[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Do we need link-catalogs for schemas?
Two concerns here: 1. There should be a way to cascade whole Bind documents, not just individual entries, as well as adopting a first-encountered entry rule. This would allow one Bind to override another, dropping inappropriate items under an entry. 2. Binding an entry to a class should be accomplished without recourse to a link. This would allow for light-weight bindings. From: Murray Maloney <murray@m...> >I think that it is definitely worth looking at Rick's proposal. >I can imagine how SOX could use and benefit from this kind >of binding mechanism for every element, attribute, datatype, >entity, notation, and even PIs and namespaces themselves. > >I would hope that such a binding mechanism would allow one >to associate XML objects with various flavors of semantics: >behaviour (IDL, Java, etc.), meaning (prose, images, etc.), >style sheets (CSS, XSL, etc.), equivalences (UML, XSchema, etc.), >and other relationships. > >Regards, > >Murray > >At 09:51 AM 10/9/98 -0400, Rick Jelliffe wrote: >> >>Perhaps it is time to (attempt to) ressuscitate XML-Bind. This was a project of >>mine which I put forward during the Namespaces debate. The thrust of this was that >>the then namespace draft conflated two things: >> * some way to *bind* GIs into public identififiers (URL+GI or whatever) {this >>is what the current namespace has limited itself to} >> * some way to *link* this identifier to all sorts of interesting information. >>I tried to push the idea that having just a simple "src" attribute in the namespace >>PI tied restricted it arbitrarily, and had the bad effect of hardwiring a single >>vendor's schema. >> >>So instead I pushed a catalog idea, and in particular that the namespace proposal >>actually reflected a need for a new kind of link: linking from element types rather >>than from instances on elements. One wants to name them because one wants to link >>to or from them. I would like to raise this link-catalog idea again. >> >>The link-catalog idea was that potentially every stakeholder (end-user, document >>creator, browser-maker, DTD/schema creator) may want to use these type-links (for >>documentation, schema distribution, etc). It would be best if this were explicitly >>marked up using XLL extended links. A document should be able to have a web of >>type-related resources linked to/from it. >> >>Now the great thing about using instance syntax for new schemas (e.g. XSchema) is >>that >>no new linking declaration system needs to be invented: we can define any kind of >>link we need and markup the element in the Xschema instance. That way we get >>type-links. >> >>So now we are at the stage: >> >>1) namespace proposal binds GI names to public identifiers >>2) XSchmema proposal (and its ilk) can allow links from GIs to a catalog (e.g. >>using a fixed attribute) *but* we need to actually do it; >>4) XLL proposal allows extended links, with which we can implement a catalog >>system, *but* we need to actually do it. >> >>So I would propose that XML-DEV should design an element set for catalog entries, >>it should cascade or be able to link with other catalogues. It might be a valuable >>enhancement to XSchema, and indicate to the W3C schema people the direction that >>people would like to go. (In particular, that there are many possible schemas, and >>even natrual language documents are valuable for defined document types.) >> >>The kind of thing I am thinking of is this: >> >><!-- example of a link-catalog --> >><XML-DEV:link-catalog> >> <entry id="lc1" GI="p" namespace="urn:www.w3.org/html4#p" > >> <description>Links for HTMLs P element type</description> >> <!-- links to schemas --> >> <a href="www.w3.org/html4.dtd#p" >> role="-//www.w3.org/NOTATION XML DTD//EN" /> >> <a href="www.schema.net/Xschema/html4.xml#p" >> role="-//www.w3.org/NOTATION XSchema//EN" /> >> <a href="www.ms.com/html4.txt#p" >> role="-//www.ms.com/NOTATION DCD//EN" /> >> <a href="www.netscape.com/html4.htm+p" >> role="-//www.w3.org//NOTATION RDF Schema//EN" /> >> <!-- links to documentation --> >> <a href="www.vhg.org/html4/p" >> role="-//XML-DEV//NOTATION Virtual Hyper Glossary//EN" /> >> <a href="www.schema.net/documentation/EN/html-paragraphs.htm" >> role="-//XML-DEV//TEXT English Documentation//EN"/> >> <a href="www.schema.net/documentation/DE/html-paragraphs.htm >> role="-//XML-DEV//TEXT Deusche Erklaerung//DE"/> >> <!-- links to further catalogs --> >> <a href="www.schema.net/link-catalogs/html/p/link-catalog.xml#lc26" >> role="-//XML-DEV//SGML Link Catalog/EN"/> >> </entry> >></XML:DEV:catalog> >> >>In this example there is a single entry. The description field indicates the >>catalog entry relates to HTML paragraphs. The first lot of links link to schema >>definitions for HTML paragraphs, given in various notations (DTD, XSchema, DCD, RDF >>Schema). Then comes documentation for it in various ways (VHG, English, German). >>Finally comes a link to another link-catalog, which allows cascading or a web of >>links. >> >>In each entry, I have used an XLL href (a URL) and used an SGML FPI (Formal Public >>Identifier) for the role atribute. Anyone who wants to define a new role would >>make up a new FPI for that role. XML-DEV would create a good starting set of FPIs >>for the catalog: >> DTD >> XSchema >> English Documentation (.. and so on for every language) >> link-catalog >> >>After that, there should be some kind of new attibute in Xschema, available on all >>elements, called perhaps "link-catalog-href". This contains a URL pointing to an >>XML-Dev link-catalog >> >>IMHO this kind of thing would be a major addition to the power of XML: the W3C >>efforts to define a new single schema definition language are, to some extent, >>misguided and out-of-sequence in that it would be better to first set up an >>infrastructure by which schemas and documentation can be located. I am not >>convinced that having multitudes of schema definition languages is a bad thing: >>perhaps it is better to let companies compete and just provide an infrastructure >>which allows them to provide good product without hijacking documents. >> >>Cheers. >> >>Rick Jelliffe xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... 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