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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 128 by ph10, Tue Mar 20 11:46:50 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4  A "configure" script is now used to configure PCRE for Unix systems. It builds  
5  a Makefile and a config.h file.  Release 7.1 20-Mar-07
6    ---------------------
7    
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.
12    
13    An important change is that the dftables auxiliary program is no longer
14    compiled and run at "make" time by default. Instead, a default set of character
15    tables (assuming ASCII coding) is used. If you want to use dftables to generate
16    the character tables as previously, add --enable-rebuild-chartables to the
17    "configure" command. You must do this if you are compiling PCRE to run on a
18    system that uses EBCDIC code.
19    
20    There is a discussion about character tables in the README file. The default is
21    not to use dftables so that that there is no problem when cross-compiling.
22    
23    
24    Release 7.0 19-Dec-06
25    ---------------------
26    
27    This release has a new major number because there have been some internal
28    upheavals to facilitate the addition of new optimizations and other facilities,
29    and to make subsequent maintenance and extension easier. Compilation is likely
30    to be a bit slower, but there should be no major effect on runtime performance.
31    Previously compiled patterns are NOT upwards compatible with this release. If
32    you have saved compiled patterns from a previous release, you will have to
33    re-compile them. Important changes that are visible to users are:
34    
35    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
36       some more scripts.
37    
38    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
39       sequence as a newline.
40    
41    3. The \R escape matches a single Unicode newline sequence as a single unit.
42    
43    4. New features that will appear in Perl 5.10 are now in PCRE. These include
44       alternative Perl syntax for named parentheses, and Perl syntax for
45       recursion.
46    
47    5. The C++ wrapper interface has been extended by the addition of a
48       QuoteMeta function and the ability to allow copy construction and
49       assignment.
50    
51    For a complete list of changes, see the ChangeLog file.
52    
53    
54    Release 6.7 04-Jul-06
55    ---------------------
56    
57    The main additions to this release are the ability to use the same name for
58    multiple sets of parentheses, and support for CRLF line endings in both the
59    library and pcregrep (and in pcretest for testing).
60    
61    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
62    significantly reduced for certain subject strings.
63    
64    
65    Release 6.5 01-Feb-06
66    ---------------------
67    
68    Important changes in this release:
69    
70    1. A number of new features have been added to pcregrep.
71    
72    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
73       supported properties have been extended with script names such as "Arabic",
74       and the derived properties "Any" and "L&". This has necessitated a change to
75       the interal format of compiled patterns. Any saved compiled patterns that
76       use \p or \P must be recompiled.
77    
78    3. The specification of recursion in patterns has been changed so that all
79       recursive subpatterns are automatically treated as atomic groups. Thus, for
80       example, (?R) is treated as if it were (?>(?R)). This is necessary because
81       otherwise there are situations where recursion does not work.
82    
83    See the ChangeLog for a complete list of changes, which include a number of bug
84    fixes and tidies.
85    
86    
87    Release 6.0 07-Jun-05
88    ---------------------
89    
90    The release number has been increased to 6.0 because of the addition of several
91    major new pieces of functionality.
92    
93    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
94    algorithm, has been added. This has a number of advantages for certain cases,
95    though it does run more slowly, and lacks the ability to capture substrings. On
96    the other hand, it does find all matches, not just the first, and it works
97    better for partial matching. The pcrematching man page discusses the
98    differences.
99    
100    The pcretest program has been enhanced so that it can make use of the new
101    pcre_dfa_exec() matching function and the extra features it provides.
102    
103    The distribution now includes a C++ wrapper library. This is built
104    automatically if a C++ compiler is found. The pcrecpp man page discusses this
105    interface.
106    
107    The code itself has been re-organized into many more files, one for each
108    function, so it no longer requires everything to be linked in when static
109    linkage is used. As a consequence, some internal functions have had to have
110    their names exposed. These functions all have names starting with _pcre_. They
111    are undocumented, and are not intended for use by outside callers.
112    
113    The pcregrep program has been enhanced with new functionality such as
114    multiline-matching and options for output more matching context. See the
115    ChangeLog for a complete list of changes to the library and the utility
116    programs.
117    
118    
119    Release 5.0 13-Sep-04
120    ---------------------
121    
122    The licence under which PCRE is released has been changed to the more
123    conventional "BSD" licence.
124    
125    In the code, some bugs have been fixed, and there are also some major changes
126    in this release (which is why I've increased the number to 5.0). Some changes
127    are internal rearrangements, and some provide a number of new facilities. The
128    new features are:
129    
130    1. There's an "automatic callout" feature that inserts callouts before every
131       item in the regex, and there's a new callout field that gives the position
132       in the pattern - useful for debugging and tracing.
133    
134    2. The extra_data structure can now be used to pass in a set of character
135       tables at exec time. This is useful if compiled regex are saved and re-used
136       at a later time when the tables may not be at the same address. If the
137       default internal tables are used, the pointer saved with the compiled
138       pattern is now set to NULL, which means that you don't need to do anything
139       special unless you are using custom tables.
140    
141    3. It is possible, with some restrictions on the content of the regex, to
142       request "partial" matching. A special return code is given if all of the
143       subject string matched part of the regex. This could be useful for testing
144       an input field as it is being typed.
145    
146    4. There is now some optional support for Unicode character properties, which
147       means that the patterns items such as \p{Lu} and \X can now be used. Only
148       the general category properties are supported. If PCRE is compiled with this
149       support, an additional 90K data structure is include, which increases the
150       size of the library dramatically.
151    
152    5. There is support for saving compiled patterns and re-using them later.
153    
154    6. There is support for running regular expressions that were compiled on a
155       different host with the opposite endianness.
156    
157    7. The pcretest program has been extended to accommodate the new features.
158    
159    The main internal rearrangement is that sequences of literal characters are no
160    longer handled as strings. Instead, each character is handled on its own. This
161    makes some UTF-8 handling easier, and makes the support of partial matching
162    possible. Compiled patterns containing long literal strings will be larger as a
163    result of this change; I hope that performance will not be much affected.
164    
165    
166    Release 4.5 01-Dec-03
167    ---------------------
168    
169    Again mainly a bug-fix and tidying release, with only a couple of new features:
170    
171    1. It's possible now to compile PCRE so that it does not use recursive
172    function calls when matching. Instead it gets memory from the heap. This slows
173    things down, but may be necessary on systems with limited stacks.
174    
175    2. UTF-8 string checking has been tightened to reject overlong sequences and to
176    check that a starting offset points to the start of a character. Failure of the
177    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
178    
179    3. PCRE can now be compiled for systems that use EBCDIC code.
180    
181    
182    Release 4.4 21-Aug-03
183    ---------------------
184    
185    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
186    checks UTF-8 strings for validity by default. There is an option to suppress
187    this, just in case anybody wants that teeny extra bit of performance.
188    
189    
190    Releases 4.1 - 4.3
191    ------------------
192    
193    Sorry, I forgot about updating the NEWS file for these releases. Please take a
194    look at ChangeLog.
195    
196    
197    Release 4.0 17-Feb-03
198    ---------------------
199    
200    There have been a lot of changes for the 4.0 release, adding additional
201    functionality and mending bugs. Below is a list of the highlights of the new
202    functionality. For full details of these features, please consult the
203    documentation. For a complete list of changes, see the ChangeLog file.
204    
205    1. Support for Perl's \Q...\E escapes.
206    
207    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
208    package. They provide some syntactic sugar for simple cases of "atomic
209    grouping".
210    
211    3. Support for the \G assertion. It is true when the current matching position
212    is at the start point of the match.
213    
214    4. A new feature that provides some of the functionality that Perl provides
215    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
216    is for the caller to provide an optional function, by setting pcre_callout to
217    its entry point. To get the function called, the regex must include (?C) at
218    appropriate points.
219    
220    5. Support for recursive calls to individual subpatterns. This makes it really
221    easy to get totally confused.
222    
223    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
224    name a group.
225    
226    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
227    option for pcregrep to make it operate in UTF-8 mode.
228    
229    8. The single man page has been split into a number of separate man pages.
230    These also give rise to individual HTML pages which are put in a separate
231    directory. There is an index.html page that lists them all. Some hyperlinking
232    between the pages has been installed.
233    
234    
235    Release 3.5 15-Aug-01
236    ---------------------
237    
238    1. The configuring system has been upgraded to use later versions of autoconf
239    and libtool. By default it builds both a shared and a static library if the OS
240    supports it. You can use --disable-shared or --disable-static on the configure
241    command if you want only one of them.
242    
243    2. The pcretest utility is now installed along with pcregrep because it is
244    useful for users (to test regexs) and by doing this, it automatically gets
245    relinked by libtool. The documentation has been turned into a man page, so
246    there are now .1, .txt, and .html versions in /doc.
247    
248    3. Upgrades to pcregrep:
249       (i)   Added long-form option names like gnu grep.
250       (ii)  Added --help to list all options with an explanatory phrase.
251       (iii) Added -r, --recursive to recurse into sub-directories.
252       (iv)  Added -f, --file to read patterns from a file.
253    
254    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
255    script, to force use of CR or LF instead of \n in the source. On non-Unix
256    systems, the value can be set in config.h.
257    
258    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
259    absolute limit. Changed the text of the error message to make this clear, and
260    likewise updated the man page.
261    
262    6. The limit of 99 on the number of capturing subpatterns has been removed.
263    The new limit is 65535, which I hope will not be a "real" limit.
264    
265    
266    Release 3.3 01-Aug-00
267    ---------------------
268    
269    There is some support for UTF-8 character strings. This is incomplete and
270    experimental. The documentation describes what is and what is not implemented.
271    Otherwise, this is just a bug-fixing release.
272    
273    
274    Release 3.0 01-Feb-00
275    ---------------------
276    
277    1. A "configure" script is now used to configure PCRE for Unix systems. It
278    builds a Makefile, a config.h file, and the pcre-config script.
279    
280    2. PCRE is built as a shared library by default.
281    
282    3. There is support for POSIX classes such as [:alpha:].
283    
284    5. There is an experimental recursion feature.
285    
286  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------
287            IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00            IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00

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