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Revision 220 - (show annotations)
Thu Aug 16 13:29:39 2007 UTC (14 years, 1 month ago) by ph10
File size: 15507 byte(s)
Tidies for 7.3-RC5 prerelease
1 News about PCRE releases
2 ------------------------
5 Release 7.3 16-Aug-07
6 ---------------------
8 Most changes are bug fixes. Some that are not:
10 1. There is some support for Perl 5.10's experimental "backtracking control
11 verbs" such as (*PRUNE).
13 2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
14 restrictive in the strings it accepts.
16 3. Checking for potential integer overflow has been made more dynamic, and as a
17 consequence there is no longer a hard limit on the size of a subpattern that
18 has a limited repeat count.
21 Release 7.2 19-Jun-07
22 ---------------------
24 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
25 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
26 and \V).
28 Correction to the notes for 7.1: the note about shared libraries for Windows is
29 wrong. Previously, three libraries were built, but each could function
30 independently. For example, the pcreposix library also included all the
31 functions from the basic pcre library. The change is that the three libraries
32 are no longer independent. They are like the Unix libraries. To use the
33 pcreposix functions, for example, you need to link with both the pcreposix and
34 the basic pcre library.
36 Some more features from Perl 5.10 have been added:
38 (?-n) and (?+n) relative references for recursion and subroutines.
40 (?(-n) and (?(+n) relative references as conditions.
42 \k{name} and \g{name} are synonyms for \k<name>.
44 \K to reset the start of the matched string; for example, (foo)\Kbar
45 matches bar preceded by foo, but only sets bar as the matched string.
47 (?| introduces a group where the capturing parentheses in each alternative
48 start from the same number; for example, (?|(abc)|(xyz)) sets capturing
49 parentheses number 1 in both cases.
51 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
54 Release 7.1 24-Apr-07
55 ---------------------
57 There is only one new feature in this release: a linebreak setting of
58 PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
59 recognizes only CRLF, CR, and LF as linebreaks.
61 A few bugs are fixed (see ChangeLog for details), but the major change is a
62 complete re-implementation of the build system. This now has full Autotools
63 support and so is now "standard" in some sense. It should help with compiling
64 PCRE in a wide variety of environments.
66 NOTE: when building shared libraries for Windows, three dlls are now built,
67 called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
68 included in a single dll.
70 Another important change is that the dftables auxiliary program is no longer
71 compiled and run at "make" time by default. Instead, a default set of character
72 tables (assuming ASCII coding) is used. If you want to use dftables to generate
73 the character tables as previously, add --enable-rebuild-chartables to the
74 "configure" command. You must do this if you are compiling PCRE to run on a
75 system that uses EBCDIC code.
77 There is a discussion about character tables in the README file. The default is
78 not to use dftables so that that there is no problem when cross-compiling.
81 Release 7.0 19-Dec-06
82 ---------------------
84 This release has a new major number because there have been some internal
85 upheavals to facilitate the addition of new optimizations and other facilities,
86 and to make subsequent maintenance and extension easier. Compilation is likely
87 to be a bit slower, but there should be no major effect on runtime performance.
88 Previously compiled patterns are NOT upwards compatible with this release. If
89 you have saved compiled patterns from a previous release, you will have to
90 re-compile them. Important changes that are visible to users are:
92 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
93 some more scripts.
95 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
96 sequence as a newline.
98 3. The \R escape matches a single Unicode newline sequence as a single unit.
100 4. New features that will appear in Perl 5.10 are now in PCRE. These include
101 alternative Perl syntax for named parentheses, and Perl syntax for
102 recursion.
104 5. The C++ wrapper interface has been extended by the addition of a
105 QuoteMeta function and the ability to allow copy construction and
106 assignment.
108 For a complete list of changes, see the ChangeLog file.
111 Release 6.7 04-Jul-06
112 ---------------------
114 The main additions to this release are the ability to use the same name for
115 multiple sets of parentheses, and support for CRLF line endings in both the
116 library and pcregrep (and in pcretest for testing).
118 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
119 significantly reduced for certain subject strings.
122 Release 6.5 01-Feb-06
123 ---------------------
125 Important changes in this release:
127 1. A number of new features have been added to pcregrep.
129 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
130 supported properties have been extended with script names such as "Arabic",
131 and the derived properties "Any" and "L&". This has necessitated a change to
132 the interal format of compiled patterns. Any saved compiled patterns that
133 use \p or \P must be recompiled.
135 3. The specification of recursion in patterns has been changed so that all
136 recursive subpatterns are automatically treated as atomic groups. Thus, for
137 example, (?R) is treated as if it were (?>(?R)). This is necessary because
138 otherwise there are situations where recursion does not work.
140 See the ChangeLog for a complete list of changes, which include a number of bug
141 fixes and tidies.
144 Release 6.0 07-Jun-05
145 ---------------------
147 The release number has been increased to 6.0 because of the addition of several
148 major new pieces of functionality.
150 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
151 algorithm, has been added. This has a number of advantages for certain cases,
152 though it does run more slowly, and lacks the ability to capture substrings. On
153 the other hand, it does find all matches, not just the first, and it works
154 better for partial matching. The pcrematching man page discusses the
155 differences.
157 The pcretest program has been enhanced so that it can make use of the new
158 pcre_dfa_exec() matching function and the extra features it provides.
160 The distribution now includes a C++ wrapper library. This is built
161 automatically if a C++ compiler is found. The pcrecpp man page discusses this
162 interface.
164 The code itself has been re-organized into many more files, one for each
165 function, so it no longer requires everything to be linked in when static
166 linkage is used. As a consequence, some internal functions have had to have
167 their names exposed. These functions all have names starting with _pcre_. They
168 are undocumented, and are not intended for use by outside callers.
170 The pcregrep program has been enhanced with new functionality such as
171 multiline-matching and options for output more matching context. See the
172 ChangeLog for a complete list of changes to the library and the utility
173 programs.
176 Release 5.0 13-Sep-04
177 ---------------------
179 The licence under which PCRE is released has been changed to the more
180 conventional "BSD" licence.
182 In the code, some bugs have been fixed, and there are also some major changes
183 in this release (which is why I've increased the number to 5.0). Some changes
184 are internal rearrangements, and some provide a number of new facilities. The
185 new features are:
187 1. There's an "automatic callout" feature that inserts callouts before every
188 item in the regex, and there's a new callout field that gives the position
189 in the pattern - useful for debugging and tracing.
191 2. The extra_data structure can now be used to pass in a set of character
192 tables at exec time. This is useful if compiled regex are saved and re-used
193 at a later time when the tables may not be at the same address. If the
194 default internal tables are used, the pointer saved with the compiled
195 pattern is now set to NULL, which means that you don't need to do anything
196 special unless you are using custom tables.
198 3. It is possible, with some restrictions on the content of the regex, to
199 request "partial" matching. A special return code is given if all of the
200 subject string matched part of the regex. This could be useful for testing
201 an input field as it is being typed.
203 4. There is now some optional support for Unicode character properties, which
204 means that the patterns items such as \p{Lu} and \X can now be used. Only
205 the general category properties are supported. If PCRE is compiled with this
206 support, an additional 90K data structure is include, which increases the
207 size of the library dramatically.
209 5. There is support for saving compiled patterns and re-using them later.
211 6. There is support for running regular expressions that were compiled on a
212 different host with the opposite endianness.
214 7. The pcretest program has been extended to accommodate the new features.
216 The main internal rearrangement is that sequences of literal characters are no
217 longer handled as strings. Instead, each character is handled on its own. This
218 makes some UTF-8 handling easier, and makes the support of partial matching
219 possible. Compiled patterns containing long literal strings will be larger as a
220 result of this change; I hope that performance will not be much affected.
223 Release 4.5 01-Dec-03
224 ---------------------
226 Again mainly a bug-fix and tidying release, with only a couple of new features:
228 1. It's possible now to compile PCRE so that it does not use recursive
229 function calls when matching. Instead it gets memory from the heap. This slows
230 things down, but may be necessary on systems with limited stacks.
232 2. UTF-8 string checking has been tightened to reject overlong sequences and to
233 check that a starting offset points to the start of a character. Failure of the
234 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
236 3. PCRE can now be compiled for systems that use EBCDIC code.
239 Release 4.4 21-Aug-03
240 ---------------------
242 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
243 checks UTF-8 strings for validity by default. There is an option to suppress
244 this, just in case anybody wants that teeny extra bit of performance.
247 Releases 4.1 - 4.3
248 ------------------
250 Sorry, I forgot about updating the NEWS file for these releases. Please take a
251 look at ChangeLog.
254 Release 4.0 17-Feb-03
255 ---------------------
257 There have been a lot of changes for the 4.0 release, adding additional
258 functionality and mending bugs. Below is a list of the highlights of the new
259 functionality. For full details of these features, please consult the
260 documentation. For a complete list of changes, see the ChangeLog file.
262 1. Support for Perl's \Q...\E escapes.
264 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
265 package. They provide some syntactic sugar for simple cases of "atomic
266 grouping".
268 3. Support for the \G assertion. It is true when the current matching position
269 is at the start point of the match.
271 4. A new feature that provides some of the functionality that Perl provides
272 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
273 is for the caller to provide an optional function, by setting pcre_callout to
274 its entry point. To get the function called, the regex must include (?C) at
275 appropriate points.
277 5. Support for recursive calls to individual subpatterns. This makes it really
278 easy to get totally confused.
280 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
281 name a group.
283 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
284 option for pcregrep to make it operate in UTF-8 mode.
286 8. The single man page has been split into a number of separate man pages.
287 These also give rise to individual HTML pages which are put in a separate
288 directory. There is an index.html page that lists them all. Some hyperlinking
289 between the pages has been installed.
292 Release 3.5 15-Aug-01
293 ---------------------
295 1. The configuring system has been upgraded to use later versions of autoconf
296 and libtool. By default it builds both a shared and a static library if the OS
297 supports it. You can use --disable-shared or --disable-static on the configure
298 command if you want only one of them.
300 2. The pcretest utility is now installed along with pcregrep because it is
301 useful for users (to test regexs) and by doing this, it automatically gets
302 relinked by libtool. The documentation has been turned into a man page, so
303 there are now .1, .txt, and .html versions in /doc.
305 3. Upgrades to pcregrep:
306 (i) Added long-form option names like gnu grep.
307 (ii) Added --help to list all options with an explanatory phrase.
308 (iii) Added -r, --recursive to recurse into sub-directories.
309 (iv) Added -f, --file to read patterns from a file.
311 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
312 script, to force use of CR or LF instead of \n in the source. On non-Unix
313 systems, the value can be set in config.h.
315 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
316 absolute limit. Changed the text of the error message to make this clear, and
317 likewise updated the man page.
319 6. The limit of 99 on the number of capturing subpatterns has been removed.
320 The new limit is 65535, which I hope will not be a "real" limit.
323 Release 3.3 01-Aug-00
324 ---------------------
326 There is some support for UTF-8 character strings. This is incomplete and
327 experimental. The documentation describes what is and what is not implemented.
328 Otherwise, this is just a bug-fixing release.
331 Release 3.0 01-Feb-00
332 ---------------------
334 1. A "configure" script is now used to configure PCRE for Unix systems. It
335 builds a Makefile, a config.h file, and the pcre-config script.
337 2. PCRE is built as a shared library by default.
339 3. There is support for POSIX classes such as [:alpha:].
341 5. There is an experimental recursion feature.
343 ----------------------------------------------------------------------------
346 Please note that there has been a change in the API such that a larger
347 ovector is required at matching time, to provide some additional workspace.
348 The new man page has details. This change was necessary in order to support
349 some of the new functionality in Perl 5.005.
353 Another (I hope this is the last!) change has been made to the API for the
354 pcre_compile() function. An additional argument has been added to make it
355 possible to pass over a pointer to character tables built in the current
356 locale by pcre_maketables(). To use the default tables, this new arguement
357 should be passed as NULL.
361 Yet another (and again I hope this really is the last) change has been made
362 to the API for the pcre_exec() function. An additional argument has been
363 added to make it possible to start the match other than at the start of the
364 subject string. This is important if there are lookbehinds. The new man
365 page has the details, but you just want to convert existing programs, all
366 you need to do is to stick in a new fifth argument to pcre_exec(), with a
367 value of zero. For example, change
369 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
370 to
371 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
373 ****


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