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Revision 261 - (hide annotations) (download)
Fri Sep 21 08:37:48 2007 UTC (7 years, 7 months ago) by ph10
File size: 16399 byte(s)
Final doc updates and file tidies for 7.4.

1 nigel 41 News about PCRE releases
2     ------------------------
4 ph10 122
5 ph10 260 Release 7.4 21-Sep-07
6 ph10 242 ---------------------
8 ph10 243 The only change of specification is the addition of options to control whether
9 ph10 242 \R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
10 ph10 243 Otherwise, the changes are bug fixes and a refactoring to reduce the number of
11 ph10 261 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.
14 ph10 242
16 ph10 228 Release 7.3 28-Aug-07
17 ph10 212 ---------------------
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.
30 ph10 227
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 ph10 226 This gets rid of some anomalous effects that previously occurred.
35 ph10 212
36 ph10 227 5. Some PCRE-specific settings for varying the newline options at the start of
37     a pattern have been added.
38 ph10 212
39 ph10 227
40 ph10 184 Release 7.2 19-Jun-07
41 ph10 157 ---------------------
43 ph10 172 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
44 ph10 181 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
45     and \V).
46 ph10 168
47 ph10 159 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 ph10 157 the basic pcre library.
55 ph10 166 Some more features from Perl 5.10 have been added:
56 ph10 157
57 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
58 ph10 172
59     (?(-n) and (?(+n) relative references as conditions.
60 ph10 182
61 ph10 181 \k{name} and \g{name} are synonyms for \k<name>.
62 ph10 172
63 ph10 168 \K to reset the start of the matched string; for example, (foo)\Kbar
64 ph10 175 matches bar preceded by foo, but only sets bar as the matched string.
65 ph10 182
66     (?| introduces a group where the capturing parentheses in each alternative
67     start from the same number; for example, (?|(abc)|(xyz)) sets capturing
68 ph10 175 parentheses number 1 in both cases.
69 ph10 166
70 ph10 182 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
71 ph10 166
72 ph10 182
73 ph10 155 Release 7.1 24-Apr-07
74 nigel 93 ---------------------
76 ph10 155 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.
79 ph10 122
80 ph10 155 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 ph10 146 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 ph10 128 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.
95 ph10 122
96 ph10 128 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 ph10 122 Release 7.0 19-Dec-06
101     ---------------------
103 nigel 93 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 nigel 91 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 nigel 87 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 nigel 77 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 nigel 75 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 nigel 73 Release 4.5 01-Dec-03
243     ---------------------
245     Again mainly a bug-fix and tidying release, with only a couple of new features:
247     1. It's possible now to compile PCRE so that it does not use recursive
248     function calls when matching. Instead it gets memory from the heap. This slows
249     things down, but may be necessary on systems with limited stacks.
251     2. UTF-8 string checking has been tightened to reject overlong sequences and to
252     check that a starting offset points to the start of a character. Failure of the
253     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
255     3. PCRE can now be compiled for systems that use EBCDIC code.
258 nigel 71 Release 4.4 21-Aug-03
259     ---------------------
261     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
262     checks UTF-8 strings for validity by default. There is an option to suppress
263     this, just in case anybody wants that teeny extra bit of performance.
266     Releases 4.1 - 4.3
267     ------------------
269     Sorry, I forgot about updating the NEWS file for these releases. Please take a
270     look at ChangeLog.
273 nigel 63 Release 4.0 17-Feb-03
274     ---------------------
276     There have been a lot of changes for the 4.0 release, adding additional
277     functionality and mending bugs. Below is a list of the highlights of the new
278     functionality. For full details of these features, please consult the
279     documentation. For a complete list of changes, see the ChangeLog file.
281     1. Support for Perl's \Q...\E escapes.
283     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
284     package. They provide some syntactic sugar for simple cases of "atomic
285     grouping".
287     3. Support for the \G assertion. It is true when the current matching position
288     is at the start point of the match.
290     4. A new feature that provides some of the functionality that Perl provides
291     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
292     is for the caller to provide an optional function, by setting pcre_callout to
293     its entry point. To get the function called, the regex must include (?C) at
294     appropriate points.
296     5. Support for recursive calls to individual subpatterns. This makes it really
297     easy to get totally confused.
299     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
300     name a group.
302     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
303     option for pcregrep to make it operate in UTF-8 mode.
305     8. The single man page has been split into a number of separate man pages.
306     These also give rise to individual HTML pages which are put in a separate
307     directory. There is an index.html page that lists them all. Some hyperlinking
308     between the pages has been installed.
311 nigel 53 Release 3.5 15-Aug-01
312     ---------------------
314     1. The configuring system has been upgraded to use later versions of autoconf
315     and libtool. By default it builds both a shared and a static library if the OS
316     supports it. You can use --disable-shared or --disable-static on the configure
317     command if you want only one of them.
319     2. The pcretest utility is now installed along with pcregrep because it is
320     useful for users (to test regexs) and by doing this, it automatically gets
321     relinked by libtool. The documentation has been turned into a man page, so
322     there are now .1, .txt, and .html versions in /doc.
324     3. Upgrades to pcregrep:
325     (i) Added long-form option names like gnu grep.
326     (ii) Added --help to list all options with an explanatory phrase.
327     (iii) Added -r, --recursive to recurse into sub-directories.
328     (iv) Added -f, --file to read patterns from a file.
330     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
331     script, to force use of CR or LF instead of \n in the source. On non-Unix
332     systems, the value can be set in config.h.
334     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
335     absolute limit. Changed the text of the error message to make this clear, and
336     likewise updated the man page.
338     6. The limit of 99 on the number of capturing subpatterns has been removed.
339     The new limit is 65535, which I hope will not be a "real" limit.
342 nigel 49 Release 3.3 01-Aug-00
343     ---------------------
345     There is some support for UTF-8 character strings. This is incomplete and
346     experimental. The documentation describes what is and what is not implemented.
347     Otherwise, this is just a bug-fixing release.
350 nigel 43 Release 3.0 01-Feb-00
351     ---------------------
352 nigel 41
353 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
354     builds a Makefile, a config.h file, and the pcre-config script.
356     2. PCRE is built as a shared library by default.
358     3. There is support for POSIX classes such as [:alpha:].
360     5. There is an experimental recursion feature.
362 nigel 41 ----------------------------------------------------------------------------
365     Please note that there has been a change in the API such that a larger
366     ovector is required at matching time, to provide some additional workspace.
367     The new man page has details. This change was necessary in order to support
368     some of the new functionality in Perl 5.005.
372     Another (I hope this is the last!) change has been made to the API for the
373     pcre_compile() function. An additional argument has been added to make it
374     possible to pass over a pointer to character tables built in the current
375     locale by pcre_maketables(). To use the default tables, this new arguement
376     should be passed as NULL.
380     Yet another (and again I hope this really is the last) change has been made
381     to the API for the pcre_exec() function. An additional argument has been
382     added to make it possible to start the match other than at the start of the
383     subject string. This is important if there are lookbehinds. The new man
384     page has the details, but you just want to convert existing programs, all
385     you need to do is to stick in a new fifth argument to pcre_exec(), with a
386     value of zero. For example, change
388     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
389     to
390     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
392     ****


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