On Sat, Mar 08, 2003 at 10:03:31AM +0100, Sylvain Wallez wrote: > Steven Noels wrote: > > >Stefano Mazzocchi wrote: > > > >>Steven Noels wrote: > > > >>>Looking at the history of sitemap-v06.rng, I can't see this has been > >>>happening a lot. Quite contrarily, some (myself included) have been > >>>advocating to relax it even further. But dropping it will > >>>effectively kill the small circle of people interested in > >>>maintaining such a thing. > >>> > >>>Reasonable? > >> > >> > >><read my lips> I AM NOT SUGGESTING TO DROP THE SCHEMA!!! </read my lips> > >> > >>is that clear enough? should I repeat it? > >> > >>I'm suggesting to remove the validation target from the build system > >>and improve the way treeprocessor handles errors. > >> > >>As I said, i don't care *how* this is done, as long as the error > >>messages that users receive are much more meaningful than those silly > >>"System ID no found" when an attribute name is wrong. > > > > > >I'm going to be stubborn about this: _if_ we drop the target (I was > >already aware of you not pushing to drop the schema, no problem here), > >then the few people who care about the schema won't be warned about > >required changes anymore. > > > >I don't see any relation between the grammar, where and when it should > >be used, and the lack of exception handling code in the tree processor. > > > >But since we are the only one who care to continue this thread, let's > >drop it. I'm going to check what Sylvain has to say about it. > > > Well, I thought I made it clear : although I've not considered the > technical details now, I would like to integrate schema-driven syntax > checks (I avoid the ambiguous "validation" word) _inside_ the > treeprocessor (i.e. at sitemap load-time) to be sure that the sitemap is > correct since we cannot assume each user will perform pre-runtime checks. > > The technical details I'm referring to are how we can get meaninful > messages from schema-driven syntax check, so that we can display them to > the user. > > The benefits of this approach are IMO mutiple : > - runtime checks, offline checks and schema-driven editors use a single > definition of the sitemap grammar, > - since this grammar becomes an integral part of the sitemap engine, it > ensures its consistency and long-term maintainance.
My rather unhelpful 2c (knee-deep in Forrest ATM): For validating an incrementally composed structure like the sitemap, it might be better to use a rule-based language like Schematron, rather than RelaxNG/XSD. Reasons being: - In Schematron, the XML is considered valid by default, and subsequently constrained. This assumption makes sense for the sitemap, because people will always be defining new components outside our control. - Schematron handles co-occurrence constraints, e.g. "only check for map:generator/driver if @src contains 'XMLDBGenerator'". With RNG I think we'd have to say "anything goes" in user-extensible sections. - Schematron schemas combine very naturally. We could have a schema per block, validating just that block's elements, and apply the block schemas iteratively. With RNG, merging block schemas would be *much* harder. - Jing error messages are completely awful. Perhaps a Schematron variant subsetted to support STXPath [1] would be the best Cocoon validation system. --Jeff (who had a long and fascinating talk with Rick Jelliffe a few weeks ago, and is now a convert, at least until I meet James Clark) [1] http://www.xml.com/pub/a/2003/02/26/stx.html > Deal ? > > Sylvain > > -- > Sylvain Wallez Anyware Technologies > http://www.apache.org/~sylvain http://www.anyware-tech.com > { XML, Java, Cocoon, OpenSource }*{ Training, Consulting, Projects } > >
