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Revision 228 - (hide annotations) (download)
Tue Aug 28 13:37:37 2007 UTC (6 years, 7 months ago) by ph10
File size: 15920 byte(s)
Final version number changes for the 7.3 release.

1 nigel 41 News about PCRE releases
2     ------------------------
3    
4 ph10 122
5 ph10 228 Release 7.3 28-Aug-07
6 ph10 212 ---------------------
7    
8     Most changes are bug fixes. Some that are not:
9    
10     1. There is some support for Perl 5.10's experimental "backtracking control
11     verbs" such as (*PRUNE).
12    
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.
15    
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.
19 ph10 227
20     4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
21     no longer advance by two characters instead of one when an unanchored match
22     fails at CRLF if there are explicit CR or LF matches within the pattern.
23 ph10 226 This gets rid of some anomalous effects that previously occurred.
24 ph10 212
25 ph10 227 5. Some PCRE-specific settings for varying the newline options at the start of
26     a pattern have been added.
27 ph10 212
28 ph10 227
29 ph10 184 Release 7.2 19-Jun-07
30 ph10 157 ---------------------
31    
32 ph10 172 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
33 ph10 181 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
34     and \V).
35 ph10 168
36 ph10 159 Correction to the notes for 7.1: the note about shared libraries for Windows is
37     wrong. Previously, three libraries were built, but each could function
38     independently. For example, the pcreposix library also included all the
39     functions from the basic pcre library. The change is that the three libraries
40     are no longer independent. They are like the Unix libraries. To use the
41     pcreposix functions, for example, you need to link with both the pcreposix and
42 ph10 157 the basic pcre library.
43    
44 ph10 166 Some more features from Perl 5.10 have been added:
45 ph10 157
46 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
47 ph10 172
48     (?(-n) and (?(+n) relative references as conditions.
49 ph10 182
50 ph10 181 \k{name} and \g{name} are synonyms for \k<name>.
51 ph10 172
52 ph10 168 \K to reset the start of the matched string; for example, (foo)\Kbar
53 ph10 175 matches bar preceded by foo, but only sets bar as the matched string.
54 ph10 182
55     (?| introduces a group where the capturing parentheses in each alternative
56     start from the same number; for example, (?|(abc)|(xyz)) sets capturing
57 ph10 175 parentheses number 1 in both cases.
58 ph10 166
59 ph10 182 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
60 ph10 166
61 ph10 182
62 ph10 155 Release 7.1 24-Apr-07
63 nigel 93 ---------------------
64    
65 ph10 155 There is only one new feature in this release: a linebreak setting of
66     PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
67     recognizes only CRLF, CR, and LF as linebreaks.
68 ph10 122
69 ph10 155 A few bugs are fixed (see ChangeLog for details), but the major change is a
70     complete re-implementation of the build system. This now has full Autotools
71     support and so is now "standard" in some sense. It should help with compiling
72     PCRE in a wide variety of environments.
73    
74 ph10 146 NOTE: when building shared libraries for Windows, three dlls are now built,
75     called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
76     included in a single dll.
77    
78     Another important change is that the dftables auxiliary program is no longer
79 ph10 128 compiled and run at "make" time by default. Instead, a default set of character
80     tables (assuming ASCII coding) is used. If you want to use dftables to generate
81     the character tables as previously, add --enable-rebuild-chartables to the
82     "configure" command. You must do this if you are compiling PCRE to run on a
83     system that uses EBCDIC code.
84 ph10 122
85 ph10 128 There is a discussion about character tables in the README file. The default is
86     not to use dftables so that that there is no problem when cross-compiling.
87    
88    
89 ph10 122 Release 7.0 19-Dec-06
90     ---------------------
91    
92 nigel 93 This release has a new major number because there have been some internal
93     upheavals to facilitate the addition of new optimizations and other facilities,
94     and to make subsequent maintenance and extension easier. Compilation is likely
95     to be a bit slower, but there should be no major effect on runtime performance.
96     Previously compiled patterns are NOT upwards compatible with this release. If
97     you have saved compiled patterns from a previous release, you will have to
98     re-compile them. Important changes that are visible to users are:
99    
100     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
101     some more scripts.
102    
103     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
104     sequence as a newline.
105    
106     3. The \R escape matches a single Unicode newline sequence as a single unit.
107    
108     4. New features that will appear in Perl 5.10 are now in PCRE. These include
109     alternative Perl syntax for named parentheses, and Perl syntax for
110     recursion.
111    
112     5. The C++ wrapper interface has been extended by the addition of a
113     QuoteMeta function and the ability to allow copy construction and
114     assignment.
115    
116     For a complete list of changes, see the ChangeLog file.
117    
118    
119 nigel 91 Release 6.7 04-Jul-06
120     ---------------------
121    
122     The main additions to this release are the ability to use the same name for
123     multiple sets of parentheses, and support for CRLF line endings in both the
124     library and pcregrep (and in pcretest for testing).
125    
126     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
127     significantly reduced for certain subject strings.
128    
129    
130 nigel 87 Release 6.5 01-Feb-06
131     ---------------------
132    
133     Important changes in this release:
134    
135     1. A number of new features have been added to pcregrep.
136    
137     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
138     supported properties have been extended with script names such as "Arabic",
139     and the derived properties "Any" and "L&". This has necessitated a change to
140     the interal format of compiled patterns. Any saved compiled patterns that
141     use \p or \P must be recompiled.
142    
143     3. The specification of recursion in patterns has been changed so that all
144     recursive subpatterns are automatically treated as atomic groups. Thus, for
145     example, (?R) is treated as if it were (?>(?R)). This is necessary because
146     otherwise there are situations where recursion does not work.
147    
148     See the ChangeLog for a complete list of changes, which include a number of bug
149     fixes and tidies.
150    
151    
152 nigel 77 Release 6.0 07-Jun-05
153     ---------------------
154    
155     The release number has been increased to 6.0 because of the addition of several
156     major new pieces of functionality.
157    
158     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
159     algorithm, has been added. This has a number of advantages for certain cases,
160     though it does run more slowly, and lacks the ability to capture substrings. On
161     the other hand, it does find all matches, not just the first, and it works
162     better for partial matching. The pcrematching man page discusses the
163     differences.
164    
165     The pcretest program has been enhanced so that it can make use of the new
166     pcre_dfa_exec() matching function and the extra features it provides.
167    
168     The distribution now includes a C++ wrapper library. This is built
169     automatically if a C++ compiler is found. The pcrecpp man page discusses this
170     interface.
171    
172     The code itself has been re-organized into many more files, one for each
173     function, so it no longer requires everything to be linked in when static
174     linkage is used. As a consequence, some internal functions have had to have
175     their names exposed. These functions all have names starting with _pcre_. They
176     are undocumented, and are not intended for use by outside callers.
177    
178     The pcregrep program has been enhanced with new functionality such as
179     multiline-matching and options for output more matching context. See the
180     ChangeLog for a complete list of changes to the library and the utility
181     programs.
182    
183    
184 nigel 75 Release 5.0 13-Sep-04
185     ---------------------
186    
187     The licence under which PCRE is released has been changed to the more
188     conventional "BSD" licence.
189    
190     In the code, some bugs have been fixed, and there are also some major changes
191     in this release (which is why I've increased the number to 5.0). Some changes
192     are internal rearrangements, and some provide a number of new facilities. The
193     new features are:
194    
195     1. There's an "automatic callout" feature that inserts callouts before every
196     item in the regex, and there's a new callout field that gives the position
197     in the pattern - useful for debugging and tracing.
198    
199     2. The extra_data structure can now be used to pass in a set of character
200     tables at exec time. This is useful if compiled regex are saved and re-used
201     at a later time when the tables may not be at the same address. If the
202     default internal tables are used, the pointer saved with the compiled
203     pattern is now set to NULL, which means that you don't need to do anything
204     special unless you are using custom tables.
205    
206     3. It is possible, with some restrictions on the content of the regex, to
207     request "partial" matching. A special return code is given if all of the
208     subject string matched part of the regex. This could be useful for testing
209     an input field as it is being typed.
210    
211     4. There is now some optional support for Unicode character properties, which
212     means that the patterns items such as \p{Lu} and \X can now be used. Only
213     the general category properties are supported. If PCRE is compiled with this
214     support, an additional 90K data structure is include, which increases the
215     size of the library dramatically.
216    
217     5. There is support for saving compiled patterns and re-using them later.
218    
219     6. There is support for running regular expressions that were compiled on a
220     different host with the opposite endianness.
221    
222     7. The pcretest program has been extended to accommodate the new features.
223    
224     The main internal rearrangement is that sequences of literal characters are no
225     longer handled as strings. Instead, each character is handled on its own. This
226     makes some UTF-8 handling easier, and makes the support of partial matching
227     possible. Compiled patterns containing long literal strings will be larger as a
228     result of this change; I hope that performance will not be much affected.
229    
230    
231 nigel 73 Release 4.5 01-Dec-03
232     ---------------------
233    
234     Again mainly a bug-fix and tidying release, with only a couple of new features:
235    
236     1. It's possible now to compile PCRE so that it does not use recursive
237     function calls when matching. Instead it gets memory from the heap. This slows
238     things down, but may be necessary on systems with limited stacks.
239    
240     2. UTF-8 string checking has been tightened to reject overlong sequences and to
241     check that a starting offset points to the start of a character. Failure of the
242     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
243    
244     3. PCRE can now be compiled for systems that use EBCDIC code.
245    
246    
247 nigel 71 Release 4.4 21-Aug-03
248     ---------------------
249    
250     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
251     checks UTF-8 strings for validity by default. There is an option to suppress
252     this, just in case anybody wants that teeny extra bit of performance.
253    
254    
255     Releases 4.1 - 4.3
256     ------------------
257    
258     Sorry, I forgot about updating the NEWS file for these releases. Please take a
259     look at ChangeLog.
260    
261    
262 nigel 63 Release 4.0 17-Feb-03
263     ---------------------
264    
265     There have been a lot of changes for the 4.0 release, adding additional
266     functionality and mending bugs. Below is a list of the highlights of the new
267     functionality. For full details of these features, please consult the
268     documentation. For a complete list of changes, see the ChangeLog file.
269    
270     1. Support for Perl's \Q...\E escapes.
271    
272     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
273     package. They provide some syntactic sugar for simple cases of "atomic
274     grouping".
275    
276     3. Support for the \G assertion. It is true when the current matching position
277     is at the start point of the match.
278    
279     4. A new feature that provides some of the functionality that Perl provides
280     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
281     is for the caller to provide an optional function, by setting pcre_callout to
282     its entry point. To get the function called, the regex must include (?C) at
283     appropriate points.
284    
285     5. Support for recursive calls to individual subpatterns. This makes it really
286     easy to get totally confused.
287    
288     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
289     name a group.
290    
291     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
292     option for pcregrep to make it operate in UTF-8 mode.
293    
294     8. The single man page has been split into a number of separate man pages.
295     These also give rise to individual HTML pages which are put in a separate
296     directory. There is an index.html page that lists them all. Some hyperlinking
297     between the pages has been installed.
298    
299    
300 nigel 53 Release 3.5 15-Aug-01
301     ---------------------
302    
303     1. The configuring system has been upgraded to use later versions of autoconf
304     and libtool. By default it builds both a shared and a static library if the OS
305     supports it. You can use --disable-shared or --disable-static on the configure
306     command if you want only one of them.
307    
308     2. The pcretest utility is now installed along with pcregrep because it is
309     useful for users (to test regexs) and by doing this, it automatically gets
310     relinked by libtool. The documentation has been turned into a man page, so
311     there are now .1, .txt, and .html versions in /doc.
312    
313     3. Upgrades to pcregrep:
314     (i) Added long-form option names like gnu grep.
315     (ii) Added --help to list all options with an explanatory phrase.
316     (iii) Added -r, --recursive to recurse into sub-directories.
317     (iv) Added -f, --file to read patterns from a file.
318    
319     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
320     script, to force use of CR or LF instead of \n in the source. On non-Unix
321     systems, the value can be set in config.h.
322    
323     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
324     absolute limit. Changed the text of the error message to make this clear, and
325     likewise updated the man page.
326    
327     6. The limit of 99 on the number of capturing subpatterns has been removed.
328     The new limit is 65535, which I hope will not be a "real" limit.
329    
330    
331 nigel 49 Release 3.3 01-Aug-00
332     ---------------------
333    
334     There is some support for UTF-8 character strings. This is incomplete and
335     experimental. The documentation describes what is and what is not implemented.
336     Otherwise, this is just a bug-fixing release.
337    
338    
339 nigel 43 Release 3.0 01-Feb-00
340     ---------------------
341 nigel 41
342 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
343     builds a Makefile, a config.h file, and the pcre-config script.
344    
345     2. PCRE is built as a shared library by default.
346    
347     3. There is support for POSIX classes such as [:alpha:].
348    
349     5. There is an experimental recursion feature.
350    
351 nigel 41 ----------------------------------------------------------------------------
352     IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
353    
354     Please note that there has been a change in the API such that a larger
355     ovector is required at matching time, to provide some additional workspace.
356     The new man page has details. This change was necessary in order to support
357     some of the new functionality in Perl 5.005.
358    
359     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
360    
361     Another (I hope this is the last!) change has been made to the API for the
362     pcre_compile() function. An additional argument has been added to make it
363     possible to pass over a pointer to character tables built in the current
364     locale by pcre_maketables(). To use the default tables, this new arguement
365     should be passed as NULL.
366    
367     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
368    
369     Yet another (and again I hope this really is the last) change has been made
370     to the API for the pcre_exec() function. An additional argument has been
371     added to make it possible to start the match other than at the start of the
372     subject string. This is important if there are lookbehinds. The new man
373     page has the details, but you just want to convert existing programs, all
374     you need to do is to stick in a new fifth argument to pcre_exec(), with a
375     value of zero. For example, change
376    
377     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
378     to
379     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
380    
381     ****

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