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Revision 128 - (show annotations) (download)
Tue Mar 20 11:46:50 2007 UTC (7 years ago) by ph10
File size: 13340 byte(s)
Make the use of dftables optional, and not the default. Further tidies to 
documentation.

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

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