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revision 49 by nigel, Sat Feb 24 21:39:33 2007 UTC revision 93 by nigel, Sat Feb 24 21:41:42 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
4    Release 7.0 23-Nov-06
5    ---------------------
7    This release has a new major number because there have been some internal
8    upheavals to facilitate the addition of new optimizations and other facilities,
9    and to make subsequent maintenance and extension easier. Compilation is likely
10    to be a bit slower, but there should be no major effect on runtime performance.
11    Previously compiled patterns are NOT upwards compatible with this release. If
12    you have saved compiled patterns from a previous release, you will have to
13    re-compile them. Important changes that are visible to users are:
15    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
16       some more scripts.
18    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
19       sequence as a newline.
21    3. The \R escape matches a single Unicode newline sequence as a single unit.
23    4. New features that will appear in Perl 5.10 are now in PCRE. These include
24       alternative Perl syntax for named parentheses, and Perl syntax for
25       recursion.
27    5. The C++ wrapper interface has been extended by the addition of a
28       QuoteMeta function and the ability to allow copy construction and
29       assignment.
31    For a complete list of changes, see the ChangeLog file.
34    Release 6.7 04-Jul-06
35    ---------------------
37    The main additions to this release are the ability to use the same name for
38    multiple sets of parentheses, and support for CRLF line endings in both the
39    library and pcregrep (and in pcretest for testing).
41    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
42    significantly reduced for certain subject strings.
45    Release 6.5 01-Feb-06
46    ---------------------
48    Important changes in this release:
50    1. A number of new features have been added to pcregrep.
52    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
53       supported properties have been extended with script names such as "Arabic",
54       and the derived properties "Any" and "L&". This has necessitated a change to
55       the interal format of compiled patterns. Any saved compiled patterns that
56       use \p or \P must be recompiled.
58    3. The specification of recursion in patterns has been changed so that all
59       recursive subpatterns are automatically treated as atomic groups. Thus, for
60       example, (?R) is treated as if it were (?>(?R)). This is necessary because
61       otherwise there are situations where recursion does not work.
63    See the ChangeLog for a complete list of changes, which include a number of bug
64    fixes and tidies.
67    Release 6.0 07-Jun-05
68    ---------------------
70    The release number has been increased to 6.0 because of the addition of several
71    major new pieces of functionality.
73    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
74    algorithm, has been added. This has a number of advantages for certain cases,
75    though it does run more slowly, and lacks the ability to capture substrings. On
76    the other hand, it does find all matches, not just the first, and it works
77    better for partial matching. The pcrematching man page discusses the
78    differences.
80    The pcretest program has been enhanced so that it can make use of the new
81    pcre_dfa_exec() matching function and the extra features it provides.
83    The distribution now includes a C++ wrapper library. This is built
84    automatically if a C++ compiler is found. The pcrecpp man page discusses this
85    interface.
87    The code itself has been re-organized into many more files, one for each
88    function, so it no longer requires everything to be linked in when static
89    linkage is used. As a consequence, some internal functions have had to have
90    their names exposed. These functions all have names starting with _pcre_. They
91    are undocumented, and are not intended for use by outside callers.
93    The pcregrep program has been enhanced with new functionality such as
94    multiline-matching and options for output more matching context. See the
95    ChangeLog for a complete list of changes to the library and the utility
96    programs.
99    Release 5.0 13-Sep-04
100    ---------------------
102    The licence under which PCRE is released has been changed to the more
103    conventional "BSD" licence.
105    In the code, some bugs have been fixed, and there are also some major changes
106    in this release (which is why I've increased the number to 5.0). Some changes
107    are internal rearrangements, and some provide a number of new facilities. The
108    new features are:
110    1. There's an "automatic callout" feature that inserts callouts before every
111       item in the regex, and there's a new callout field that gives the position
112       in the pattern - useful for debugging and tracing.
114    2. The extra_data structure can now be used to pass in a set of character
115       tables at exec time. This is useful if compiled regex are saved and re-used
116       at a later time when the tables may not be at the same address. If the
117       default internal tables are used, the pointer saved with the compiled
118       pattern is now set to NULL, which means that you don't need to do anything
119       special unless you are using custom tables.
121    3. It is possible, with some restrictions on the content of the regex, to
122       request "partial" matching. A special return code is given if all of the
123       subject string matched part of the regex. This could be useful for testing
124       an input field as it is being typed.
126    4. There is now some optional support for Unicode character properties, which
127       means that the patterns items such as \p{Lu} and \X can now be used. Only
128       the general category properties are supported. If PCRE is compiled with this
129       support, an additional 90K data structure is include, which increases the
130       size of the library dramatically.
132    5. There is support for saving compiled patterns and re-using them later.
134    6. There is support for running regular expressions that were compiled on a
135       different host with the opposite endianness.
137    7. The pcretest program has been extended to accommodate the new features.
139    The main internal rearrangement is that sequences of literal characters are no
140    longer handled as strings. Instead, each character is handled on its own. This
141    makes some UTF-8 handling easier, and makes the support of partial matching
142    possible. Compiled patterns containing long literal strings will be larger as a
143    result of this change; I hope that performance will not be much affected.
146    Release 4.5 01-Dec-03
147    ---------------------
149    Again mainly a bug-fix and tidying release, with only a couple of new features:
151    1. It's possible now to compile PCRE so that it does not use recursive
152    function calls when matching. Instead it gets memory from the heap. This slows
153    things down, but may be necessary on systems with limited stacks.
155    2. UTF-8 string checking has been tightened to reject overlong sequences and to
156    check that a starting offset points to the start of a character. Failure of the
157    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
159    3. PCRE can now be compiled for systems that use EBCDIC code.
162    Release 4.4 21-Aug-03
163    ---------------------
165    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
166    checks UTF-8 strings for validity by default. There is an option to suppress
167    this, just in case anybody wants that teeny extra bit of performance.
170    Releases 4.1 - 4.3
171    ------------------
173    Sorry, I forgot about updating the NEWS file for these releases. Please take a
174    look at ChangeLog.
177    Release 4.0 17-Feb-03
178    ---------------------
180    There have been a lot of changes for the 4.0 release, adding additional
181    functionality and mending bugs. Below is a list of the highlights of the new
182    functionality. For full details of these features, please consult the
183    documentation. For a complete list of changes, see the ChangeLog file.
185    1. Support for Perl's \Q...\E escapes.
187    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
188    package. They provide some syntactic sugar for simple cases of "atomic
189    grouping".
191    3. Support for the \G assertion. It is true when the current matching position
192    is at the start point of the match.
194    4. A new feature that provides some of the functionality that Perl provides
195    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
196    is for the caller to provide an optional function, by setting pcre_callout to
197    its entry point. To get the function called, the regex must include (?C) at
198    appropriate points.
200    5. Support for recursive calls to individual subpatterns. This makes it really
201    easy to get totally confused.
203    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
204    name a group.
206    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
207    option for pcregrep to make it operate in UTF-8 mode.
209    8. The single man page has been split into a number of separate man pages.
210    These also give rise to individual HTML pages which are put in a separate
211    directory. There is an index.html page that lists them all. Some hyperlinking
212    between the pages has been installed.
215    Release 3.5 15-Aug-01
216    ---------------------
218    1. The configuring system has been upgraded to use later versions of autoconf
219    and libtool. By default it builds both a shared and a static library if the OS
220    supports it. You can use --disable-shared or --disable-static on the configure
221    command if you want only one of them.
223    2. The pcretest utility is now installed along with pcregrep because it is
224    useful for users (to test regexs) and by doing this, it automatically gets
225    relinked by libtool. The documentation has been turned into a man page, so
226    there are now .1, .txt, and .html versions in /doc.
228    3. Upgrades to pcregrep:
229       (i)   Added long-form option names like gnu grep.
230       (ii)  Added --help to list all options with an explanatory phrase.
231       (iii) Added -r, --recursive to recurse into sub-directories.
232       (iv)  Added -f, --file to read patterns from a file.
234    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
235    script, to force use of CR or LF instead of \n in the source. On non-Unix
236    systems, the value can be set in config.h.
238    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
239    absolute limit. Changed the text of the error message to make this clear, and
240    likewise updated the man page.
242    6. The limit of 99 on the number of capturing subpatterns has been removed.
243    The new limit is 65535, which I hope will not be a "real" limit.
246  Release 3.3 01-Aug-00  Release 3.3 01-Aug-00
247  ---------------------  ---------------------

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