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

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)

****
