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Sat Feb 24 21:40:45 2007 UTC (8 years, 2 months ago) by nigel
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Load pcre-6.0 into code/trunk.

1 nigel 41 News about PCRE releases
2     ------------------------
4 nigel 77 Release 6.0 07-Jun-05
5     ---------------------
7     The release number has been increased to 6.0 because of the addition of several
8     major new pieces of functionality.
10     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
11     algorithm, has been added. This has a number of advantages for certain cases,
12     though it does run more slowly, and lacks the ability to capture substrings. On
13     the other hand, it does find all matches, not just the first, and it works
14     better for partial matching. The pcrematching man page discusses the
15     differences.
17     The pcretest program has been enhanced so that it can make use of the new
18     pcre_dfa_exec() matching function and the extra features it provides.
20     The distribution now includes a C++ wrapper library. This is built
21     automatically if a C++ compiler is found. The pcrecpp man page discusses this
22     interface.
24     The code itself has been re-organized into many more files, one for each
25     function, so it no longer requires everything to be linked in when static
26     linkage is used. As a consequence, some internal functions have had to have
27     their names exposed. These functions all have names starting with _pcre_. They
28     are undocumented, and are not intended for use by outside callers.
30     The pcregrep program has been enhanced with new functionality such as
31     multiline-matching and options for output more matching context. See the
32     ChangeLog for a complete list of changes to the library and the utility
33     programs.
36 nigel 75 Release 5.0 13-Sep-04
37     ---------------------
39     The licence under which PCRE is released has been changed to the more
40     conventional "BSD" licence.
42     In the code, some bugs have been fixed, and there are also some major changes
43     in this release (which is why I've increased the number to 5.0). Some changes
44     are internal rearrangements, and some provide a number of new facilities. The
45     new features are:
47     1. There's an "automatic callout" feature that inserts callouts before every
48     item in the regex, and there's a new callout field that gives the position
49     in the pattern - useful for debugging and tracing.
51     2. The extra_data structure can now be used to pass in a set of character
52     tables at exec time. This is useful if compiled regex are saved and re-used
53     at a later time when the tables may not be at the same address. If the
54     default internal tables are used, the pointer saved with the compiled
55     pattern is now set to NULL, which means that you don't need to do anything
56     special unless you are using custom tables.
58     3. It is possible, with some restrictions on the content of the regex, to
59     request "partial" matching. A special return code is given if all of the
60     subject string matched part of the regex. This could be useful for testing
61     an input field as it is being typed.
63     4. There is now some optional support for Unicode character properties, which
64     means that the patterns items such as \p{Lu} and \X can now be used. Only
65     the general category properties are supported. If PCRE is compiled with this
66     support, an additional 90K data structure is include, which increases the
67     size of the library dramatically.
69     5. There is support for saving compiled patterns and re-using them later.
71     6. There is support for running regular expressions that were compiled on a
72     different host with the opposite endianness.
74     7. The pcretest program has been extended to accommodate the new features.
76     The main internal rearrangement is that sequences of literal characters are no
77     longer handled as strings. Instead, each character is handled on its own. This
78     makes some UTF-8 handling easier, and makes the support of partial matching
79     possible. Compiled patterns containing long literal strings will be larger as a
80     result of this change; I hope that performance will not be much affected.
83 nigel 73 Release 4.5 01-Dec-03
84     ---------------------
86     Again mainly a bug-fix and tidying release, with only a couple of new features:
88     1. It's possible now to compile PCRE so that it does not use recursive
89     function calls when matching. Instead it gets memory from the heap. This slows
90     things down, but may be necessary on systems with limited stacks.
92     2. UTF-8 string checking has been tightened to reject overlong sequences and to
93     check that a starting offset points to the start of a character. Failure of the
94     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
96     3. PCRE can now be compiled for systems that use EBCDIC code.
99 nigel 71 Release 4.4 21-Aug-03
100     ---------------------
102     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
103     checks UTF-8 strings for validity by default. There is an option to suppress
104     this, just in case anybody wants that teeny extra bit of performance.
107     Releases 4.1 - 4.3
108     ------------------
110     Sorry, I forgot about updating the NEWS file for these releases. Please take a
111     look at ChangeLog.
114 nigel 63 Release 4.0 17-Feb-03
115     ---------------------
117     There have been a lot of changes for the 4.0 release, adding additional
118     functionality and mending bugs. Below is a list of the highlights of the new
119     functionality. For full details of these features, please consult the
120     documentation. For a complete list of changes, see the ChangeLog file.
122     1. Support for Perl's \Q...\E escapes.
124     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
125     package. They provide some syntactic sugar for simple cases of "atomic
126     grouping".
128     3. Support for the \G assertion. It is true when the current matching position
129     is at the start point of the match.
131     4. A new feature that provides some of the functionality that Perl provides
132     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
133     is for the caller to provide an optional function, by setting pcre_callout to
134     its entry point. To get the function called, the regex must include (?C) at
135     appropriate points.
137     5. Support for recursive calls to individual subpatterns. This makes it really
138     easy to get totally confused.
140     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
141     name a group.
143     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
144     option for pcregrep to make it operate in UTF-8 mode.
146     8. The single man page has been split into a number of separate man pages.
147     These also give rise to individual HTML pages which are put in a separate
148     directory. There is an index.html page that lists them all. Some hyperlinking
149     between the pages has been installed.
152 nigel 53 Release 3.5 15-Aug-01
153     ---------------------
155     1. The configuring system has been upgraded to use later versions of autoconf
156     and libtool. By default it builds both a shared and a static library if the OS
157     supports it. You can use --disable-shared or --disable-static on the configure
158     command if you want only one of them.
160     2. The pcretest utility is now installed along with pcregrep because it is
161     useful for users (to test regexs) and by doing this, it automatically gets
162     relinked by libtool. The documentation has been turned into a man page, so
163     there are now .1, .txt, and .html versions in /doc.
165     3. Upgrades to pcregrep:
166     (i) Added long-form option names like gnu grep.
167     (ii) Added --help to list all options with an explanatory phrase.
168     (iii) Added -r, --recursive to recurse into sub-directories.
169     (iv) Added -f, --file to read patterns from a file.
171     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
172     script, to force use of CR or LF instead of \n in the source. On non-Unix
173     systems, the value can be set in config.h.
175     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
176     absolute limit. Changed the text of the error message to make this clear, and
177     likewise updated the man page.
179     6. The limit of 99 on the number of capturing subpatterns has been removed.
180     The new limit is 65535, which I hope will not be a "real" limit.
183 nigel 49 Release 3.3 01-Aug-00
184     ---------------------
186     There is some support for UTF-8 character strings. This is incomplete and
187     experimental. The documentation describes what is and what is not implemented.
188     Otherwise, this is just a bug-fixing release.
191 nigel 43 Release 3.0 01-Feb-00
192     ---------------------
193 nigel 41
194 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
195     builds a Makefile, a config.h file, and the pcre-config script.
197     2. PCRE is built as a shared library by default.
199     3. There is support for POSIX classes such as [:alpha:].
201     5. There is an experimental recursion feature.
203 nigel 41 ----------------------------------------------------------------------------
206     Please note that there has been a change in the API such that a larger
207     ovector is required at matching time, to provide some additional workspace.
208     The new man page has details. This change was necessary in order to support
209     some of the new functionality in Perl 5.005.
213     Another (I hope this is the last!) change has been made to the API for the
214     pcre_compile() function. An additional argument has been added to make it
215     possible to pass over a pointer to character tables built in the current
216     locale by pcre_maketables(). To use the default tables, this new arguement
217     should be passed as NULL.
221     Yet another (and again I hope this really is the last) change has been made
222     to the API for the pcre_exec() function. An additional argument has been
223     added to make it possible to start the match other than at the start of the
224     subject string. This is important if there are lookbehinds. The new man
225     page has the details, but you just want to convert existing programs, all
226     you need to do is to stick in a new fifth argument to pcre_exec(), with a
227     value of zero. For example, change
229     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
230     to
231     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
233     ****

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