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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 261 by ph10, Fri Sep 21 08:37:48 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
5    Release 7.4 21-Sep-07
6    ---------------------
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.
16    Release 7.3 28-Aug-07
17    ---------------------
19    Most changes are bug fixes. Some that are not:
21    1. There is some support for Perl 5.10's experimental "backtracking control
22       verbs" such as (*PRUNE).
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.
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.
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.
36    5. Some PCRE-specific settings for varying the newline options at the start of
37       a pattern have been added.
40    Release 7.2 19-Jun-07
41    ---------------------
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).
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.
55    Some more features from Perl 5.10 have been added:
57      (?-n) and (?+n) relative references for recursion and subroutines.
59      (?(-n) and (?(+n) relative references as conditions.
61      \k{name} and \g{name} are synonyms for \k<name>.
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.
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.
70      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
73    Release 7.1 24-Apr-07
74    ---------------------
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.
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.
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.
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.
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.
100    Release 7.0 19-Dec-06
101    ---------------------
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:
111    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
112       some more scripts.
114    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
115       sequence as a newline.
117    3. The \R escape matches a single Unicode newline sequence as a single unit.
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.
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.
127    For a complete list of changes, see the ChangeLog file.
130    Release 6.7 04-Jul-06
131    ---------------------
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).
137    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
138    significantly reduced for certain subject strings.
141    Release 6.5 01-Feb-06
142    ---------------------
144    Important changes in this release:
146    1. A number of new features have been added to pcregrep.
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.
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.
159    See the ChangeLog for a complete list of changes, which include a number of bug
160    fixes and tidies.
163    Release 6.0 07-Jun-05
164    ---------------------
166    The release number has been increased to 6.0 because of the addition of several
167    major new pieces of functionality.
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.
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.
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.
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.
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.
195    Release 5.0 13-Sep-04
196    ---------------------
198    The licence under which PCRE is released has been changed to the more
199    conventional "BSD" licence.
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:
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.
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.
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.
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.
228    5. There is support for saving compiled patterns and re-using them later.
230    6. There is support for running regular expressions that were compiled on a
231       different host with the opposite endianness.
233    7. The pcretest program has been extended to accommodate the new features.
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.
242  Release 4.5 01-Dec-03  Release 4.5 01-Dec-03
243  ---------------------  ---------------------

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