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revision 53 by nigel, Sat Feb 24 21:39:42 2007 UTC revision 146 by ph10, Thu Apr 5 09:17:28 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
5    Release 7.1 20-Mar-07
6    ---------------------
8    There are no new features in this release. A few bugs are fixed (see ChangeLog
9    for details), but the major change is a complete re-implementation of the build
10    system. This now has full Autotools support and so is now "standard" in some
11    sense. It should help with compiling PCRE in a wide variety of environments.
13    NOTE: when building shared libraries for Windows, three dlls are now built,
14    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
15    included in a single dll.
17    Another important change is that the dftables auxiliary program is no longer
18    compiled and run at "make" time by default. Instead, a default set of character
19    tables (assuming ASCII coding) is used. If you want to use dftables to generate
20    the character tables as previously, add --enable-rebuild-chartables to the
21    "configure" command. You must do this if you are compiling PCRE to run on a
22    system that uses EBCDIC code.
24    There is a discussion about character tables in the README file. The default is
25    not to use dftables so that that there is no problem when cross-compiling.
28    Release 7.0 19-Dec-06
29    ---------------------
31    This release has a new major number because there have been some internal
32    upheavals to facilitate the addition of new optimizations and other facilities,
33    and to make subsequent maintenance and extension easier. Compilation is likely
34    to be a bit slower, but there should be no major effect on runtime performance.
35    Previously compiled patterns are NOT upwards compatible with this release. If
36    you have saved compiled patterns from a previous release, you will have to
37    re-compile them. Important changes that are visible to users are:
39    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
40       some more scripts.
42    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
43       sequence as a newline.
45    3. The \R escape matches a single Unicode newline sequence as a single unit.
47    4. New features that will appear in Perl 5.10 are now in PCRE. These include
48       alternative Perl syntax for named parentheses, and Perl syntax for
49       recursion.
51    5. The C++ wrapper interface has been extended by the addition of a
52       QuoteMeta function and the ability to allow copy construction and
53       assignment.
55    For a complete list of changes, see the ChangeLog file.
58    Release 6.7 04-Jul-06
59    ---------------------
61    The main additions to this release are the ability to use the same name for
62    multiple sets of parentheses, and support for CRLF line endings in both the
63    library and pcregrep (and in pcretest for testing).
65    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
66    significantly reduced for certain subject strings.
69    Release 6.5 01-Feb-06
70    ---------------------
72    Important changes in this release:
74    1. A number of new features have been added to pcregrep.
76    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
77       supported properties have been extended with script names such as "Arabic",
78       and the derived properties "Any" and "L&". This has necessitated a change to
79       the interal format of compiled patterns. Any saved compiled patterns that
80       use \p or \P must be recompiled.
82    3. The specification of recursion in patterns has been changed so that all
83       recursive subpatterns are automatically treated as atomic groups. Thus, for
84       example, (?R) is treated as if it were (?>(?R)). This is necessary because
85       otherwise there are situations where recursion does not work.
87    See the ChangeLog for a complete list of changes, which include a number of bug
88    fixes and tidies.
91    Release 6.0 07-Jun-05
92    ---------------------
94    The release number has been increased to 6.0 because of the addition of several
95    major new pieces of functionality.
97    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
98    algorithm, has been added. This has a number of advantages for certain cases,
99    though it does run more slowly, and lacks the ability to capture substrings. On
100    the other hand, it does find all matches, not just the first, and it works
101    better for partial matching. The pcrematching man page discusses the
102    differences.
104    The pcretest program has been enhanced so that it can make use of the new
105    pcre_dfa_exec() matching function and the extra features it provides.
107    The distribution now includes a C++ wrapper library. This is built
108    automatically if a C++ compiler is found. The pcrecpp man page discusses this
109    interface.
111    The code itself has been re-organized into many more files, one for each
112    function, so it no longer requires everything to be linked in when static
113    linkage is used. As a consequence, some internal functions have had to have
114    their names exposed. These functions all have names starting with _pcre_. They
115    are undocumented, and are not intended for use by outside callers.
117    The pcregrep program has been enhanced with new functionality such as
118    multiline-matching and options for output more matching context. See the
119    ChangeLog for a complete list of changes to the library and the utility
120    programs.
123    Release 5.0 13-Sep-04
124    ---------------------
126    The licence under which PCRE is released has been changed to the more
127    conventional "BSD" licence.
129    In the code, some bugs have been fixed, and there are also some major changes
130    in this release (which is why I've increased the number to 5.0). Some changes
131    are internal rearrangements, and some provide a number of new facilities. The
132    new features are:
134    1. There's an "automatic callout" feature that inserts callouts before every
135       item in the regex, and there's a new callout field that gives the position
136       in the pattern - useful for debugging and tracing.
138    2. The extra_data structure can now be used to pass in a set of character
139       tables at exec time. This is useful if compiled regex are saved and re-used
140       at a later time when the tables may not be at the same address. If the
141       default internal tables are used, the pointer saved with the compiled
142       pattern is now set to NULL, which means that you don't need to do anything
143       special unless you are using custom tables.
145    3. It is possible, with some restrictions on the content of the regex, to
146       request "partial" matching. A special return code is given if all of the
147       subject string matched part of the regex. This could be useful for testing
148       an input field as it is being typed.
150    4. There is now some optional support for Unicode character properties, which
151       means that the patterns items such as \p{Lu} and \X can now be used. Only
152       the general category properties are supported. If PCRE is compiled with this
153       support, an additional 90K data structure is include, which increases the
154       size of the library dramatically.
156    5. There is support for saving compiled patterns and re-using them later.
158    6. There is support for running regular expressions that were compiled on a
159       different host with the opposite endianness.
161    7. The pcretest program has been extended to accommodate the new features.
163    The main internal rearrangement is that sequences of literal characters are no
164    longer handled as strings. Instead, each character is handled on its own. This
165    makes some UTF-8 handling easier, and makes the support of partial matching
166    possible. Compiled patterns containing long literal strings will be larger as a
167    result of this change; I hope that performance will not be much affected.
170    Release 4.5 01-Dec-03
171    ---------------------
173    Again mainly a bug-fix and tidying release, with only a couple of new features:
175    1. It's possible now to compile PCRE so that it does not use recursive
176    function calls when matching. Instead it gets memory from the heap. This slows
177    things down, but may be necessary on systems with limited stacks.
179    2. UTF-8 string checking has been tightened to reject overlong sequences and to
180    check that a starting offset points to the start of a character. Failure of the
181    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
183    3. PCRE can now be compiled for systems that use EBCDIC code.
186    Release 4.4 21-Aug-03
187    ---------------------
189    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
190    checks UTF-8 strings for validity by default. There is an option to suppress
191    this, just in case anybody wants that teeny extra bit of performance.
194    Releases 4.1 - 4.3
195    ------------------
197    Sorry, I forgot about updating the NEWS file for these releases. Please take a
198    look at ChangeLog.
201    Release 4.0 17-Feb-03
202    ---------------------
204    There have been a lot of changes for the 4.0 release, adding additional
205    functionality and mending bugs. Below is a list of the highlights of the new
206    functionality. For full details of these features, please consult the
207    documentation. For a complete list of changes, see the ChangeLog file.
209    1. Support for Perl's \Q...\E escapes.
211    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
212    package. They provide some syntactic sugar for simple cases of "atomic
213    grouping".
215    3. Support for the \G assertion. It is true when the current matching position
216    is at the start point of the match.
218    4. A new feature that provides some of the functionality that Perl provides
219    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
220    is for the caller to provide an optional function, by setting pcre_callout to
221    its entry point. To get the function called, the regex must include (?C) at
222    appropriate points.
224    5. Support for recursive calls to individual subpatterns. This makes it really
225    easy to get totally confused.
227    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
228    name a group.
230    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
231    option for pcregrep to make it operate in UTF-8 mode.
233    8. The single man page has been split into a number of separate man pages.
234    These also give rise to individual HTML pages which are put in a separate
235    directory. There is an index.html page that lists them all. Some hyperlinking
236    between the pages has been installed.
239  Release 3.5 15-Aug-01  Release 3.5 15-Aug-01
240  ---------------------  ---------------------

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