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Sat Feb 24 21:41:34 2007 UTC (8 years, 2 months ago) by nigel
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Load pcre-6.7 into code/trunk.

1 nigel 41 News about PCRE releases
2     ------------------------
4 nigel 91 Release 6.7 04-Jul-06
5     ---------------------
7     The main additions to this release are the ability to use the same name for
8     multiple sets of parentheses, and support for CRLF line endings in both the
9     library and pcregrep (and in pcretest for testing).
11     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
12     significantly reduced for certain subject strings.
15 nigel 87 Release 6.5 01-Feb-06
16     ---------------------
18     Important changes in this release:
20     1. A number of new features have been added to pcregrep.
22     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
23     supported properties have been extended with script names such as "Arabic",
24     and the derived properties "Any" and "L&". This has necessitated a change to
25     the interal format of compiled patterns. Any saved compiled patterns that
26     use \p or \P must be recompiled.
28     3. The specification of recursion in patterns has been changed so that all
29     recursive subpatterns are automatically treated as atomic groups. Thus, for
30     example, (?R) is treated as if it were (?>(?R)). This is necessary because
31     otherwise there are situations where recursion does not work.
33     See the ChangeLog for a complete list of changes, which include a number of bug
34     fixes and tidies.
37 nigel 77 Release 6.0 07-Jun-05
38     ---------------------
40     The release number has been increased to 6.0 because of the addition of several
41     major new pieces of functionality.
43     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
44     algorithm, has been added. This has a number of advantages for certain cases,
45     though it does run more slowly, and lacks the ability to capture substrings. On
46     the other hand, it does find all matches, not just the first, and it works
47     better for partial matching. The pcrematching man page discusses the
48     differences.
50     The pcretest program has been enhanced so that it can make use of the new
51     pcre_dfa_exec() matching function and the extra features it provides.
53     The distribution now includes a C++ wrapper library. This is built
54     automatically if a C++ compiler is found. The pcrecpp man page discusses this
55     interface.
57     The code itself has been re-organized into many more files, one for each
58     function, so it no longer requires everything to be linked in when static
59     linkage is used. As a consequence, some internal functions have had to have
60     their names exposed. These functions all have names starting with _pcre_. They
61     are undocumented, and are not intended for use by outside callers.
63     The pcregrep program has been enhanced with new functionality such as
64     multiline-matching and options for output more matching context. See the
65     ChangeLog for a complete list of changes to the library and the utility
66     programs.
69 nigel 75 Release 5.0 13-Sep-04
70     ---------------------
72     The licence under which PCRE is released has been changed to the more
73     conventional "BSD" licence.
75     In the code, some bugs have been fixed, and there are also some major changes
76     in this release (which is why I've increased the number to 5.0). Some changes
77     are internal rearrangements, and some provide a number of new facilities. The
78     new features are:
80     1. There's an "automatic callout" feature that inserts callouts before every
81     item in the regex, and there's a new callout field that gives the position
82     in the pattern - useful for debugging and tracing.
84     2. The extra_data structure can now be used to pass in a set of character
85     tables at exec time. This is useful if compiled regex are saved and re-used
86     at a later time when the tables may not be at the same address. If the
87     default internal tables are used, the pointer saved with the compiled
88     pattern is now set to NULL, which means that you don't need to do anything
89     special unless you are using custom tables.
91     3. It is possible, with some restrictions on the content of the regex, to
92     request "partial" matching. A special return code is given if all of the
93     subject string matched part of the regex. This could be useful for testing
94     an input field as it is being typed.
96     4. There is now some optional support for Unicode character properties, which
97     means that the patterns items such as \p{Lu} and \X can now be used. Only
98     the general category properties are supported. If PCRE is compiled with this
99     support, an additional 90K data structure is include, which increases the
100     size of the library dramatically.
102     5. There is support for saving compiled patterns and re-using them later.
104     6. There is support for running regular expressions that were compiled on a
105     different host with the opposite endianness.
107     7. The pcretest program has been extended to accommodate the new features.
109     The main internal rearrangement is that sequences of literal characters are no
110     longer handled as strings. Instead, each character is handled on its own. This
111     makes some UTF-8 handling easier, and makes the support of partial matching
112     possible. Compiled patterns containing long literal strings will be larger as a
113     result of this change; I hope that performance will not be much affected.
116 nigel 73 Release 4.5 01-Dec-03
117     ---------------------
119     Again mainly a bug-fix and tidying release, with only a couple of new features:
121     1. It's possible now to compile PCRE so that it does not use recursive
122     function calls when matching. Instead it gets memory from the heap. This slows
123     things down, but may be necessary on systems with limited stacks.
125     2. UTF-8 string checking has been tightened to reject overlong sequences and to
126     check that a starting offset points to the start of a character. Failure of the
127     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
129     3. PCRE can now be compiled for systems that use EBCDIC code.
132 nigel 71 Release 4.4 21-Aug-03
133     ---------------------
135     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
136     checks UTF-8 strings for validity by default. There is an option to suppress
137     this, just in case anybody wants that teeny extra bit of performance.
140     Releases 4.1 - 4.3
141     ------------------
143     Sorry, I forgot about updating the NEWS file for these releases. Please take a
144     look at ChangeLog.
147 nigel 63 Release 4.0 17-Feb-03
148     ---------------------
150     There have been a lot of changes for the 4.0 release, adding additional
151     functionality and mending bugs. Below is a list of the highlights of the new
152     functionality. For full details of these features, please consult the
153     documentation. For a complete list of changes, see the ChangeLog file.
155     1. Support for Perl's \Q...\E escapes.
157     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
158     package. They provide some syntactic sugar for simple cases of "atomic
159     grouping".
161     3. Support for the \G assertion. It is true when the current matching position
162     is at the start point of the match.
164     4. A new feature that provides some of the functionality that Perl provides
165     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
166     is for the caller to provide an optional function, by setting pcre_callout to
167     its entry point. To get the function called, the regex must include (?C) at
168     appropriate points.
170     5. Support for recursive calls to individual subpatterns. This makes it really
171     easy to get totally confused.
173     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
174     name a group.
176     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
177     option for pcregrep to make it operate in UTF-8 mode.
179     8. The single man page has been split into a number of separate man pages.
180     These also give rise to individual HTML pages which are put in a separate
181     directory. There is an index.html page that lists them all. Some hyperlinking
182     between the pages has been installed.
185 nigel 53 Release 3.5 15-Aug-01
186     ---------------------
188     1. The configuring system has been upgraded to use later versions of autoconf
189     and libtool. By default it builds both a shared and a static library if the OS
190     supports it. You can use --disable-shared or --disable-static on the configure
191     command if you want only one of them.
193     2. The pcretest utility is now installed along with pcregrep because it is
194     useful for users (to test regexs) and by doing this, it automatically gets
195     relinked by libtool. The documentation has been turned into a man page, so
196     there are now .1, .txt, and .html versions in /doc.
198     3. Upgrades to pcregrep:
199     (i) Added long-form option names like gnu grep.
200     (ii) Added --help to list all options with an explanatory phrase.
201     (iii) Added -r, --recursive to recurse into sub-directories.
202     (iv) Added -f, --file to read patterns from a file.
204     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
205     script, to force use of CR or LF instead of \n in the source. On non-Unix
206     systems, the value can be set in config.h.
208     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
209     absolute limit. Changed the text of the error message to make this clear, and
210     likewise updated the man page.
212     6. The limit of 99 on the number of capturing subpatterns has been removed.
213     The new limit is 65535, which I hope will not be a "real" limit.
216 nigel 49 Release 3.3 01-Aug-00
217     ---------------------
219     There is some support for UTF-8 character strings. This is incomplete and
220     experimental. The documentation describes what is and what is not implemented.
221     Otherwise, this is just a bug-fixing release.
224 nigel 43 Release 3.0 01-Feb-00
225     ---------------------
226 nigel 41
227 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
228     builds a Makefile, a config.h file, and the pcre-config script.
230     2. PCRE is built as a shared library by default.
232     3. There is support for POSIX classes such as [:alpha:].
234     5. There is an experimental recursion feature.
236 nigel 41 ----------------------------------------------------------------------------
239     Please note that there has been a change in the API such that a larger
240     ovector is required at matching time, to provide some additional workspace.
241     The new man page has details. This change was necessary in order to support
242     some of the new functionality in Perl 5.005.
246     Another (I hope this is the last!) change has been made to the API for the
247     pcre_compile() function. An additional argument has been added to make it
248     possible to pass over a pointer to character tables built in the current
249     locale by pcre_maketables(). To use the default tables, this new arguement
250     should be passed as NULL.
254     Yet another (and again I hope this really is the last) change has been made
255     to the API for the pcre_exec() function. An additional argument has been
256     added to make it possible to start the match other than at the start of the
257     subject string. This is important if there are lookbehinds. The new man
258     page has the details, but you just want to convert existing programs, all
259     you need to do is to stick in a new fifth argument to pcre_exec(), with a
260     value of zero. For example, change
262     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
263     to
264     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
266     ****

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