/[pcre]/code/tags/pcre-6.6/NEWS
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revision 53 by nigel, Sat Feb 24 21:39:42 2007 UTC revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    Release 5.0 13-Sep-04
5    ---------------------
6    
7    The licence under which PCRE is released has been changed to the more
8    conventional "BSD" licence.
9    
10    In the code, some bugs have been fixed, and there are also some major changes
11    in this release (which is why I've increased the number to 5.0). Some changes
12    are internal rearrangements, and some provide a number of new facilities. The
13    new features are:
14    
15    1. There's an "automatic callout" feature that inserts callouts before every
16       item in the regex, and there's a new callout field that gives the position
17       in the pattern - useful for debugging and tracing.
18    
19    2. The extra_data structure can now be used to pass in a set of character
20       tables at exec time. This is useful if compiled regex are saved and re-used
21       at a later time when the tables may not be at the same address. If the
22       default internal tables are used, the pointer saved with the compiled
23       pattern is now set to NULL, which means that you don't need to do anything
24       special unless you are using custom tables.
25    
26    3. It is possible, with some restrictions on the content of the regex, to
27       request "partial" matching. A special return code is given if all of the
28       subject string matched part of the regex. This could be useful for testing
29       an input field as it is being typed.
30    
31    4. There is now some optional support for Unicode character properties, which
32       means that the patterns items such as \p{Lu} and \X can now be used. Only
33       the general category properties are supported. If PCRE is compiled with this
34       support, an additional 90K data structure is include, which increases the
35       size of the library dramatically.
36    
37    5. There is support for saving compiled patterns and re-using them later.
38    
39    6. There is support for running regular expressions that were compiled on a
40       different host with the opposite endianness.
41    
42    7. The pcretest program has been extended to accommodate the new features.
43    
44    The main internal rearrangement is that sequences of literal characters are no
45    longer handled as strings. Instead, each character is handled on its own. This
46    makes some UTF-8 handling easier, and makes the support of partial matching
47    possible. Compiled patterns containing long literal strings will be larger as a
48    result of this change; I hope that performance will not be much affected.
49    
50    
51    Release 4.5 01-Dec-03
52    ---------------------
53    
54    Again mainly a bug-fix and tidying release, with only a couple of new features:
55    
56    1. It's possible now to compile PCRE so that it does not use recursive
57    function calls when matching. Instead it gets memory from the heap. This slows
58    things down, but may be necessary on systems with limited stacks.
59    
60    2. UTF-8 string checking has been tightened to reject overlong sequences and to
61    check that a starting offset points to the start of a character. Failure of the
62    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
63    
64    3. PCRE can now be compiled for systems that use EBCDIC code.
65    
66    
67    Release 4.4 21-Aug-03
68    ---------------------
69    
70    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
71    checks UTF-8 strings for validity by default. There is an option to suppress
72    this, just in case anybody wants that teeny extra bit of performance.
73    
74    
75    Releases 4.1 - 4.3
76    ------------------
77    
78    Sorry, I forgot about updating the NEWS file for these releases. Please take a
79    look at ChangeLog.
80    
81    
82    Release 4.0 17-Feb-03
83    ---------------------
84    
85    There have been a lot of changes for the 4.0 release, adding additional
86    functionality and mending bugs. Below is a list of the highlights of the new
87    functionality. For full details of these features, please consult the
88    documentation. For a complete list of changes, see the ChangeLog file.
89    
90    1. Support for Perl's \Q...\E escapes.
91    
92    2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
93    package. They provide some syntactic sugar for simple cases of "atomic
94    grouping".
95    
96    3. Support for the \G assertion. It is true when the current matching position
97    is at the start point of the match.
98    
99    4. A new feature that provides some of the functionality that Perl provides
100    with (?{...}). The facility is termed a "callout". The way it is done in PCRE
101    is for the caller to provide an optional function, by setting pcre_callout to
102    its entry point. To get the function called, the regex must include (?C) at
103    appropriate points.
104    
105    5. Support for recursive calls to individual subpatterns. This makes it really
106    easy to get totally confused.
107    
108    6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
109    name a group.
110    
111    7. Several extensions to UTF-8 support; it is now fairly complete. There is an
112    option for pcregrep to make it operate in UTF-8 mode.
113    
114    8. The single man page has been split into a number of separate man pages.
115    These also give rise to individual HTML pages which are put in a separate
116    directory. There is an index.html page that lists them all. Some hyperlinking
117    between the pages has been installed.
118    
119    
120  Release 3.5 15-Aug-01  Release 3.5 15-Aug-01
121  ---------------------  ---------------------
122    

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