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Revision 172 - (hide annotations) (download)
Tue Jun 5 10:40:13 2007 UTC (7 years, 10 months ago) by ph10
File size: 14711 byte(s)
Drastically reduce workspace used for alternatives in groups; also some 
trailing space removals for a test release.

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


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