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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4  A "configure" script is now used to configure PCRE for Unix systems. It builds  Release 6.7 04-Jul-06
5  a Makefile and a config.h file.  ---------------------
6    
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).
10    
11    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
12    significantly reduced for certain subject strings.
13    
14    
15    Release 6.5 01-Feb-06
16    ---------------------
17    
18    Important changes in this release:
19    
20    1. A number of new features have been added to pcregrep.
21    
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.
27    
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.
32    
33    See the ChangeLog for a complete list of changes, which include a number of bug
34    fixes and tidies.
35    
36    
37    Release 6.0 07-Jun-05
38    ---------------------
39    
40    The release number has been increased to 6.0 because of the addition of several
41    major new pieces of functionality.
42    
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.
49    
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.
52    
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.
56    
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.
62    
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.
67    
68    
69    Release 5.0 13-Sep-04
70    ---------------------
71    
72    The licence under which PCRE is released has been changed to the more
73    conventional "BSD" licence.
74    
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:
79    
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.
83    
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.
90    
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.
95    
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.
101    
102    5. There is support for saving compiled patterns and re-using them later.
103    
104    6. There is support for running regular expressions that were compiled on a
105       different host with the opposite endianness.
106    
107    7. The pcretest program has been extended to accommodate the new features.
108    
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.
114    
115    
116    Release 4.5 01-Dec-03
117    ---------------------
118    
119    Again mainly a bug-fix and tidying release, with only a couple of new features:
120    
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.
124    
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.
128    
129    3. PCRE can now be compiled for systems that use EBCDIC code.
130    
131    
132    Release 4.4 21-Aug-03
133    ---------------------
134    
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.
138    
139    
140    Releases 4.1 - 4.3
141    ------------------
142    
143    Sorry, I forgot about updating the NEWS file for these releases. Please take a
144    look at ChangeLog.
145    
146    
147    Release 4.0 17-Feb-03
148    ---------------------
149    
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.
154    
155    1. Support for Perl's \Q...\E escapes.
156    
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".
160    
161    3. Support for the \G assertion. It is true when the current matching position
162    is at the start point of the match.
163    
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.
169    
170    5. Support for recursive calls to individual subpatterns. This makes it really
171    easy to get totally confused.
172    
173    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
174    name a group.
175    
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.
178    
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.
183    
184    
185    Release 3.5 15-Aug-01
186    ---------------------
187    
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.
192    
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.
197    
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.
203    
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.
207    
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.
211    
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.
214    
215    
216    Release 3.3 01-Aug-00
217    ---------------------
218    
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.
222    
223    
224    Release 3.0 01-Feb-00
225    ---------------------
226    
227    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.
229    
230    2. PCRE is built as a shared library by default.
231    
232    3. There is support for POSIX classes such as [:alpha:].
233    
234    5. There is an experimental recursion feature.
235    
236  ----------------------------------------------------------------------------  ----------------------------------------------------------------------------
237            IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00            IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00

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