At 01:50 PM 12/30/00 -0800, Tim Bray wrote: >>But it would have to be done low, fast, and under the radar... Okay, I'm at T+16 on the suggestion, and feeling low. >2. the simple XLink element (I don't think you need extended, and > by using simple you could graft the whole thing onto an XHTML > <div> or some such). >3. a namespace in which are defined a bunch of reserved > role attribute values > >These things would look like web pages and would display >nicely in a browser. The idea is that the xlinks would >point to related resources of various types. The role >namespace would contain precooked values for various >kinds of related resources (e.g. css stylesheet, xsd >schema, dtd) whose use is widespread enough to achieve >some consensus. Obviously, you could have links to >more than one dtd or xsd or whatever. Sounds good. I've got a slightly lighter suggestion. The document at the namespace URI could be any well-formed XML, but the only content in it which matters for purposes of automated processing is simple XLinks. Simple XLinks can contain three URI values: href, role, and arcrole. I'll suggest that we use two of them: href, which must be dereferenceable, and role, which is PURELY AN IDENTIFIER. (Maybe there's a place for arcrole as well, I don't know.) <simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="myschema.xsd" xlink:role="http://www.w3.org/TR/xmlschema-1/"> <simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="myschema.dtd" xlink:role="http://www.w3.org/TR/REC-xml"> <simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="myschema.rlx" xlink:role="http://www.xml.gr.jp/relax/"> <simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="myschema.css" xlink:role="http://www.w3.org/TR/REC-CSS2"> ...etc... This repeats the cardinal sin of dereferencing, but in a context I'd consider safer. It separates content from identifier more cleanly, and avoids the protocol dependence of MIME content-type negotiation. I'd strongly suggest that all namespace declarations and other attribute declarations must appear in the instance document - no defaulting allowed. Maybe, maybe not. See what y'all think. I gotta get back to this chapter on W3C XML Schema Description Language. Simon St.Laurent XML Elements of Style / XML: A Primer, 2nd Ed. XHTML: Migrating Toward XML http://www.simonstl.com - XML essays and books
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