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Thu Aug 16 13:29:39 2007 UTC (7 years, 2 months ago) by ph10
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Tidies for 7.3-RC5 prerelease

1 nigel 41 News about PCRE releases
2     ------------------------
3    
4 ph10 122
5 ph10 220 Release 7.3 16-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    
20    
21 ph10 184 Release 7.2 19-Jun-07
22 ph10 157 ---------------------
23    
24 ph10 172 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
25 ph10 181 recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
26     and \V).
27 ph10 168
28 ph10 159 Correction to the notes for 7.1: the note about shared libraries for Windows is
29     wrong. Previously, three libraries were built, but each could function
30     independently. For example, the pcreposix library also included all the
31     functions from the basic pcre library. The change is that the three libraries
32     are no longer independent. They are like the Unix libraries. To use the
33     pcreposix functions, for example, you need to link with both the pcreposix and
34 ph10 157 the basic pcre library.
35    
36 ph10 166 Some more features from Perl 5.10 have been added:
37 ph10 157
38 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
39 ph10 172
40     (?(-n) and (?(+n) relative references as conditions.
41 ph10 182
42 ph10 181 \k{name} and \g{name} are synonyms for \k<name>.
43 ph10 172
44 ph10 168 \K to reset the start of the matched string; for example, (foo)\Kbar
45 ph10 175 matches bar preceded by foo, but only sets bar as the matched string.
46 ph10 182
47     (?| introduces a group where the capturing parentheses in each alternative
48     start from the same number; for example, (?|(abc)|(xyz)) sets capturing
49 ph10 175 parentheses number 1 in both cases.
50 ph10 166
51 ph10 182 \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
52 ph10 166
53 ph10 182
54 ph10 155 Release 7.1 24-Apr-07
55 nigel 93 ---------------------
56    
57 ph10 155 There is only one new feature in this release: a linebreak setting of
58     PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
59     recognizes only CRLF, CR, and LF as linebreaks.
60 ph10 122
61 ph10 155 A few bugs are fixed (see ChangeLog for details), but the major change is a
62     complete re-implementation of the build system. This now has full Autotools
63     support and so is now "standard" in some sense. It should help with compiling
64     PCRE in a wide variety of environments.
65    
66 ph10 146 NOTE: when building shared libraries for Windows, three dlls are now built,
67     called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
68     included in a single dll.
69    
70     Another important change is that the dftables auxiliary program is no longer
71 ph10 128 compiled and run at "make" time by default. Instead, a default set of character
72     tables (assuming ASCII coding) is used. If you want to use dftables to generate
73     the character tables as previously, add --enable-rebuild-chartables to the
74     "configure" command. You must do this if you are compiling PCRE to run on a
75     system that uses EBCDIC code.
76 ph10 122
77 ph10 128 There is a discussion about character tables in the README file. The default is
78     not to use dftables so that that there is no problem when cross-compiling.
79    
80    
81 ph10 122 Release 7.0 19-Dec-06
82     ---------------------
83    
84 nigel 93 This release has a new major number because there have been some internal
85     upheavals to facilitate the addition of new optimizations and other facilities,
86     and to make subsequent maintenance and extension easier. Compilation is likely
87     to be a bit slower, but there should be no major effect on runtime performance.
88     Previously compiled patterns are NOT upwards compatible with this release. If
89     you have saved compiled patterns from a previous release, you will have to
90     re-compile them. Important changes that are visible to users are:
91    
92     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
93     some more scripts.
94    
95     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
96     sequence as a newline.
97    
98     3. The \R escape matches a single Unicode newline sequence as a single unit.
99    
100     4. New features that will appear in Perl 5.10 are now in PCRE. These include
101     alternative Perl syntax for named parentheses, and Perl syntax for
102     recursion.
103    
104     5. The C++ wrapper interface has been extended by the addition of a
105     QuoteMeta function and the ability to allow copy construction and
106     assignment.
107    
108     For a complete list of changes, see the ChangeLog file.
109    
110    
111 nigel 91 Release 6.7 04-Jul-06
112     ---------------------
113    
114     The main additions to this release are the ability to use the same name for
115     multiple sets of parentheses, and support for CRLF line endings in both the
116     library and pcregrep (and in pcretest for testing).
117    
118     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
119     significantly reduced for certain subject strings.
120    
121    
122 nigel 87 Release 6.5 01-Feb-06
123     ---------------------
124    
125     Important changes in this release:
126    
127     1. A number of new features have been added to pcregrep.
128    
129     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
130     supported properties have been extended with script names such as "Arabic",
131     and the derived properties "Any" and "L&". This has necessitated a change to
132     the interal format of compiled patterns. Any saved compiled patterns that
133     use \p or \P must be recompiled.
134    
135     3. The specification of recursion in patterns has been changed so that all
136     recursive subpatterns are automatically treated as atomic groups. Thus, for
137     example, (?R) is treated as if it were (?>(?R)). This is necessary because
138     otherwise there are situations where recursion does not work.
139    
140     See the ChangeLog for a complete list of changes, which include a number of bug
141     fixes and tidies.
142    
143    
144 nigel 77 Release 6.0 07-Jun-05
145     ---------------------
146    
147     The release number has been increased to 6.0 because of the addition of several
148     major new pieces of functionality.
149    
150     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
151     algorithm, has been added. This has a number of advantages for certain cases,
152     though it does run more slowly, and lacks the ability to capture substrings. On
153     the other hand, it does find all matches, not just the first, and it works
154     better for partial matching. The pcrematching man page discusses the
155     differences.
156    
157     The pcretest program has been enhanced so that it can make use of the new
158     pcre_dfa_exec() matching function and the extra features it provides.
159    
160     The distribution now includes a C++ wrapper library. This is built
161     automatically if a C++ compiler is found. The pcrecpp man page discusses this
162     interface.
163    
164     The code itself has been re-organized into many more files, one for each
165     function, so it no longer requires everything to be linked in when static
166     linkage is used. As a consequence, some internal functions have had to have
167     their names exposed. These functions all have names starting with _pcre_. They
168     are undocumented, and are not intended for use by outside callers.
169    
170     The pcregrep program has been enhanced with new functionality such as
171     multiline-matching and options for output more matching context. See the
172     ChangeLog for a complete list of changes to the library and the utility
173     programs.
174    
175    
176 nigel 75 Release 5.0 13-Sep-04
177     ---------------------
178    
179     The licence under which PCRE is released has been changed to the more
180     conventional "BSD" licence.
181    
182     In the code, some bugs have been fixed, and there are also some major changes
183     in this release (which is why I've increased the number to 5.0). Some changes
184     are internal rearrangements, and some provide a number of new facilities. The
185     new features are:
186    
187     1. There's an "automatic callout" feature that inserts callouts before every
188     item in the regex, and there's a new callout field that gives the position
189     in the pattern - useful for debugging and tracing.
190    
191     2. The extra_data structure can now be used to pass in a set of character
192     tables at exec time. This is useful if compiled regex are saved and re-used
193     at a later time when the tables may not be at the same address. If the
194     default internal tables are used, the pointer saved with the compiled
195     pattern is now set to NULL, which means that you don't need to do anything
196     special unless you are using custom tables.
197    
198     3. It is possible, with some restrictions on the content of the regex, to
199     request "partial" matching. A special return code is given if all of the
200     subject string matched part of the regex. This could be useful for testing
201     an input field as it is being typed.
202    
203     4. There is now some optional support for Unicode character properties, which
204     means that the patterns items such as \p{Lu} and \X can now be used. Only
205     the general category properties are supported. If PCRE is compiled with this
206     support, an additional 90K data structure is include, which increases the
207     size of the library dramatically.
208    
209     5. There is support for saving compiled patterns and re-using them later.
210    
211     6. There is support for running regular expressions that were compiled on a
212     different host with the opposite endianness.
213    
214     7. The pcretest program has been extended to accommodate the new features.
215    
216     The main internal rearrangement is that sequences of literal characters are no
217     longer handled as strings. Instead, each character is handled on its own. This
218     makes some UTF-8 handling easier, and makes the support of partial matching
219     possible. Compiled patterns containing long literal strings will be larger as a
220     result of this change; I hope that performance will not be much affected.
221    
222    
223 nigel 73 Release 4.5 01-Dec-03
224     ---------------------
225    
226     Again mainly a bug-fix and tidying release, with only a couple of new features:
227    
228     1. It's possible now to compile PCRE so that it does not use recursive
229     function calls when matching. Instead it gets memory from the heap. This slows
230     things down, but may be necessary on systems with limited stacks.
231    
232     2. UTF-8 string checking has been tightened to reject overlong sequences and to
233     check that a starting offset points to the start of a character. Failure of the
234     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
235    
236     3. PCRE can now be compiled for systems that use EBCDIC code.
237    
238    
239 nigel 71 Release 4.4 21-Aug-03
240     ---------------------
241    
242     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
243     checks UTF-8 strings for validity by default. There is an option to suppress
244     this, just in case anybody wants that teeny extra bit of performance.
245    
246    
247     Releases 4.1 - 4.3
248     ------------------
249    
250     Sorry, I forgot about updating the NEWS file for these releases. Please take a
251     look at ChangeLog.
252    
253    
254 nigel 63 Release 4.0 17-Feb-03
255     ---------------------
256    
257     There have been a lot of changes for the 4.0 release, adding additional
258     functionality and mending bugs. Below is a list of the highlights of the new
259     functionality. For full details of these features, please consult the
260     documentation. For a complete list of changes, see the ChangeLog file.
261    
262     1. Support for Perl's \Q...\E escapes.
263    
264     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
265     package. They provide some syntactic sugar for simple cases of "atomic
266     grouping".
267    
268     3. Support for the \G assertion. It is true when the current matching position
269     is at the start point of the match.
270    
271     4. A new feature that provides some of the functionality that Perl provides
272     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
273     is for the caller to provide an optional function, by setting pcre_callout to
274     its entry point. To get the function called, the regex must include (?C) at
275     appropriate points.
276    
277     5. Support for recursive calls to individual subpatterns. This makes it really
278     easy to get totally confused.
279    
280     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
281     name a group.
282    
283     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
284     option for pcregrep to make it operate in UTF-8 mode.
285    
286     8. The single man page has been split into a number of separate man pages.
287     These also give rise to individual HTML pages which are put in a separate
288     directory. There is an index.html page that lists them all. Some hyperlinking
289     between the pages has been installed.
290    
291    
292 nigel 53 Release 3.5 15-Aug-01
293     ---------------------
294    
295     1. The configuring system has been upgraded to use later versions of autoconf
296     and libtool. By default it builds both a shared and a static library if the OS
297     supports it. You can use --disable-shared or --disable-static on the configure
298     command if you want only one of them.
299    
300     2. The pcretest utility is now installed along with pcregrep because it is
301     useful for users (to test regexs) and by doing this, it automatically gets
302     relinked by libtool. The documentation has been turned into a man page, so
303     there are now .1, .txt, and .html versions in /doc.
304    
305     3. Upgrades to pcregrep:
306     (i) Added long-form option names like gnu grep.
307     (ii) Added --help to list all options with an explanatory phrase.
308     (iii) Added -r, --recursive to recurse into sub-directories.
309     (iv) Added -f, --file to read patterns from a file.
310    
311     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
312     script, to force use of CR or LF instead of \n in the source. On non-Unix
313     systems, the value can be set in config.h.
314    
315     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
316     absolute limit. Changed the text of the error message to make this clear, and
317     likewise updated the man page.
318    
319     6. The limit of 99 on the number of capturing subpatterns has been removed.
320     The new limit is 65535, which I hope will not be a "real" limit.
321    
322    
323 nigel 49 Release 3.3 01-Aug-00
324     ---------------------
325    
326     There is some support for UTF-8 character strings. This is incomplete and
327     experimental. The documentation describes what is and what is not implemented.
328     Otherwise, this is just a bug-fixing release.
329    
330    
331 nigel 43 Release 3.0 01-Feb-00
332     ---------------------
333 nigel 41
334 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
335     builds a Makefile, a config.h file, and the pcre-config script.
336    
337     2. PCRE is built as a shared library by default.
338    
339     3. There is support for POSIX classes such as [:alpha:].
340    
341     5. There is an experimental recursion feature.
342    
343 nigel 41 ----------------------------------------------------------------------------
344     IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
345    
346     Please note that there has been a change in the API such that a larger
347     ovector is required at matching time, to provide some additional workspace.
348     The new man page has details. This change was necessary in order to support
349     some of the new functionality in Perl 5.005.
350    
351     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
352    
353     Another (I hope this is the last!) change has been made to the API for the
354     pcre_compile() function. An additional argument has been added to make it
355     possible to pass over a pointer to character tables built in the current
356     locale by pcre_maketables(). To use the default tables, this new arguement
357     should be passed as NULL.
358    
359     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
360    
361     Yet another (and again I hope this really is the last) change has been made
362     to the API for the pcre_exec() function. An additional argument has been
363     added to make it possible to start the match other than at the start of the
364     subject string. This is important if there are lookbehinds. The new man
365     page has the details, but you just want to convert existing programs, all
366     you need to do is to stick in a new fifth argument to pcre_exec(), with a
367     value of zero. For example, change
368    
369     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
370     to
371     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
372    
373     ****

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