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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 289 by ph10, Sun Dec 23 12:17:20 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
4  A "configure" script is now used to configure PCRE for Unix systems. It builds  Release 7.5 23-Dec-07
5  a Makefile and a config.h file.  ---------------------
7    This is mainly a bug-fix release. However the ability to link pcregrep with
8    libz or libbz2 and the ability to link pcretest with libreadline have been
9    added. Also the --line-offsets and --file-offsets options were added to
10    pcregrep.
13    Release 7.4 21-Sep-07
14    ---------------------
16    The only change of specification is the addition of options to control whether
17    \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
18    Otherwise, the changes are bug fixes and a refactoring to reduce the number of
19    relocations needed in a shared library. There have also been some documentation
20    updates, in particular, some more information about using CMake to build PCRE
21    has been added to the NON-UNIX-USE file.
24    Release 7.3 28-Aug-07
25    ---------------------
27    Most changes are bug fixes. Some that are not:
29    1. There is some support for Perl 5.10's experimental "backtracking control
30       verbs" such as (*PRUNE).
32    2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
33       restrictive in the strings it accepts.
35    3. Checking for potential integer overflow has been made more dynamic, and as a
36       consequence there is no longer a hard limit on the size of a subpattern that
37       has a limited repeat count.
39    4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
40       no longer advance by two characters instead of one when an unanchored match
41       fails at CRLF if there are explicit CR or LF matches within the pattern.
42       This gets rid of some anomalous effects that previously occurred.
44    5. Some PCRE-specific settings for varying the newline options at the start of
45       a pattern have been added.
48    Release 7.2 19-Jun-07
49    ---------------------
51    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
52    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
53    and \V).
55    Correction to the notes for 7.1: the note about shared libraries for Windows is
56    wrong. Previously, three libraries were built, but each could function
57    independently. For example, the pcreposix library also included all the
58    functions from the basic pcre library. The change is that the three libraries
59    are no longer independent. They are like the Unix libraries. To use the
60    pcreposix functions, for example, you need to link with both the pcreposix and
61    the basic pcre library.
63    Some more features from Perl 5.10 have been added:
65      (?-n) and (?+n) relative references for recursion and subroutines.
67      (?(-n) and (?(+n) relative references as conditions.
69      \k{name} and \g{name} are synonyms for \k<name>.
71      \K to reset the start of the matched string; for example, (foo)\Kbar
72      matches bar preceded by foo, but only sets bar as the matched string.
74      (?| introduces a group where the capturing parentheses in each alternative
75      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
76      parentheses number 1 in both cases.
78      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
81    Release 7.1 24-Apr-07
82    ---------------------
84    There is only one new feature in this release: a linebreak setting of
85    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
86    recognizes only CRLF, CR, and LF as linebreaks.
88    A few bugs are fixed (see ChangeLog for details), but the major change is a
89    complete re-implementation of the build system. This now has full Autotools
90    support and so is now "standard" in some sense. It should help with compiling
91    PCRE in a wide variety of environments.
93    NOTE: when building shared libraries for Windows, three dlls are now built,
94    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
95    included in a single dll.
97    Another important change is that the dftables auxiliary program is no longer
98    compiled and run at "make" time by default. Instead, a default set of character
99    tables (assuming ASCII coding) is used. If you want to use dftables to generate
100    the character tables as previously, add --enable-rebuild-chartables to the
101    "configure" command. You must do this if you are compiling PCRE to run on a
102    system that uses EBCDIC code.
104    There is a discussion about character tables in the README file. The default is
105    not to use dftables so that that there is no problem when cross-compiling.
108    Release 7.0 19-Dec-06
109    ---------------------
111    This release has a new major number because there have been some internal
112    upheavals to facilitate the addition of new optimizations and other facilities,
113    and to make subsequent maintenance and extension easier. Compilation is likely
114    to be a bit slower, but there should be no major effect on runtime performance.
115    Previously compiled patterns are NOT upwards compatible with this release. If
116    you have saved compiled patterns from a previous release, you will have to
117    re-compile them. Important changes that are visible to users are:
119    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
120       some more scripts.
122    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
123       sequence as a newline.
125    3. The \R escape matches a single Unicode newline sequence as a single unit.
127    4. New features that will appear in Perl 5.10 are now in PCRE. These include
128       alternative Perl syntax for named parentheses, and Perl syntax for
129       recursion.
131    5. The C++ wrapper interface has been extended by the addition of a
132       QuoteMeta function and the ability to allow copy construction and
133       assignment.
135    For a complete list of changes, see the ChangeLog file.
138    Release 6.7 04-Jul-06
139    ---------------------
141    The main additions to this release are the ability to use the same name for
142    multiple sets of parentheses, and support for CRLF line endings in both the
143    library and pcregrep (and in pcretest for testing).
145    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
146    significantly reduced for certain subject strings.
149    Release 6.5 01-Feb-06
150    ---------------------
152    Important changes in this release:
154    1. A number of new features have been added to pcregrep.
156    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
157       supported properties have been extended with script names such as "Arabic",
158       and the derived properties "Any" and "L&". This has necessitated a change to
159       the interal format of compiled patterns. Any saved compiled patterns that
160       use \p or \P must be recompiled.
162    3. The specification of recursion in patterns has been changed so that all
163       recursive subpatterns are automatically treated as atomic groups. Thus, for
164       example, (?R) is treated as if it were (?>(?R)). This is necessary because
165       otherwise there are situations where recursion does not work.
167    See the ChangeLog for a complete list of changes, which include a number of bug
168    fixes and tidies.
171    Release 6.0 07-Jun-05
172    ---------------------
174    The release number has been increased to 6.0 because of the addition of several
175    major new pieces of functionality.
177    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
178    algorithm, has been added. This has a number of advantages for certain cases,
179    though it does run more slowly, and lacks the ability to capture substrings. On
180    the other hand, it does find all matches, not just the first, and it works
181    better for partial matching. The pcrematching man page discusses the
182    differences.
184    The pcretest program has been enhanced so that it can make use of the new
185    pcre_dfa_exec() matching function and the extra features it provides.
187    The distribution now includes a C++ wrapper library. This is built
188    automatically if a C++ compiler is found. The pcrecpp man page discusses this
189    interface.
191    The code itself has been re-organized into many more files, one for each
192    function, so it no longer requires everything to be linked in when static
193    linkage is used. As a consequence, some internal functions have had to have
194    their names exposed. These functions all have names starting with _pcre_. They
195    are undocumented, and are not intended for use by outside callers.
197    The pcregrep program has been enhanced with new functionality such as
198    multiline-matching and options for output more matching context. See the
199    ChangeLog for a complete list of changes to the library and the utility
200    programs.
203    Release 5.0 13-Sep-04
204    ---------------------
206    The licence under which PCRE is released has been changed to the more
207    conventional "BSD" licence.
209    In the code, some bugs have been fixed, and there are also some major changes
210    in this release (which is why I've increased the number to 5.0). Some changes
211    are internal rearrangements, and some provide a number of new facilities. The
212    new features are:
214    1. There's an "automatic callout" feature that inserts callouts before every
215       item in the regex, and there's a new callout field that gives the position
216       in the pattern - useful for debugging and tracing.
218    2. The extra_data structure can now be used to pass in a set of character
219       tables at exec time. This is useful if compiled regex are saved and re-used
220       at a later time when the tables may not be at the same address. If the
221       default internal tables are used, the pointer saved with the compiled
222       pattern is now set to NULL, which means that you don't need to do anything
223       special unless you are using custom tables.
225    3. It is possible, with some restrictions on the content of the regex, to
226       request "partial" matching. A special return code is given if all of the
227       subject string matched part of the regex. This could be useful for testing
228       an input field as it is being typed.
230    4. There is now some optional support for Unicode character properties, which
231       means that the patterns items such as \p{Lu} and \X can now be used. Only
232       the general category properties are supported. If PCRE is compiled with this
233       support, an additional 90K data structure is include, which increases the
234       size of the library dramatically.
236    5. There is support for saving compiled patterns and re-using them later.
238    6. There is support for running regular expressions that were compiled on a
239       different host with the opposite endianness.
241    7. The pcretest program has been extended to accommodate the new features.
243    The main internal rearrangement is that sequences of literal characters are no
244    longer handled as strings. Instead, each character is handled on its own. This
245    makes some UTF-8 handling easier, and makes the support of partial matching
246    possible. Compiled patterns containing long literal strings will be larger as a
247    result of this change; I hope that performance will not be much affected.
250    Release 4.5 01-Dec-03
251    ---------------------
253    Again mainly a bug-fix and tidying release, with only a couple of new features:
255    1. It's possible now to compile PCRE so that it does not use recursive
256    function calls when matching. Instead it gets memory from the heap. This slows
257    things down, but may be necessary on systems with limited stacks.
259    2. UTF-8 string checking has been tightened to reject overlong sequences and to
260    check that a starting offset points to the start of a character. Failure of the
261    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
263    3. PCRE can now be compiled for systems that use EBCDIC code.
266    Release 4.4 21-Aug-03
267    ---------------------
269    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
270    checks UTF-8 strings for validity by default. There is an option to suppress
271    this, just in case anybody wants that teeny extra bit of performance.
274    Releases 4.1 - 4.3
275    ------------------
277    Sorry, I forgot about updating the NEWS file for these releases. Please take a
278    look at ChangeLog.
281    Release 4.0 17-Feb-03
282    ---------------------
284    There have been a lot of changes for the 4.0 release, adding additional
285    functionality and mending bugs. Below is a list of the highlights of the new
286    functionality. For full details of these features, please consult the
287    documentation. For a complete list of changes, see the ChangeLog file.
289    1. Support for Perl's \Q...\E escapes.
291    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
292    package. They provide some syntactic sugar for simple cases of "atomic
293    grouping".
295    3. Support for the \G assertion. It is true when the current matching position
296    is at the start point of the match.
298    4. A new feature that provides some of the functionality that Perl provides
299    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
300    is for the caller to provide an optional function, by setting pcre_callout to
301    its entry point. To get the function called, the regex must include (?C) at
302    appropriate points.
304    5. Support for recursive calls to individual subpatterns. This makes it really
305    easy to get totally confused.
307    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
308    name a group.
310    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
311    option for pcregrep to make it operate in UTF-8 mode.
313    8. The single man page has been split into a number of separate man pages.
314    These also give rise to individual HTML pages which are put in a separate
315    directory. There is an index.html page that lists them all. Some hyperlinking
316    between the pages has been installed.
319    Release 3.5 15-Aug-01
320    ---------------------
322    1. The configuring system has been upgraded to use later versions of autoconf
323    and libtool. By default it builds both a shared and a static library if the OS
324    supports it. You can use --disable-shared or --disable-static on the configure
325    command if you want only one of them.
327    2. The pcretest utility is now installed along with pcregrep because it is
328    useful for users (to test regexs) and by doing this, it automatically gets
329    relinked by libtool. The documentation has been turned into a man page, so
330    there are now .1, .txt, and .html versions in /doc.
332    3. Upgrades to pcregrep:
333       (i)   Added long-form option names like gnu grep.
334       (ii)  Added --help to list all options with an explanatory phrase.
335       (iii) Added -r, --recursive to recurse into sub-directories.
336       (iv)  Added -f, --file to read patterns from a file.
338    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
339    script, to force use of CR or LF instead of \n in the source. On non-Unix
340    systems, the value can be set in config.h.
342    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
343    absolute limit. Changed the text of the error message to make this clear, and
344    likewise updated the man page.
346    6. The limit of 99 on the number of capturing subpatterns has been removed.
347    The new limit is 65535, which I hope will not be a "real" limit.
350    Release 3.3 01-Aug-00
351    ---------------------
353    There is some support for UTF-8 character strings. This is incomplete and
354    experimental. The documentation describes what is and what is not implemented.
355    Otherwise, this is just a bug-fixing release.
358    Release 3.0 01-Feb-00
359    ---------------------
361    1. A "configure" script is now used to configure PCRE for Unix systems. It
362    builds a Makefile, a config.h file, and the pcre-config script.
364    2. PCRE is built as a shared library by default.
366    3. There is support for POSIX classes such as [:alpha:].
368    5. There is an experimental recursion feature.
370  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------

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