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

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