News about PCRE releases ------------------------ 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...) 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) ****