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