discusses the
225     differences.
227     The pcretest program has been enhanced so that it can make use of the new
228     pcre_dfa_exec() matching function and the extra features it provides.
230     The distribution now includes a C++ wrapper library. This is built
231     automatically if a C++ compiler is found. The pcrecpp man page discusses this
232     interface.
234     The code itself has been re-organized into many more files, one for each
235     function, so it no longer requires everything to be linked in when static
236     linkage is used. As a consequence, some internal functions have had to have
237     their names exposed. These functions all have names starting with _pcre_. They
238     are undocumented, and are not intended for use by outside callers.
240     The pcregrep program has been enhanced with new functionality such as
241     multiline-matching and options for output more matching context. See the
242     ChangeLog for a complete list of changes to the library and the utility
243     programs.
246 nigel 75 Release 5.0 13-Sep-04
247     ---------------------
249     The licence under which PCRE is released has been changed to the more
250     conventional "BSD" licence.
252     In the code, some bugs have been fixed, and there are also some major changes
253     in this release (which is why I've increased the number to 5.0). Some changes
254     are internal rearrangements, and some provide a number of new facilities. The
255     new features are:
257     1. There's an "automatic callout" feature that inserts callouts before every
258     item in the regex, and there's a new callout field that gives the position
259     in the pattern - useful for debugging and tracing.
261     2. The extra_data structure can now be used to pass in a set of character
262     tables at exec time. This is useful if compiled regex are saved and re-used
263     at a later time when the tables may not be at the same address. If the
264     default internal tables are used, the pointer saved with the compiled
265     pattern is now set to NULL, which means that you don't need to do anything
266     special unless you are using custom tables.
268     3. It is possible, with some restrictions on the content of the regex, to
269     request "partial" matching. A special return code is given if all of the
270     subject string matched part of the regex. This could be useful for testing
271     an input field as it is being typed.
273     4. There is now some optional support for Unicode character properties, which
274     means that the patterns items such as \p{Lu} and \X can now be used. Only
275     the general category properties are supported. If PCRE is compiled with this
276     support, an additional 90K data structure is include, which increases the
277     size of the library dramatically.
279     5. There is support for saving compiled patterns and re-using them later.
281     6. There is support for running regular expressions that were compiled on a
282     different host with the opposite endianness.
284     7. The pcretest program has been extended to accommodate the new features.
286     The main internal rearrangement is that sequences of literal characters are no
287     longer handled as strings. Instead, each character is handled on its own. This
288     makes some UTF-8 handling easier, and makes the support of partial matching
289     possible. Compiled patterns containing long literal strings will be larger as a
290     result of this change; I hope that performance will not be much affected.
293 nigel 73 Release 4.5 01-Dec-03
294     ---------------------
296     Again mainly a bug-fix and tidying release, with only a couple of new features:
298     1. It's possible now to compile PCRE so that it does not use recursive
299     function calls when matching. Instead it gets memory from the heap. This slows
300     things down, but may be necessary on systems with limited stacks.
302     2. UTF-8 string checking has been tightened to reject overlong sequences and to
303     check that a starting offset points to the start of a character. Failure of the
304     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
306     3. PCRE can now be compiled for systems that use EBCDIC code.
309 nigel 71 Release 4.4 21-Aug-03
310     ---------------------
312     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
313     checks UTF-8 strings for validity by default. There is an option to suppress
314     this, just in case anybody wants that teeny extra bit of performance.
317     Releases 4.1 - 4.3
318     ------------------
320     Sorry, I forgot about updating the NEWS file for these releases. Please take a
321     look at ChangeLog.
324 nigel 63 Release 4.0 17-Feb-03
325     ---------------------
327     There have been a lot of changes for the 4.0 release, adding additional
328     functionality and mending bugs. Below is a list of the highlights of the new
329     functionality. For full details of these features, please consult the
330     documentation. For a complete list of changes, see the ChangeLog file.
332     1. Support for Perl's \Q...\E escapes.
334     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
335     package. They provide some syntactic sugar for simple cases of "atomic
336     grouping".
338     3. Support for the \G assertion. It is true when the current matching position
339     is at the start point of the match.
341     4. A new feature that provides some of the functionality that Perl provides
342     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
343     is for the caller to provide an optional function, by setting pcre_callout to
344     its entry point. To get the function called, the regex must include (?C) at
345     appropriate points.
347     5. Support for recursive calls to individual subpatterns. This makes it really
348     easy to get totally confused.
350     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
351     name a group.
353     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
354     option for pcregrep to make it operate in UTF-8 mode.
356     8. The single man page has been split into a number of separate man pages.
357     These also give rise to individual HTML pages which are put in a separate
358     directory. There is an index.html page that lists them all. Some hyperlinking
359     between the pages has been installed.
362 nigel 53 Release 3.5 15-Aug-01
363     ---------------------
365     1. The configuring system has been upgraded to use later versions of autoconf
366     and libtool. By default it builds both a shared and a static library if the OS
367     supports it. You can use --disable-shared or --disable-static on the configure
368     command if you want only one of them.
370     2. The pcretest utility is now installed along with pcregrep because it is
371     useful for users (to test regexs) and by doing this, it automatically gets
372     relinked by libtool. The documentation has been turned into a man page, so
373     there are now .1, .txt, and .html versions in /doc.
375     3. Upgrades to pcregrep:
376     (i) Added long-form option names like gnu grep.
377     (ii) Added --help to list all options with an explanatory phrase.
378     (iii) Added -r, --recursive to recurse into sub-directories.
379     (iv) Added -f, --file to read patterns from a file.
381     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
382     script, to force use of CR or LF instead of \n in the source. On non-Unix
383     systems, the value can be set in config.h.
385     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
386     absolute limit. Changed the text of the error message to make this clear, and
387     likewise updated the man page.
389     6. The limit of 99 on the number of capturing subpatterns has been removed.
390     The new limit is 65535, which I hope will not be a "real" limit.
393 nigel 49 Release 3.3 01-Aug-00
394     ---------------------
396     There is some support for UTF-8 character strings. This is incomplete and
397     experimental. The documentation describes what is and what is not implemented.
398     Otherwise, this is just a bug-fixing release.
401 nigel 43 Release 3.0 01-Feb-00
402     ---------------------
403 nigel 41
404 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
405     builds a Makefile, a config.h file, and the pcre-config script.
407     2. PCRE is built as a shared library by default.
409     3. There is support for POSIX classes such as [:alpha:].
411     5. There is an experimental recursion feature.
413 nigel 41 ----------------------------------------------------------------------------
416     Please note that there has been a change in the API such that a larger
417     ovector is required at matching time, to provide some additional workspace.
418     The new man page has details. This change was necessary in order to support
419     some of the new functionality in Perl 5.005.
423     Another (I hope this is the last!) change has been made to the API for the
424     pcre_compile() function. An additional argument has been added to make it
425     possible to pass over a pointer to character tables built in the current
426     locale by pcre_maketables(). To use the default tables, this new arguement
427     should be passed as NULL.
431     Yet another (and again I hope this really is the last) change has been made
432     to the API for the pcre_exec() function. An additional argument has been
433     added to make it possible to start the match other than at the start of the
434     subject string. This is important if there are lookbehinds. The new man
435     page has the details, but you just want to convert existing programs, all
436     you need to do is to stick in a new fifth argument to pcre_exec(), with a
437     value of zero. For example, change
439     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
440     to
441     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
443     ****


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