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Revision 167 - (hide annotations) (download)
Wed May 9 15:53:54 2007 UTC (6 years, 11 months ago) by ph10
File size: 14425 byte(s)
Add (?(-n) and (?(+n) relative conditions.

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

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