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Revision 155 - (hide annotations) (download)
Tue Apr 24 13:36:11 2007 UTC (8 years ago) by ph10
File size: 13671 byte(s)
Tidies and final updates for 7.1.

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


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