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Contents of /code/tags/pcre-7.0/NEWS

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Revision 94 - (show annotations)
Sat Feb 24 21:41:45 2007 UTC (14 years, 2 months ago) by nigel
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Tag code/trunk as code/tags/pcre-7.0.
1 News about PCRE releases
2 ------------------------
4 Release 7.0 23-Nov-06
5 ---------------------
7 This release has a new major number because there have been some internal
8 upheavals to facilitate the addition of new optimizations and other facilities,
9 and to make subsequent maintenance and extension easier. Compilation is likely
10 to be a bit slower, but there should be no major effect on runtime performance.
11 Previously compiled patterns are NOT upwards compatible with this release. If
12 you have saved compiled patterns from a previous release, you will have to
13 re-compile them. Important changes that are visible to users are:
15 1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
16 some more scripts.
18 2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
19 sequence as a newline.
21 3. The \R escape matches a single Unicode newline sequence as a single unit.
23 4. New features that will appear in Perl 5.10 are now in PCRE. These include
24 alternative Perl syntax for named parentheses, and Perl syntax for
25 recursion.
27 5. The C++ wrapper interface has been extended by the addition of a
28 QuoteMeta function and the ability to allow copy construction and
29 assignment.
31 For a complete list of changes, see the ChangeLog file.
34 Release 6.7 04-Jul-06
35 ---------------------
37 The main additions to this release are the ability to use the same name for
38 multiple sets of parentheses, and support for CRLF line endings in both the
39 library and pcregrep (and in pcretest for testing).
41 Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
42 significantly reduced for certain subject strings.
45 Release 6.5 01-Feb-06
46 ---------------------
48 Important changes in this release:
50 1. A number of new features have been added to pcregrep.
52 2. The Unicode property tables have been updated to Unicode 4.1.0, and the
53 supported properties have been extended with script names such as "Arabic",
54 and the derived properties "Any" and "L&". This has necessitated a change to
55 the interal format of compiled patterns. Any saved compiled patterns that
56 use \p or \P must be recompiled.
58 3. The specification of recursion in patterns has been changed so that all
59 recursive subpatterns are automatically treated as atomic groups. Thus, for
60 example, (?R) is treated as if it were (?>(?R)). This is necessary because
61 otherwise there are situations where recursion does not work.
63 See the ChangeLog for a complete list of changes, which include a number of bug
64 fixes and tidies.
67 Release 6.0 07-Jun-05
68 ---------------------
70 The release number has been increased to 6.0 because of the addition of several
71 major new pieces of functionality.
73 A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
74 algorithm, has been added. This has a number of advantages for certain cases,
75 though it does run more slowly, and lacks the ability to capture substrings. On
76 the other hand, it does find all matches, not just the first, and it works
77 better for partial matching. The pcrematching man page discusses the
78 differences.
80 The pcretest program has been enhanced so that it can make use of the new
81 pcre_dfa_exec() matching function and the extra features it provides.
83 The distribution now includes a C++ wrapper library. This is built
84 automatically if a C++ compiler is found. The pcrecpp man page discusses this
85 interface.
87 The code itself has been re-organized into many more files, one for each
88 function, so it no longer requires everything to be linked in when static
89 linkage is used. As a consequence, some internal functions have had to have
90 their names exposed. These functions all have names starting with _pcre_. They
91 are undocumented, and are not intended for use by outside callers.
93 The pcregrep program has been enhanced with new functionality such as
94 multiline-matching and options for output more matching context. See the
95 ChangeLog for a complete list of changes to the library and the utility
96 programs.
99 Release 5.0 13-Sep-04
100 ---------------------
102 The licence under which PCRE is released has been changed to the more
103 conventional "BSD" licence.
105 In the code, some bugs have been fixed, and there are also some major changes
106 in this release (which is why I've increased the number to 5.0). Some changes
107 are internal rearrangements, and some provide a number of new facilities. The
108 new features are:
110 1. There's an "automatic callout" feature that inserts callouts before every
111 item in the regex, and there's a new callout field that gives the position
112 in the pattern - useful for debugging and tracing.
114 2. The extra_data structure can now be used to pass in a set of character
115 tables at exec time. This is useful if compiled regex are saved and re-used
116 at a later time when the tables may not be at the same address. If the
117 default internal tables are used, the pointer saved with the compiled
118 pattern is now set to NULL, which means that you don't need to do anything
119 special unless you are using custom tables.
121 3. It is possible, with some restrictions on the content of the regex, to
122 request "partial" matching. A special return code is given if all of the
123 subject string matched part of the regex. This could be useful for testing
124 an input field as it is being typed.
126 4. There is now some optional support for Unicode character properties, which
127 means that the patterns items such as \p{Lu} and \X can now be used. Only
128 the general category properties are supported. If PCRE is compiled with this
129 support, an additional 90K data structure is include, which increases the
130 size of the library dramatically.
132 5. There is support for saving compiled patterns and re-using them later.
134 6. There is support for running regular expressions that were compiled on a
135 different host with the opposite endianness.
137 7. The pcretest program has been extended to accommodate the new features.
139 The main internal rearrangement is that sequences of literal characters are no
140 longer handled as strings. Instead, each character is handled on its own. This
141 makes some UTF-8 handling easier, and makes the support of partial matching
142 possible. Compiled patterns containing long literal strings will be larger as a
143 result of this change; I hope that performance will not be much affected.
146 Release 4.5 01-Dec-03
147 ---------------------
149 Again mainly a bug-fix and tidying release, with only a couple of new features:
151 1. It's possible now to compile PCRE so that it does not use recursive
152 function calls when matching. Instead it gets memory from the heap. This slows
153 things down, but may be necessary on systems with limited stacks.
155 2. UTF-8 string checking has been tightened to reject overlong sequences and to
156 check that a starting offset points to the start of a character. Failure of the
157 latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
159 3. PCRE can now be compiled for systems that use EBCDIC code.
162 Release 4.4 21-Aug-03
163 ---------------------
165 This is mainly a bug-fix and tidying release. The only new feature is that PCRE
166 checks UTF-8 strings for validity by default. There is an option to suppress
167 this, just in case anybody wants that teeny extra bit of performance.
170 Releases 4.1 - 4.3
171 ------------------
173 Sorry, I forgot about updating the NEWS file for these releases. Please take a
174 look at ChangeLog.
177 Release 4.0 17-Feb-03
178 ---------------------
180 There have been a lot of changes for the 4.0 release, adding additional
181 functionality and mending bugs. Below is a list of the highlights of the new
182 functionality. For full details of these features, please consult the
183 documentation. For a complete list of changes, see the ChangeLog file.
185 1. Support for Perl's \Q...\E escapes.
187 2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
188 package. They provide some syntactic sugar for simple cases of "atomic
189 grouping".
191 3. Support for the \G assertion. It is true when the current matching position
192 is at the start point of the match.
194 4. A new feature that provides some of the functionality that Perl provides
195 with (?{...}). The facility is termed a "callout". The way it is done in PCRE
196 is for the caller to provide an optional function, by setting pcre_callout to
197 its entry point. To get the function called, the regex must include (?C) at
198 appropriate points.
200 5. Support for recursive calls to individual subpatterns. This makes it really
201 easy to get totally confused.
203 6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
204 name a group.
206 7. Several extensions to UTF-8 support; it is now fairly complete. There is an
207 option for pcregrep to make it operate in UTF-8 mode.
209 8. The single man page has been split into a number of separate man pages.
210 These also give rise to individual HTML pages which are put in a separate
211 directory. There is an index.html page that lists them all. Some hyperlinking
212 between the pages has been installed.
215 Release 3.5 15-Aug-01
216 ---------------------
218 1. The configuring system has been upgraded to use later versions of autoconf
219 and libtool. By default it builds both a shared and a static library if the OS
220 supports it. You can use --disable-shared or --disable-static on the configure
221 command if you want only one of them.
223 2. The pcretest utility is now installed along with pcregrep because it is
224 useful for users (to test regexs) and by doing this, it automatically gets
225 relinked by libtool. The documentation has been turned into a man page, so
226 there are now .1, .txt, and .html versions in /doc.
228 3. Upgrades to pcregrep:
229 (i) Added long-form option names like gnu grep.
230 (ii) Added --help to list all options with an explanatory phrase.
231 (iii) Added -r, --recursive to recurse into sub-directories.
232 (iv) Added -f, --file to read patterns from a file.
234 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
235 script, to force use of CR or LF instead of \n in the source. On non-Unix
236 systems, the value can be set in config.h.
238 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
239 absolute limit. Changed the text of the error message to make this clear, and
240 likewise updated the man page.
242 6. The limit of 99 on the number of capturing subpatterns has been removed.
243 The new limit is 65535, which I hope will not be a "real" limit.
246 Release 3.3 01-Aug-00
247 ---------------------
249 There is some support for UTF-8 character strings. This is incomplete and
250 experimental. The documentation describes what is and what is not implemented.
251 Otherwise, this is just a bug-fixing release.
254 Release 3.0 01-Feb-00
255 ---------------------
257 1. A "configure" script is now used to configure PCRE for Unix systems. It
258 builds a Makefile, a config.h file, and the pcre-config script.
260 2. PCRE is built as a shared library by default.
262 3. There is support for POSIX classes such as [:alpha:].
264 5. There is an experimental recursion feature.
266 ----------------------------------------------------------------------------
269 Please note that there has been a change in the API such that a larger
270 ovector is required at matching time, to provide some additional workspace.
271 The new man page has details. This change was necessary in order to support
272 some of the new functionality in Perl 5.005.
276 Another (I hope this is the last!) change has been made to the API for the
277 pcre_compile() function. An additional argument has been added to make it
278 possible to pass over a pointer to character tables built in the current
279 locale by pcre_maketables(). To use the default tables, this new arguement
280 should be passed as NULL.
284 Yet another (and again I hope this really is the last) change has been made
285 to the API for the pcre_exec() function. An additional argument has been
286 added to make it possible to start the match other than at the start of the
287 subject string. This is important if there are lookbehinds. The new man
288 page has the details, but you just want to convert existing programs, all
289 you need to do is to stick in a new fifth argument to pcre_exec(), with a
290 value of zero. For example, change
292 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
293 to
294 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
296 ****

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