xml-dev - quick proposal

["Simon St.Laurent" <simonstl@simonstl.com>]

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