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revision 53 by nigel, Sat Feb 24 21:39:42 2007 UTC revision 168 by ph10, Tue May 29 15:18:18 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    
5    Release 7.2 30-Apr-07
6    ---------------------
7    
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).
10    
11    Correction to the notes for 7.1: the note about shared libraries for Windows is
12    wrong. Previously, three libraries were built, but each could function
13    independently. For example, the pcreposix library also included all the
14    functions from the basic pcre library. The change is that the three libraries
15    are no longer independent. They are like the Unix libraries. To use the
16    pcreposix functions, for example, you need to link with both the pcreposix and
17    the basic pcre library.
18    
19    Some more features from Perl 5.10 have been added:
20    
21      (?-n) and (?+n) relative references for recursion and subroutines.
22    
23      (Not sure if this one is actually in Perl 5.10)
24      (?(-n) and (?(+n) relative references as conditions.
25    
26      \K to reset the start of the matched string; for example, (foo)\Kbar
27      matches bar preceded by foo, but only sets bar as the matched string
28    
29    
30    Release 7.1 24-Apr-07
31    ---------------------
32    
33    There is only one new feature in this release: a linebreak setting of
34    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
35    recognizes only CRLF, CR, and LF as linebreaks.
36    
37    A few bugs are fixed (see ChangeLog for details), but the major change is a
38    complete re-implementation of the build system. This now has full Autotools
39    support and so is now "standard" in some sense. It should help with compiling
40    PCRE in a wide variety of environments.
41    
42    NOTE: when building shared libraries for Windows, three dlls are now built,
43    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
44    included in a single dll.
45    
46    Another important change is that the dftables auxiliary program is no longer
47    compiled and run at "make" time by default. Instead, a default set of character
48    tables (assuming ASCII coding) is used. If you want to use dftables to generate
49    the character tables as previously, add --enable-rebuild-chartables to the
50    "configure" command. You must do this if you are compiling PCRE to run on a
51    system that uses EBCDIC code.
52    
53    There is a discussion about character tables in the README file. The default is
54    not to use dftables so that that there is no problem when cross-compiling.
55    
56    
57    Release 7.0 19-Dec-06
58    ---------------------
59    
60    This release has a new major number because there have been some internal
61    upheavals to facilitate the addition of new optimizations and other facilities,
62    and to make subsequent maintenance and extension easier. Compilation is likely
63    to be a bit slower, but there should be no major effect on runtime performance.
64    Previously compiled patterns are NOT upwards compatible with this release. If
65    you have saved compiled patterns from a previous release, you will have to
66    re-compile them. Important changes that are visible to users are:
67    
68    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
69       some more scripts.
70    
71    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
72       sequence as a newline.
73    
74    3. The \R escape matches a single Unicode newline sequence as a single unit.
75    
76    4. New features that will appear in Perl 5.10 are now in PCRE. These include
77       alternative Perl syntax for named parentheses, and Perl syntax for
78       recursion.
79    
80    5. The C++ wrapper interface has been extended by the addition of a
81       QuoteMeta function and the ability to allow copy construction and
82       assignment.
83    
84    For a complete list of changes, see the ChangeLog file.
85    
86    
87    Release 6.7 04-Jul-06
88    ---------------------
89    
90    The main additions to this release are the ability to use the same name for
91    multiple sets of parentheses, and support for CRLF line endings in both the
92    library and pcregrep (and in pcretest for testing).
93    
94    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
95    significantly reduced for certain subject strings.
96    
97    
98    Release 6.5 01-Feb-06
99    ---------------------
100    
101    Important changes in this release:
102    
103    1. A number of new features have been added to pcregrep.
104    
105    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
106       supported properties have been extended with script names such as "Arabic",
107       and the derived properties "Any" and "L&". This has necessitated a change to
108       the interal format of compiled patterns. Any saved compiled patterns that
109       use \p or \P must be recompiled.
110    
111    3. The specification of recursion in patterns has been changed so that all
112       recursive subpatterns are automatically treated as atomic groups. Thus, for
113       example, (?R) is treated as if it were (?>(?R)). This is necessary because
114       otherwise there are situations where recursion does not work.
115    
116    See the ChangeLog for a complete list of changes, which include a number of bug
117    fixes and tidies.
118    
119    
120    Release 6.0 07-Jun-05
121    ---------------------
122    
123    The release number has been increased to 6.0 because of the addition of several
124    major new pieces of functionality.
125    
126    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
127    algorithm, has been added. This has a number of advantages for certain cases,
128    though it does run more slowly, and lacks the ability to capture substrings. On
129    the other hand, it does find all matches, not just the first, and it works
130    better for partial matching. The pcrematching man page discusses the
131    differences.
132    
133    The pcretest program has been enhanced so that it can make use of the new
134    pcre_dfa_exec() matching function and the extra features it provides.
135    
136    The distribution now includes a C++ wrapper library. This is built
137    automatically if a C++ compiler is found. The pcrecpp man page discusses this
138    interface.
139    
140    The code itself has been re-organized into many more files, one for each
141    function, so it no longer requires everything to be linked in when static
142    linkage is used. As a consequence, some internal functions have had to have
143    their names exposed. These functions all have names starting with _pcre_. They
144    are undocumented, and are not intended for use by outside callers.
145    
146    The pcregrep program has been enhanced with new functionality such as
147    multiline-matching and options for output more matching context. See the
148    ChangeLog for a complete list of changes to the library and the utility
149    programs.
150    
151    
152    Release 5.0 13-Sep-04
153    ---------------------
154    
155    The licence under which PCRE is released has been changed to the more
156    conventional "BSD" licence.
157    
158    In the code, some bugs have been fixed, and there are also some major changes
159    in this release (which is why I've increased the number to 5.0). Some changes
160    are internal rearrangements, and some provide a number of new facilities. The
161    new features are:
162    
163    1. There's an "automatic callout" feature that inserts callouts before every
164       item in the regex, and there's a new callout field that gives the position
165       in the pattern - useful for debugging and tracing.
166    
167    2. The extra_data structure can now be used to pass in a set of character
168       tables at exec time. This is useful if compiled regex are saved and re-used
169       at a later time when the tables may not be at the same address. If the
170       default internal tables are used, the pointer saved with the compiled
171       pattern is now set to NULL, which means that you don't need to do anything
172       special unless you are using custom tables.
173    
174    3. It is possible, with some restrictions on the content of the regex, to
175       request "partial" matching. A special return code is given if all of the
176       subject string matched part of the regex. This could be useful for testing
177       an input field as it is being typed.
178    
179    4. There is now some optional support for Unicode character properties, which
180       means that the patterns items such as \p{Lu} and \X can now be used. Only
181       the general category properties are supported. If PCRE is compiled with this
182       support, an additional 90K data structure is include, which increases the
183       size of the library dramatically.
184    
185    5. There is support for saving compiled patterns and re-using them later.
186    
187    6. There is support for running regular expressions that were compiled on a
188       different host with the opposite endianness.
189    
190    7. The pcretest program has been extended to accommodate the new features.
191    
192    The main internal rearrangement is that sequences of literal characters are no
193    longer handled as strings. Instead, each character is handled on its own. This
194    makes some UTF-8 handling easier, and makes the support of partial matching
195    possible. Compiled patterns containing long literal strings will be larger as a
196    result of this change; I hope that performance will not be much affected.
197    
198    
199    Release 4.5 01-Dec-03
200    ---------------------
201    
202    Again mainly a bug-fix and tidying release, with only a couple of new features:
203    
204    1. It's possible now to compile PCRE so that it does not use recursive
205    function calls when matching. Instead it gets memory from the heap. This slows
206    things down, but may be necessary on systems with limited stacks.
207    
208    2. UTF-8 string checking has been tightened to reject overlong sequences and to
209    check that a starting offset points to the start of a character. Failure of the
210    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
211    
212    3. PCRE can now be compiled for systems that use EBCDIC code.
213    
214    
215    Release 4.4 21-Aug-03
216    ---------------------
217    
218    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
219    checks UTF-8 strings for validity by default. There is an option to suppress
220    this, just in case anybody wants that teeny extra bit of performance.
221    
222    
223    Releases 4.1 - 4.3
224    ------------------
225    
226    Sorry, I forgot about updating the NEWS file for these releases. Please take a
227    look at ChangeLog.
228    
229    
230    Release 4.0 17-Feb-03
231    ---------------------
232    
233    There have been a lot of changes for the 4.0 release, adding additional
234    functionality and mending bugs. Below is a list of the highlights of the new
235    functionality. For full details of these features, please consult the
236    documentation. For a complete list of changes, see the ChangeLog file.
237    
238    1. Support for Perl's \Q...\E escapes.
239    
240    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
241    package. They provide some syntactic sugar for simple cases of "atomic
242    grouping".
243    
244    3. Support for the \G assertion. It is true when the current matching position
245    is at the start point of the match.
246    
247    4. A new feature that provides some of the functionality that Perl provides
248    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
249    is for the caller to provide an optional function, by setting pcre_callout to
250    its entry point. To get the function called, the regex must include (?C) at
251    appropriate points.
252    
253    5. Support for recursive calls to individual subpatterns. This makes it really
254    easy to get totally confused.
255    
256    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
257    name a group.
258    
259    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
260    option for pcregrep to make it operate in UTF-8 mode.
261    
262    8. The single man page has been split into a number of separate man pages.
263    These also give rise to individual HTML pages which are put in a separate
264    directory. There is an index.html page that lists them all. Some hyperlinking
265    between the pages has been installed.
266    
267    
268  Release 3.5 15-Aug-01  Release 3.5 15-Aug-01
269  ---------------------  ---------------------
270    

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