[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Objections to / uses of PSVI?
Jeni Tennison wrote: > Second, I think that there will be situations where the PSVI is *not* > easily serializable in the form of the original schema and regenerated > later. As a really basic example from the XQuery WD: > > <shoe size="{7}"/> > > This creates a shoe element with a size attribute that has a typed > value of the xs:integer 7. This could be generated without a schema > being available. (The other situation, where it's generated with a > schema available, but in which the size attribute has to take a > xs:token, would, I'm sure, be magically prevented through static type > checking.) > > So what happens then? You have an XQuery node tree that includes a > size attribute whose value should be interpreted as the xs:integer 7, > and no schema. If you just serialized that as: > > <shoe size="7" /> > > then you'd lose information -- the size attribute would be of the type > xs:anySimpleType in any consequent transformations. So you have to add > schema information somehow to the serialized PSVI, which means > creating a schema based on the observed structure of the document. We > know that's possible (any number of editors do it) but it's not > particularly easy and will add a huge overhead to processors. Plus the > deconstruction/reconstitution method means there's an overhead on the > receiving end as well, when the next service in the pipeline has to > reconstitute the PSVI from the instance and the associated schema. > > The other option would be to have a PSVI serialization format that > actually expressed the PSVI in XML (like the one generated by XSV) > rather than trying to use the XML+schema approach. In a perfect world, > parsers encountering XML in the PSVI markup language would generate > exactly the same PSVI from that as they would from the equivalent > XML+schema. Then we could all go around exchanging information in the > PSVI markup language rather than plain old boring XML. I'm only > partially joking. I now understand Rick Jelliffe's comment about separating the future into PSVI and XML worlds. Assuming the PSVI is read/write (and there is no reason to believe that it shouldn't be), I can do things like using the DOM to create schema-less documents with typed nodes. Since serializing this accurately means (as you point out) serializing the type information, we've just lost XML. -- Ron
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|