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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 155 by ph10, Tue Apr 24 13:36:11 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 7.1 24-Apr-07
6    ---------------------
8    There is only one new feature in this release: a linebreak setting of
9    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
10    recognizes only CRLF, CR, and LF as linebreaks.
12    A few bugs are fixed (see ChangeLog for details), but the major change is a
13    complete re-implementation of the build system. This now has full Autotools
14    support and so is now "standard" in some sense. It should help with compiling
15    PCRE in a wide variety of environments.
17    NOTE: when building shared libraries for Windows, three dlls are now built,
18    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
19    included in a single dll.
21    Another important change is that the dftables auxiliary program is no longer
22    compiled and run at "make" time by default. Instead, a default set of character
23    tables (assuming ASCII coding) is used. If you want to use dftables to generate
24    the character tables as previously, add --enable-rebuild-chartables to the
25    "configure" command. You must do this if you are compiling PCRE to run on a
26    system that uses EBCDIC code.
28    There is a discussion about character tables in the README file. The default is
29    not to use dftables so that that there is no problem when cross-compiling.
32    Release 7.0 19-Dec-06
33    ---------------------
35    This release has a new major number because there have been some internal
36    upheavals to facilitate the addition of new optimizations and other facilities,
37    and to make subsequent maintenance and extension easier. Compilation is likely
38    to be a bit slower, but there should be no major effect on runtime performance.
39    Previously compiled patterns are NOT upwards compatible with this release. If
40    you have saved compiled patterns from a previous release, you will have to
41    re-compile them. Important changes that are visible to users are:
43    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
44       some more scripts.
46    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
47       sequence as a newline.
49    3. The \R escape matches a single Unicode newline sequence as a single unit.
51    4. New features that will appear in Perl 5.10 are now in PCRE. These include
52       alternative Perl syntax for named parentheses, and Perl syntax for
53       recursion.
55    5. The C++ wrapper interface has been extended by the addition of a
56       QuoteMeta function and the ability to allow copy construction and
57       assignment.
59    For a complete list of changes, see the ChangeLog file.
62    Release 6.7 04-Jul-06
63    ---------------------
65    The main additions to this release are the ability to use the same name for
66    multiple sets of parentheses, and support for CRLF line endings in both the
67    library and pcregrep (and in pcretest for testing).
69    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
70    significantly reduced for certain subject strings.
73    Release 6.5 01-Feb-06
74    ---------------------
76    Important changes in this release:
78    1. A number of new features have been added to pcregrep.
80    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
81       supported properties have been extended with script names such as "Arabic",
82       and the derived properties "Any" and "L&". This has necessitated a change to
83       the interal format of compiled patterns. Any saved compiled patterns that
84       use \p or \P must be recompiled.
86    3. The specification of recursion in patterns has been changed so that all
87       recursive subpatterns are automatically treated as atomic groups. Thus, for
88       example, (?R) is treated as if it were (?>(?R)). This is necessary because
89       otherwise there are situations where recursion does not work.
91    See the ChangeLog for a complete list of changes, which include a number of bug
92    fixes and tidies.
95    Release 6.0 07-Jun-05
96    ---------------------
98    The release number has been increased to 6.0 because of the addition of several
99    major new pieces of functionality.
101    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
102    algorithm, has been added. This has a number of advantages for certain cases,
103    though it does run more slowly, and lacks the ability to capture substrings. On
104    the other hand, it does find all matches, not just the first, and it works
105    better for partial matching. The pcrematching man page discusses the
106    differences.
108    The pcretest program has been enhanced so that it can make use of the new
109    pcre_dfa_exec() matching function and the extra features it provides.
111    The distribution now includes a C++ wrapper library. This is built
112    automatically if a C++ compiler is found. The pcrecpp man page discusses this
113    interface.
115    The code itself has been re-organized into many more files, one for each
116    function, so it no longer requires everything to be linked in when static
117    linkage is used. As a consequence, some internal functions have had to have
118    their names exposed. These functions all have names starting with _pcre_. They
119    are undocumented, and are not intended for use by outside callers.
121    The pcregrep program has been enhanced with new functionality such as
122    multiline-matching and options for output more matching context. See the
123    ChangeLog for a complete list of changes to the library and the utility
124    programs.
127    Release 5.0 13-Sep-04
128    ---------------------
130    The licence under which PCRE is released has been changed to the more
131    conventional "BSD" licence.
133    In the code, some bugs have been fixed, and there are also some major changes
134    in this release (which is why I've increased the number to 5.0). Some changes
135    are internal rearrangements, and some provide a number of new facilities. The
136    new features are:
138    1. There's an "automatic callout" feature that inserts callouts before every
139       item in the regex, and there's a new callout field that gives the position
140       in the pattern - useful for debugging and tracing.
142    2. The extra_data structure can now be used to pass in a set of character
143       tables at exec time. This is useful if compiled regex are saved and re-used
144       at a later time when the tables may not be at the same address. If the
145       default internal tables are used, the pointer saved with the compiled
146       pattern is now set to NULL, which means that you don't need to do anything
147       special unless you are using custom tables.
149    3. It is possible, with some restrictions on the content of the regex, to
150       request "partial" matching. A special return code is given if all of the
151       subject string matched part of the regex. This could be useful for testing
152       an input field as it is being typed.
154    4. There is now some optional support for Unicode character properties, which
155       means that the patterns items such as \p{Lu} and \X can now be used. Only
156       the general category properties are supported. If PCRE is compiled with this
157       support, an additional 90K data structure is include, which increases the
158       size of the library dramatically.
160    5. There is support for saving compiled patterns and re-using them later.
162    6. There is support for running regular expressions that were compiled on a
163       different host with the opposite endianness.
165    7. The pcretest program has been extended to accommodate the new features.
167    The main internal rearrangement is that sequences of literal characters are no
168    longer handled as strings. Instead, each character is handled on its own. This
169    makes some UTF-8 handling easier, and makes the support of partial matching
170    possible. Compiled patterns containing long literal strings will be larger as a
171    result of this change; I hope that performance will not be much affected.
174    Release 4.5 01-Dec-03
175    ---------------------
177    Again mainly a bug-fix and tidying release, with only a couple of new features:
179    1. It's possible now to compile PCRE so that it does not use recursive
180    function calls when matching. Instead it gets memory from the heap. This slows
181    things down, but may be necessary on systems with limited stacks.
183    2. UTF-8 string checking has been tightened to reject overlong sequences and to
184    check that a starting offset points to the start of a character. Failure of the
185    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
187    3. PCRE can now be compiled for systems that use EBCDIC code.
190    Release 4.4 21-Aug-03
191    ---------------------
193    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
194    checks UTF-8 strings for validity by default. There is an option to suppress
195    this, just in case anybody wants that teeny extra bit of performance.
198    Releases 4.1 - 4.3
199    ------------------
201    Sorry, I forgot about updating the NEWS file for these releases. Please take a
202    look at ChangeLog.
205    Release 4.0 17-Feb-03
206    ---------------------
208    There have been a lot of changes for the 4.0 release, adding additional
209    functionality and mending bugs. Below is a list of the highlights of the new
210    functionality. For full details of these features, please consult the
211    documentation. For a complete list of changes, see the ChangeLog file.
213    1. Support for Perl's \Q...\E escapes.
215    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
216    package. They provide some syntactic sugar for simple cases of "atomic
217    grouping".
219    3. Support for the \G assertion. It is true when the current matching position
220    is at the start point of the match.
222    4. A new feature that provides some of the functionality that Perl provides
223    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
224    is for the caller to provide an optional function, by setting pcre_callout to
225    its entry point. To get the function called, the regex must include (?C) at
226    appropriate points.
228    5. Support for recursive calls to individual subpatterns. This makes it really
229    easy to get totally confused.
231    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
232    name a group.
234    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
235    option for pcregrep to make it operate in UTF-8 mode.
237    8. The single man page has been split into a number of separate man pages.
238    These also give rise to individual HTML pages which are put in a separate
239    directory. There is an index.html page that lists them all. Some hyperlinking
240    between the pages has been installed.
243    Release 3.5 15-Aug-01
244    ---------------------
246    1. The configuring system has been upgraded to use later versions of autoconf
247    and libtool. By default it builds both a shared and a static library if the OS
248    supports it. You can use --disable-shared or --disable-static on the configure
249    command if you want only one of them.
251    2. The pcretest utility is now installed along with pcregrep because it is
252    useful for users (to test regexs) and by doing this, it automatically gets
253    relinked by libtool. The documentation has been turned into a man page, so
254    there are now .1, .txt, and .html versions in /doc.
256    3. Upgrades to pcregrep:
257       (i)   Added long-form option names like gnu grep.
258       (ii)  Added --help to list all options with an explanatory phrase.
259       (iii) Added -r, --recursive to recurse into sub-directories.
260       (iv)  Added -f, --file to read patterns from a file.
262    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
263    script, to force use of CR or LF instead of \n in the source. On non-Unix
264    systems, the value can be set in config.h.
266    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
267    absolute limit. Changed the text of the error message to make this clear, and
268    likewise updated the man page.
270    6. The limit of 99 on the number of capturing subpatterns has been removed.
271    The new limit is 65535, which I hope will not be a "real" limit.
274    Release 3.3 01-Aug-00
275    ---------------------
277    There is some support for UTF-8 character strings. This is incomplete and
278    experimental. The documentation describes what is and what is not implemented.
279    Otherwise, this is just a bug-fixing release.
282    Release 3.0 01-Feb-00
283    ---------------------
285    1. A "configure" script is now used to configure PCRE for Unix systems. It
286    builds a Makefile, a config.h file, and the pcre-config script.
288    2. PCRE is built as a shared library by default.
290    3. There is support for POSIX classes such as [:alpha:].
292    5. There is an experimental recursion feature.
294  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------

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