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revision 49 by nigel, Sat Feb 24 21:39:33 2007 UTC revision 374 by ph10, Fri Sep 5 16:42:28 2008 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
5    Release 7.8 05-Sep-08
6    ---------------------
8    More bug fixes, plus a performance improvement in Unicode character property
9    lookup.
12    Release 7.7 07-May-08
13    ---------------------
15    This is once again mainly a bug-fix release, but there are a couple of new
16    features.
19    Release 7.6 28-Jan-08
20    ---------------------
22    The main reason for having this release so soon after 7.5 is because it fixes a
23    potential buffer overflow problem in pcre_compile() when run in UTF-8 mode. In
24    addition, the CMake configuration files have been brought up to date.
27    Release 7.5 10-Jan-08
28    ---------------------
30    This is mainly a bug-fix release. However the ability to link pcregrep with
31    libz or libbz2 and the ability to link pcretest with libreadline have been
32    added. Also the --line-offsets and --file-offsets options were added to
33    pcregrep.
36    Release 7.4 21-Sep-07
37    ---------------------
39    The only change of specification is the addition of options to control whether
40    \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
41    Otherwise, the changes are bug fixes and a refactoring to reduce the number of
42    relocations needed in a shared library. There have also been some documentation
43    updates, in particular, some more information about using CMake to build PCRE
44    has been added to the NON-UNIX-USE file.
47    Release 7.3 28-Aug-07
48    ---------------------
50    Most changes are bug fixes. Some that are not:
52    1. There is some support for Perl 5.10's experimental "backtracking control
53       verbs" such as (*PRUNE).
55    2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
56       restrictive in the strings it accepts.
58    3. Checking for potential integer overflow has been made more dynamic, and as a
59       consequence there is no longer a hard limit on the size of a subpattern that
60       has a limited repeat count.
62    4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
63       no longer advance by two characters instead of one when an unanchored match
64       fails at CRLF if there are explicit CR or LF matches within the pattern.
65       This gets rid of some anomalous effects that previously occurred.
67    5. Some PCRE-specific settings for varying the newline options at the start of
68       a pattern have been added.
71    Release 7.2 19-Jun-07
72    ---------------------
74    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
75    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
76    and \V).
78    Correction to the notes for 7.1: the note about shared libraries for Windows is
79    wrong. Previously, three libraries were built, but each could function
80    independently. For example, the pcreposix library also included all the
81    functions from the basic pcre library. The change is that the three libraries
82    are no longer independent. They are like the Unix libraries. To use the
83    pcreposix functions, for example, you need to link with both the pcreposix and
84    the basic pcre library.
86    Some more features from Perl 5.10 have been added:
88      (?-n) and (?+n) relative references for recursion and subroutines.
90      (?(-n) and (?(+n) relative references as conditions.
92      \k{name} and \g{name} are synonyms for \k<name>.
94      \K to reset the start of the matched string; for example, (foo)\Kbar
95      matches bar preceded by foo, but only sets bar as the matched string.
97      (?| introduces a group where the capturing parentheses in each alternative
98      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
99      parentheses number 1 in both cases.
101      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
104    Release 7.1 24-Apr-07
105    ---------------------
107    There is only one new feature in this release: a linebreak setting of
108    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
109    recognizes only CRLF, CR, and LF as linebreaks.
111    A few bugs are fixed (see ChangeLog for details), but the major change is a
112    complete re-implementation of the build system. This now has full Autotools
113    support and so is now "standard" in some sense. It should help with compiling
114    PCRE in a wide variety of environments.
116    NOTE: when building shared libraries for Windows, three dlls are now built,
117    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
118    included in a single dll.
120    Another important change is that the dftables auxiliary program is no longer
121    compiled and run at "make" time by default. Instead, a default set of character
122    tables (assuming ASCII coding) is used. If you want to use dftables to generate
123    the character tables as previously, add --enable-rebuild-chartables to the
124    "configure" command. You must do this if you are compiling PCRE to run on a
125    system that uses EBCDIC code.
127    There is a discussion about character tables in the README file. The default is
128    not to use dftables so that that there is no problem when cross-compiling.
131    Release 7.0 19-Dec-06
132    ---------------------
134    This release has a new major number because there have been some internal
135    upheavals to facilitate the addition of new optimizations and other facilities,
136    and to make subsequent maintenance and extension easier. Compilation is likely
137    to be a bit slower, but there should be no major effect on runtime performance.
138    Previously compiled patterns are NOT upwards compatible with this release. If
139    you have saved compiled patterns from a previous release, you will have to
140    re-compile them. Important changes that are visible to users are:
142    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
143       some more scripts.
145    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
146       sequence as a newline.
148    3. The \R escape matches a single Unicode newline sequence as a single unit.
150    4. New features that will appear in Perl 5.10 are now in PCRE. These include
151       alternative Perl syntax for named parentheses, and Perl syntax for
152       recursion.
154    5. The C++ wrapper interface has been extended by the addition of a
155       QuoteMeta function and the ability to allow copy construction and
156       assignment.
158    For a complete list of changes, see the ChangeLog file.
161    Release 6.7 04-Jul-06
162    ---------------------
164    The main additions to this release are the ability to use the same name for
165    multiple sets of parentheses, and support for CRLF line endings in both the
166    library and pcregrep (and in pcretest for testing).
168    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
169    significantly reduced for certain subject strings.
172    Release 6.5 01-Feb-06
173    ---------------------
175    Important changes in this release:
177    1. A number of new features have been added to pcregrep.
179    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
180       supported properties have been extended with script names such as "Arabic",
181       and the derived properties "Any" and "L&". This has necessitated a change to
182       the interal format of compiled patterns. Any saved compiled patterns that
183       use \p or \P must be recompiled.
185    3. The specification of recursion in patterns has been changed so that all
186       recursive subpatterns are automatically treated as atomic groups. Thus, for
187       example, (?R) is treated as if it were (?>(?R)). This is necessary because
188       otherwise there are situations where recursion does not work.
190    See the ChangeLog for a complete list of changes, which include a number of bug
191    fixes and tidies.
194    Release 6.0 07-Jun-05
195    ---------------------
197    The release number has been increased to 6.0 because of the addition of several
198    major new pieces of functionality.
200    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
201    algorithm, has been added. This has a number of advantages for certain cases,
202    though it does run more slowly, and lacks the ability to capture substrings. On
203    the other hand, it does find all matches, not just the first, and it works
204    better for partial matching. The pcrematching man page discusses the
205    differences.
207    The pcretest program has been enhanced so that it can make use of the new
208    pcre_dfa_exec() matching function and the extra features it provides.
210    The distribution now includes a C++ wrapper library. This is built
211    automatically if a C++ compiler is found. The pcrecpp man page discusses this
212    interface.
214    The code itself has been re-organized into many more files, one for each
215    function, so it no longer requires everything to be linked in when static
216    linkage is used. As a consequence, some internal functions have had to have
217    their names exposed. These functions all have names starting with _pcre_. They
218    are undocumented, and are not intended for use by outside callers.
220    The pcregrep program has been enhanced with new functionality such as
221    multiline-matching and options for output more matching context. See the
222    ChangeLog for a complete list of changes to the library and the utility
223    programs.
226    Release 5.0 13-Sep-04
227    ---------------------
229    The licence under which PCRE is released has been changed to the more
230    conventional "BSD" licence.
232    In the code, some bugs have been fixed, and there are also some major changes
233    in this release (which is why I've increased the number to 5.0). Some changes
234    are internal rearrangements, and some provide a number of new facilities. The
235    new features are:
237    1. There's an "automatic callout" feature that inserts callouts before every
238       item in the regex, and there's a new callout field that gives the position
239       in the pattern - useful for debugging and tracing.
241    2. The extra_data structure can now be used to pass in a set of character
242       tables at exec time. This is useful if compiled regex are saved and re-used
243       at a later time when the tables may not be at the same address. If the
244       default internal tables are used, the pointer saved with the compiled
245       pattern is now set to NULL, which means that you don't need to do anything
246       special unless you are using custom tables.
248    3. It is possible, with some restrictions on the content of the regex, to
249       request "partial" matching. A special return code is given if all of the
250       subject string matched part of the regex. This could be useful for testing
251       an input field as it is being typed.
253    4. There is now some optional support for Unicode character properties, which
254       means that the patterns items such as \p{Lu} and \X can now be used. Only
255       the general category properties are supported. If PCRE is compiled with this
256       support, an additional 90K data structure is include, which increases the
257       size of the library dramatically.
259    5. There is support for saving compiled patterns and re-using them later.
261    6. There is support for running regular expressions that were compiled on a
262       different host with the opposite endianness.
264    7. The pcretest program has been extended to accommodate the new features.
266    The main internal rearrangement is that sequences of literal characters are no
267    longer handled as strings. Instead, each character is handled on its own. This
268    makes some UTF-8 handling easier, and makes the support of partial matching
269    possible. Compiled patterns containing long literal strings will be larger as a
270    result of this change; I hope that performance will not be much affected.
273    Release 4.5 01-Dec-03
274    ---------------------
276    Again mainly a bug-fix and tidying release, with only a couple of new features:
278    1. It's possible now to compile PCRE so that it does not use recursive
279    function calls when matching. Instead it gets memory from the heap. This slows
280    things down, but may be necessary on systems with limited stacks.
282    2. UTF-8 string checking has been tightened to reject overlong sequences and to
283    check that a starting offset points to the start of a character. Failure of the
284    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
286    3. PCRE can now be compiled for systems that use EBCDIC code.
289    Release 4.4 21-Aug-03
290    ---------------------
292    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
293    checks UTF-8 strings for validity by default. There is an option to suppress
294    this, just in case anybody wants that teeny extra bit of performance.
297    Releases 4.1 - 4.3
298    ------------------
300    Sorry, I forgot about updating the NEWS file for these releases. Please take a
301    look at ChangeLog.
304    Release 4.0 17-Feb-03
305    ---------------------
307    There have been a lot of changes for the 4.0 release, adding additional
308    functionality and mending bugs. Below is a list of the highlights of the new
309    functionality. For full details of these features, please consult the
310    documentation. For a complete list of changes, see the ChangeLog file.
312    1. Support for Perl's \Q...\E escapes.
314    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
315    package. They provide some syntactic sugar for simple cases of "atomic
316    grouping".
318    3. Support for the \G assertion. It is true when the current matching position
319    is at the start point of the match.
321    4. A new feature that provides some of the functionality that Perl provides
322    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
323    is for the caller to provide an optional function, by setting pcre_callout to
324    its entry point. To get the function called, the regex must include (?C) at
325    appropriate points.
327    5. Support for recursive calls to individual subpatterns. This makes it really
328    easy to get totally confused.
330    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
331    name a group.
333    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
334    option for pcregrep to make it operate in UTF-8 mode.
336    8. The single man page has been split into a number of separate man pages.
337    These also give rise to individual HTML pages which are put in a separate
338    directory. There is an index.html page that lists them all. Some hyperlinking
339    between the pages has been installed.
342    Release 3.5 15-Aug-01
343    ---------------------
345    1. The configuring system has been upgraded to use later versions of autoconf
346    and libtool. By default it builds both a shared and a static library if the OS
347    supports it. You can use --disable-shared or --disable-static on the configure
348    command if you want only one of them.
350    2. The pcretest utility is now installed along with pcregrep because it is
351    useful for users (to test regexs) and by doing this, it automatically gets
352    relinked by libtool. The documentation has been turned into a man page, so
353    there are now .1, .txt, and .html versions in /doc.
355    3. Upgrades to pcregrep:
356       (i)   Added long-form option names like gnu grep.
357       (ii)  Added --help to list all options with an explanatory phrase.
358       (iii) Added -r, --recursive to recurse into sub-directories.
359       (iv)  Added -f, --file to read patterns from a file.
361    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
362    script, to force use of CR or LF instead of \n in the source. On non-Unix
363    systems, the value can be set in config.h.
365    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
366    absolute limit. Changed the text of the error message to make this clear, and
367    likewise updated the man page.
369    6. The limit of 99 on the number of capturing subpatterns has been removed.
370    The new limit is 65535, which I hope will not be a "real" limit.
373  Release 3.3 01-Aug-00  Release 3.3 01-Aug-00
374  ---------------------  ---------------------

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