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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 181 by ph10, Wed Jun 13 14:55:18 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    
5    Release 7.2 13-Jun-07
6    ---------------------
7    
8    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
9    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
10    and \V).
11    
12    Correction to the notes for 7.1: the note about shared libraries for Windows is
13    wrong. Previously, three libraries were built, but each could function
14    independently. For example, the pcreposix library also included all the
15    functions from the basic pcre library. The change is that the three libraries
16    are no longer independent. They are like the Unix libraries. To use the
17    pcreposix functions, for example, you need to link with both the pcreposix and
18    the basic pcre library.
19    
20    Some more features from Perl 5.10 have been added:
21    
22      (?-n) and (?+n) relative references for recursion and subroutines.
23    
24      (?(-n) and (?(+n) relative references as conditions.
25    
26      \k{name} and \g{name} are synonyms for \k<name>.
27    
28      \K to reset the start of the matched string; for example, (foo)\Kbar
29      matches bar preceded by foo, but only sets bar as the matched string.
30    
31      (?| introduces a group where the capturing parentheses in each alternative
32      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
33      parentheses number 1 in both cases.
34    
35      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
36    
37    
38    Release 7.1 24-Apr-07
39    ---------------------
40    
41    There is only one new feature in this release: a linebreak setting of
42    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
43    recognizes only CRLF, CR, and LF as linebreaks.
44    
45    A few bugs are fixed (see ChangeLog for details), but the major change is a
46    complete re-implementation of the build system. This now has full Autotools
47    support and so is now "standard" in some sense. It should help with compiling
48    PCRE in a wide variety of environments.
49    
50    NOTE: when building shared libraries for Windows, three dlls are now built,
51    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
52    included in a single dll.
53    
54    Another important change is that the dftables auxiliary program is no longer
55    compiled and run at "make" time by default. Instead, a default set of character
56    tables (assuming ASCII coding) is used. If you want to use dftables to generate
57    the character tables as previously, add --enable-rebuild-chartables to the
58    "configure" command. You must do this if you are compiling PCRE to run on a
59    system that uses EBCDIC code.
60    
61    There is a discussion about character tables in the README file. The default is
62    not to use dftables so that that there is no problem when cross-compiling.
63    
64    
65    Release 7.0 19-Dec-06
66    ---------------------
67    
68    This release has a new major number because there have been some internal
69    upheavals to facilitate the addition of new optimizations and other facilities,
70    and to make subsequent maintenance and extension easier. Compilation is likely
71    to be a bit slower, but there should be no major effect on runtime performance.
72    Previously compiled patterns are NOT upwards compatible with this release. If
73    you have saved compiled patterns from a previous release, you will have to
74    re-compile them. Important changes that are visible to users are:
75    
76    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
77       some more scripts.
78    
79    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
80       sequence as a newline.
81    
82    3. The \R escape matches a single Unicode newline sequence as a single unit.
83    
84    4. New features that will appear in Perl 5.10 are now in PCRE. These include
85       alternative Perl syntax for named parentheses, and Perl syntax for
86       recursion.
87    
88    5. The C++ wrapper interface has been extended by the addition of a
89       QuoteMeta function and the ability to allow copy construction and
90       assignment.
91    
92    For a complete list of changes, see the ChangeLog file.
93    
94    
95    Release 6.7 04-Jul-06
96    ---------------------
97    
98    The main additions to this release are the ability to use the same name for
99    multiple sets of parentheses, and support for CRLF line endings in both the
100    library and pcregrep (and in pcretest for testing).
101    
102    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
103    significantly reduced for certain subject strings.
104    
105    
106    Release 6.5 01-Feb-06
107    ---------------------
108    
109    Important changes in this release:
110    
111    1. A number of new features have been added to pcregrep.
112    
113    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
114       supported properties have been extended with script names such as "Arabic",
115       and the derived properties "Any" and "L&". This has necessitated a change to
116       the interal format of compiled patterns. Any saved compiled patterns that
117       use \p or \P must be recompiled.
118    
119    3. The specification of recursion in patterns has been changed so that all
120       recursive subpatterns are automatically treated as atomic groups. Thus, for
121       example, (?R) is treated as if it were (?>(?R)). This is necessary because
122       otherwise there are situations where recursion does not work.
123    
124    See the ChangeLog for a complete list of changes, which include a number of bug
125    fixes and tidies.
126    
127    
128    Release 6.0 07-Jun-05
129    ---------------------
130    
131    The release number has been increased to 6.0 because of the addition of several
132    major new pieces of functionality.
133    
134    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
135    algorithm, has been added. This has a number of advantages for certain cases,
136    though it does run more slowly, and lacks the ability to capture substrings. On
137    the other hand, it does find all matches, not just the first, and it works
138    better for partial matching. The pcrematching man page discusses the
139    differences.
140    
141    The pcretest program has been enhanced so that it can make use of the new
142    pcre_dfa_exec() matching function and the extra features it provides.
143    
144    The distribution now includes a C++ wrapper library. This is built
145    automatically if a C++ compiler is found. The pcrecpp man page discusses this
146    interface.
147    
148    The code itself has been re-organized into many more files, one for each
149    function, so it no longer requires everything to be linked in when static
150    linkage is used. As a consequence, some internal functions have had to have
151    their names exposed. These functions all have names starting with _pcre_. They
152    are undocumented, and are not intended for use by outside callers.
153    
154    The pcregrep program has been enhanced with new functionality such as
155    multiline-matching and options for output more matching context. See the
156    ChangeLog for a complete list of changes to the library and the utility
157    programs.
158    
159    
160    Release 5.0 13-Sep-04
161    ---------------------
162    
163    The licence under which PCRE is released has been changed to the more
164    conventional "BSD" licence.
165    
166    In the code, some bugs have been fixed, and there are also some major changes
167    in this release (which is why I've increased the number to 5.0). Some changes
168    are internal rearrangements, and some provide a number of new facilities. The
169    new features are:
170    
171    1. There's an "automatic callout" feature that inserts callouts before every
172       item in the regex, and there's a new callout field that gives the position
173       in the pattern - useful for debugging and tracing.
174    
175    2. The extra_data structure can now be used to pass in a set of character
176       tables at exec time. This is useful if compiled regex are saved and re-used
177       at a later time when the tables may not be at the same address. If the
178       default internal tables are used, the pointer saved with the compiled
179       pattern is now set to NULL, which means that you don't need to do anything
180       special unless you are using custom tables.
181    
182    3. It is possible, with some restrictions on the content of the regex, to
183       request "partial" matching. A special return code is given if all of the
184       subject string matched part of the regex. This could be useful for testing
185       an input field as it is being typed.
186    
187    4. There is now some optional support for Unicode character properties, which
188       means that the patterns items such as \p{Lu} and \X can now be used. Only
189       the general category properties are supported. If PCRE is compiled with this
190       support, an additional 90K data structure is include, which increases the
191       size of the library dramatically.
192    
193    5. There is support for saving compiled patterns and re-using them later.
194    
195    6. There is support for running regular expressions that were compiled on a
196       different host with the opposite endianness.
197    
198    7. The pcretest program has been extended to accommodate the new features.
199    
200    The main internal rearrangement is that sequences of literal characters are no
201    longer handled as strings. Instead, each character is handled on its own. This
202    makes some UTF-8 handling easier, and makes the support of partial matching
203    possible. Compiled patterns containing long literal strings will be larger as a
204    result of this change; I hope that performance will not be much affected.
205    
206    
207  Release 4.5 01-Dec-03  Release 4.5 01-Dec-03
208  ---------------------  ---------------------
209    

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