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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 13-Jun-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, \h, \H, \v,
10    and \V).
12    Correction to the notes for 7.1: the note about shared libraries for Windows is
13    wrong. Previously, three libraries were built, but each could function
14    independently. For example, the pcreposix library also included all the
15    functions from the basic pcre library. The change is that the three libraries
16    are no longer independent. They are like the Unix libraries. To use the
17    pcreposix functions, for example, you need to link with both the pcreposix and
18    the basic pcre library.
20    Some more features from Perl 5.10 have been added:
22      (?-n) and (?+n) relative references for recursion and subroutines.
24      (?(-n) and (?(+n) relative references as conditions.
26      \k{name} and \g{name} are synonyms for \k<name>.
28      \K to reset the start of the matched string; for example, (foo)\Kbar
29      matches bar preceded by foo, but only sets bar as the matched string.
31      (?| introduces a group where the capturing parentheses in each alternative
32      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
33      parentheses number 1 in both cases.
35      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
38    Release 7.1 24-Apr-07
39    ---------------------
41    There is only one new feature in this release: a linebreak setting of
42    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
43    recognizes only CRLF, CR, and LF as linebreaks.
45    A few bugs are fixed (see ChangeLog for details), but the major change is a
46    complete re-implementation of the build system. This now has full Autotools
47    support and so is now "standard" in some sense. It should help with compiling
48    PCRE in a wide variety of environments.
50    NOTE: when building shared libraries for Windows, three dlls are now built,
51    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
52    included in a single dll.
54    Another important change is that the dftables auxiliary program is no longer
55    compiled and run at "make" time by default. Instead, a default set of character
56    tables (assuming ASCII coding) is used. If you want to use dftables to generate
57    the character tables as previously, add --enable-rebuild-chartables to the
58    "configure" command. You must do this if you are compiling PCRE to run on a
59    system that uses EBCDIC code.
61    There is a discussion about character tables in the README file. The default is
62    not to use dftables so that that there is no problem when cross-compiling.
65    Release 7.0 19-Dec-06
66    ---------------------
68    This release has a new major number because there have been some internal
69    upheavals to facilitate the addition of new optimizations and other facilities,
70    and to make subsequent maintenance and extension easier. Compilation is likely
71    to be a bit slower, but there should be no major effect on runtime performance.
72    Previously compiled patterns are NOT upwards compatible with this release. If
73    you have saved compiled patterns from a previous release, you will have to
74    re-compile them. Important changes that are visible to users are:
76    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
77       some more scripts.
79    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
80       sequence as a newline.
82    3. The \R escape matches a single Unicode newline sequence as a single unit.
84    4. New features that will appear in Perl 5.10 are now in PCRE. These include
85       alternative Perl syntax for named parentheses, and Perl syntax for
86       recursion.
88    5. The C++ wrapper interface has been extended by the addition of a
89       QuoteMeta function and the ability to allow copy construction and
90       assignment.
92    For a complete list of changes, see the ChangeLog file.
95    Release 6.7 04-Jul-06
96    ---------------------
98    The main additions to this release are the ability to use the same name for
99    multiple sets of parentheses, and support for CRLF line endings in both the
100    library and pcregrep (and in pcretest for testing).
102    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
103    significantly reduced for certain subject strings.
106    Release 6.5 01-Feb-06
107    ---------------------
109    Important changes in this release:
111    1. A number of new features have been added to pcregrep.
113    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
114       supported properties have been extended with script names such as "Arabic",
115       and the derived properties "Any" and "L&". This has necessitated a change to
116       the interal format of compiled patterns. Any saved compiled patterns that
117       use \p or \P must be recompiled.
119    3. The specification of recursion in patterns has been changed so that all
120       recursive subpatterns are automatically treated as atomic groups. Thus, for
121       example, (?R) is treated as if it were (?>(?R)). This is necessary because
122       otherwise there are situations where recursion does not work.
124    See the ChangeLog for a complete list of changes, which include a number of bug
125    fixes and tidies.
128    Release 6.0 07-Jun-05
129    ---------------------
131    The release number has been increased to 6.0 because of the addition of several
132    major new pieces of functionality.
134    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
135    algorithm, has been added. This has a number of advantages for certain cases,
136    though it does run more slowly, and lacks the ability to capture substrings. On
137    the other hand, it does find all matches, not just the first, and it works
138    better for partial matching. The pcrematching man page discusses the
139    differences.
141    The pcretest program has been enhanced so that it can make use of the new
142    pcre_dfa_exec() matching function and the extra features it provides.
144    The distribution now includes a C++ wrapper library. This is built
145    automatically if a C++ compiler is found. The pcrecpp man page discusses this
146    interface.
148    The code itself has been re-organized into many more files, one for each
149    function, so it no longer requires everything to be linked in when static
150    linkage is used. As a consequence, some internal functions have had to have
151    their names exposed. These functions all have names starting with _pcre_. They
152    are undocumented, and are not intended for use by outside callers.
154    The pcregrep program has been enhanced with new functionality such as
155    multiline-matching and options for output more matching context. See the
156    ChangeLog for a complete list of changes to the library and the utility
157    programs.
160    Release 5.0 13-Sep-04
161    ---------------------
163    The licence under which PCRE is released has been changed to the more
164    conventional "BSD" licence.
166    In the code, some bugs have been fixed, and there are also some major changes
167    in this release (which is why I've increased the number to 5.0). Some changes
168    are internal rearrangements, and some provide a number of new facilities. The
169    new features are:
171    1. There's an "automatic callout" feature that inserts callouts before every
172       item in the regex, and there's a new callout field that gives the position
173       in the pattern - useful for debugging and tracing.
175    2. The extra_data structure can now be used to pass in a set of character
176       tables at exec time. This is useful if compiled regex are saved and re-used
177       at a later time when the tables may not be at the same address. If the
178       default internal tables are used, the pointer saved with the compiled
179       pattern is now set to NULL, which means that you don't need to do anything
180       special unless you are using custom tables.
182    3. It is possible, with some restrictions on the content of the regex, to
183       request "partial" matching. A special return code is given if all of the
184       subject string matched part of the regex. This could be useful for testing
185       an input field as it is being typed.
187    4. There is now some optional support for Unicode character properties, which
188       means that the patterns items such as \p{Lu} and \X can now be used. Only
189       the general category properties are supported. If PCRE is compiled with this
190       support, an additional 90K data structure is include, which increases the
191       size of the library dramatically.
193    5. There is support for saving compiled patterns and re-using them later.
195    6. There is support for running regular expressions that were compiled on a
196       different host with the opposite endianness.
198    7. The pcretest program has been extended to accommodate the new features.
200    The main internal rearrangement is that sequences of literal characters are no
201    longer handled as strings. Instead, each character is handled on its own. This
202    makes some UTF-8 handling easier, and makes the support of partial matching
203    possible. Compiled patterns containing long literal strings will be larger as a
204    result of this change; I hope that performance will not be much affected.
207    Release 4.5 01-Dec-03
208    ---------------------
210    Again mainly a bug-fix and tidying release, with only a couple of new features:
212    1. It's possible now to compile PCRE so that it does not use recursive
213    function calls when matching. Instead it gets memory from the heap. This slows
214    things down, but may be necessary on systems with limited stacks.
216    2. UTF-8 string checking has been tightened to reject overlong sequences and to
217    check that a starting offset points to the start of a character. Failure of the
218    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
220    3. PCRE can now be compiled for systems that use EBCDIC code.
223    Release 4.4 21-Aug-03
224    ---------------------
226    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
227    checks UTF-8 strings for validity by default. There is an option to suppress
228    this, just in case anybody wants that teeny extra bit of performance.
231    Releases 4.1 - 4.3
232    ------------------
234    Sorry, I forgot about updating the NEWS file for these releases. Please take a
235    look at ChangeLog.
238    Release 4.0 17-Feb-03
239    ---------------------
241    There have been a lot of changes for the 4.0 release, adding additional
242    functionality and mending bugs. Below is a list of the highlights of the new
243    functionality. For full details of these features, please consult the
244    documentation. For a complete list of changes, see the ChangeLog file.
246    1. Support for Perl's \Q...\E escapes.
248    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
249    package. They provide some syntactic sugar for simple cases of "atomic
250    grouping".
252    3. Support for the \G assertion. It is true when the current matching position
253    is at the start point of the match.
255    4. A new feature that provides some of the functionality that Perl provides
256    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
257    is for the caller to provide an optional function, by setting pcre_callout to
258    its entry point. To get the function called, the regex must include (?C) at
259    appropriate points.
261    5. Support for recursive calls to individual subpatterns. This makes it really
262    easy to get totally confused.
264    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
265    name a group.
267    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
268    option for pcregrep to make it operate in UTF-8 mode.
270    8. The single man page has been split into a number of separate man pages.
271    These also give rise to individual HTML pages which are put in a separate
272    directory. There is an index.html page that lists them all. Some hyperlinking
273    between the pages has been installed.
276    Release 3.5 15-Aug-01
277    ---------------------
279    1. The configuring system has been upgraded to use later versions of autoconf
280    and libtool. By default it builds both a shared and a static library if the OS
281    supports it. You can use --disable-shared or --disable-static on the configure
282    command if you want only one of them.
284    2. The pcretest utility is now installed along with pcregrep because it is
285    useful for users (to test regexs) and by doing this, it automatically gets
286    relinked by libtool. The documentation has been turned into a man page, so
287    there are now .1, .txt, and .html versions in /doc.
289    3. Upgrades to pcregrep:
290       (i)   Added long-form option names like gnu grep.
291       (ii)  Added --help to list all options with an explanatory phrase.
292       (iii) Added -r, --recursive to recurse into sub-directories.
293       (iv)  Added -f, --file to read patterns from a file.
295    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
296    script, to force use of CR or LF instead of \n in the source. On non-Unix
297    systems, the value can be set in config.h.
299    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
300    absolute limit. Changed the text of the error message to make this clear, and
301    likewise updated the man page.
303    6. The limit of 99 on the number of capturing subpatterns has been removed.
304    The new limit is 65535, which I hope will not be a "real" limit.
307    Release 3.3 01-Aug-00
308    ---------------------
310    There is some support for UTF-8 character strings. This is incomplete and
311    experimental. The documentation describes what is and what is not implemented.
312    Otherwise, this is just a bug-fixing release.
315    Release 3.0 01-Feb-00
316    ---------------------
318    1. A "configure" script is now used to configure PCRE for Unix systems. It
319    builds a Makefile, a config.h file, and the pcre-config script.
321    2. PCRE is built as a shared library by default.
323    3. There is support for POSIX classes such as [:alpha:].
325    5. There is an experimental recursion feature.
327  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------

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