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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 220 by ph10, Thu Aug 16 13:29:39 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  
5  a Makefile and a config.h file.  Release 7.3 16-Aug-07
6    ---------------------
8    Most changes are bug fixes. Some that are not:
10    1. There is some support for Perl 5.10's experimental "backtracking control
11       verbs" such as (*PRUNE).
13    2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
14       restrictive in the strings it accepts.
16    3. Checking for potential integer overflow has been made more dynamic, and as a
17       consequence there is no longer a hard limit on the size of a subpattern that
18       has a limited repeat count.
21    Release 7.2 19-Jun-07
22    ---------------------
24    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
25    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
26    and \V).
28    Correction to the notes for 7.1: the note about shared libraries for Windows is
29    wrong. Previously, three libraries were built, but each could function
30    independently. For example, the pcreposix library also included all the
31    functions from the basic pcre library. The change is that the three libraries
32    are no longer independent. They are like the Unix libraries. To use the
33    pcreposix functions, for example, you need to link with both the pcreposix and
34    the basic pcre library.
36    Some more features from Perl 5.10 have been added:
38      (?-n) and (?+n) relative references for recursion and subroutines.
40      (?(-n) and (?(+n) relative references as conditions.
42      \k{name} and \g{name} are synonyms for \k<name>.
44      \K to reset the start of the matched string; for example, (foo)\Kbar
45      matches bar preceded by foo, but only sets bar as the matched string.
47      (?| introduces a group where the capturing parentheses in each alternative
48      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
49      parentheses number 1 in both cases.
51      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
54    Release 7.1 24-Apr-07
55    ---------------------
57    There is only one new feature in this release: a linebreak setting of
58    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
59    recognizes only CRLF, CR, and LF as linebreaks.
61    A few bugs are fixed (see ChangeLog for details), but the major change is a
62    complete re-implementation of the build system. This now has full Autotools
63    support and so is now "standard" in some sense. It should help with compiling
64    PCRE in a wide variety of environments.
66    NOTE: when building shared libraries for Windows, three dlls are now built,
67    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
68    included in a single dll.
70    Another important change is that the dftables auxiliary program is no longer
71    compiled and run at "make" time by default. Instead, a default set of character
72    tables (assuming ASCII coding) is used. If you want to use dftables to generate
73    the character tables as previously, add --enable-rebuild-chartables to the
74    "configure" command. You must do this if you are compiling PCRE to run on a
75    system that uses EBCDIC code.
77    There is a discussion about character tables in the README file. The default is
78    not to use dftables so that that there is no problem when cross-compiling.
81    Release 7.0 19-Dec-06
82    ---------------------
84    This release has a new major number because there have been some internal
85    upheavals to facilitate the addition of new optimizations and other facilities,
86    and to make subsequent maintenance and extension easier. Compilation is likely
87    to be a bit slower, but there should be no major effect on runtime performance.
88    Previously compiled patterns are NOT upwards compatible with this release. If
89    you have saved compiled patterns from a previous release, you will have to
90    re-compile them. Important changes that are visible to users are:
92    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
93       some more scripts.
95    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
96       sequence as a newline.
98    3. The \R escape matches a single Unicode newline sequence as a single unit.
100    4. New features that will appear in Perl 5.10 are now in PCRE. These include
101       alternative Perl syntax for named parentheses, and Perl syntax for
102       recursion.
104    5. The C++ wrapper interface has been extended by the addition of a
105       QuoteMeta function and the ability to allow copy construction and
106       assignment.
108    For a complete list of changes, see the ChangeLog file.
111    Release 6.7 04-Jul-06
112    ---------------------
114    The main additions to this release are the ability to use the same name for
115    multiple sets of parentheses, and support for CRLF line endings in both the
116    library and pcregrep (and in pcretest for testing).
118    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
119    significantly reduced for certain subject strings.
122    Release 6.5 01-Feb-06
123    ---------------------
125    Important changes in this release:
127    1. A number of new features have been added to pcregrep.
129    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
130       supported properties have been extended with script names such as "Arabic",
131       and the derived properties "Any" and "L&". This has necessitated a change to
132       the interal format of compiled patterns. Any saved compiled patterns that
133       use \p or \P must be recompiled.
135    3. The specification of recursion in patterns has been changed so that all
136       recursive subpatterns are automatically treated as atomic groups. Thus, for
137       example, (?R) is treated as if it were (?>(?R)). This is necessary because
138       otherwise there are situations where recursion does not work.
140    See the ChangeLog for a complete list of changes, which include a number of bug
141    fixes and tidies.
144    Release 6.0 07-Jun-05
145    ---------------------
147    The release number has been increased to 6.0 because of the addition of several
148    major new pieces of functionality.
150    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
151    algorithm, has been added. This has a number of advantages for certain cases,
152    though it does run more slowly, and lacks the ability to capture substrings. On
153    the other hand, it does find all matches, not just the first, and it works
154    better for partial matching. The pcrematching man page discusses the
155    differences.
157    The pcretest program has been enhanced so that it can make use of the new
158    pcre_dfa_exec() matching function and the extra features it provides.
160    The distribution now includes a C++ wrapper library. This is built
161    automatically if a C++ compiler is found. The pcrecpp man page discusses this
162    interface.
164    The code itself has been re-organized into many more files, one for each
165    function, so it no longer requires everything to be linked in when static
166    linkage is used. As a consequence, some internal functions have had to have
167    their names exposed. These functions all have names starting with _pcre_. They
168    are undocumented, and are not intended for use by outside callers.
170    The pcregrep program has been enhanced with new functionality such as
171    multiline-matching and options for output more matching context. See the
172    ChangeLog for a complete list of changes to the library and the utility
173    programs.
176    Release 5.0 13-Sep-04
177    ---------------------
179    The licence under which PCRE is released has been changed to the more
180    conventional "BSD" licence.
182    In the code, some bugs have been fixed, and there are also some major changes
183    in this release (which is why I've increased the number to 5.0). Some changes
184    are internal rearrangements, and some provide a number of new facilities. The
185    new features are:
187    1. There's an "automatic callout" feature that inserts callouts before every
188       item in the regex, and there's a new callout field that gives the position
189       in the pattern - useful for debugging and tracing.
191    2. The extra_data structure can now be used to pass in a set of character
192       tables at exec time. This is useful if compiled regex are saved and re-used
193       at a later time when the tables may not be at the same address. If the
194       default internal tables are used, the pointer saved with the compiled
195       pattern is now set to NULL, which means that you don't need to do anything
196       special unless you are using custom tables.
198    3. It is possible, with some restrictions on the content of the regex, to
199       request "partial" matching. A special return code is given if all of the
200       subject string matched part of the regex. This could be useful for testing
201       an input field as it is being typed.
203    4. There is now some optional support for Unicode character properties, which
204       means that the patterns items such as \p{Lu} and \X can now be used. Only
205       the general category properties are supported. If PCRE is compiled with this
206       support, an additional 90K data structure is include, which increases the
207       size of the library dramatically.
209    5. There is support for saving compiled patterns and re-using them later.
211    6. There is support for running regular expressions that were compiled on a
212       different host with the opposite endianness.
214    7. The pcretest program has been extended to accommodate the new features.
216    The main internal rearrangement is that sequences of literal characters are no
217    longer handled as strings. Instead, each character is handled on its own. This
218    makes some UTF-8 handling easier, and makes the support of partial matching
219    possible. Compiled patterns containing long literal strings will be larger as a
220    result of this change; I hope that performance will not be much affected.
223    Release 4.5 01-Dec-03
224    ---------------------
226    Again mainly a bug-fix and tidying release, with only a couple of new features:
228    1. It's possible now to compile PCRE so that it does not use recursive
229    function calls when matching. Instead it gets memory from the heap. This slows
230    things down, but may be necessary on systems with limited stacks.
232    2. UTF-8 string checking has been tightened to reject overlong sequences and to
233    check that a starting offset points to the start of a character. Failure of the
234    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
236    3. PCRE can now be compiled for systems that use EBCDIC code.
239    Release 4.4 21-Aug-03
240    ---------------------
242    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
243    checks UTF-8 strings for validity by default. There is an option to suppress
244    this, just in case anybody wants that teeny extra bit of performance.
247    Releases 4.1 - 4.3
248    ------------------
250    Sorry, I forgot about updating the NEWS file for these releases. Please take a
251    look at ChangeLog.
254    Release 4.0 17-Feb-03
255    ---------------------
257    There have been a lot of changes for the 4.0 release, adding additional
258    functionality and mending bugs. Below is a list of the highlights of the new
259    functionality. For full details of these features, please consult the
260    documentation. For a complete list of changes, see the ChangeLog file.
262    1. Support for Perl's \Q...\E escapes.
264    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
265    package. They provide some syntactic sugar for simple cases of "atomic
266    grouping".
268    3. Support for the \G assertion. It is true when the current matching position
269    is at the start point of the match.
271    4. A new feature that provides some of the functionality that Perl provides
272    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
273    is for the caller to provide an optional function, by setting pcre_callout to
274    its entry point. To get the function called, the regex must include (?C) at
275    appropriate points.
277    5. Support for recursive calls to individual subpatterns. This makes it really
278    easy to get totally confused.
280    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
281    name a group.
283    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
284    option for pcregrep to make it operate in UTF-8 mode.
286    8. The single man page has been split into a number of separate man pages.
287    These also give rise to individual HTML pages which are put in a separate
288    directory. There is an index.html page that lists them all. Some hyperlinking
289    between the pages has been installed.
292    Release 3.5 15-Aug-01
293    ---------------------
295    1. The configuring system has been upgraded to use later versions of autoconf
296    and libtool. By default it builds both a shared and a static library if the OS
297    supports it. You can use --disable-shared or --disable-static on the configure
298    command if you want only one of them.
300    2. The pcretest utility is now installed along with pcregrep because it is
301    useful for users (to test regexs) and by doing this, it automatically gets
302    relinked by libtool. The documentation has been turned into a man page, so
303    there are now .1, .txt, and .html versions in /doc.
305    3. Upgrades to pcregrep:
306       (i)   Added long-form option names like gnu grep.
307       (ii)  Added --help to list all options with an explanatory phrase.
308       (iii) Added -r, --recursive to recurse into sub-directories.
309       (iv)  Added -f, --file to read patterns from a file.
311    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
312    script, to force use of CR or LF instead of \n in the source. On non-Unix
313    systems, the value can be set in config.h.
315    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
316    absolute limit. Changed the text of the error message to make this clear, and
317    likewise updated the man page.
319    6. The limit of 99 on the number of capturing subpatterns has been removed.
320    The new limit is 65535, which I hope will not be a "real" limit.
323    Release 3.3 01-Aug-00
324    ---------------------
326    There is some support for UTF-8 character strings. This is incomplete and
327    experimental. The documentation describes what is and what is not implemented.
328    Otherwise, this is just a bug-fixing release.
331    Release 3.0 01-Feb-00
332    ---------------------
334    1. A "configure" script is now used to configure PCRE for Unix systems. It
335    builds a Makefile, a config.h file, and the pcre-config script.
337    2. PCRE is built as a shared library by default.
339    3. There is support for POSIX classes such as [:alpha:].
341    5. There is an experimental recursion feature.
343  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------

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