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Revision 75 - (show annotations) (download)
Sat Feb 24 21:40:37 2007 UTC (7 years, 1 month ago) by nigel
File size: 8460 byte(s)
Load pcre-5.0 into code/trunk.

1 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
121 ---------------------
122
123 1. The configuring system has been upgraded to use later versions of autoconf
124 and libtool. By default it builds both a shared and a static library if the OS
125 supports it. You can use --disable-shared or --disable-static on the configure
126 command if you want only one of them.
127
128 2. The pcretest utility is now installed along with pcregrep because it is
129 useful for users (to test regexs) and by doing this, it automatically gets
130 relinked by libtool. The documentation has been turned into a man page, so
131 there are now .1, .txt, and .html versions in /doc.
132
133 3. Upgrades to pcregrep:
134 (i) Added long-form option names like gnu grep.
135 (ii) Added --help to list all options with an explanatory phrase.
136 (iii) Added -r, --recursive to recurse into sub-directories.
137 (iv) Added -f, --file to read patterns from a file.
138
139 4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
140 script, to force use of CR or LF instead of \n in the source. On non-Unix
141 systems, the value can be set in config.h.
142
143 5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
144 absolute limit. Changed the text of the error message to make this clear, and
145 likewise updated the man page.
146
147 6. The limit of 99 on the number of capturing subpatterns has been removed.
148 The new limit is 65535, which I hope will not be a "real" limit.
149
150
151 Release 3.3 01-Aug-00
152 ---------------------
153
154 There is some support for UTF-8 character strings. This is incomplete and
155 experimental. The documentation describes what is and what is not implemented.
156 Otherwise, this is just a bug-fixing release.
157
158
159 Release 3.0 01-Feb-00
160 ---------------------
161
162 1. A "configure" script is now used to configure PCRE for Unix systems. It
163 builds a Makefile, a config.h file, and the pcre-config script.
164
165 2. PCRE is built as a shared library by default.
166
167 3. There is support for POSIX classes such as [:alpha:].
168
169 5. There is an experimental recursion feature.
170
171 ----------------------------------------------------------------------------
172 IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
173
174 Please note that there has been a change in the API such that a larger
175 ovector is required at matching time, to provide some additional workspace.
176 The new man page has details. This change was necessary in order to support
177 some of the new functionality in Perl 5.005.
178
179 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
180
181 Another (I hope this is the last!) change has been made to the API for the
182 pcre_compile() function. An additional argument has been added to make it
183 possible to pass over a pointer to character tables built in the current
184 locale by pcre_maketables(). To use the default tables, this new arguement
185 should be passed as NULL.
186
187 IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
188
189 Yet another (and again I hope this really is the last) change has been made
190 to the API for the pcre_exec() function. An additional argument has been
191 added to make it possible to start the match other than at the start of the
192 subject string. This is important if there are lookbehinds. The new man
193 page has the details, but you just want to convert existing programs, all
194 you need to do is to stick in a new fifth argument to pcre_exec(), with a
195 value of zero. For example, change
196
197 pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
198 to
199 pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
200
201 ****

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