Version 1.4 of XSV Released
Date: 12 Nov 2001 15:36:30 +0000 From: "Henry S. Thompson" <firstname.lastname@example.org> To: email@example.com, firstname.lastname@example.org Subject: Version 1.4 of XSV released: derivation-by-restriction experiment
The web interface , the self-installer  and the sources  for XSV, our W3C XML Schema validator, have all been updated with a new version.
"Version 1.4 introduces a cheap-but-effective approximation to enforcement of the constraints on derivation by restriction for complex type definitions. This works by enforcing the subset invariant, and rejects any content model for a type definition derived by restriction which allows anything not allowed by the base type definition's content model. This is slightly weaker than the REC: i.e., everything it rules out is ruled out by the REC, but a few things ruled out by the REC will not be caught."
Note this is not what the REC envisages, but it will go a lot further towards enforcing interoperability between XSV and other processors which do enforce the REC as intended.
Nothing is as good as full conformance, but I hope this step, which only took about three hours to implement, will be of use never-the-less.
As with any substantial change, there may be bugs lurking -- I'll fix them as quickly as possible provided bug reports contain enough information to reproduce the bugs.
 http://www.w3.org/2001/03/webdata/xsv  ftp://ftp.cogsci.ed.ac.uk/pub/XSV/XSV14.EXE  http://dev.w3.org/cvsweb/xmlschema/ -- see http://www.ltg.ed.ac.uk/~ht/xsv-status.html for installation instructions
Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh W3C Fellow 1999--2001, part-time member of W3C Team 2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440 Fax: (44) 131 650-4587, e-mail: email@example.com URL: http://www.ltg.ed.ac.uk/~ht/