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revision 71 by nigel, Sat Feb 24 21:40:24 2007 UTC revision 226 by ph10, Tue Aug 21 11:46:08 2007 UTC
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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    
5    Release 7.3 20-Aug-07
6    ---------------------
7    
8    Most changes are bug fixes. Some that are not:
9    
10    1. There is some support for Perl 5.10's experimental "backtracking control
11       verbs" such as (*PRUNE).
12    
13    2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
14       restrictive in the strings it accepts.
15    
16    3. Checking for potential integer overflow has been made more dynamic, and as a
17       consequence there is no longer a hard limit on the size of a subpattern that
18       has a limited repeat count.
19    
20    4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
21       no longer advance by two characters instead of one when an unanchored match
22       fails at CRLF if there are explicit CR or LF matches within the pattern.
23       This gets rid of some anomalous effects that previously occurred.
24    
25    
26    Release 7.2 19-Jun-07
27    ---------------------
28    
29    WARNING: saved patterns that were compiled by earlier versions of PCRE must be
30    recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
31    and \V).
32    
33    Correction to the notes for 7.1: the note about shared libraries for Windows is
34    wrong. Previously, three libraries were built, but each could function
35    independently. For example, the pcreposix library also included all the
36    functions from the basic pcre library. The change is that the three libraries
37    are no longer independent. They are like the Unix libraries. To use the
38    pcreposix functions, for example, you need to link with both the pcreposix and
39    the basic pcre library.
40    
41    Some more features from Perl 5.10 have been added:
42    
43      (?-n) and (?+n) relative references for recursion and subroutines.
44    
45      (?(-n) and (?(+n) relative references as conditions.
46    
47      \k{name} and \g{name} are synonyms for \k<name>.
48    
49      \K to reset the start of the matched string; for example, (foo)\Kbar
50      matches bar preceded by foo, but only sets bar as the matched string.
51    
52      (?| introduces a group where the capturing parentheses in each alternative
53      start from the same number; for example, (?|(abc)|(xyz)) sets capturing
54      parentheses number 1 in both cases.
55    
56      \h, \H, \v, \V match horizontal and vertical whitespace, respectively.
57    
58    
59    Release 7.1 24-Apr-07
60    ---------------------
61    
62    There is only one new feature in this release: a linebreak setting of
63    PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
64    recognizes only CRLF, CR, and LF as linebreaks.
65    
66    A few bugs are fixed (see ChangeLog for details), but the major change is a
67    complete re-implementation of the build system. This now has full Autotools
68    support and so is now "standard" in some sense. It should help with compiling
69    PCRE in a wide variety of environments.
70    
71    NOTE: when building shared libraries for Windows, three dlls are now built,
72    called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
73    included in a single dll.
74    
75    Another important change is that the dftables auxiliary program is no longer
76    compiled and run at "make" time by default. Instead, a default set of character
77    tables (assuming ASCII coding) is used. If you want to use dftables to generate
78    the character tables as previously, add --enable-rebuild-chartables to the
79    "configure" command. You must do this if you are compiling PCRE to run on a
80    system that uses EBCDIC code.
81    
82    There is a discussion about character tables in the README file. The default is
83    not to use dftables so that that there is no problem when cross-compiling.
84    
85    
86    Release 7.0 19-Dec-06
87    ---------------------
88    
89    This release has a new major number because there have been some internal
90    upheavals to facilitate the addition of new optimizations and other facilities,
91    and to make subsequent maintenance and extension easier. Compilation is likely
92    to be a bit slower, but there should be no major effect on runtime performance.
93    Previously compiled patterns are NOT upwards compatible with this release. If
94    you have saved compiled patterns from a previous release, you will have to
95    re-compile them. Important changes that are visible to users are:
96    
97    1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
98       some more scripts.
99    
100    2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
101       sequence as a newline.
102    
103    3. The \R escape matches a single Unicode newline sequence as a single unit.
104    
105    4. New features that will appear in Perl 5.10 are now in PCRE. These include
106       alternative Perl syntax for named parentheses, and Perl syntax for
107       recursion.
108    
109    5. The C++ wrapper interface has been extended by the addition of a
110       QuoteMeta function and the ability to allow copy construction and
111       assignment.
112    
113    For a complete list of changes, see the ChangeLog file.
114    
115    
116    Release 6.7 04-Jul-06
117    ---------------------
118    
119    The main additions to this release are the ability to use the same name for
120    multiple sets of parentheses, and support for CRLF line endings in both the
121    library and pcregrep (and in pcretest for testing).
122    
123    Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
124    significantly reduced for certain subject strings.
125    
126    
127    Release 6.5 01-Feb-06
128    ---------------------
129    
130    Important changes in this release:
131    
132    1. A number of new features have been added to pcregrep.
133    
134    2. The Unicode property tables have been updated to Unicode 4.1.0, and the
135       supported properties have been extended with script names such as "Arabic",
136       and the derived properties "Any" and "L&". This has necessitated a change to
137       the interal format of compiled patterns. Any saved compiled patterns that
138       use \p or \P must be recompiled.
139    
140    3. The specification of recursion in patterns has been changed so that all
141       recursive subpatterns are automatically treated as atomic groups. Thus, for
142       example, (?R) is treated as if it were (?>(?R)). This is necessary because
143       otherwise there are situations where recursion does not work.
144    
145    See the ChangeLog for a complete list of changes, which include a number of bug
146    fixes and tidies.
147    
148    
149    Release 6.0 07-Jun-05
150    ---------------------
151    
152    The release number has been increased to 6.0 because of the addition of several
153    major new pieces of functionality.
154    
155    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
156    algorithm, has been added. This has a number of advantages for certain cases,
157    though it does run more slowly, and lacks the ability to capture substrings. On
158    the other hand, it does find all matches, not just the first, and it works
159    better for partial matching. The pcrematching man page discusses the
160    differences.
161    
162    The pcretest program has been enhanced so that it can make use of the new
163    pcre_dfa_exec() matching function and the extra features it provides.
164    
165    The distribution now includes a C++ wrapper library. This is built
166    automatically if a C++ compiler is found. The pcrecpp man page discusses this
167    interface.
168    
169    The code itself has been re-organized into many more files, one for each
170    function, so it no longer requires everything to be linked in when static
171    linkage is used. As a consequence, some internal functions have had to have
172    their names exposed. These functions all have names starting with _pcre_. They
173    are undocumented, and are not intended for use by outside callers.
174    
175    The pcregrep program has been enhanced with new functionality such as
176    multiline-matching and options for output more matching context. See the
177    ChangeLog for a complete list of changes to the library and the utility
178    programs.
179    
180    
181    Release 5.0 13-Sep-04
182    ---------------------
183    
184    The licence under which PCRE is released has been changed to the more
185    conventional "BSD" licence.
186    
187    In the code, some bugs have been fixed, and there are also some major changes
188    in this release (which is why I've increased the number to 5.0). Some changes
189    are internal rearrangements, and some provide a number of new facilities. The
190    new features are:
191    
192    1. There's an "automatic callout" feature that inserts callouts before every
193       item in the regex, and there's a new callout field that gives the position
194       in the pattern - useful for debugging and tracing.
195    
196    2. The extra_data structure can now be used to pass in a set of character
197       tables at exec time. This is useful if compiled regex are saved and re-used
198       at a later time when the tables may not be at the same address. If the
199       default internal tables are used, the pointer saved with the compiled
200       pattern is now set to NULL, which means that you don't need to do anything
201       special unless you are using custom tables.
202    
203    3. It is possible, with some restrictions on the content of the regex, to
204       request "partial" matching. A special return code is given if all of the
205       subject string matched part of the regex. This could be useful for testing
206       an input field as it is being typed.
207    
208    4. There is now some optional support for Unicode character properties, which
209       means that the patterns items such as \p{Lu} and \X can now be used. Only
210       the general category properties are supported. If PCRE is compiled with this
211       support, an additional 90K data structure is include, which increases the
212       size of the library dramatically.
213    
214    5. There is support for saving compiled patterns and re-using them later.
215    
216    6. There is support for running regular expressions that were compiled on a
217       different host with the opposite endianness.
218    
219    7. The pcretest program has been extended to accommodate the new features.
220    
221    The main internal rearrangement is that sequences of literal characters are no
222    longer handled as strings. Instead, each character is handled on its own. This
223    makes some UTF-8 handling easier, and makes the support of partial matching
224    possible. Compiled patterns containing long literal strings will be larger as a
225    result of this change; I hope that performance will not be much affected.
226    
227    
228    Release 4.5 01-Dec-03
229    ---------------------
230    
231    Again mainly a bug-fix and tidying release, with only a couple of new features:
232    
233    1. It's possible now to compile PCRE so that it does not use recursive
234    function calls when matching. Instead it gets memory from the heap. This slows
235    things down, but may be necessary on systems with limited stacks.
236    
237    2. UTF-8 string checking has been tightened to reject overlong sequences and to
238    check that a starting offset points to the start of a character. Failure of the
239    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
240    
241    3. PCRE can now be compiled for systems that use EBCDIC code.
242    
243    
244  Release 4.4 21-Aug-03  Release 4.4 21-Aug-03
245  ---------------------  ---------------------
246    

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