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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    Release 6.5 01-Feb-06
5    ---------------------
6    
7    Important changes in this release:
8    
9    1. A number of new features have been added to pcregrep.
10    
11    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
12       supported properties have been extended with script names such as "Arabic",
13       and the derived properties "Any" and "L&". This has necessitated a change to
14       the interal format of compiled patterns. Any saved compiled patterns that
15       use \p or \P must be recompiled.
16    
17    3. The specification of recursion in patterns has been changed so that all
18       recursive subpatterns are automatically treated as atomic groups. Thus, for
19       example, (?R) is treated as if it were (?>(?R)). This is necessary because
20       otherwise there are situations where recursion does not work.
21    
22    See the ChangeLog for a complete list of changes, which include a number of bug
23    fixes and tidies.
24    
25    
26    Release 6.0 07-Jun-05
27    ---------------------
28    
29    The release number has been increased to 6.0 because of the addition of several
30    major new pieces of functionality.
31    
32    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
33    algorithm, has been added. This has a number of advantages for certain cases,
34    though it does run more slowly, and lacks the ability to capture substrings. On
35    the other hand, it does find all matches, not just the first, and it works
36    better for partial matching. The pcrematching man page discusses the
37    differences.
38    
39    The pcretest program has been enhanced so that it can make use of the new
40    pcre_dfa_exec() matching function and the extra features it provides.
41    
42    The distribution now includes a C++ wrapper library. This is built
43    automatically if a C++ compiler is found. The pcrecpp man page discusses this
44    interface.
45    
46    The code itself has been re-organized into many more files, one for each
47    function, so it no longer requires everything to be linked in when static
48    linkage is used. As a consequence, some internal functions have had to have
49    their names exposed. These functions all have names starting with _pcre_. They
50    are undocumented, and are not intended for use by outside callers.
51    
52    The pcregrep program has been enhanced with new functionality such as
53    multiline-matching and options for output more matching context. See the
54    ChangeLog for a complete list of changes to the library and the utility
55    programs.
56    
57    
58    Release 5.0 13-Sep-04
59    ---------------------
60    
61    The licence under which PCRE is released has been changed to the more
62    conventional "BSD" licence.
63    
64    In the code, some bugs have been fixed, and there are also some major changes
65    in this release (which is why I've increased the number to 5.0). Some changes
66    are internal rearrangements, and some provide a number of new facilities. The
67    new features are:
68    
69    1. There's an "automatic callout" feature that inserts callouts before every
70       item in the regex, and there's a new callout field that gives the position
71       in the pattern - useful for debugging and tracing.
72    
73    2. The extra_data structure can now be used to pass in a set of character
74       tables at exec time. This is useful if compiled regex are saved and re-used
75       at a later time when the tables may not be at the same address. If the
76       default internal tables are used, the pointer saved with the compiled
77       pattern is now set to NULL, which means that you don't need to do anything
78       special unless you are using custom tables.
79    
80    3. It is possible, with some restrictions on the content of the regex, to
81       request "partial" matching. A special return code is given if all of the
82       subject string matched part of the regex. This could be useful for testing
83       an input field as it is being typed.
84    
85    4. There is now some optional support for Unicode character properties, which
86       means that the patterns items such as \p{Lu} and \X can now be used. Only
87       the general category properties are supported. If PCRE is compiled with this
88       support, an additional 90K data structure is include, which increases the
89       size of the library dramatically.
90    
91    5. There is support for saving compiled patterns and re-using them later.
92    
93    6. There is support for running regular expressions that were compiled on a
94       different host with the opposite endianness.
95    
96    7. The pcretest program has been extended to accommodate the new features.
97    
98    The main internal rearrangement is that sequences of literal characters are no
99    longer handled as strings. Instead, each character is handled on its own. This
100    makes some UTF-8 handling easier, and makes the support of partial matching
101    possible. Compiled patterns containing long literal strings will be larger as a
102    result of this change; I hope that performance will not be much affected.
103    
104    
105    Release 4.5 01-Dec-03
106    ---------------------
107    
108    Again mainly a bug-fix and tidying release, with only a couple of new features:
109    
110    1. It's possible now to compile PCRE so that it does not use recursive
111    function calls when matching. Instead it gets memory from the heap. This slows
112    things down, but may be necessary on systems with limited stacks.
113    
114    2. UTF-8 string checking has been tightened to reject overlong sequences and to
115    check that a starting offset points to the start of a character. Failure of the
116    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
117    
118    3. PCRE can now be compiled for systems that use EBCDIC code.
119    
120    
121    Release 4.4 21-Aug-03
122    ---------------------
123    
124    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
125    checks UTF-8 strings for validity by default. There is an option to suppress
126    this, just in case anybody wants that teeny extra bit of performance.
127    
128    
129    Releases 4.1 - 4.3
130    ------------------
131    
132    Sorry, I forgot about updating the NEWS file for these releases. Please take a
133    look at ChangeLog.
134    
135    
136    Release 4.0 17-Feb-03
137    ---------------------
138    
139    There have been a lot of changes for the 4.0 release, adding additional
140    functionality and mending bugs. Below is a list of the highlights of the new
141    functionality. For full details of these features, please consult the
142    documentation. For a complete list of changes, see the ChangeLog file.
143    
144    1. Support for Perl's \Q...\E escapes.
145    
146    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
147    package. They provide some syntactic sugar for simple cases of "atomic
148    grouping".
149    
150    3. Support for the \G assertion. It is true when the current matching position
151    is at the start point of the match.
152    
153    4. A new feature that provides some of the functionality that Perl provides
154    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
155    is for the caller to provide an optional function, by setting pcre_callout to
156    its entry point. To get the function called, the regex must include (?C) at
157    appropriate points.
158    
159    5. Support for recursive calls to individual subpatterns. This makes it really
160    easy to get totally confused.
161    
162    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
163    name a group.
164    
165    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
166    option for pcregrep to make it operate in UTF-8 mode.
167    
168    8. The single man page has been split into a number of separate man pages.
169    These also give rise to individual HTML pages which are put in a separate
170    directory. There is an index.html page that lists them all. Some hyperlinking
171    between the pages has been installed.
172    
173    
174    Release 3.5 15-Aug-01
175    ---------------------
176    
177    1. The configuring system has been upgraded to use later versions of autoconf
178    and libtool. By default it builds both a shared and a static library if the OS
179    supports it. You can use --disable-shared or --disable-static on the configure
180    command if you want only one of them.
181    
182    2. The pcretest utility is now installed along with pcregrep because it is
183    useful for users (to test regexs) and by doing this, it automatically gets
184    relinked by libtool. The documentation has been turned into a man page, so
185    there are now .1, .txt, and .html versions in /doc.
186    
187    3. Upgrades to pcregrep:
188       (i)   Added long-form option names like gnu grep.
189       (ii)  Added --help to list all options with an explanatory phrase.
190       (iii) Added -r, --recursive to recurse into sub-directories.
191       (iv)  Added -f, --file to read patterns from a file.
192    
193    4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
194    script, to force use of CR or LF instead of \n in the source. On non-Unix
195    systems, the value can be set in config.h.
196    
197    5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
198    absolute limit. Changed the text of the error message to make this clear, and
199    likewise updated the man page.
200    
201    6. The limit of 99 on the number of capturing subpatterns has been removed.
202    The new limit is 65535, which I hope will not be a "real" limit.
203    
204    
205    Release 3.3 01-Aug-00
206    ---------------------
207    
208    There is some support for UTF-8 character strings. This is incomplete and
209    experimental. The documentation describes what is and what is not implemented.
210    Otherwise, this is just a bug-fixing release.
211    
212    
213  Release 3.0 01-Feb-00  Release 3.0 01-Feb-00
214  ---------------------  ---------------------
215    

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