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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC
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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  Release 4.5 01-Dec-03
106  ---------------------  ---------------------
107    

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