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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 157 by ph10, Tue May 1 09:19:56 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
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    ---------------------
7    
8    Correction to the notes for 7.1: the note about shared libraries for Windows is
9    wrong. Previously, three libraries were built, but each could function
10    independently. For example, the pcreposix library also included all the
11    functions from the basic pcre library. The change is that the three libraries
12    are no longer independent. They are like the Unix libraries. To use the
13    pcreposix functions, for example, you need to link with both the pcreposix and
14    the basic pcre library.
15    
16    
17    Release 7.1 24-Apr-07
18    ---------------------
19    
20    There is only one new feature in this release: a linebreak setting of
21    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
22    recognizes only CRLF, CR, and LF as linebreaks.
23    
24    A few bugs are fixed (see ChangeLog for details), but the major change is a
25    complete re-implementation of the build system. This now has full Autotools
26    support and so is now "standard" in some sense. It should help with compiling
27    PCRE in a wide variety of environments.
28    
29    NOTE: when building shared libraries for Windows, three dlls are now built,
30    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
31    included in a single dll.
32    
33    Another important change is that the dftables auxiliary program is no longer
34    compiled and run at "make" time by default. Instead, a default set of character
35    tables (assuming ASCII coding) is used. If you want to use dftables to generate
36    the character tables as previously, add --enable-rebuild-chartables to the
37    "configure" command. You must do this if you are compiling PCRE to run on a
38    system that uses EBCDIC code.
39    
40    There is a discussion about character tables in the README file. The default is
41    not to use dftables so that that there is no problem when cross-compiling.
42    
43    
44    Release 7.0 19-Dec-06
45    ---------------------
46    
47    This release has a new major number because there have been some internal
48    upheavals to facilitate the addition of new optimizations and other facilities,
49    and to make subsequent maintenance and extension easier. Compilation is likely
50    to be a bit slower, but there should be no major effect on runtime performance.
51    Previously compiled patterns are NOT upwards compatible with this release. If
52    you have saved compiled patterns from a previous release, you will have to
53    re-compile them. Important changes that are visible to users are:
54    
55    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
56       some more scripts.
57    
58    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
59       sequence as a newline.
60    
61    3. The \R escape matches a single Unicode newline sequence as a single unit.
62    
63    4. New features that will appear in Perl 5.10 are now in PCRE. These include
64       alternative Perl syntax for named parentheses, and Perl syntax for
65       recursion.
66    
67    5. The C++ wrapper interface has been extended by the addition of a
68       QuoteMeta function and the ability to allow copy construction and
69       assignment.
70    
71    For a complete list of changes, see the ChangeLog file.
72    
73    
74    Release 6.7 04-Jul-06
75    ---------------------
76    
77    The main additions to this release are the ability to use the same name for
78    multiple sets of parentheses, and support for CRLF line endings in both the
79    library and pcregrep (and in pcretest for testing).
80    
81    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
82    significantly reduced for certain subject strings.
83    
84    
85    Release 6.5 01-Feb-06
86    ---------------------
87    
88    Important changes in this release:
89    
90    1. A number of new features have been added to pcregrep.
91    
92    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
93       supported properties have been extended with script names such as "Arabic",
94       and the derived properties "Any" and "L&". This has necessitated a change to
95       the interal format of compiled patterns. Any saved compiled patterns that
96       use \p or \P must be recompiled.
97    
98    3. The specification of recursion in patterns has been changed so that all
99       recursive subpatterns are automatically treated as atomic groups. Thus, for
100       example, (?R) is treated as if it were (?>(?R)). This is necessary because
101       otherwise there are situations where recursion does not work.
102    
103    See the ChangeLog for a complete list of changes, which include a number of bug
104    fixes and tidies.
105    
106    
107    Release 6.0 07-Jun-05
108    ---------------------
109    
110    The release number has been increased to 6.0 because of the addition of several
111    major new pieces of functionality.
112    
113    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
114    algorithm, has been added. This has a number of advantages for certain cases,
115    though it does run more slowly, and lacks the ability to capture substrings. On
116    the other hand, it does find all matches, not just the first, and it works
117    better for partial matching. The pcrematching man page discusses the
118    differences.
119    
120    The pcretest program has been enhanced so that it can make use of the new
121    pcre_dfa_exec() matching function and the extra features it provides.
122    
123    The distribution now includes a C++ wrapper library. This is built
124    automatically if a C++ compiler is found. The pcrecpp man page discusses this
125    interface.
126    
127    The code itself has been re-organized into many more files, one for each
128    function, so it no longer requires everything to be linked in when static
129    linkage is used. As a consequence, some internal functions have had to have
130    their names exposed. These functions all have names starting with _pcre_. They
131    are undocumented, and are not intended for use by outside callers.
132    
133    The pcregrep program has been enhanced with new functionality such as
134    multiline-matching and options for output more matching context. See the
135    ChangeLog for a complete list of changes to the library and the utility
136    programs.
137    
138    
139    Release 5.0 13-Sep-04
140    ---------------------
141    
142    The licence under which PCRE is released has been changed to the more
143    conventional "BSD" licence.
144    
145    In the code, some bugs have been fixed, and there are also some major changes
146    in this release (which is why I've increased the number to 5.0). Some changes
147    are internal rearrangements, and some provide a number of new facilities. The
148    new features are:
149    
150    1. There's an "automatic callout" feature that inserts callouts before every
151       item in the regex, and there's a new callout field that gives the position
152       in the pattern - useful for debugging and tracing.
153    
154    2. The extra_data structure can now be used to pass in a set of character
155       tables at exec time. This is useful if compiled regex are saved and re-used
156       at a later time when the tables may not be at the same address. If the
157       default internal tables are used, the pointer saved with the compiled
158       pattern is now set to NULL, which means that you don't need to do anything
159       special unless you are using custom tables.
160    
161    3. It is possible, with some restrictions on the content of the regex, to
162       request "partial" matching. A special return code is given if all of the
163       subject string matched part of the regex. This could be useful for testing
164       an input field as it is being typed.
165    
166    4. There is now some optional support for Unicode character properties, which
167       means that the patterns items such as \p{Lu} and \X can now be used. Only
168       the general category properties are supported. If PCRE is compiled with this
169       support, an additional 90K data structure is include, which increases the
170       size of the library dramatically.
171    
172    5. There is support for saving compiled patterns and re-using them later.
173    
174    6. There is support for running regular expressions that were compiled on a
175       different host with the opposite endianness.
176    
177    7. The pcretest program has been extended to accommodate the new features.
178    
179    The main internal rearrangement is that sequences of literal characters are no
180    longer handled as strings. Instead, each character is handled on its own. This
181    makes some UTF-8 handling easier, and makes the support of partial matching
182    possible. Compiled patterns containing long literal strings will be larger as a
183    result of this change; I hope that performance will not be much affected.
184    
185    
186    Release 4.5 01-Dec-03
187    ---------------------
188    
189    Again mainly a bug-fix and tidying release, with only a couple of new features:
190    
191    1. It's possible now to compile PCRE so that it does not use recursive
192    function calls when matching. Instead it gets memory from the heap. This slows
193    things down, but may be necessary on systems with limited stacks.
194    
195    2. UTF-8 string checking has been tightened to reject overlong sequences and to
196    check that a starting offset points to the start of a character. Failure of the
197    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
198    
199    3. PCRE can now be compiled for systems that use EBCDIC code.
200    
201    
202    Release 4.4 21-Aug-03
203    ---------------------
204    
205    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
206    checks UTF-8 strings for validity by default. There is an option to suppress
207    this, just in case anybody wants that teeny extra bit of performance.
208    
209    
210    Releases 4.1 - 4.3
211    ------------------
212    
213    Sorry, I forgot about updating the NEWS file for these releases. Please take a
214    look at ChangeLog.
215    
216    
217    Release 4.0 17-Feb-03
218    ---------------------
219    
220    There have been a lot of changes for the 4.0 release, adding additional
221    functionality and mending bugs. Below is a list of the highlights of the new
222    functionality. For full details of these features, please consult the
223    documentation. For a complete list of changes, see the ChangeLog file.
224    
225    1. Support for Perl's \Q...\E escapes.
226    
227    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
228    package. They provide some syntactic sugar for simple cases of "atomic
229    grouping".
230    
231    3. Support for the \G assertion. It is true when the current matching position
232    is at the start point of the match.
233    
234    4. A new feature that provides some of the functionality that Perl provides
235    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
236    is for the caller to provide an optional function, by setting pcre_callout to
237    its entry point. To get the function called, the regex must include (?C) at
238    appropriate points.
239    
240    5. Support for recursive calls to individual subpatterns. This makes it really
241    easy to get totally confused.
242    
243    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
244    name a group.
245    
246    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
247    option for pcregrep to make it operate in UTF-8 mode.
248    
249    8. The single man page has been split into a number of separate man pages.
250    These also give rise to individual HTML pages which are put in a separate
251    directory. There is an index.html page that lists them all. Some hyperlinking
252    between the pages has been installed.
253    
254    
255    Release 3.5 15-Aug-01
256    ---------------------
257    
258    1. The configuring system has been upgraded to use later versions of autoconf
259    and libtool. By default it builds both a shared and a static library if the OS
260    supports it. You can use --disable-shared or --disable-static on the configure
261    command if you want only one of them.
262    
263    2. The pcretest utility is now installed along with pcregrep because it is
264    useful for users (to test regexs) and by doing this, it automatically gets
265    relinked by libtool. The documentation has been turned into a man page, so
266    there are now .1, .txt, and .html versions in /doc.
267    
268    3. Upgrades to pcregrep:
269       (i)   Added long-form option names like gnu grep.
270       (ii)  Added --help to list all options with an explanatory phrase.
271       (iii) Added -r, --recursive to recurse into sub-directories.
272       (iv)  Added -f, --file to read patterns from a file.
273    
274    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
275    script, to force use of CR or LF instead of \n in the source. On non-Unix
276    systems, the value can be set in config.h.
277    
278    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
279    absolute limit. Changed the text of the error message to make this clear, and
280    likewise updated the man page.
281    
282    6. The limit of 99 on the number of capturing subpatterns has been removed.
283    The new limit is 65535, which I hope will not be a "real" limit.
284    
285    
286    Release 3.3 01-Aug-00
287    ---------------------
288    
289    There is some support for UTF-8 character strings. This is incomplete and
290    experimental. The documentation describes what is and what is not implemented.
291    Otherwise, this is just a bug-fixing release.
292    
293    
294    Release 3.0 01-Feb-00
295    ---------------------
296    
297    1. A "configure" script is now used to configure PCRE for Unix systems. It
298    builds a Makefile, a config.h file, and the pcre-config script.
299    
300    2. PCRE is built as a shared library by default.
301    
302    3. There is support for POSIX classes such as [:alpha:].
303    
304    5. There is an experimental recursion feature.
305    
306  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------
307            IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00            IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00

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