Contents of /code/trunk/NEWS

News about PCRE releases
------------------------


Release 7.4 13-Sep-07
---------------------

The only change of specification is the addition of options to control whether
\R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
Otherwise, the changes are bug fixes and a refactoring to reduce the number of
relocations needed in a shared library.


Release 7.3 28-Aug-07
---------------------

Most changes are bug fixes. Some that are not:

1. There is some support for Perl 5.10's experimental "backtracking control
   verbs" such as (*PRUNE).

2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
   restrictive in the strings it accepts.

3. Checking for potential integer overflow has been made more dynamic, and as a
   consequence there is no longer a hard limit on the size of a subpattern that
   has a limited repeat count.

4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
   no longer advance by two characters instead of one when an unanchored match
   fails at CRLF if there are explicit CR or LF matches within the pattern.
   This gets rid of some anomalous effects that previously occurred.

5. Some PCRE-specific settings for varying the newline options at the start of
   a pattern have been added.


Release 7.2 19-Jun-07
---------------------

WARNING: saved patterns that were compiled by earlier versions of PCRE must be
recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
and \V).

Correction to the notes for 7.1: the note about shared libraries for Windows is
wrong. Previously, three libraries were built, but each could function
independently. For example, the pcreposix library also included all the
functions from the basic pcre library. The change is that the three libraries
are no longer independent. They are like the Unix libraries. To use the
pcreposix functions, for example, you need to link with both the pcreposix and
the basic pcre library.

Some more features from Perl 5.10 have been added:

  (?-n) and (?+n) relative references for recursion and subroutines.

  (?(-n) and (?(+n) relative references as conditions.

  \k{name} and \g{name} are synonyms for \k<name>.

  \K to reset the start of the matched string; for example, (foo)\Kbar
  matches bar preceded by foo, but only sets bar as the matched string.

  (?| introduces a group where the capturing parentheses in each alternative
  start from the same number; for example, (?|(abc)|(xyz)) sets capturing
  parentheses number 1 in both cases.

  \h, \H, \v, \V match horizontal and vertical whitespace, respectively.


Release 7.1 24-Apr-07
---------------------

There is only one new feature in this release: a linebreak setting of
PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
recognizes only CRLF, CR, and LF as linebreaks.

A few bugs are fixed (see ChangeLog for details), but the major change is a
complete re-implementation of the build system. This now has full Autotools
support and so is now "standard" in some sense. It should help with compiling
PCRE in a wide variety of environments.

NOTE: when building shared libraries for Windows, three dlls are now built,
called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
included in a single dll.

Another important change is that the dftables auxiliary program is no longer
compiled and run at "make" time by default. Instead, a default set of character
tables (assuming ASCII coding) is used. If you want to use dftables to generate
the character tables as previously, add --enable-rebuild-chartables to the
"configure" command. You must do this if you are compiling PCRE to run on a
system that uses EBCDIC code.

There is a discussion about character tables in the README file. The default is
not to use dftables so that that there is no problem when cross-compiling.


Release 7.0 19-Dec-06
---------------------

This release has a new major number because there have been some internal
upheavals to facilitate the addition of new optimizations and other facilities,
and to make subsequent maintenance and extension easier. Compilation is likely
to be a bit slower, but there should be no major effect on runtime performance.
Previously compiled patterns are NOT upwards compatible with this release. If
you have saved compiled patterns from a previous release, you will have to
re-compile them. Important changes that are visible to users are:

1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
   some more scripts.

2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
   sequence as a newline.

3. The \R escape matches a single Unicode newline sequence as a single unit.

4. New features that will appear in Perl 5.10 are now in PCRE. These include
   alternative Perl syntax for named parentheses, and Perl syntax for
   recursion.

5. The C++ wrapper interface has been extended by the addition of a
   QuoteMeta function and the ability to allow copy construction and
   assignment.

For a complete list of changes, see the ChangeLog file.


Release 6.7 04-Jul-06
---------------------

The main additions to this release are the ability to use the same name for
multiple sets of parentheses, and support for CRLF line endings in both the
library and pcregrep (and in pcretest for testing).

Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
significantly reduced for certain subject strings.


Release 6.5 01-Feb-06
---------------------

Important changes in this release:

1. A number of new features have been added to pcregrep.

2. The Unicode property tables have been updated to Unicode 4.1.0, and the
   supported properties have been extended with script names such as "Arabic",
   and the derived properties "Any" and "L&". This has necessitated a change to
   the interal format of compiled patterns. Any saved compiled patterns that
   use \p or \P must be recompiled.

3. The specification of recursion in patterns has been changed so that all
   recursive subpatterns are automatically treated as atomic groups. Thus, for
   example, (?R) is treated as if it were (?>(?R)). This is necessary because
   otherwise there are situations where recursion does not work.

See the ChangeLog for a complete list of changes, which include a number of bug
fixes and tidies.


Release 6.0 07-Jun-05
---------------------

The release number has been increased to 6.0 because of the addition of several
major new pieces of functionality.

A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
algorithm, has been added. This has a number of advantages for certain cases,
though it does run more slowly, and lacks the ability to capture substrings. On
the other hand, it does find all matches, not just the first, and it works
better for partial matching. The pcrematching man page discusses the
differences.

The pcretest program has been enhanced so that it can make use of the new
pcre_dfa_exec() matching function and the extra features it provides.

The distribution now includes a C++ wrapper library. This is built
automatically if a C++ compiler is found. The pcrecpp man page discusses this
interface.

The code itself has been re-organized into many more files, one for each
function, so it no longer requires everything to be linked in when static
linkage is used. As a consequence, some internal functions have had to have
their names exposed. These functions all have names starting with _pcre_. They
are undocumented, and are not intended for use by outside callers.

The pcregrep program has been enhanced with new functionality such as
multiline-matching and options for output more matching context. See the
ChangeLog for a complete list of changes to the library and the utility
programs.


Release 5.0 13-Sep-04
---------------------

The licence under which PCRE is released has been changed to the more
conventional "BSD" licence.

In the code, some bugs have been fixed, and there are also some major changes
in this release (which is why I've increased the number to 5.0). Some changes
are internal rearrangements, and some provide a number of new facilities. The
new features are:

1. There's an "automatic callout" feature that inserts callouts before every
   item in the regex, and there's a new callout field that gives the position
   in the pattern - useful for debugging and tracing.

2. The extra_data structure can now be used to pass in a set of character
   tables at exec time. This is useful if compiled regex are saved and re-used
   at a later time when the tables may not be at the same address. If the
   default internal tables are used, the pointer saved with the compiled
   pattern is now set to NULL, which means that you don't need to do anything
   special unless you are using custom tables.

3. It is possible, with some restrictions on the content of the regex, to
   request "partial" matching. A special return code is given if all of the
   subject string matched part of the regex. This could be useful for testing
   an input field as it is being typed.

4. There is now some optional support for Unicode character properties, which
   means that the patterns items such as \p{Lu} and \X can now be used. Only
   the general category properties are supported. If PCRE is compiled with this
   support, an additional 90K data structure is include, which increases the
   size of the library dramatically.

5. There is support for saving compiled patterns and re-using them later.

6. There is support for running regular expressions that were compiled on a
   different host with the opposite endianness.

7. The pcretest program has been extended to accommodate the new features.

The main internal rearrangement is that sequences of literal characters are no
longer handled as strings. Instead, each character is handled on its own. This
makes some UTF-8 handling easier, and makes the support of partial matching
possible. Compiled patterns containing long literal strings will be larger as a
result of this change; I hope that performance will not be much affected.


Release 4.5 01-Dec-03
---------------------

Again mainly a bug-fix and tidying release, with only a couple of new features:

1. It's possible now to compile PCRE so that it does not use recursive
function calls when matching. Instead it gets memory from the heap. This slows
things down, but may be necessary on systems with limited stacks.

2. UTF-8 string checking has been tightened to reject overlong sequences and to
check that a starting offset points to the start of a character. Failure of the
latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.

3. PCRE can now be compiled for systems that use EBCDIC code.


Release 4.4 21-Aug-03
---------------------

This is mainly a bug-fix and tidying release. The only new feature is that PCRE
checks UTF-8 strings for validity by default. There is an option to suppress
this, just in case anybody wants that teeny extra bit of performance.


Releases 4.1 - 4.3
------------------

Sorry, I forgot about updating the NEWS file for these releases. Please take a
look at ChangeLog.


Release 4.0 17-Feb-03
---------------------

There have been a lot of changes for the 4.0 release, adding additional
functionality and mending bugs. Below is a list of the highlights of the new
functionality. For full details of these features, please consult the
documentation. For a complete list of changes, see the ChangeLog file.

1. Support for Perl's \Q...\E escapes.

2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
package. They provide some syntactic sugar for simple cases of "atomic
grouping".

3. Support for the \G assertion. It is true when the current matching position
is at the start point of the match.

4. A new feature that provides some of the functionality that Perl provides
with (?{...}). The facility is termed a "callout". The way it is done in PCRE
is for the caller to provide an optional function, by setting pcre_callout to
its entry point. To get the function called, the regex must include (?C) at
appropriate points.

5. Support for recursive calls to individual subpatterns. This makes it really
easy to get totally confused.

6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
name a group.

7. Several extensions to UTF-8 support; it is now fairly complete. There is an
option for pcregrep to make it operate in UTF-8 mode.

8. The single man page has been split into a number of separate man pages.
These also give rise to individual HTML pages which are put in a separate
directory. There is an index.html page that lists them all. Some hyperlinking
between the pages has been installed.


Release 3.5 15-Aug-01
---------------------

1. The configuring system has been upgraded to use later versions of autoconf
and libtool. By default it builds both a shared and a static library if the OS
supports it. You can use --disable-shared or --disable-static on the configure
command if you want only one of them.

2. The pcretest utility is now installed along with pcregrep because it is
useful for users (to test regexs) and by doing this, it automatically gets
relinked by libtool. The documentation has been turned into a man page, so
there are now .1, .txt, and .html versions in /doc.

3. Upgrades to pcregrep:
   (i)   Added long-form option names like gnu grep.
   (ii)  Added --help to list all options with an explanatory phrase.
   (iii) Added -r, --recursive to recurse into sub-directories.
   (iv)  Added -f, --file to read patterns from a file.

4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
script, to force use of CR or LF instead of \n in the source. On non-Unix
systems, the value can be set in config.h.

5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
absolute limit. Changed the text of the error message to make this clear, and
likewise updated the man page.

6. The limit of 99 on the number of capturing subpatterns has been removed.
The new limit is 65535, which I hope will not be a "real" limit.


Release 3.3 01-Aug-00
---------------------

There is some support for UTF-8 character strings. This is incomplete and
experimental. The documentation describes what is and what is not implemented.
Otherwise, this is just a bug-fixing release.


Release 3.0 01-Feb-00
---------------------

1. A "configure" script is now used to configure PCRE for Unix systems. It
builds a Makefile, a config.h file, and the pcre-config script.

2. PCRE is built as a shared library by default.

3. There is support for POSIX classes such as [:alpha:].

5. There is an experimental recursion feature.

----------------------------------------------------------------------------
          IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00

Please note that there has been a change in the API such that a larger
ovector is required at matching time, to provide some additional workspace.
The new man page has details. This change was necessary in order to support
some of the new functionality in Perl 5.005.

          IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00

Another (I hope this is the last!) change has been made to the API for the
pcre_compile() function. An additional argument has been added to make it
possible to pass over a pointer to character tables built in the current
locale by pcre_maketables(). To use the default tables, this new arguement
should be passed as NULL.

          IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05

Yet another (and again I hope this really is the last) change has been made
to the API for the pcre_exec() function. An additional argument has been
added to make it possible to start the match other than at the start of the
subject string. This is important if there are lookbehinds. The new man
page has the details, but you just want to convert existing programs, all
you need to do is to stick in a new fifth argument to pcre_exec(), with a
value of zero. For example, change

  pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
to
  pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)

****
1	nigel	41	News about PCRE releases
2			------------------------
3
4	ph10	122
5	ph10	242	Release 7.4 13-Sep-07
6			---------------------
7
8	ph10	243	The only change of specification is the addition of options to control whether
9	ph10	242	\R matches any Unicode line ending (the default) or just CR, LF, and CRLF.
10	ph10	243	Otherwise, the changes are bug fixes and a refactoring to reduce the number of
11	ph10	242	relocations needed in a shared library.
12
13
14	ph10	228	Release 7.3 28-Aug-07
15	ph10	212	---------------------
16
17			Most changes are bug fixes. Some that are not:
18
19			1. There is some support for Perl 5.10's experimental "backtracking control
20			verbs" such as (*PRUNE).
21
22			2. UTF-8 checking is now as per RFC 3629 instead of RFC 2279; this is more
23			restrictive in the strings it accepts.
24
25			3. Checking for potential integer overflow has been made more dynamic, and as a
26			consequence there is no longer a hard limit on the size of a subpattern that
27			has a limited repeat count.
28	ph10	227
29			4. When CRLF is a valid line-ending sequence, pcre_exec() and pcre_dfa_exec()
30			no longer advance by two characters instead of one when an unanchored match
31			fails at CRLF if there are explicit CR or LF matches within the pattern.
32	ph10	226	This gets rid of some anomalous effects that previously occurred.
33	ph10	212
34	ph10	227	5. Some PCRE-specific settings for varying the newline options at the start of
35			a pattern have been added.
36	ph10	212
37	ph10	227
38	ph10	184	Release 7.2 19-Jun-07
39	ph10	157	---------------------
40
41	ph10	172	WARNING: saved patterns that were compiled by earlier versions of PCRE must be
42	ph10	181	recompiled for use with 7.2 (necessitated by the addition of \K, \h, \H, \v,
43			and \V).
44	ph10	168
45	ph10	159	Correction to the notes for 7.1: the note about shared libraries for Windows is
46			wrong. Previously, three libraries were built, but each could function
47			independently. For example, the pcreposix library also included all the
48			functions from the basic pcre library. The change is that the three libraries
49			are no longer independent. They are like the Unix libraries. To use the
50			pcreposix functions, for example, you need to link with both the pcreposix and
51	ph10	157	the basic pcre library.
52
53	ph10	166	Some more features from Perl 5.10 have been added:
54	ph10	157
55	ph10	166	(?-n) and (?+n) relative references for recursion and subroutines.
56	ph10	172
57			(?(-n) and (?(+n) relative references as conditions.
58	ph10	182
59	ph10	181	\k{name} and \g{name} are synonyms for \k<name>.
60	ph10	172
61	ph10	168	\K to reset the start of the matched string; for example, (foo)\Kbar
62	ph10	175	matches bar preceded by foo, but only sets bar as the matched string.
63	ph10	182
64			(?\| introduces a group where the capturing parentheses in each alternative
65			start from the same number; for example, (?\|(abc)\|(xyz)) sets capturing
66	ph10	175	parentheses number 1 in both cases.
67	ph10	166
68	ph10	182	\h, \H, \v, \V match horizontal and vertical whitespace, respectively.
69	ph10	166
70	ph10	182
71	ph10	155	Release 7.1 24-Apr-07
72	nigel	93	---------------------
73
74	ph10	155	There is only one new feature in this release: a linebreak setting of
75			PCRE_NEWLINE_ANYCRLF. It is a cut-down version of PCRE_NEWLINE_ANY, which
76			recognizes only CRLF, CR, and LF as linebreaks.
77	ph10	122
78	ph10	155	A few bugs are fixed (see ChangeLog for details), but the major change is a
79			complete re-implementation of the build system. This now has full Autotools
80			support and so is now "standard" in some sense. It should help with compiling
81			PCRE in a wide variety of environments.
82
83	ph10	146	NOTE: when building shared libraries for Windows, three dlls are now built,
84			called libpcre, libpcreposix, and libpcrecpp. Previously, everything was
85			included in a single dll.
86
87			Another important change is that the dftables auxiliary program is no longer
88	ph10	128	compiled and run at "make" time by default. Instead, a default set of character
89			tables (assuming ASCII coding) is used. If you want to use dftables to generate
90			the character tables as previously, add --enable-rebuild-chartables to the
91			"configure" command. You must do this if you are compiling PCRE to run on a
92			system that uses EBCDIC code.
93	ph10	122
94	ph10	128	There is a discussion about character tables in the README file. The default is
95			not to use dftables so that that there is no problem when cross-compiling.
96
97
98	ph10	122	Release 7.0 19-Dec-06
99			---------------------
100
101	nigel	93	This release has a new major number because there have been some internal
102			upheavals to facilitate the addition of new optimizations and other facilities,
103			and to make subsequent maintenance and extension easier. Compilation is likely
104			to be a bit slower, but there should be no major effect on runtime performance.
105			Previously compiled patterns are NOT upwards compatible with this release. If
106			you have saved compiled patterns from a previous release, you will have to
107			re-compile them. Important changes that are visible to users are:
108
109			1. The Unicode property tables have been updated to Unicode 5.0.0, which adds
110			some more scripts.
111
112			2. The option PCRE_NEWLINE_ANY causes PCRE to recognize any Unicode newline
113			sequence as a newline.
114
115			3. The \R escape matches a single Unicode newline sequence as a single unit.
116
117			4. New features that will appear in Perl 5.10 are now in PCRE. These include
118			alternative Perl syntax for named parentheses, and Perl syntax for
119			recursion.
120
121			5. The C++ wrapper interface has been extended by the addition of a
122			QuoteMeta function and the ability to allow copy construction and
123			assignment.
124
125			For a complete list of changes, see the ChangeLog file.
126
127
128	nigel	91	Release 6.7 04-Jul-06
129			---------------------
130
131			The main additions to this release are the ability to use the same name for
132			multiple sets of parentheses, and support for CRLF line endings in both the
133			library and pcregrep (and in pcretest for testing).
134
135			Thanks to Ian Taylor, the stack usage for many kinds of pattern has been
136			significantly reduced for certain subject strings.
137
138
139	nigel	87	Release 6.5 01-Feb-06
140			---------------------
141
142			Important changes in this release:
143
144			1. A number of new features have been added to pcregrep.
145
146			2. The Unicode property tables have been updated to Unicode 4.1.0, and the
147			supported properties have been extended with script names such as "Arabic",
148			and the derived properties "Any" and "L&". This has necessitated a change to
149			the interal format of compiled patterns. Any saved compiled patterns that
150			use \p or \P must be recompiled.
151
152			3. The specification of recursion in patterns has been changed so that all
153			recursive subpatterns are automatically treated as atomic groups. Thus, for
154			example, (?R) is treated as if it were (?>(?R)). This is necessary because
155			otherwise there are situations where recursion does not work.
156
157			See the ChangeLog for a complete list of changes, which include a number of bug
158			fixes and tidies.
159
160
161	nigel	77	Release 6.0 07-Jun-05
162			---------------------
163
164			The release number has been increased to 6.0 because of the addition of several
165			major new pieces of functionality.
166
167			A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
168			algorithm, has been added. This has a number of advantages for certain cases,
169			though it does run more slowly, and lacks the ability to capture substrings. On
170			the other hand, it does find all matches, not just the first, and it works
171			better for partial matching. The pcrematching man page discusses the
172			differences.
173
174			The pcretest program has been enhanced so that it can make use of the new
175			pcre_dfa_exec() matching function and the extra features it provides.
176
177			The distribution now includes a C++ wrapper library. This is built
178			automatically if a C++ compiler is found. The pcrecpp man page discusses this
179			interface.
180
181			The code itself has been re-organized into many more files, one for each
182			function, so it no longer requires everything to be linked in when static
183			linkage is used. As a consequence, some internal functions have had to have
184			their names exposed. These functions all have names starting with _pcre_. They
185			are undocumented, and are not intended for use by outside callers.
186
187			The pcregrep program has been enhanced with new functionality such as
188			multiline-matching and options for output more matching context. See the
189			ChangeLog for a complete list of changes to the library and the utility
190			programs.
191
192
193	nigel	75	Release 5.0 13-Sep-04
194			---------------------
195
196			The licence under which PCRE is released has been changed to the more
197			conventional "BSD" licence.
198
199			In the code, some bugs have been fixed, and there are also some major changes
200			in this release (which is why I've increased the number to 5.0). Some changes
201			are internal rearrangements, and some provide a number of new facilities. The
202			new features are:
203
204			1. There's an "automatic callout" feature that inserts callouts before every
205			item in the regex, and there's a new callout field that gives the position
206			in the pattern - useful for debugging and tracing.
207
208			2. The extra_data structure can now be used to pass in a set of character
209			tables at exec time. This is useful if compiled regex are saved and re-used
210			at a later time when the tables may not be at the same address. If the
211			default internal tables are used, the pointer saved with the compiled
212			pattern is now set to NULL, which means that you don't need to do anything
213			special unless you are using custom tables.
214
215			3. It is possible, with some restrictions on the content of the regex, to
216			request "partial" matching. A special return code is given if all of the
217			subject string matched part of the regex. This could be useful for testing
218			an input field as it is being typed.
219
220			4. There is now some optional support for Unicode character properties, which
221			means that the patterns items such as \p{Lu} and \X can now be used. Only
222			the general category properties are supported. If PCRE is compiled with this
223			support, an additional 90K data structure is include, which increases the
224			size of the library dramatically.
225
226			5. There is support for saving compiled patterns and re-using them later.
227
228			6. There is support for running regular expressions that were compiled on a
229			different host with the opposite endianness.
230
231			7. The pcretest program has been extended to accommodate the new features.
232
233			The main internal rearrangement is that sequences of literal characters are no
234			longer handled as strings. Instead, each character is handled on its own. This
235			makes some UTF-8 handling easier, and makes the support of partial matching
236			possible. Compiled patterns containing long literal strings will be larger as a
237			result of this change; I hope that performance will not be much affected.
238
239
240	nigel	73	Release 4.5 01-Dec-03
241			---------------------
242
243			Again mainly a bug-fix and tidying release, with only a couple of new features:
244
245			1. It's possible now to compile PCRE so that it does not use recursive
246			function calls when matching. Instead it gets memory from the heap. This slows
247			things down, but may be necessary on systems with limited stacks.
248
249			2. UTF-8 string checking has been tightened to reject overlong sequences and to
250			check that a starting offset points to the start of a character. Failure of the
251			latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
252
253			3. PCRE can now be compiled for systems that use EBCDIC code.
254
255
256	nigel	71	Release 4.4 21-Aug-03
257			---------------------
258
259			This is mainly a bug-fix and tidying release. The only new feature is that PCRE
260			checks UTF-8 strings for validity by default. There is an option to suppress
261			this, just in case anybody wants that teeny extra bit of performance.
262
263
264			Releases 4.1 - 4.3
265			------------------
266
267			Sorry, I forgot about updating the NEWS file for these releases. Please take a
268			look at ChangeLog.
269
270
271	nigel	63	Release 4.0 17-Feb-03
272			---------------------
273
274			There have been a lot of changes for the 4.0 release, adding additional
275			functionality and mending bugs. Below is a list of the highlights of the new
276			functionality. For full details of these features, please consult the
277			documentation. For a complete list of changes, see the ChangeLog file.
278
279			1. Support for Perl's \Q...\E escapes.
280
281			2. "Possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's Java
282			package. They provide some syntactic sugar for simple cases of "atomic
283			grouping".
284
285			3. Support for the \G assertion. It is true when the current matching position
286			is at the start point of the match.
287
288			4. A new feature that provides some of the functionality that Perl provides
289			with (?{...}). The facility is termed a "callout". The way it is done in PCRE
290			is for the caller to provide an optional function, by setting pcre_callout to
291			its entry point. To get the function called, the regex must include (?C) at
292			appropriate points.
293
294			5. Support for recursive calls to individual subpatterns. This makes it really
295			easy to get totally confused.
296
297			6. Support for named subpatterns. The Python syntax (?P<name>...) is used to
298			name a group.
299
300			7. Several extensions to UTF-8 support; it is now fairly complete. There is an
301			option for pcregrep to make it operate in UTF-8 mode.
302
303			8. The single man page has been split into a number of separate man pages.
304			These also give rise to individual HTML pages which are put in a separate
305			directory. There is an index.html page that lists them all. Some hyperlinking
306			between the pages has been installed.
307
308
309	nigel	53	Release 3.5 15-Aug-01
310			---------------------
311
312			1. The configuring system has been upgraded to use later versions of autoconf
313			and libtool. By default it builds both a shared and a static library if the OS
314			supports it. You can use --disable-shared or --disable-static on the configure
315			command if you want only one of them.
316
317			2. The pcretest utility is now installed along with pcregrep because it is
318			useful for users (to test regexs) and by doing this, it automatically gets
319			relinked by libtool. The documentation has been turned into a man page, so
320			there are now .1, .txt, and .html versions in /doc.
321
322			3. Upgrades to pcregrep:
323			(i) Added long-form option names like gnu grep.
324			(ii) Added --help to list all options with an explanatory phrase.
325			(iii) Added -r, --recursive to recurse into sub-directories.
326			(iv) Added -f, --file to read patterns from a file.
327
328			4. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
329			script, to force use of CR or LF instead of \n in the source. On non-Unix
330			systems, the value can be set in config.h.
331
332			5. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
333			absolute limit. Changed the text of the error message to make this clear, and
334			likewise updated the man page.
335
336			6. The limit of 99 on the number of capturing subpatterns has been removed.
337			The new limit is 65535, which I hope will not be a "real" limit.
338
339
340	nigel	49	Release 3.3 01-Aug-00
341			---------------------
342
343			There is some support for UTF-8 character strings. This is incomplete and
344			experimental. The documentation describes what is and what is not implemented.
345			Otherwise, this is just a bug-fixing release.
346
347
348	nigel	43	Release 3.0 01-Feb-00
349			---------------------
350	nigel	41
351	nigel	43	1. A "configure" script is now used to configure PCRE for Unix systems. It
352			builds a Makefile, a config.h file, and the pcre-config script.
353
354			2. PCRE is built as a shared library by default.
355
356			3. There is support for POSIX classes such as [:alpha:].
357
358			5. There is an experimental recursion feature.
359
360	nigel	41	----------------------------------------------------------------------------
361			IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00
362
363			Please note that there has been a change in the API such that a larger
364			ovector is required at matching time, to provide some additional workspace.
365			The new man page has details. This change was necessary in order to support
366			some of the new functionality in Perl 5.005.
367
368			IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.00
369
370			Another (I hope this is the last!) change has been made to the API for the
371			pcre_compile() function. An additional argument has been added to make it
372			possible to pass over a pointer to character tables built in the current
373			locale by pcre_maketables(). To use the default tables, this new arguement
374			should be passed as NULL.
375
376			IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05
377
378			Yet another (and again I hope this really is the last) change has been made
379			to the API for the pcre_exec() function. An additional argument has been
380			added to make it possible to start the match other than at the start of the
381			subject string. This is important if there are lookbehinds. The new man
382			page has the details, but you just want to convert existing programs, all
383			you need to do is to stick in a new fifth argument to pcre_exec(), with a
384			value of zero. For example, change
385
386			pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)
387			to
388			pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)
389
390			****
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