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Contents of /code/tags/pcre-7.1/NEWS

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Revision 156 - (show annotations) (download)
Tue Apr 24 13:49:23 2007 UTC (7 years, 3 months ago) by ph10
File size: 13671 byte(s)
Tag the PCRE 7.1 release.

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

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