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Revision 128 - (hide annotations) (download)
Tue Mar 20 11:46:50 2007 UTC (7 years, 4 months ago) by ph10
File size: 13340 byte(s)
Make the use of dftables optional, and not the default. Further tidies to 
documentation.

1 nigel 41 News about PCRE releases
2     ------------------------
3    
4 ph10 122
5 ph10 128 Release 7.1 20-Mar-07
6 nigel 93 ---------------------
7    
8 ph10 122 There are no new features in this release. A few bugs are fixed (see ChangeLog
9     for details), but the major change is a complete re-implementation of the build
10 ph10 123 system. This now has full Autotools support and so is now "standard" in some
11 ph10 122 sense. It should help with compiling PCRE in a wide variety of environments.
12    
13 ph10 128 An important change is that the dftables auxiliary program is no longer
14     compiled and run at "make" time by default. Instead, a default set of character
15     tables (assuming ASCII coding) is used. If you want to use dftables to generate
16     the character tables as previously, add --enable-rebuild-chartables to the
17     "configure" command. You must do this if you are compiling PCRE to run on a
18     system that uses EBCDIC code.
19 ph10 122
20 ph10 128 There is a discussion about character tables in the README file. The default is
21     not to use dftables so that that there is no problem when cross-compiling.
22    
23    
24 ph10 122 Release 7.0 19-Dec-06
25     ---------------------
26    
27 nigel 93 This release has a new major number because there have been some internal
28     upheavals to facilitate the addition of new optimizations and other facilities,
29     and to make subsequent maintenance and extension easier. Compilation is likely
30     to be a bit slower, but there should be no major effect on runtime performance.
31     Previously compiled patterns are NOT upwards compatible with this release. If
32     you have saved compiled patterns from a previous release, you will have to
33     re-compile them. Important changes that are visible to users are:
34    
35     1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
36     some more scripts.
37    
38     2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
39     sequence as a newline.
40    
41     3. The \R escape matches a single Unicode newline sequence as a single unit.
42    
43     4. New features that will appear in Perl 5.10 are now in PCRE. These include
44     alternative Perl syntax for named parentheses, and Perl syntax for
45     recursion.
46    
47     5. The C++ wrapper interface has been extended by the addition of a
48     QuoteMeta function and the ability to allow copy construction and
49     assignment.
50    
51     For a complete list of changes, see the ChangeLog file.
52    
53    
54 nigel 91 Release 6.7 04-Jul-06
55     ---------------------
56    
57     The main additions to this release are the ability to use the same name for
58     multiple sets of parentheses, and support for CRLF line endings in both the
59     library and pcregrep (and in pcretest for testing).
60    
61     Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
62     significantly reduced for certain subject strings.
63    
64    
65 nigel 87 Release 6.5 01-Feb-06
66     ---------------------
67    
68     Important changes in this release:
69    
70     1. A number of new features have been added to pcregrep.
71    
72     2. The Unicode property tables have been updated to Unicode 4.1.0, and the
73     supported properties have been extended with script names such as "Arabic",
74     and the derived properties "Any" and "L&". This has necessitated a change to
75     the interal format of compiled patterns. Any saved compiled patterns that
76     use \p or \P must be recompiled.
77    
78     3. The specification of recursion in patterns has been changed so that all
79     recursive subpatterns are automatically treated as atomic groups. Thus, for
80     example, (?R) is treated as if it were (?>(?R)). This is necessary because
81     otherwise there are situations where recursion does not work.
82    
83     See the ChangeLog for a complete list of changes, which include a number of bug
84     fixes and tidies.
85    
86    
87 nigel 77 Release 6.0 07-Jun-05
88     ---------------------
89    
90     The release number has been increased to 6.0 because of the addition of several
91     major new pieces of functionality.
92    
93     A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
94     algorithm, has been added. This has a number of advantages for certain cases,
95     though it does run more slowly, and lacks the ability to capture substrings. On
96     the other hand, it does find all matches, not just the first, and it works
97     better for partial matching. The pcrematching man page discusses the
98     differences.
99    
100     The pcretest program has been enhanced so that it can make use of the new
101     pcre_dfa_exec() matching function and the extra features it provides.
102    
103     The distribution now includes a C++ wrapper library. This is built
104     automatically if a C++ compiler is found. The pcrecpp man page discusses this
105     interface.
106    
107     The code itself has been re-organized into many more files, one for each
108     function, so it no longer requires everything to be linked in when static
109     linkage is used. As a consequence, some internal functions have had to have
110     their names exposed. These functions all have names starting with _pcre_. They
111     are undocumented, and are not intended for use by outside callers.
112    
113     The pcregrep program has been enhanced with new functionality such as
114     multiline-matching and options for output more matching context. See the
115     ChangeLog for a complete list of changes to the library and the utility
116     programs.
117    
118    
119 nigel 75 Release 5.0 13-Sep-04
120     ---------------------
121    
122     The licence under which PCRE is released has been changed to the more
123     conventional "BSD" licence.
124    
125     In the code, some bugs have been fixed, and there are also some major changes
126     in this release (which is why I've increased the number to 5.0). Some changes
127     are internal rearrangements, and some provide a number of new facilities. The
128     new features are:
129    
130     1. There's an "automatic callout" feature that inserts callouts before every
131     item in the regex, and there's a new callout field that gives the position
132     in the pattern - useful for debugging and tracing.
133    
134     2. The extra_data structure can now be used to pass in a set of character
135     tables at exec time. This is useful if compiled regex are saved and re-used
136     at a later time when the tables may not be at the same address. If the
137     default internal tables are used, the pointer saved with the compiled
138     pattern is now set to NULL, which means that you don't need to do anything
139     special unless you are using custom tables.
140    
141     3. It is possible, with some restrictions on the content of the regex, to
142     request "partial" matching. A special return code is given if all of the
143     subject string matched part of the regex. This could be useful for testing
144     an input field as it is being typed.
145    
146     4. There is now some optional support for Unicode character properties, which
147     means that the patterns items such as \p{Lu} and \X can now be used. Only
148     the general category properties are supported. If PCRE is compiled with this
149     support, an additional 90K data structure is include, which increases the
150     size of the library dramatically.
151    
152     5. There is support for saving compiled patterns and re-using them later.
153    
154     6. There is support for running regular expressions that were compiled on a
155     different host with the opposite endianness.
156    
157     7. The pcretest program has been extended to accommodate the new features.
158    
159     The main internal rearrangement is that sequences of literal characters are no
160     longer handled as strings. Instead, each character is handled on its own. This
161     makes some UTF-8 handling easier, and makes the support of partial matching
162     possible. Compiled patterns containing long literal strings will be larger as a
163     result of this change; I hope that performance will not be much affected.
164    
165    
166 nigel 73 Release 4.5 01-Dec-03
167     ---------------------
168    
169     Again mainly a bug-fix and tidying release, with only a couple of new features:
170    
171     1. It's possible now to compile PCRE so that it does not use recursive
172     function calls when matching. Instead it gets memory from the heap. This slows
173     things down, but may be necessary on systems with limited stacks.
174    
175     2. UTF-8 string checking has been tightened to reject overlong sequences and to
176     check that a starting offset points to the start of a character. Failure of the
177     latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
178    
179     3. PCRE can now be compiled for systems that use EBCDIC code.
180    
181    
182 nigel 71 Release 4.4 21-Aug-03
183     ---------------------
184    
185     This is mainly a bug-fix and tidying release. The only new feature is that PCRE
186     checks UTF-8 strings for validity by default. There is an option to suppress
187     this, just in case anybody wants that teeny extra bit of performance.
188    
189    
190     Releases 4.1 - 4.3
191     ------------------
192    
193     Sorry, I forgot about updating the NEWS file for these releases. Please take a
194     look at ChangeLog.
195    
196    
197 nigel 63 Release 4.0 17-Feb-03
198     ---------------------
199    
200     There have been a lot of changes for the 4.0 release, adding additional
201     functionality and mending bugs. Below is a list of the highlights of the new
202     functionality. For full details of these features, please consult the
203     documentation. For a complete list of changes, see the ChangeLog file.
204    
205     1. Support for Perl's \Q...\E escapes.
206    
207     2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
208     package. They provide some syntactic sugar for simple cases of "atomic
209     grouping".
210    
211     3. Support for the \G assertion. It is true when the current matching position
212     is at the start point of the match.
213    
214     4. A new feature that provides some of the functionality that Perl provides
215     with (?{...}). The facility is termed a "callout". The way it is done in PCRE
216     is for the caller to provide an optional function, by setting pcre_callout to
217     its entry point. To get the function called, the regex must include (?C) at
218     appropriate points.
219    
220     5. Support for recursive calls to individual subpatterns. This makes it really
221     easy to get totally confused.
222    
223     6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
224     name a group.
225    
226     7. Several extensions to UTF-8 support; it is now fairly complete. There is an
227     option for pcregrep to make it operate in UTF-8 mode.
228    
229     8. The single man page has been split into a number of separate man pages.
230     These also give rise to individual HTML pages which are put in a separate
231     directory. There is an index.html page that lists them all. Some hyperlinking
232     between the pages has been installed.
233    
234    
235 nigel 53 Release 3.5 15-Aug-01
236     ---------------------
237    
238     1. The configuring system has been upgraded to use later versions of autoconf
239     and libtool. By default it builds both a shared and a static library if the OS
240     supports it. You can use --disable-shared or --disable-static on the configure
241     command if you want only one of them.
242    
243     2. The pcretest utility is now installed along with pcregrep because it is
244     useful for users (to test regexs) and by doing this, it automatically gets
245     relinked by libtool. The documentation has been turned into a man page, so
246     there are now .1, .txt, and .html versions in /doc.
247    
248     3. Upgrades to pcregrep:
249     (i) Added long-form option names like gnu grep.
250     (ii) Added --help to list all options with an explanatory phrase.
251     (iii) Added -r, --recursive to recurse into sub-directories.
252     (iv) Added -f, --file to read patterns from a file.
253    
254     4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
255     script, to force use of CR or LF instead of \n in the source. On non-Unix
256     systems, the value can be set in config.h.
257    
258     5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
259     absolute limit. Changed the text of the error message to make this clear, and
260     likewise updated the man page.
261    
262     6. The limit of 99 on the number of capturing subpatterns has been removed.
263     The new limit is 65535, which I hope will not be a "real" limit.
264    
265    
266 nigel 49 Release 3.3 01-Aug-00
267     ---------------------
268    
269     There is some support for UTF-8 character strings. This is incomplete and
270     experimental. The documentation describes what is and what is not implemented.
271     Otherwise, this is just a bug-fixing release.
272    
273    
274 nigel 43 Release 3.0 01-Feb-00
275     ---------------------
276 nigel 41
277 nigel 43 1. A "configure" script is now used to configure PCRE for Unix systems. It
278     builds a Makefile, a config.h file, and the pcre-config script.
279    
280     2. PCRE is built as a shared library by default.
281    
282     3. There is support for POSIX classes such as [:alpha:].
283    
284     5. There is an experimental recursion feature.
285    
286 nigel 41 ----------------------------------------------------------------------------
287     IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
288    
289     Please note that there has been a change in the API such that a larger
290     ovector is required at matching time, to provide some additional workspace.
291     The new man page has details. This change was necessary in order to support
292     some of the new functionality in Perl 5.005.
293    
294     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
295    
296     Another (I hope this is the last!) change has been made to the API for the
297     pcre_compile() function. An additional argument has been added to make it
298     possible to pass over a pointer to character tables built in the current
299     locale by pcre_maketables(). To use the default tables, this new arguement
300     should be passed as NULL.
301    
302     IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
303    
304     Yet another (and again I hope this really is the last) change has been made
305     to the API for the pcre_exec() function. An additional argument has been
306     added to make it possible to start the match other than at the start of the
307     subject string. This is important if there are lookbehinds. The new man
308     page has the details, but you just want to convert existing programs, all
309     you need to do is to stick in a new fifth argument to pcre_exec(), with a
310     value of zero. For example, change
311    
312     pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
313     to
314     pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
315    
316     ****

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