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Contents of /code/tags/pcre-7.2/NEWS

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Revision 168 - (show annotations) (download)
Tue May 29 15:18:18 2007 UTC (7 years, 6 months ago) by ph10
Original Path: code/trunk/NEWS
File size: 14719 byte(s)
Add support for the Perl 5.10 \K facility.

1 News about PCRE releases
2 ------------------------
3
4
5 Release 7.2 30-Apr-07
6 ---------------------
7
8 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
9 recompiled for use with 7.2 (necessitated by the addition of \K).
10
11 Correction to the notes for 7.1: the note about shared libraries for Windows is
12 wrong. Previously, three libraries were built, but each could function
13 independently. For example, the pcreposix library also included all the
14 functions from the basic pcre library. The change is that the three libraries
15 are no longer independent. They are like the Unix libraries. To use the
16 pcreposix functions, for example, you need to link with both the pcreposix and
17 the basic pcre library.
18
19 Some more features from Perl 5.10 have been added:
20
21 (?-n) and (?+n) relative references for recursion and subroutines.
22
23 (Not sure if this one is actually in Perl 5.10)
24 (?(-n) and (?(+n) relative references as conditions.
25
26 \K to reset the start of the matched string; for example, (foo)\Kbar
27 matches bar preceded by foo, but only sets bar as the matched string
28
29
30 Release 7.1 24-Apr-07
31 ---------------------
32
33 There is only one new feature in this release: a linebreak setting of
34 PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
35 recognizes only CRLF, CR, and LF as linebreaks.
36
37 A few bugs are fixed (see ChangeLog for details), but the major change is a
38 complete re-implementation of the build system. This now has full Autotools
39 support and so is now "standard" in some sense. It should help with compiling
40 PCRE in a wide variety of environments.
41
42 NOTE: when building shared libraries for Windows, three dlls are now built,
43 called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
44 included in a single dll.
45
46 Another important change is that the dftables auxiliary program is no longer
47 compiled and run at "make" time by default. Instead, a default set of character
48 tables (assuming ASCII coding) is used. If you want to use dftables to generate
49 the character tables as previously, add --enable-rebuild-chartables to the
50 "configure" command. You must do this if you are compiling PCRE to run on a
51 system that uses EBCDIC code.
52
53 There is a discussion about character tables in the README file. The default is
54 not to use dftables so that that there is no problem when cross-compiling.
55
56
57 Release 7.0 19-Dec-06
58 ---------------------
59
60 This release has a new major number because there have been some internal
61 upheavals to facilitate the addition of new optimizations and other facilities,
62 and to make subsequent maintenance and extension easier. Compilation is likely
63 to be a bit slower, but there should be no major effect on runtime performance.
64 Previously compiled patterns are NOT upwards compatible with this release. If
65 you have saved compiled patterns from a previous release, you will have to
66 re-compile them. Important changes that are visible to users are:
67
68 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
69 some more scripts.
70
71 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
72 sequence as a newline.
73
74 3. The \R escape matches a single Unicode newline sequence as a single unit.
75
76 4. New features that will appear in Perl 5.10 are now in PCRE. These include
77 alternative Perl syntax for named parentheses, and Perl syntax for
78 recursion.
79
80 5. The C++ wrapper interface has been extended by the addition of a
81 QuoteMeta function and the ability to allow copy construction and
82 assignment.
83
84 For a complete list of changes, see the ChangeLog file.
85
86
87 Release 6.7 04-Jul-06
88 ---------------------
89
90 The main additions to this release are the ability to use the same name for
91 multiple sets of parentheses, and support for CRLF line endings in both the
92 library and pcregrep (and in pcretest for testing).
93
94 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
95 significantly reduced for certain subject strings.
96
97
98 Release 6.5 01-Feb-06
99 ---------------------
100
101 Important changes in this release:
102
103 1. A number of new features have been added to pcregrep.
104
105 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
106 supported properties have been extended with script names such as "Arabic",
107 and the derived properties "Any" and "L&". This has necessitated a change to
108 the interal format of compiled patterns. Any saved compiled patterns that
109 use \p or \P must be recompiled.
110
111 3. The specification of recursion in patterns has been changed so that all
112 recursive subpatterns are automatically treated as atomic groups. Thus, for
113 example, (?R) is treated as if it were (?>(?R)). This is necessary because
114 otherwise there are situations where recursion does not work.
115
116 See the ChangeLog for a complete list of changes, which include a number of bug
117 fixes and tidies.
118
119
120 Release 6.0 07-Jun-05
121 ---------------------
122
123 The release number has been increased to 6.0 because of the addition of several
124 major new pieces of functionality.
125
126 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
127 algorithm, has been added. This has a number of advantages for certain cases,
128 though it does run more slowly, and lacks the ability to capture substrings. On
129 the other hand, it does find all matches, not just the first, and it works
130 better for partial matching. The pcrematching man page discusses the
131 differences.
132
133 The pcretest program has been enhanced so that it can make use of the new
134 pcre_dfa_exec() matching function and the extra features it provides.
135
136 The distribution now includes a C++ wrapper library. This is built
137 automatically if a C++ compiler is found. The pcrecpp man page discusses this
138 interface.
139
140 The code itself has been re-organized into many more files, one for each
141 function, so it no longer requires everything to be linked in when static
142 linkage is used. As a consequence, some internal functions have had to have
143 their names exposed. These functions all have names starting with _pcre_. They
144 are undocumented, and are not intended for use by outside callers.
145
146 The pcregrep program has been enhanced with new functionality such as
147 multiline-matching and options for output more matching context. See the
148 ChangeLog for a complete list of changes to the library and the utility
149 programs.
150
151
152 Release 5.0 13-Sep-04
153 ---------------------
154
155 The licence under which PCRE is released has been changed to the more
156 conventional "BSD" licence.
157
158 In the code, some bugs have been fixed, and there are also some major changes
159 in this release (which is why I've increased the number to 5.0). Some changes
160 are internal rearrangements, and some provide a number of new facilities. The
161 new features are:
162
163 1. There's an "automatic callout" feature that inserts callouts before every
164 item in the regex, and there's a new callout field that gives the position
165 in the pattern - useful for debugging and tracing.
166
167 2. The extra_data structure can now be used to pass in a set of character
168 tables at exec time. This is useful if compiled regex are saved and re-used
169 at a later time when the tables may not be at the same address. If the
170 default internal tables are used, the pointer saved with the compiled
171 pattern is now set to NULL, which means that you don't need to do anything
172 special unless you are using custom tables.
173
174 3. It is possible, with some restrictions on the content of the regex, to
175 request "partial" matching. A special return code is given if all of the
176 subject string matched part of the regex. This could be useful for testing
177 an input field as it is being typed.
178
179 4. There is now some optional support for Unicode character properties, which
180 means that the patterns items such as \p{Lu} and \X can now be used. Only
181 the general category properties are supported. If PCRE is compiled with this
182 support, an additional 90K data structure is include, which increases the
183 size of the library dramatically.
184
185 5. There is support for saving compiled patterns and re-using them later.
186
187 6. There is support for running regular expressions that were compiled on a
188 different host with the opposite endianness.
189
190 7. The pcretest program has been extended to accommodate the new features.
191
192 The main internal rearrangement is that sequences of literal characters are no
193 longer handled as strings. Instead, each character is handled on its own. This
194 makes some UTF-8 handling easier, and makes the support of partial matching
195 possible. Compiled patterns containing long literal strings will be larger as a
196 result of this change; I hope that performance will not be much affected.
197
198
199 Release 4.5 01-Dec-03
200 ---------------------
201
202 Again mainly a bug-fix and tidying release, with only a couple of new features:
203
204 1. It's possible now to compile PCRE so that it does not use recursive
205 function calls when matching. Instead it gets memory from the heap. This slows
206 things down, but may be necessary on systems with limited stacks.
207
208 2. UTF-8 string checking has been tightened to reject overlong sequences and to
209 check that a starting offset points to the start of a character. Failure of the
210 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
211
212 3. PCRE can now be compiled for systems that use EBCDIC code.
213
214
215 Release 4.4 21-Aug-03
216 ---------------------
217
218 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
219 checks UTF-8 strings for validity by default. There is an option to suppress
220 this, just in case anybody wants that teeny extra bit of performance.
221
222
223 Releases 4.1 - 4.3
224 ------------------
225
226 Sorry, I forgot about updating the NEWS file for these releases. Please take a
227 look at ChangeLog.
228
229
230 Release 4.0 17-Feb-03
231 ---------------------
232
233 There have been a lot of changes for the 4.0 release, adding additional
234 functionality and mending bugs. Below is a list of the highlights of the new
235 functionality. For full details of these features, please consult the
236 documentation. For a complete list of changes, see the ChangeLog file.
237
238 1. Support for Perl's \Q...\E escapes.
239
240 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
241 package. They provide some syntactic sugar for simple cases of "atomic
242 grouping".
243
244 3. Support for the \G assertion. It is true when the current matching position
245 is at the start point of the match.
246
247 4. A new feature that provides some of the functionality that Perl provides
248 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
249 is for the caller to provide an optional function, by setting pcre_callout to
250 its entry point. To get the function called, the regex must include (?C) at
251 appropriate points.
252
253 5. Support for recursive calls to individual subpatterns. This makes it really
254 easy to get totally confused.
255
256 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
257 name a group.
258
259 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
260 option for pcregrep to make it operate in UTF-8 mode.
261
262 8. The single man page has been split into a number of separate man pages.
263 These also give rise to individual HTML pages which are put in a separate
264 directory. There is an index.html page that lists them all. Some hyperlinking
265 between the pages has been installed.
266
267
268 Release 3.5 15-Aug-01
269 ---------------------
270
271 1. The configuring system has been upgraded to use later versions of autoconf
272 and libtool. By default it builds both a shared and a static library if the OS
273 supports it. You can use --disable-shared or --disable-static on the configure
274 command if you want only one of them.
275
276 2. The pcretest utility is now installed along with pcregrep because it is
277 useful for users (to test regexs) and by doing this, it automatically gets
278 relinked by libtool. The documentation has been turned into a man page, so
279 there are now .1, .txt, and .html versions in /doc.
280
281 3. Upgrades to pcregrep:
282 (i) Added long-form option names like gnu grep.
283 (ii) Added --help to list all options with an explanatory phrase.
284 (iii) Added -r, --recursive to recurse into sub-directories.
285 (iv) Added -f, --file to read patterns from a file.
286
287 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
288 script, to force use of CR or LF instead of \n in the source. On non-Unix
289 systems, the value can be set in config.h.
290
291 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
292 absolute limit. Changed the text of the error message to make this clear, and
293 likewise updated the man page.
294
295 6. The limit of 99 on the number of capturing subpatterns has been removed.
296 The new limit is 65535, which I hope will not be a "real" limit.
297
298
299 Release 3.3 01-Aug-00
300 ---------------------
301
302 There is some support for UTF-8 character strings. This is incomplete and
303 experimental. The documentation describes what is and what is not implemented.
304 Otherwise, this is just a bug-fixing release.
305
306
307 Release 3.0 01-Feb-00
308 ---------------------
309
310 1. A "configure" script is now used to configure PCRE for Unix systems. It
311 builds a Makefile, a config.h file, and the pcre-config script.
312
313 2. PCRE is built as a shared library by default.
314
315 3. There is support for POSIX classes such as [:alpha:].
316
317 5. There is an experimental recursion feature.
318
319 ----------------------------------------------------------------------------
320 IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
321
322 Please note that there has been a change in the API such that a larger
323 ovector is required at matching time, to provide some additional workspace.
324 The new man page has details. This change was necessary in order to support
325 some of the new functionality in Perl 5.005.
326
327 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
328
329 Another (I hope this is the last!) change has been made to the API for the
330 pcre_compile() function. An additional argument has been added to make it
331 possible to pass over a pointer to character tables built in the current
332 locale by pcre_maketables(). To use the default tables, this new arguement
333 should be passed as NULL.
334
335 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
336
337 Yet another (and again I hope this really is the last) change has been made
338 to the API for the pcre_exec() function. An additional argument has been
339 added to make it possible to start the match other than at the start of the
340 subject string. This is important if there are lookbehinds. The new man
341 page has the details, but you just want to convert existing programs, all
342 you need to do is to stick in a new fifth argument to pcre_exec(), with a
343 value of zero. For example, change
344
345 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
346 to
347 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
348
349 ****

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