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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 7.2 30-Apr-07
6    ---------------------
8    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
9    recompiled for use with 7.2 (necessitated by the addition of \K).
11    Correction to the notes for 7.1: the note about shared libraries for Windows is
12    wrong. Previously, three libraries were built, but each could function
13    independently. For example, the pcreposix library also included all the
14    functions from the basic pcre library. The change is that the three libraries
15    are no longer independent. They are like the Unix libraries. To use the
16    pcreposix functions, for example, you need to link with both the pcreposix and
17    the basic pcre library.
19    Some more features from Perl 5.10 have been added:
21      (?-n) and (?+n) relative references for recursion and subroutines.
23      (Not sure if this one is actually in Perl 5.10)
24      (?(-n) and (?(+n) relative references as conditions.
26      \K to reset the start of the matched string; for example, (foo)\Kbar
27      matches bar preceded by foo, but only sets bar as the matched string.
29      (?| introduces a group where the capturing parentheses in each alternative
30      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
31      parentheses number 1 in both cases.
33      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
36    Release 7.1 24-Apr-07
37    ---------------------
39    There is only one new feature in this release: a linebreak setting of
40    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
41    recognizes only CRLF, CR, and LF as linebreaks.
43    A few bugs are fixed (see ChangeLog for details), but the major change is a
44    complete re-implementation of the build system. This now has full Autotools
45    support and so is now "standard" in some sense. It should help with compiling
46    PCRE in a wide variety of environments.
48    NOTE: when building shared libraries for Windows, three dlls are now built,
49    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
50    included in a single dll.
52    Another important change is that the dftables auxiliary program is no longer
53    compiled and run at "make" time by default. Instead, a default set of character
54    tables (assuming ASCII coding) is used. If you want to use dftables to generate
55    the character tables as previously, add --enable-rebuild-chartables to the
56    "configure" command. You must do this if you are compiling PCRE to run on a
57    system that uses EBCDIC code.
59    There is a discussion about character tables in the README file. The default is
60    not to use dftables so that that there is no problem when cross-compiling.
63    Release 7.0 19-Dec-06
64    ---------------------
66    This release has a new major number because there have been some internal
67    upheavals to facilitate the addition of new optimizations and other facilities,
68    and to make subsequent maintenance and extension easier. Compilation is likely
69    to be a bit slower, but there should be no major effect on runtime performance.
70    Previously compiled patterns are NOT upwards compatible with this release. If
71    you have saved compiled patterns from a previous release, you will have to
72    re-compile them. Important changes that are visible to users are:
74    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
75       some more scripts.
77    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
78       sequence as a newline.
80    3. The \R escape matches a single Unicode newline sequence as a single unit.
82    4. New features that will appear in Perl 5.10 are now in PCRE. These include
83       alternative Perl syntax for named parentheses, and Perl syntax for
84       recursion.
86    5. The C++ wrapper interface has been extended by the addition of a
87       QuoteMeta function and the ability to allow copy construction and
88       assignment.
90    For a complete list of changes, see the ChangeLog file.
93    Release 6.7 04-Jul-06
94    ---------------------
96    The main additions to this release are the ability to use the same name for
97    multiple sets of parentheses, and support for CRLF line endings in both the
98    library and pcregrep (and in pcretest for testing).
100    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
101    significantly reduced for certain subject strings.
104    Release 6.5 01-Feb-06
105    ---------------------
107    Important changes in this release:
109    1. A number of new features have been added to pcregrep.
111    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
112       supported properties have been extended with script names such as "Arabic",
113       and the derived properties "Any" and "L&". This has necessitated a change to
114       the interal format of compiled patterns. Any saved compiled patterns that
115       use \p or \P must be recompiled.
117    3. The specification of recursion in patterns has been changed so that all
118       recursive subpatterns are automatically treated as atomic groups. Thus, for
119       example, (?R) is treated as if it were (?>(?R)). This is necessary because
120       otherwise there are situations where recursion does not work.
122    See the ChangeLog for a complete list of changes, which include a number of bug
123    fixes and tidies.
126    Release 6.0 07-Jun-05
127    ---------------------
129    The release number has been increased to 6.0 because of the addition of several
130    major new pieces of functionality.
132    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
133    algorithm, has been added. This has a number of advantages for certain cases,
134    though it does run more slowly, and lacks the ability to capture substrings. On
135    the other hand, it does find all matches, not just the first, and it works
136    better for partial matching. The pcrematching man page discusses the
137    differences.
139    The pcretest program has been enhanced so that it can make use of the new
140    pcre_dfa_exec() matching function and the extra features it provides.
142    The distribution now includes a C++ wrapper library. This is built
143    automatically if a C++ compiler is found. The pcrecpp man page discusses this
144    interface.
146    The code itself has been re-organized into many more files, one for each
147    function, so it no longer requires everything to be linked in when static
148    linkage is used. As a consequence, some internal functions have had to have
149    their names exposed. These functions all have names starting with _pcre_. They
150    are undocumented, and are not intended for use by outside callers.
152    The pcregrep program has been enhanced with new functionality such as
153    multiline-matching and options for output more matching context. See the
154    ChangeLog for a complete list of changes to the library and the utility
155    programs.
158    Release 5.0 13-Sep-04
159    ---------------------
161    The licence under which PCRE is released has been changed to the more
162    conventional "BSD" licence.
164    In the code, some bugs have been fixed, and there are also some major changes
165    in this release (which is why I've increased the number to 5.0). Some changes
166    are internal rearrangements, and some provide a number of new facilities. The
167    new features are:
169    1. There's an "automatic callout" feature that inserts callouts before every
170       item in the regex, and there's a new callout field that gives the position
171       in the pattern - useful for debugging and tracing.
173    2. The extra_data structure can now be used to pass in a set of character
174       tables at exec time. This is useful if compiled regex are saved and re-used
175       at a later time when the tables may not be at the same address. If the
176       default internal tables are used, the pointer saved with the compiled
177       pattern is now set to NULL, which means that you don't need to do anything
178       special unless you are using custom tables.
180    3. It is possible, with some restrictions on the content of the regex, to
181       request "partial" matching. A special return code is given if all of the
182       subject string matched part of the regex. This could be useful for testing
183       an input field as it is being typed.
185    4. There is now some optional support for Unicode character properties, which
186       means that the patterns items such as \p{Lu} and \X can now be used. Only
187       the general category properties are supported. If PCRE is compiled with this
188       support, an additional 90K data structure is include, which increases the
189       size of the library dramatically.
191    5. There is support for saving compiled patterns and re-using them later.
193    6. There is support for running regular expressions that were compiled on a
194       different host with the opposite endianness.
196    7. The pcretest program has been extended to accommodate the new features.
198    The main internal rearrangement is that sequences of literal characters are no
199    longer handled as strings. Instead, each character is handled on its own. This
200    makes some UTF-8 handling easier, and makes the support of partial matching
201    possible. Compiled patterns containing long literal strings will be larger as a
202    result of this change; I hope that performance will not be much affected.
205    Release 4.5 01-Dec-03
206    ---------------------
208    Again mainly a bug-fix and tidying release, with only a couple of new features:
210    1. It's possible now to compile PCRE so that it does not use recursive
211    function calls when matching. Instead it gets memory from the heap. This slows
212    things down, but may be necessary on systems with limited stacks.
214    2. UTF-8 string checking has been tightened to reject overlong sequences and to
215    check that a starting offset points to the start of a character. Failure of the
216    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
218    3. PCRE can now be compiled for systems that use EBCDIC code.
221    Release 4.4 21-Aug-03
222    ---------------------
224    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
225    checks UTF-8 strings for validity by default. There is an option to suppress
226    this, just in case anybody wants that teeny extra bit of performance.
229    Releases 4.1 - 4.3
230    ------------------
232    Sorry, I forgot about updating the NEWS file for these releases. Please take a
233    look at ChangeLog.
236    Release 4.0 17-Feb-03
237    ---------------------
239    There have been a lot of changes for the 4.0 release, adding additional
240    functionality and mending bugs. Below is a list of the highlights of the new
241    functionality. For full details of these features, please consult the
242    documentation. For a complete list of changes, see the ChangeLog file.
244    1. Support for Perl's \Q...\E escapes.
246    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
247    package. They provide some syntactic sugar for simple cases of "atomic
248    grouping".
250    3. Support for the \G assertion. It is true when the current matching position
251    is at the start point of the match.
253    4. A new feature that provides some of the functionality that Perl provides
254    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
255    is for the caller to provide an optional function, by setting pcre_callout to
256    its entry point. To get the function called, the regex must include (?C) at
257    appropriate points.
259    5. Support for recursive calls to individual subpatterns. This makes it really
260    easy to get totally confused.
262    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
263    name a group.
265    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
266    option for pcregrep to make it operate in UTF-8 mode.
268    8. The single man page has been split into a number of separate man pages.
269    These also give rise to individual HTML pages which are put in a separate
270    directory. There is an index.html page that lists them all. Some hyperlinking
271    between the pages has been installed.
274    Release 3.5 15-Aug-01
275    ---------------------
277    1. The configuring system has been upgraded to use later versions of autoconf
278    and libtool. By default it builds both a shared and a static library if the OS
279    supports it. You can use --disable-shared or --disable-static on the configure
280    command if you want only one of them.
282    2. The pcretest utility is now installed along with pcregrep because it is
283    useful for users (to test regexs) and by doing this, it automatically gets
284    relinked by libtool. The documentation has been turned into a man page, so
285    there are now .1, .txt, and .html versions in /doc.
287    3. Upgrades to pcregrep:
288       (i)   Added long-form option names like gnu grep.
289       (ii)  Added --help to list all options with an explanatory phrase.
290       (iii) Added -r, --recursive to recurse into sub-directories.
291       (iv)  Added -f, --file to read patterns from a file.
293    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
294    script, to force use of CR or LF instead of \n in the source. On non-Unix
295    systems, the value can be set in config.h.
297    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
298    absolute limit. Changed the text of the error message to make this clear, and
299    likewise updated the man page.
301    6. The limit of 99 on the number of capturing subpatterns has been removed.
302    The new limit is 65535, which I hope will not be a "real" limit.
305    Release 3.3 01-Aug-00
306    ---------------------
308    There is some support for UTF-8 character strings. This is incomplete and
309    experimental. The documentation describes what is and what is not implemented.
310    Otherwise, this is just a bug-fixing release.
313    Release 3.0 01-Feb-00
314    ---------------------
316    1. A "configure" script is now used to configure PCRE for Unix systems. It
317    builds a Makefile, a config.h file, and the pcre-config script.
319    2. PCRE is built as a shared library by default.
321    3. There is support for POSIX classes such as [:alpha:].
323    5. There is an experimental recursion feature.
325  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------

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