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revision 43 by nigel, Sat Feb 24 21:39:21 2007 UTC revision 228 by ph10, Tue Aug 28 13:37:37 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    
5    Release 7.3 28-Aug-07
6    ---------------------
7    
8    Most changes are bug fixes. Some that are not:
9    
10    1. There is some support for Perl 5.10's experimental "backtracking control
11       verbs" such as (*PRUNE).
12    
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.
15    
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.
19    
20    4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
21       no longer advance by two characters instead of one when an unanchored match
22       fails at CRLF if there are explicit CR or LF matches within the pattern.
23       This gets rid of some anomalous effects that previously occurred.
24    
25    5. Some PCRE-specific settings for varying the newline options at the start of
26       a pattern have been added.
27    
28    
29    Release 7.2 19-Jun-07
30    ---------------------
31    
32    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
33    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
34    and \V).
35    
36    Correction to the notes for 7.1: the note about shared libraries for Windows is
37    wrong. Previously, three libraries were built, but each could function
38    independently. For example, the pcreposix library also included all the
39    functions from the basic pcre library. The change is that the three libraries
40    are no longer independent. They are like the Unix libraries. To use the
41    pcreposix functions, for example, you need to link with both the pcreposix and
42    the basic pcre library.
43    
44    Some more features from Perl 5.10 have been added:
45    
46      (?-n) and (?+n) relative references for recursion and subroutines.
47    
48      (?(-n) and (?(+n) relative references as conditions.
49    
50      \k{name} and \g{name} are synonyms for \k<name>.
51    
52      \K to reset the start of the matched string; for example, (foo)\Kbar
53      matches bar preceded by foo, but only sets bar as the matched string.
54    
55      (?| introduces a group where the capturing parentheses in each alternative
56      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
57      parentheses number 1 in both cases.
58    
59      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
60    
61    
62    Release 7.1 24-Apr-07
63    ---------------------
64    
65    There is only one new feature in this release: a linebreak setting of
66    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
67    recognizes only CRLF, CR, and LF as linebreaks.
68    
69    A few bugs are fixed (see ChangeLog for details), but the major change is a
70    complete re-implementation of the build system. This now has full Autotools
71    support and so is now "standard" in some sense. It should help with compiling
72    PCRE in a wide variety of environments.
73    
74    NOTE: when building shared libraries for Windows, three dlls are now built,
75    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
76    included in a single dll.
77    
78    Another important change is that the dftables auxiliary program is no longer
79    compiled and run at "make" time by default. Instead, a default set of character
80    tables (assuming ASCII coding) is used. If you want to use dftables to generate
81    the character tables as previously, add --enable-rebuild-chartables to the
82    "configure" command. You must do this if you are compiling PCRE to run on a
83    system that uses EBCDIC code.
84    
85    There is a discussion about character tables in the README file. The default is
86    not to use dftables so that that there is no problem when cross-compiling.
87    
88    
89    Release 7.0 19-Dec-06
90    ---------------------
91    
92    This release has a new major number because there have been some internal
93    upheavals to facilitate the addition of new optimizations and other facilities,
94    and to make subsequent maintenance and extension easier. Compilation is likely
95    to be a bit slower, but there should be no major effect on runtime performance.
96    Previously compiled patterns are NOT upwards compatible with this release. If
97    you have saved compiled patterns from a previous release, you will have to
98    re-compile them. Important changes that are visible to users are:
99    
100    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
101       some more scripts.
102    
103    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
104       sequence as a newline.
105    
106    3. The \R escape matches a single Unicode newline sequence as a single unit.
107    
108    4. New features that will appear in Perl 5.10 are now in PCRE. These include
109       alternative Perl syntax for named parentheses, and Perl syntax for
110       recursion.
111    
112    5. The C++ wrapper interface has been extended by the addition of a
113       QuoteMeta function and the ability to allow copy construction and
114       assignment.
115    
116    For a complete list of changes, see the ChangeLog file.
117    
118    
119    Release 6.7 04-Jul-06
120    ---------------------
121    
122    The main additions to this release are the ability to use the same name for
123    multiple sets of parentheses, and support for CRLF line endings in both the
124    library and pcregrep (and in pcretest for testing).
125    
126    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
127    significantly reduced for certain subject strings.
128    
129    
130    Release 6.5 01-Feb-06
131    ---------------------
132    
133    Important changes in this release:
134    
135    1. A number of new features have been added to pcregrep.
136    
137    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
138       supported properties have been extended with script names such as "Arabic",
139       and the derived properties "Any" and "L&". This has necessitated a change to
140       the interal format of compiled patterns. Any saved compiled patterns that
141       use \p or \P must be recompiled.
142    
143    3. The specification of recursion in patterns has been changed so that all
144       recursive subpatterns are automatically treated as atomic groups. Thus, for
145       example, (?R) is treated as if it were (?>(?R)). This is necessary because
146       otherwise there are situations where recursion does not work.
147    
148    See the ChangeLog for a complete list of changes, which include a number of bug
149    fixes and tidies.
150    
151    
152    Release 6.0 07-Jun-05
153    ---------------------
154    
155    The release number has been increased to 6.0 because of the addition of several
156    major new pieces of functionality.
157    
158    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
159    algorithm, has been added. This has a number of advantages for certain cases,
160    though it does run more slowly, and lacks the ability to capture substrings. On
161    the other hand, it does find all matches, not just the first, and it works
162    better for partial matching. The pcrematching man page discusses the
163    differences.
164    
165    The pcretest program has been enhanced so that it can make use of the new
166    pcre_dfa_exec() matching function and the extra features it provides.
167    
168    The distribution now includes a C++ wrapper library. This is built
169    automatically if a C++ compiler is found. The pcrecpp man page discusses this
170    interface.
171    
172    The code itself has been re-organized into many more files, one for each
173    function, so it no longer requires everything to be linked in when static
174    linkage is used. As a consequence, some internal functions have had to have
175    their names exposed. These functions all have names starting with _pcre_. They
176    are undocumented, and are not intended for use by outside callers.
177    
178    The pcregrep program has been enhanced with new functionality such as
179    multiline-matching and options for output more matching context. See the
180    ChangeLog for a complete list of changes to the library and the utility
181    programs.
182    
183    
184    Release 5.0 13-Sep-04
185    ---------------------
186    
187    The licence under which PCRE is released has been changed to the more
188    conventional "BSD" licence.
189    
190    In the code, some bugs have been fixed, and there are also some major changes
191    in this release (which is why I've increased the number to 5.0). Some changes
192    are internal rearrangements, and some provide a number of new facilities. The
193    new features are:
194    
195    1. There's an "automatic callout" feature that inserts callouts before every
196       item in the regex, and there's a new callout field that gives the position
197       in the pattern - useful for debugging and tracing.
198    
199    2. The extra_data structure can now be used to pass in a set of character
200       tables at exec time. This is useful if compiled regex are saved and re-used
201       at a later time when the tables may not be at the same address. If the
202       default internal tables are used, the pointer saved with the compiled
203       pattern is now set to NULL, which means that you don't need to do anything
204       special unless you are using custom tables.
205    
206    3. It is possible, with some restrictions on the content of the regex, to
207       request "partial" matching. A special return code is given if all of the
208       subject string matched part of the regex. This could be useful for testing
209       an input field as it is being typed.
210    
211    4. There is now some optional support for Unicode character properties, which
212       means that the patterns items such as \p{Lu} and \X can now be used. Only
213       the general category properties are supported. If PCRE is compiled with this
214       support, an additional 90K data structure is include, which increases the
215       size of the library dramatically.
216    
217    5. There is support for saving compiled patterns and re-using them later.
218    
219    6. There is support for running regular expressions that were compiled on a
220       different host with the opposite endianness.
221    
222    7. The pcretest program has been extended to accommodate the new features.
223    
224    The main internal rearrangement is that sequences of literal characters are no
225    longer handled as strings. Instead, each character is handled on its own. This
226    makes some UTF-8 handling easier, and makes the support of partial matching
227    possible. Compiled patterns containing long literal strings will be larger as a
228    result of this change; I hope that performance will not be much affected.
229    
230    
231    Release 4.5 01-Dec-03
232    ---------------------
233    
234    Again mainly a bug-fix and tidying release, with only a couple of new features:
235    
236    1. It's possible now to compile PCRE so that it does not use recursive
237    function calls when matching. Instead it gets memory from the heap. This slows
238    things down, but may be necessary on systems with limited stacks.
239    
240    2. UTF-8 string checking has been tightened to reject overlong sequences and to
241    check that a starting offset points to the start of a character. Failure of the
242    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
243    
244    3. PCRE can now be compiled for systems that use EBCDIC code.
245    
246    
247    Release 4.4 21-Aug-03
248    ---------------------
249    
250    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
251    checks UTF-8 strings for validity by default. There is an option to suppress
252    this, just in case anybody wants that teeny extra bit of performance.
253    
254    
255    Releases 4.1 - 4.3
256    ------------------
257    
258    Sorry, I forgot about updating the NEWS file for these releases. Please take a
259    look at ChangeLog.
260    
261    
262    Release 4.0 17-Feb-03
263    ---------------------
264    
265    There have been a lot of changes for the 4.0 release, adding additional
266    functionality and mending bugs. Below is a list of the highlights of the new
267    functionality. For full details of these features, please consult the
268    documentation. For a complete list of changes, see the ChangeLog file.
269    
270    1. Support for Perl's \Q...\E escapes.
271    
272    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
273    package. They provide some syntactic sugar for simple cases of "atomic
274    grouping".
275    
276    3. Support for the \G assertion. It is true when the current matching position
277    is at the start point of the match.
278    
279    4. A new feature that provides some of the functionality that Perl provides
280    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
281    is for the caller to provide an optional function, by setting pcre_callout to
282    its entry point. To get the function called, the regex must include (?C) at
283    appropriate points.
284    
285    5. Support for recursive calls to individual subpatterns. This makes it really
286    easy to get totally confused.
287    
288    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
289    name a group.
290    
291    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
292    option for pcregrep to make it operate in UTF-8 mode.
293    
294    8. The single man page has been split into a number of separate man pages.
295    These also give rise to individual HTML pages which are put in a separate
296    directory. There is an index.html page that lists them all. Some hyperlinking
297    between the pages has been installed.
298    
299    
300    Release 3.5 15-Aug-01
301    ---------------------
302    
303    1. The configuring system has been upgraded to use later versions of autoconf
304    and libtool. By default it builds both a shared and a static library if the OS
305    supports it. You can use --disable-shared or --disable-static on the configure
306    command if you want only one of them.
307    
308    2. The pcretest utility is now installed along with pcregrep because it is
309    useful for users (to test regexs) and by doing this, it automatically gets
310    relinked by libtool. The documentation has been turned into a man page, so
311    there are now .1, .txt, and .html versions in /doc.
312    
313    3. Upgrades to pcregrep:
314       (i)   Added long-form option names like gnu grep.
315       (ii)  Added --help to list all options with an explanatory phrase.
316       (iii) Added -r, --recursive to recurse into sub-directories.
317       (iv)  Added -f, --file to read patterns from a file.
318    
319    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
320    script, to force use of CR or LF instead of \n in the source. On non-Unix
321    systems, the value can be set in config.h.
322    
323    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
324    absolute limit. Changed the text of the error message to make this clear, and
325    likewise updated the man page.
326    
327    6. The limit of 99 on the number of capturing subpatterns has been removed.
328    The new limit is 65535, which I hope will not be a "real" limit.
329    
330    
331    Release 3.3 01-Aug-00
332    ---------------------
333    
334    There is some support for UTF-8 character strings. This is incomplete and
335    experimental. The documentation describes what is and what is not implemented.
336    Otherwise, this is just a bug-fixing release.
337    
338    
339  Release 3.0 01-Feb-00  Release 3.0 01-Feb-00
340  ---------------------  ---------------------
341    

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