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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    
5    Release 7.4 21-Sep-07
6    ---------------------
7    
8    The only change of specification is the addition of options to control whether
9    \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
10    Otherwise, the changes are bug fixes and a refactoring to reduce the number of
11    relocations needed in a shared library. There have also been some documentation
12    updates, in particular, some more information about using CMake to build PCRE
13    has been added to the NON-UNIX-USE file.
14    
15    
16    Release 7.3 28-Aug-07
17    ---------------------
18    
19    Most changes are bug fixes. Some that are not:
20    
21    1. There is some support for Perl 5.10's experimental "backtracking control
22       verbs" such as (*PRUNE).
23    
24    2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
25       restrictive in the strings it accepts.
26    
27    3. Checking for potential integer overflow has been made more dynamic, and as a
28       consequence there is no longer a hard limit on the size of a subpattern that
29       has a limited repeat count.
30    
31    4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
32       no longer advance by two characters instead of one when an unanchored match
33       fails at CRLF if there are explicit CR or LF matches within the pattern.
34       This gets rid of some anomalous effects that previously occurred.
35    
36    5. Some PCRE-specific settings for varying the newline options at the start of
37       a pattern have been added.
38    
39    
40    Release 7.2 19-Jun-07
41    ---------------------
42    
43    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
44    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
45    and \V).
46    
47    Correction to the notes for 7.1: the note about shared libraries for Windows is
48    wrong. Previously, three libraries were built, but each could function
49    independently. For example, the pcreposix library also included all the
50    functions from the basic pcre library. The change is that the three libraries
51    are no longer independent. They are like the Unix libraries. To use the
52    pcreposix functions, for example, you need to link with both the pcreposix and
53    the basic pcre library.
54    
55    Some more features from Perl 5.10 have been added:
56    
57      (?-n) and (?+n) relative references for recursion and subroutines.
58    
59      (?(-n) and (?(+n) relative references as conditions.
60    
61      \k{name} and \g{name} are synonyms for \k<name>.
62    
63      \K to reset the start of the matched string; for example, (foo)\Kbar
64      matches bar preceded by foo, but only sets bar as the matched string.
65    
66      (?| introduces a group where the capturing parentheses in each alternative
67      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
68      parentheses number 1 in both cases.
69    
70      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
71    
72    
73    Release 7.1 24-Apr-07
74    ---------------------
75    
76    There is only one new feature in this release: a linebreak setting of
77    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
78    recognizes only CRLF, CR, and LF as linebreaks.
79    
80    A few bugs are fixed (see ChangeLog for details), but the major change is a
81    complete re-implementation of the build system. This now has full Autotools
82    support and so is now "standard" in some sense. It should help with compiling
83    PCRE in a wide variety of environments.
84    
85    NOTE: when building shared libraries for Windows, three dlls are now built,
86    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
87    included in a single dll.
88    
89    Another important change is that the dftables auxiliary program is no longer
90    compiled and run at "make" time by default. Instead, a default set of character
91    tables (assuming ASCII coding) is used. If you want to use dftables to generate
92    the character tables as previously, add --enable-rebuild-chartables to the
93    "configure" command. You must do this if you are compiling PCRE to run on a
94    system that uses EBCDIC code.
95    
96    There is a discussion about character tables in the README file. The default is
97    not to use dftables so that that there is no problem when cross-compiling.
98    
99    
100    Release 7.0 19-Dec-06
101    ---------------------
102    
103    This release has a new major number because there have been some internal
104    upheavals to facilitate the addition of new optimizations and other facilities,
105    and to make subsequent maintenance and extension easier. Compilation is likely
106    to be a bit slower, but there should be no major effect on runtime performance.
107    Previously compiled patterns are NOT upwards compatible with this release. If
108    you have saved compiled patterns from a previous release, you will have to
109    re-compile them. Important changes that are visible to users are:
110    
111    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
112       some more scripts.
113    
114    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
115       sequence as a newline.
116    
117    3. The \R escape matches a single Unicode newline sequence as a single unit.
118    
119    4. New features that will appear in Perl 5.10 are now in PCRE. These include
120       alternative Perl syntax for named parentheses, and Perl syntax for
121       recursion.
122    
123    5. The C++ wrapper interface has been extended by the addition of a
124       QuoteMeta function and the ability to allow copy construction and
125       assignment.
126    
127    For a complete list of changes, see the ChangeLog file.
128    
129    
130    Release 6.7 04-Jul-06
131    ---------------------
132    
133    The main additions to this release are the ability to use the same name for
134    multiple sets of parentheses, and support for CRLF line endings in both the
135    library and pcregrep (and in pcretest for testing).
136    
137    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
138    significantly reduced for certain subject strings.
139    
140    
141    Release 6.5 01-Feb-06
142    ---------------------
143    
144    Important changes in this release:
145    
146    1. A number of new features have been added to pcregrep.
147    
148    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
149       supported properties have been extended with script names such as "Arabic",
150       and the derived properties "Any" and "L&". This has necessitated a change to
151       the interal format of compiled patterns. Any saved compiled patterns that
152       use \p or \P must be recompiled.
153    
154    3. The specification of recursion in patterns has been changed so that all
155       recursive subpatterns are automatically treated as atomic groups. Thus, for
156       example, (?R) is treated as if it were (?>(?R)). This is necessary because
157       otherwise there are situations where recursion does not work.
158    
159    See the ChangeLog for a complete list of changes, which include a number of bug
160    fixes and tidies.
161    
162    
163    Release 6.0 07-Jun-05
164    ---------------------
165    
166    The release number has been increased to 6.0 because of the addition of several
167    major new pieces of functionality.
168    
169    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
170    algorithm, has been added. This has a number of advantages for certain cases,
171    though it does run more slowly, and lacks the ability to capture substrings. On
172    the other hand, it does find all matches, not just the first, and it works
173    better for partial matching. The pcrematching man page discusses the
174    differences.
175    
176    The pcretest program has been enhanced so that it can make use of the new
177    pcre_dfa_exec() matching function and the extra features it provides.
178    
179    The distribution now includes a C++ wrapper library. This is built
180    automatically if a C++ compiler is found. The pcrecpp man page discusses this
181    interface.
182    
183    The code itself has been re-organized into many more files, one for each
184    function, so it no longer requires everything to be linked in when static
185    linkage is used. As a consequence, some internal functions have had to have
186    their names exposed. These functions all have names starting with _pcre_. They
187    are undocumented, and are not intended for use by outside callers.
188    
189    The pcregrep program has been enhanced with new functionality such as
190    multiline-matching and options for output more matching context. See the
191    ChangeLog for a complete list of changes to the library and the utility
192    programs.
193    
194    
195    Release 5.0 13-Sep-04
196    ---------------------
197    
198    The licence under which PCRE is released has been changed to the more
199    conventional "BSD" licence.
200    
201    In the code, some bugs have been fixed, and there are also some major changes
202    in this release (which is why I've increased the number to 5.0). Some changes
203    are internal rearrangements, and some provide a number of new facilities. The
204    new features are:
205    
206    1. There's an "automatic callout" feature that inserts callouts before every
207       item in the regex, and there's a new callout field that gives the position
208       in the pattern - useful for debugging and tracing.
209    
210    2. The extra_data structure can now be used to pass in a set of character
211       tables at exec time. This is useful if compiled regex are saved and re-used
212       at a later time when the tables may not be at the same address. If the
213       default internal tables are used, the pointer saved with the compiled
214       pattern is now set to NULL, which means that you don't need to do anything
215       special unless you are using custom tables.
216    
217    3. It is possible, with some restrictions on the content of the regex, to
218       request "partial" matching. A special return code is given if all of the
219       subject string matched part of the regex. This could be useful for testing
220       an input field as it is being typed.
221    
222    4. There is now some optional support for Unicode character properties, which
223       means that the patterns items such as \p{Lu} and \X can now be used. Only
224       the general category properties are supported. If PCRE is compiled with this
225       support, an additional 90K data structure is include, which increases the
226       size of the library dramatically.
227    
228    5. There is support for saving compiled patterns and re-using them later.
229    
230    6. There is support for running regular expressions that were compiled on a
231       different host with the opposite endianness.
232    
233    7. The pcretest program has been extended to accommodate the new features.
234    
235    The main internal rearrangement is that sequences of literal characters are no
236    longer handled as strings. Instead, each character is handled on its own. This
237    makes some UTF-8 handling easier, and makes the support of partial matching
238    possible. Compiled patterns containing long literal strings will be larger as a
239    result of this change; I hope that performance will not be much affected.
240    
241    
242    Release 4.5 01-Dec-03
243    ---------------------
244    
245    Again mainly a bug-fix and tidying release, with only a couple of new features:
246    
247    1. It's possible now to compile PCRE so that it does not use recursive
248    function calls when matching. Instead it gets memory from the heap. This slows
249    things down, but may be necessary on systems with limited stacks.
250    
251    2. UTF-8 string checking has been tightened to reject overlong sequences and to
252    check that a starting offset points to the start of a character. Failure of the
253    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
254    
255    3. PCRE can now be compiled for systems that use EBCDIC code.
256    
257    
258    Release 4.4 21-Aug-03
259    ---------------------
260    
261    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
262    checks UTF-8 strings for validity by default. There is an option to suppress
263    this, just in case anybody wants that teeny extra bit of performance.
264    
265    
266    Releases 4.1 - 4.3
267    ------------------
268    
269    Sorry, I forgot about updating the NEWS file for these releases. Please take a
270    look at ChangeLog.
271    
272    
273    Release 4.0 17-Feb-03
274    ---------------------
275    
276    There have been a lot of changes for the 4.0 release, adding additional
277    functionality and mending bugs. Below is a list of the highlights of the new
278    functionality. For full details of these features, please consult the
279    documentation. For a complete list of changes, see the ChangeLog file.
280    
281    1. Support for Perl's \Q...\E escapes.
282    
283    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
284    package. They provide some syntactic sugar for simple cases of "atomic
285    grouping".
286    
287    3. Support for the \G assertion. It is true when the current matching position
288    is at the start point of the match.
289    
290    4. A new feature that provides some of the functionality that Perl provides
291    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
292    is for the caller to provide an optional function, by setting pcre_callout to
293    its entry point. To get the function called, the regex must include (?C) at
294    appropriate points.
295    
296    5. Support for recursive calls to individual subpatterns. This makes it really
297    easy to get totally confused.
298    
299    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
300    name a group.
301    
302    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
303    option for pcregrep to make it operate in UTF-8 mode.
304    
305    8. The single man page has been split into a number of separate man pages.
306    These also give rise to individual HTML pages which are put in a separate
307    directory. There is an index.html page that lists them all. Some hyperlinking
308    between the pages has been installed.
309    
310    
311    Release 3.5 15-Aug-01
312    ---------------------
313    
314    1. The configuring system has been upgraded to use later versions of autoconf
315    and libtool. By default it builds both a shared and a static library if the OS
316    supports it. You can use --disable-shared or --disable-static on the configure
317    command if you want only one of them.
318    
319    2. The pcretest utility is now installed along with pcregrep because it is
320    useful for users (to test regexs) and by doing this, it automatically gets
321    relinked by libtool. The documentation has been turned into a man page, so
322    there are now .1, .txt, and .html versions in /doc.
323    
324    3. Upgrades to pcregrep:
325       (i)   Added long-form option names like gnu grep.
326       (ii)  Added --help to list all options with an explanatory phrase.
327       (iii) Added -r, --recursive to recurse into sub-directories.
328       (iv)  Added -f, --file to read patterns from a file.
329    
330    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
331    script, to force use of CR or LF instead of \n in the source. On non-Unix
332    systems, the value can be set in config.h.
333    
334    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
335    absolute limit. Changed the text of the error message to make this clear, and
336    likewise updated the man page.
337    
338    6. The limit of 99 on the number of capturing subpatterns has been removed.
339    The new limit is 65535, which I hope will not be a "real" limit.
340    
341    
342  Release 3.3 01-Aug-00  Release 3.3 01-Aug-00
343  ---------------------  ---------------------
344    

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