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Wed May 9 14:48:28 2007 UTC (7 years, 11 months ago) by ph10
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Add (?-n) and (?+n) relative references.

1 nigel 41 News about PCRE releases
2     ------------------------
4 ph10 122
5 ph10 157 Release 7.2 30-Apr-07
6     ---------------------
8 ph10 159 Correction to the notes for 7.1: the note about shared libraries for Windows is
9     wrong. Previously, three libraries were built, but each could function
10     independently. For example, the pcreposix library also included all the
11     functions from the basic pcre library. The change is that the three libraries
12     are no longer independent. They are like the Unix libraries. To use the
13     pcreposix functions, for example, you need to link with both the pcreposix and
14 ph10 157 the basic pcre library.
16 ph10 166 Some more features from Perl 5.10 have been added:
17 ph10 157
18 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
21 ph10 155 Release 7.1 24-Apr-07
22 nigel 93 ---------------------
24 ph10 155 There is only one new feature in this release: a linebreak setting of
25     PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
26     recognizes only CRLF, CR, and LF as linebreaks.
27 ph10 122
28 ph10 155 A few bugs are fixed (see ChangeLog for details), but the major change is a
29     complete re-implementation of the build system. This now has full Autotools
30     support and so is now "standard" in some sense. It should help with compiling
31     PCRE in a wide variety of environments.
33 ph10 146 NOTE: when building shared libraries for Windows, three dlls are now built,
34     called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
35     included in a single dll.
37     Another important change is that the dftables auxiliary program is no longer
38 ph10 128 compiled and run at "make" time by default. Instead, a default set of character
39     tables (assuming ASCII coding) is used. If you want to use dftables to generate
40     the character tables as previously, add --enable-rebuild-chartables to the
41     "configure" command. You must do this if you are compiling PCRE to run on a
42     system that uses EBCDIC code.
43 ph10 122
44 ph10 128 There is a discussion about character tables in the README file. The default is
45     not to use dftables so that that there is no problem when cross-compiling.
48 ph10 122 Release 7.0 19-Dec-06
49     ---------------------
51 nigel 93 This release has a new major number because there have been some internal
52     upheavals to facilitate the addition of new optimizations and other facilities,
53     and to make subsequent maintenance and extension easier. Compilation is likely
54     to be a bit slower, but there should be no major effect on runtime performance.
55     Previously compiled patterns are NOT upwards compatible with this release. If
56     you have saved compiled patterns from a previous release, you will have to
57     re-compile them. Important changes that are visible to users are:
59     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
60     some more scripts.
62     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
63     sequence as a newline.
65     3. The \R escape matches a single Unicode newline sequence as a single unit.
67     4. New features that will appear in Perl 5.10 are now in PCRE. These include
68     alternative Perl syntax for named parentheses, and Perl syntax for
69     recursion.
71     5. The C++ wrapper interface has been extended by the addition of a
72     QuoteMeta function and the ability to allow copy construction and
73     assignment.
75     For a complete list of changes, see the ChangeLog file.
78 nigel 91 Release 6.7 04-Jul-06
79     ---------------------
81     The main additions to this release are the ability to use the same name for
82     multiple sets of parentheses, and support for CRLF line endings in both the
83     library and pcregrep (and in pcretest for testing).
85     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
86     significantly reduced for certain subject strings.
89 nigel 87 Release 6.5 01-Feb-06
90     ---------------------
92     Important changes in this release:
94     1. A number of new features have been added to pcregrep.
96     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
97     supported properties have been extended with script names such as "Arabic",
98     and the derived properties "Any" and "L&". This has necessitated a change to
99     the interal format of compiled patterns. Any saved compiled patterns that
100     use \p or \P must be recompiled.
102     3. The specification of recursion in patterns has been changed so that all
103     recursive subpatterns are automatically treated as atomic groups. Thus, for
104     example, (?R) is treated as if it were (?>(?R)). This is necessary because
105     otherwise there are situations where recursion does not work.
107     See the ChangeLog for a complete list of changes, which include a number of bug
108     fixes and tidies.
111 nigel 77 Release 6.0 07-Jun-05
112     ---------------------
114     The release number has been increased to 6.0 because of the addition of several
115     major new pieces of functionality.
117     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
118     algorithm, has been added. This has a number of advantages for certain cases,
119     though it does run more slowly, and lacks the ability to capture substrings. On
120     the other hand, it does find all matches, not just the first, and it works
121     better for partial matching. The pcrematching man page discusses the
122     differences.
124     The pcretest program has been enhanced so that it can make use of the new
125     pcre_dfa_exec() matching function and the extra features it provides.
127     The distribution now includes a C++ wrapper library. This is built
128     automatically if a C++ compiler is found. The pcrecpp man page discusses this
129     interface.
131     The code itself has been re-organized into many more files, one for each
132     function, so it no longer requires everything to be linked in when static
133     linkage is used. As a consequence, some internal functions have had to have
134     their names exposed. These functions all have names starting with _pcre_. They
135     are undocumented, and are not intended for use by outside callers.
137     The pcregrep program has been enhanced with new functionality such as
138     multiline-matching and options for output more matching context. See the
139     ChangeLog for a complete list of changes to the library and the utility
140     programs.
143 nigel 75 Release 5.0 13-Sep-04
144     ---------------------
146     The licence under which PCRE is released has been changed to the more
147     conventional "BSD" licence.
149     In the code, some bugs have been fixed, and there are also some major changes
150     in this release (which is why I've increased the number to 5.0). Some changes
151     are internal rearrangements, and some provide a number of new facilities. The
152     new features are:
154     1. There's an "automatic callout" feature that inserts callouts before every
155     item in the regex, and there's a new callout field that gives the position
156     in the pattern - useful for debugging and tracing.
158     2. The extra_data structure can now be used to pass in a set of character
159     tables at exec time. This is useful if compiled regex are saved and re-used
160     at a later time when the tables may not be at the same address. If the
161     default internal tables are used, the pointer saved with the compiled
162     pattern is now set to NULL, which means that you don't need to do anything
163     special unless you are using custom tables.
165     3. It is possible, with some restrictions on the content of the regex, to
166     request "partial" matching. A special return code is given if all of the
167     subject string matched part of the regex. This could be useful for testing
168     an input field as it is being typed.
170     4. There is now some optional support for Unicode character properties, which
171     means that the patterns items such as \p{Lu} and \X can now be used. Only
172     the general category properties are supported. If PCRE is compiled with this
173     support, an additional 90K data structure is include, which increases the
174     size of the library dramatically.
176     5. There is support for saving compiled patterns and re-using them later.
178     6. There is support for running regular expressions that were compiled on a
179     different host with the opposite endianness.
181     7. The pcretest program has been extended to accommodate the new features.
183     The main internal rearrangement is that sequences of literal characters are no
184     longer handled as strings. Instead, each character is handled on its own. This
185     makes some UTF-8 handling easier, and makes the support of partial matching
186     possible. Compiled patterns containing long literal strings will be larger as a
187     result of this change; I hope that performance will not be much affected.
190 nigel 73 Release 4.5 01-Dec-03
191     ---------------------
193     Again mainly a bug-fix and tidying release, with only a couple of new features:
195     1. It's possible now to compile PCRE so that it does not use recursive
196     function calls when matching. Instead it gets memory from the heap. This slows
197     things down, but may be necessary on systems with limited stacks.
199     2. UTF-8 string checking has been tightened to reject overlong sequences and to
200     check that a starting offset points to the start of a character. Failure of the
201     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
203     3. PCRE can now be compiled for systems that use EBCDIC code.
206 nigel 71 Release 4.4 21-Aug-03
207     ---------------------
209     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
210     checks UTF-8 strings for validity by default. There is an option to suppress
211     this, just in case anybody wants that teeny extra bit of performance.
214     Releases 4.1 - 4.3
215     ------------------
217     Sorry, I forgot about updating the NEWS file for these releases. Please take a
218     look at ChangeLog.
221 nigel 63 Release 4.0 17-Feb-03
222     ---------------------
224     There have been a lot of changes for the 4.0 release, adding additional
225     functionality and mending bugs. Below is a list of the highlights of the new
226     functionality. For full details of these features, please consult the
227     documentation. For a complete list of changes, see the ChangeLog file.
229     1. Support for Perl's \Q...\E escapes.
231     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
232     package. They provide some syntactic sugar for simple cases of "atomic
233     grouping".
235     3. Support for the \G assertion. It is true when the current matching position
236     is at the start point of the match.
238     4. A new feature that provides some of the functionality that Perl provides
239     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
240     is for the caller to provide an optional function, by setting pcre_callout to
241     its entry point. To get the function called, the regex must include (?C) at
242     appropriate points.
244     5. Support for recursive calls to individual subpatterns. This makes it really
245     easy to get totally confused.
247     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
248     name a group.
250     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
251     option for pcregrep to make it operate in UTF-8 mode.
253     8. The single man page has been split into a number of separate man pages.
254     These also give rise to individual HTML pages which are put in a separate
255     directory. There is an index.html page that lists them all. Some hyperlinking
256     between the pages has been installed.
259 nigel 53 Release 3.5 15-Aug-01
260     ---------------------
262     1. The configuring system has been upgraded to use later versions of autoconf
263     and libtool. By default it builds both a shared and a static library if the OS
264     supports it. You can use --disable-shared or --disable-static on the configure
265     command if you want only one of them.
267     2. The pcretest utility is now installed along with pcregrep because it is
268     useful for users (to test regexs) and by doing this, it automatically gets
269     relinked by libtool. The documentation has been turned into a man page, so
270     there are now .1, .txt, and .html versions in /doc.
272     3. Upgrades to pcregrep:
273     (i) Added long-form option names like gnu grep.
274     (ii) Added --help to list all options with an explanatory phrase.
275     (iii) Added -r, --recursive to recurse into sub-directories.
276     (iv) Added -f, --file to read patterns from a file.
278     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
279     script, to force use of CR or LF instead of \n in the source. On non-Unix
280     systems, the value can be set in config.h.
282     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
283     absolute limit. Changed the text of the error message to make this clear, and
284     likewise updated the man page.
286     6. The limit of 99 on the number of capturing subpatterns has been removed.
287     The new limit is 65535, which I hope will not be a "real" limit.
290 nigel 49 Release 3.3 01-Aug-00
291     ---------------------
293     There is some support for UTF-8 character strings. This is incomplete and
294     experimental. The documentation describes what is and what is not implemented.
295     Otherwise, this is just a bug-fixing release.
298 nigel 43 Release 3.0 01-Feb-00
299     ---------------------
300 nigel 41
301 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
302     builds a Makefile, a config.h file, and the pcre-config script.
304     2. PCRE is built as a shared library by default.
306     3. There is support for POSIX classes such as [:alpha:].
308     5. There is an experimental recursion feature.
310 nigel 41 ----------------------------------------------------------------------------
313     Please note that there has been a change in the API such that a larger
314     ovector is required at matching time, to provide some additional workspace.
315     The new man page has details. This change was necessary in order to support
316     some of the new functionality in Perl 5.005.
320     Another (I hope this is the last!) change has been made to the API for the
321     pcre_compile() function. An additional argument has been added to make it
322     possible to pass over a pointer to character tables built in the current
323     locale by pcre_maketables(). To use the default tables, this new arguement
324     should be passed as NULL.
328     Yet another (and again I hope this really is the last) change has been made
329     to the API for the pcre_exec() function. An additional argument has been
330     added to make it possible to start the match other than at the start of the
331     subject string. This is important if there are lookbehinds. The new man
332     page has the details, but you just want to convert existing programs, all
333     you need to do is to stick in a new fifth argument to pcre_exec(), with a
334     value of zero. For example, change
336     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
337     to
338     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
340     ****


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