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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Still banging on about extensibility and validation
 On 5/30/06, Fraser Goffin <goffinf@g...> wrote: > > NVDL as a domain specific language is addressing the use case of validation of > extended documents, ... > > I could be wrong, but I didn't think NVDL was just about validation of > extensions ? > > I saw (see) it as providing an ability to apply validation processing > to individual parts of a document regardless of whether they are part > of a common specification This could be me not splitting things finely enough here, but to me that sounds like an extension of the common specification. >or part of extensibility agreed between > communicating parties. > My understanding is than NVDL facilitates a > slight change in the way that we can think about XML instances, from > one which considers the instance as a whole, to one which allows us to > view it as a set of related but individually processable parts ? > Well, extensions tend to be related to that which they extend but I would probably want an architecture that allowed me to individually process core and extending information. Although I just realized that 'information' is probably not the word I wanted to use here because it would not allow me to describe suscinctly the usage scenario that I described earlier. Cheers, Bryan Rasmussen > On 29/05/06, bryan rasmussen <rasmussen.bryan@g...> wrote: > > > > > > >2. propogation of text nodes up from elements in namespace y to > > > >elements in namespace x, example: > > > > > > > ><x:x> > > > ><y:y>text node</y:y> > > > ></x:x> > > > > > > > >in this scenario y:y is extending x:x, > > > > > > But it is distinct. > > > > > > >and conceptually we assume that they share the text node. > > > > > > They do not. In the data model for that fragment, x:x has three > > > children: two text nodes of only white-space, and one element node > > > being y:y ... the string "text node" is only a child of y:y. > > > > It seems that XML has a lot of different data models or has had a lot > > of different data models over the years. That this usage does not > > follow any data model for XML doesn't argue against the assumption to > > me, since what I'm arguing about is an assumption about common usages > > of extension. > > > > > > > > >so when split they should be > > > > > > > ><x:x>text node</x:x> > > > >and <y:y>text node</y:y> > > > > > > I disagree. I don't know of any data model for XML in which text > > > nodes are "copied" or considered a property of an ancestor. > > > > > > >I think this is a reasonably common usage but I'm not sure if NVDL > > > >handles it. I suppose the argument could be made that this is an > > > >extremely dangerous and dirty usage, and we would not want to automate > > > >that kind of splitting of data. > > > > > > On that I agree ... but since the data model does not "split" the > > > data as you describe, it fortunately isn't an issue for NVDL. > > > > > The argument is not that it should or shouldn't happen, but more > > questioning how far extensibility should go and what the needs for > > validation of extended documents are. NVDL as a domain specific > > language is addressing the use case of validation of extended > > documents, as such it has made decisions for handling various > > extension scenarios, if there are scenarios it skips then it should be > > argued for why they are skipped. > > > > I suggested one reason why one would skip that scenario is that it is dirty. > > > > I think in XML Schema some reasons why common validation scenarios > > were skipped was that they did not fit the theoretical model of XML > > Schema (this is just an idea on my end), and I think that is a good > > argument for a language to make (but if it is so in the context of XML > > Schema it just so happened my first ever use of it needed some of the > > missing validation possibilities, and this lack has not endeared the > > language to me, there can be tradeoffs between purity and necessity.) > > > > A third argument might be that, hey that scenario is hardly ever used. > > nobody asks for it. > > > > I think realistically NVDL is something needed for Compound documents > > type situations, but there are a lot of things needed in that > > situation. > > > > Cheers, > > Bryan Rasmussen > > > > ----------------------------------------------------------------- > > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > > initiative of OASIS <http://www.oasis-open.org> > > > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > > > To subscribe or unsubscribe from this list use the subscription > > manager: <http://www.oasis-open.org/mlmanage/index.php> > > > > > 
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