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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    Release 8.00 19-Oct-09
5    ----------------------
6    
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.
17    
18    
19    Release 7.9 11-Apr-09
20    ---------------------
21    
22    Mostly bugfixes and tidies with just a couple of minor functional additions.
23    
24    
25    Release 7.8 05-Sep-08
26    ---------------------
27    
28    More bug fixes, plus a performance improvement in Unicode character property
29    lookup.
30    
31    
32    Release 7.7 07-May-08
33    ---------------------
34    
35    This is once again mainly a bug-fix release, but there are a couple of new
36    features.
37    
38    
39    Release 7.6 28-Jan-08
40    ---------------------
41    
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.
45    
46    
47    Release 7.5 10-Jan-08
48    ---------------------
49    
50    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.
54    
55    
56    Release 7.4 21-Sep-07
57    ---------------------
58    
59    The only change of specification is the addition of options to control whether
60    \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
61    Otherwise, the changes are bug fixes and a refactoring to reduce the number of
62    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    
66    
67    Release 7.3 28-Aug-07
68    ---------------------
69    
70    Most changes are bug fixes. Some that are not:
71    
72    1. There is some support for Perl 5.10's experimental "backtracking control
73       verbs" such as (*PRUNE).
74    
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.
77    
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    
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       This gets rid of some anomalous effects that previously occurred.
86    
87    5. Some PCRE-specific settings for varying the newline options at the start of
88       a pattern have been added.
89    
90    
91    Release 7.2 19-Jun-07
92    ---------------------
93    
94    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
95    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
96    and \V).
97    
98    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    the basic pcre library.
105    
106    Some more features from Perl 5.10 have been added:
107    
108      (?-n) and (?+n) relative references for recursion and subroutines.
109    
110      (?(-n) and (?(+n) relative references as conditions.
111    
112      \k{name} and \g{name} are synonyms for \k<name>.
113    
114      \K to reset the start of the matched string; for example, (foo)\Kbar
115      matches bar preceded by foo, but only sets bar as the matched string.
116    
117      (?| introduces a group where the capturing parentheses in each alternative
118      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
119      parentheses number 1 in both cases.
120    
121      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
122    
123    
124    Release 7.1 24-Apr-07
125    ---------------------
126    
127    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    
131    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.
135    
136    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.
139    
140    Another important change is that the dftables auxiliary program is no longer
141    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    
147    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.
149    
150    
151    Release 7.0 19-Dec-06
152    ---------------------
153    
154    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:
161    
162    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
163       some more scripts.
164    
165    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
166       sequence as a newline.
167    
168    3. The \R escape matches a single Unicode newline sequence as a single unit.
169    
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.
173    
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.
177    
178    For a complete list of changes, see the ChangeLog file.
179    
180    
181    Release 6.7 04-Jul-06
182    ---------------------
183    
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).
187    
188    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
189    significantly reduced for certain subject strings.
190    
191    
192    Release 6.5 01-Feb-06
193    ---------------------
194    
195    Important changes in this release:
196    
197    1. A number of new features have been added to pcregrep.
198    
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.
204    
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.
209    
210    See the ChangeLog for a complete list of changes, which include a number of bug
211    fixes and tidies.
212    
213    
214    Release 6.0 07-Jun-05
215    ---------------------
216    
217    The release number has been increased to 6.0 because of the addition of several
218    major new pieces of functionality.
219    
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.
226    
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.
229    
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.
233    
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.
239    
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.
244    
245    
246    Release 5.0 13-Sep-04
247    ---------------------
248    
249    The licence under which PCRE is released has been changed to the more
250    conventional "BSD" licence.
251    
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:
256    
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.
260    
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.
267    
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.
272    
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.
278    
279    5. There is support for saving compiled patterns and re-using them later.
280    
281    6. There is support for running regular expressions that were compiled on a
282       different host with the opposite endianness.
283    
284    7. The pcretest program has been extended to accommodate the new features.
285    
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.
291    
292    
293    Release 4.5 01-Dec-03
294    ---------------------
295    
296    Again mainly a bug-fix and tidying release, with only a couple of new features:
297    
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.
301    
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.
305    
306    3. PCRE can now be compiled for systems that use EBCDIC code.
307    
308    
309    Release 4.4 21-Aug-03
310    ---------------------
311    
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.
315    
316    
317    Releases 4.1 - 4.3
318    ------------------
319    
320    Sorry, I forgot about updating the NEWS file for these releases. Please take a
321    look at ChangeLog.
322    
323    
324    Release 4.0 17-Feb-03
325    ---------------------
326    
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.
331    
332    1. Support for Perl's \Q...\E escapes.
333    
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".
337    
338    3. Support for the \G assertion. It is true when the current matching position
339    is at the start point of the match.
340    
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.
346    
347    5. Support for recursive calls to individual subpatterns. This makes it really
348    easy to get totally confused.
349    
350    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
351    name a group.
352    
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.
355    
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.
360    
361    
362    Release 3.5 15-Aug-01
363    ---------------------
364    
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.
369    
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.
374    
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.
380    
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.
384    
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.
388    
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.
391    
392    
393    Release 3.3 01-Aug-00
394    ---------------------
395    
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.
399    
400    
401  Release 3.0 01-Feb-00  Release 3.0 01-Feb-00
402  ---------------------  ---------------------
403    

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