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Revision 178 - (hide annotations) (download)
Wed Jun 13 08:44:34 2007 UTC (7 years, 4 months ago) by ph10
File size: 14983 byte(s)
Add support for \h, \H, \v, \V.

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 172 WARNING: saved patterns that were compiled by earlier versions of PCRE must be
9 ph10 168 recompiled for use with 7.2 (necessitated by the addition of \K).
10    
11 ph10 159 Correction to the notes for 7.1: the note about shared libraries for Windows is
12     wrong. Previously, three libraries were built, but each could function
13     independently. For example, the pcreposix library also included all the
14     functions from the basic pcre library. The change is that the three libraries
15     are no longer independent. They are like the Unix libraries. To use the
16     pcreposix functions, for example, you need to link with both the pcreposix and
17 ph10 157 the basic pcre library.
18    
19 ph10 166 Some more features from Perl 5.10 have been added:
20 ph10 157
21 ph10 166 (?-n) and (?+n) relative references for recursion and subroutines.
22 ph10 172
23 ph10 167 (Not sure if this one is actually in Perl 5.10)
24 ph10 172 (?(-n) and (?(+n) relative references as conditions.
25    
26 ph10 168 \K to reset the start of the matched string; for example, (foo)\Kbar
27 ph10 175 matches bar preceded by foo, but only sets bar as the matched string.
28    
29     (?| introduces a group where the capturing parentheses in each alternative
30     start from the same number; for example, (?|(abc)|(xyz)) sets capturing
31     parentheses number 1 in both cases.
32 ph10 178
33     \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
34 ph10 166
35    
36 ph10 155 Release 7.1 24-Apr-07
37 nigel 93 ---------------------
38    
39 ph10 155 There is only one new feature in this release: a linebreak setting of
40     PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
41     recognizes only CRLF, CR, and LF as linebreaks.
42 ph10 122
43 ph10 155 A few bugs are fixed (see ChangeLog for details), but the major change is a
44     complete re-implementation of the build system. This now has full Autotools
45     support and so is now "standard" in some sense. It should help with compiling
46     PCRE in a wide variety of environments.
47    
48 ph10 146 NOTE: when building shared libraries for Windows, three dlls are now built,
49     called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
50     included in a single dll.
51    
52     Another important change is that the dftables auxiliary program is no longer
53 ph10 128 compiled and run at "make" time by default. Instead, a default set of character
54     tables (assuming ASCII coding) is used. If you want to use dftables to generate
55     the character tables as previously, add --enable-rebuild-chartables to the
56     "configure" command. You must do this if you are compiling PCRE to run on a
57     system that uses EBCDIC code.
58 ph10 122
59 ph10 128 There is a discussion about character tables in the README file. The default is
60     not to use dftables so that that there is no problem when cross-compiling.
61    
62    
63 ph10 122 Release 7.0 19-Dec-06
64     ---------------------
65    
66 nigel 93 This release has a new major number because there have been some internal
67     upheavals to facilitate the addition of new optimizations and other facilities,
68     and to make subsequent maintenance and extension easier. Compilation is likely
69     to be a bit slower, but there should be no major effect on runtime performance.
70     Previously compiled patterns are NOT upwards compatible with this release. If
71     you have saved compiled patterns from a previous release, you will have to
72     re-compile them. Important changes that are visible to users are:
73    
74     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
75     some more scripts.
76    
77     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
78     sequence as a newline.
79    
80     3. The \R escape matches a single Unicode newline sequence as a single unit.
81    
82     4. New features that will appear in Perl 5.10 are now in PCRE. These include
83     alternative Perl syntax for named parentheses, and Perl syntax for
84     recursion.
85    
86     5. The C++ wrapper interface has been extended by the addition of a
87     QuoteMeta function and the ability to allow copy construction and
88     assignment.
89    
90     For a complete list of changes, see the ChangeLog file.
91    
92    
93 nigel 91 Release 6.7 04-Jul-06
94     ---------------------
95    
96     The main additions to this release are the ability to use the same name for
97     multiple sets of parentheses, and support for CRLF line endings in both the
98     library and pcregrep (and in pcretest for testing).
99    
100     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
101     significantly reduced for certain subject strings.
102    
103    
104 nigel 87 Release 6.5 01-Feb-06
105     ---------------------
106    
107     Important changes in this release:
108    
109     1. A number of new features have been added to pcregrep.
110    
111     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
112     supported properties have been extended with script names such as "Arabic",
113     and the derived properties "Any" and "L&". This has necessitated a change to
114     the interal format of compiled patterns. Any saved compiled patterns that
115     use \p or \P must be recompiled.
116    
117     3. The specification of recursion in patterns has been changed so that all
118     recursive subpatterns are automatically treated as atomic groups. Thus, for
119     example, (?R) is treated as if it were (?>(?R)). This is necessary because
120     otherwise there are situations where recursion does not work.
121    
122     See the ChangeLog for a complete list of changes, which include a number of bug
123     fixes and tidies.
124    
125    
126 nigel 77 Release 6.0 07-Jun-05
127     ---------------------
128    
129     The release number has been increased to 6.0 because of the addition of several
130     major new pieces of functionality.
131    
132     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
133     algorithm, has been added. This has a number of advantages for certain cases,
134     though it does run more slowly, and lacks the ability to capture substrings. On
135     the other hand, it does find all matches, not just the first, and it works
136     better for partial matching. The pcrematching man page discusses the
137     differences.
138    
139     The pcretest program has been enhanced so that it can make use of the new
140     pcre_dfa_exec() matching function and the extra features it provides.
141    
142     The distribution now includes a C++ wrapper library. This is built
143     automatically if a C++ compiler is found. The pcrecpp man page discusses this
144     interface.
145    
146     The code itself has been re-organized into many more files, one for each
147     function, so it no longer requires everything to be linked in when static
148     linkage is used. As a consequence, some internal functions have had to have
149     their names exposed. These functions all have names starting with _pcre_. They
150     are undocumented, and are not intended for use by outside callers.
151    
152     The pcregrep program has been enhanced with new functionality such as
153     multiline-matching and options for output more matching context. See the
154     ChangeLog for a complete list of changes to the library and the utility
155     programs.
156    
157    
158 nigel 75 Release 5.0 13-Sep-04
159     ---------------------
160    
161     The licence under which PCRE is released has been changed to the more
162     conventional "BSD" licence.
163    
164     In the code, some bugs have been fixed, and there are also some major changes
165     in this release (which is why I've increased the number to 5.0). Some changes
166     are internal rearrangements, and some provide a number of new facilities. The
167     new features are:
168    
169     1. There's an "automatic callout" feature that inserts callouts before every
170     item in the regex, and there's a new callout field that gives the position
171     in the pattern - useful for debugging and tracing.
172    
173     2. The extra_data structure can now be used to pass in a set of character
174     tables at exec time. This is useful if compiled regex are saved and re-used
175     at a later time when the tables may not be at the same address. If the
176     default internal tables are used, the pointer saved with the compiled
177     pattern is now set to NULL, which means that you don't need to do anything
178     special unless you are using custom tables.
179    
180     3. It is possible, with some restrictions on the content of the regex, to
181     request "partial" matching. A special return code is given if all of the
182     subject string matched part of the regex. This could be useful for testing
183     an input field as it is being typed.
184    
185     4. There is now some optional support for Unicode character properties, which
186     means that the patterns items such as \p{Lu} and \X can now be used. Only
187     the general category properties are supported. If PCRE is compiled with this
188     support, an additional 90K data structure is include, which increases the
189     size of the library dramatically.
190    
191     5. There is support for saving compiled patterns and re-using them later.
192    
193     6. There is support for running regular expressions that were compiled on a
194     different host with the opposite endianness.
195    
196     7. The pcretest program has been extended to accommodate the new features.
197    
198     The main internal rearrangement is that sequences of literal characters are no
199     longer handled as strings. Instead, each character is handled on its own. This
200     makes some UTF-8 handling easier, and makes the support of partial matching
201     possible. Compiled patterns containing long literal strings will be larger as a
202     result of this change; I hope that performance will not be much affected.
203    
204    
205 nigel 73 Release 4.5 01-Dec-03
206     ---------------------
207    
208     Again mainly a bug-fix and tidying release, with only a couple of new features:
209    
210     1. It's possible now to compile PCRE so that it does not use recursive
211     function calls when matching. Instead it gets memory from the heap. This slows
212     things down, but may be necessary on systems with limited stacks.
213    
214     2. UTF-8 string checking has been tightened to reject overlong sequences and to
215     check that a starting offset points to the start of a character. Failure of the
216     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
217    
218     3. PCRE can now be compiled for systems that use EBCDIC code.
219    
220    
221 nigel 71 Release 4.4 21-Aug-03
222     ---------------------
223    
224     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
225     checks UTF-8 strings for validity by default. There is an option to suppress
226     this, just in case anybody wants that teeny extra bit of performance.
227    
228    
229     Releases 4.1 - 4.3
230     ------------------
231    
232     Sorry, I forgot about updating the NEWS file for these releases. Please take a
233     look at ChangeLog.
234    
235    
236 nigel 63 Release 4.0 17-Feb-03
237     ---------------------
238    
239     There have been a lot of changes for the 4.0 release, adding additional
240     functionality and mending bugs. Below is a list of the highlights of the new
241     functionality. For full details of these features, please consult the
242     documentation. For a complete list of changes, see the ChangeLog file.
243    
244     1. Support for Perl's \Q...\E escapes.
245    
246     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
247     package. They provide some syntactic sugar for simple cases of "atomic
248     grouping".
249    
250     3. Support for the \G assertion. It is true when the current matching position
251     is at the start point of the match.
252    
253     4. A new feature that provides some of the functionality that Perl provides
254     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
255     is for the caller to provide an optional function, by setting pcre_callout to
256     its entry point. To get the function called, the regex must include (?C) at
257     appropriate points.
258    
259     5. Support for recursive calls to individual subpatterns. This makes it really
260     easy to get totally confused.
261    
262     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
263     name a group.
264    
265     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
266     option for pcregrep to make it operate in UTF-8 mode.
267    
268     8. The single man page has been split into a number of separate man pages.
269     These also give rise to individual HTML pages which are put in a separate
270     directory. There is an index.html page that lists them all. Some hyperlinking
271     between the pages has been installed.
272    
273    
274 nigel 53 Release 3.5 15-Aug-01
275     ---------------------
276    
277     1. The configuring system has been upgraded to use later versions of autoconf
278     and libtool. By default it builds both a shared and a static library if the OS
279     supports it. You can use --disable-shared or --disable-static on the configure
280     command if you want only one of them.
281    
282     2. The pcretest utility is now installed along with pcregrep because it is
283     useful for users (to test regexs) and by doing this, it automatically gets
284     relinked by libtool. The documentation has been turned into a man page, so
285     there are now .1, .txt, and .html versions in /doc.
286    
287     3. Upgrades to pcregrep:
288     (i) Added long-form option names like gnu grep.
289     (ii) Added --help to list all options with an explanatory phrase.
290     (iii) Added -r, --recursive to recurse into sub-directories.
291     (iv) Added -f, --file to read patterns from a file.
292    
293     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
294     script, to force use of CR or LF instead of \n in the source. On non-Unix
295     systems, the value can be set in config.h.
296    
297     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
298     absolute limit. Changed the text of the error message to make this clear, and
299     likewise updated the man page.
300    
301     6. The limit of 99 on the number of capturing subpatterns has been removed.
302     The new limit is 65535, which I hope will not be a "real" limit.
303    
304    
305 nigel 49 Release 3.3 01-Aug-00
306     ---------------------
307    
308     There is some support for UTF-8 character strings. This is incomplete and
309     experimental. The documentation describes what is and what is not implemented.
310     Otherwise, this is just a bug-fixing release.
311    
312    
313 nigel 43 Release 3.0 01-Feb-00
314     ---------------------
315 nigel 41
316 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
317     builds a Makefile, a config.h file, and the pcre-config script.
318    
319     2. PCRE is built as a shared library by default.
320    
321     3. There is support for POSIX classes such as [:alpha:].
322    
323     5. There is an experimental recursion feature.
324    
325 nigel 41 ----------------------------------------------------------------------------
326     IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
327    
328     Please note that there has been a change in the API such that a larger
329     ovector is required at matching time, to provide some additional workspace.
330     The new man page has details. This change was necessary in order to support
331     some of the new functionality in Perl 5.005.
332    
333     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
334    
335     Another (I hope this is the last!) change has been made to the API for the
336     pcre_compile() function. An additional argument has been added to make it
337     possible to pass over a pointer to character tables built in the current
338     locale by pcre_maketables(). To use the default tables, this new arguement
339     should be passed as NULL.
340    
341     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
342    
343     Yet another (and again I hope this really is the last) change has been made
344     to the API for the pcre_exec() function. An additional argument has been
345     added to make it possible to start the match other than at the start of the
346     subject string. This is important if there are lookbehinds. The new man
347     page has the details, but you just want to convert existing programs, all
348     you need to do is to stick in a new fifth argument to pcre_exec(), with a
349     value of zero. For example, change
350    
351     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
352     to
353     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
354    
355     ****

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