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Hi Ronald, Ronald Bourret wrote: > Eric van der Vlist wrote: > >>Just wanted to recap here some ideas and questions related to W3C XML >>Schema which, I think, would be interesting to pursue. >> >>1) Little intrusive XML PSVI >>http://lists.xml.org/archives/xml-dev/200110/threads.html#00556 >> > > This is a nice idea. Thanks! > Unfortunately, I see a couple of problems with it: > > 1) The result of a schema-validated document is no longer valid. This is > because the PSVI information wasn't specified in the original schema and > it is not realistic to expect people to include PSVI items in their > schema. I am not so much expecting people to include PSVI items in their schema, but rather validators to do so. And having a PSVI which would be as much "schema agnostic" as possible would allow to get some kind of compatibility between the output of different schema languages (even those which could be "home made" and implemented as a SAX filter or a XSLT transformations designed for a specific application and able to check all the "business rules"). This would have the benefit of making PSVI "real": I think that it would be much more concrete for people if they could "see" it within angle brackets! In this context, it would be more "elegant" if the document with PSVI was still valid, but I don't see it as a major issue. If people want to validate the document again, the stripping of the PSVI information could be done by a trivial XSLT transformation or SAX filter. > 2) This requires all tools that accept schema-validated documents to be > smart enough to ignore the PSVI elements/attributes. It's not clear that > this is that much better than having to rewrite those programs to treat > (for example) xmlns attributes as namespace declarations, not > attributes. That's a real issue (and that's why I haven't qualified this proposal as "non intrusive"). It will not be transparent, but I don't see how we could make it transparent with XML 1.0, namespaces and XPath being what they are. It could be non intrusive if the PSVI info was added using PIs (which might not have been a bad idea since a PSVI is litteraly a Processing Instruction) but you wouldn't be able to get the info easily into XPath expressions. It would be almost non intrusive if the PSVI info was added using attributes, but would wouldn't be able to add "attributes to attributes" and I don't think it can fit either. My bet is that we can still live with a "little intrusive" PSVI and give some guidelines on how to write applications for which this is transparent. Thanks Eric > > -- Ron -- Rendez-vous à Paris pour le Forum XML. http://www.technoforum.fr/Pages/forumXML01/index.html ------------------------------------------------------------------------ Eric van der Vlist http://xmlfr.org http://dyomedea.com http://xsltunit.org http://4xt.org http://examplotron.org ------------------------------------------------------------------------
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