DWH_File (the Deep 'n' Wide Hash) - persistence for complex datastructures and objects in Perl version 0.23 INSTALLATION: $ perl Makefile.PL $ make $ make test $ make intall DWH_File consists of the DWH_File.pm module and a number of modules under the DHW_File::* name space. It's all pure perl and every module contains one package. Every package defines a perl class. WHAT IT DOES: DWH_File is used in a similar manner to NDBM_File, DB_File etc. In fact it depends on one of these. DWH_File expands the functionality to save not only the hash that is tied but also all the data that this hash contains references to - that is it'll save all you list of lists and list of hashes and so forth. And what's more, it will save objects as well - if they'll comply with some very simple rules which don't impose any limitations to their functionality or structure except that they can't themselves be tied to anyone else. See the "Models" section of the embedded documentation for details. .pod documentation is included in the DWH_File.pm file. NOTE: From version 0.1 on and again from version 0.22, the file format has changed. File conversions should not be that complicated though, but I haven't written any converter myself. It wouldn't surprise me if it works to dump the contents of at DWH_File-tied hash to a file using Storable or the like and then read it back in a hash tied to the new version of DWH_File. The old versions are available from CPAN at http://www.cpan.org/authors/id/S/SU/SUMUS/ TO DO: DWH_File does what I need it to do in it's present form, so i can't promise to be very eager to develop it further - but here are some of the things I have in mind: * support for garbage collection despite circular references * support for checking file consistency and repair options * more error checking and recovery generally * make a logging facility (existed in pre-0.1 versions) * make linked-list arrays available as alternative * make different hash-key-registry options available (array, linked list, bulk) * make version-convertion available for archives as new versions appear * test whether 0.1 format is actually more efficient than 0.03 format * adding developer-oriented documentation and building a decent DWH_File site under www.orqwood.dk Moreover I've changed the design in 0.22 in order to be able to support distribution of data and behaviour. Actually implementing this will probably take me a while... HISTORY 0.23 - Added a skeleton mechanism for classes who declare themselves "DWH_File::Aware" (by including this abstract class in their heritage) to control the way their data is tied to DWH_File. Also made the internal tieing process more dynamic to promote reuse in special tieing-classes external to DWH_File core. And a bugfix: The return value of delete() operations on hashes was errouneous. This is fixed. Also added a couple of testcases to verify this. 0.22 - Now references used as keys anywhere in a DWH_Filed structure are real live references (and not just textual representations which are meaningful only in the very first runtime invication of the application using DWH_File). This has certain consequences. See the .pod. Besides there has been an internal change of design and formats. (Registry has changed it's meaning, kernel properties feature added and used by registries and class pools. Tied hashes now identify themselves using URIs (file://....) in stead of by regeistering globally in a (singleton) dictionary. This also has certain consequences which are briefly summarized in the .pod. 0.21 - Fixed bug in push() to arrays (reference values were stored as flat strings). Also added a digit in version number so we're back on track and comply with CPAN conventions :-) 0.2 - Slight revision of untie management. Now allows selecting specific DBM-module (a feature, that never came into the rewrite 0.1, though documentation still claimed it was there). 0.1 - Complete rewrite. New version much more OO-based. New file-format using binary encodings in stead of decimal strings (supposedly more efficient). More comme il faut distribution with MakeFile.pl and automated tests etc. 0.03 - Fixed bug introduced in 0.02 which caused wild duplication of blessed references (objects) 0.02 - Fixed bug which caused deep recursion when storing structures that wich contained reference cycles before storing. 0.01 - Initially published version Jakob Schmidt <schmidt@orqwood.dk> 2003 January 25 Visit http://www.orqwood.dk/perl5/dwh for complete info on DWH_File and it's accomplices LOG $Log: README,v $ Revision 1.7 2003/01/25 21:12:13 schmidt Changes for 0.23 added, date and version nos updated Revision 1.6 2003/01/04 23:29:54 schmidt Updated for version 0.22 Revision 1.5 2002/11/02 22:51:04 schmidt Update date Revision 1.4 2002/11/02 22:49:18 schmidt History and version for 0.21 Revision 1.3 2002/10/25 20:50:08 schmidt History entry for version 0.2 entered Revision 1.2 2002/09/29 23:05:10 schmidt Made a few changes to get ready for release version 0.1 on CPAN Revision 1.1.1.1 2002/09/27 22:41:49 schmidt Imported