Re: [xml-dev] XPath and a continuous, uniform information space

[Uche Ogbuji <uche@ogbuji.net>]

I want to say that this message belongs in the XML-DEV Hall of Fame.  Brilliantly put, all the points.  I'll admit that Michael's original points baffled me entirely, but he does say now that he over-simplified, so fair play.  But again Hans-Juergen's response articulated some aspects of XML-on-Web architecture better than anything else I've seen before.  I won't be able to resist remarking that I wish he'd been the one articulating HyTime's Grove Model ;)

On Wed, Aug 14, 2013 at 4:53 PM, Hans-Juergen Rennau <hrennau@yahoo.de> wrote:

Web architecture of XML technology?
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Finally, you wrote: "I'm sure that's achievable, but the web architecture doesn't encourage it." To me it is a question if it is really web architecture what is responsible for the status quo, or not simply the limited features of XML/XPath itself - is it not XML/XPath what is responsible how links are expressed and resolved?

This point deserves some reinforcement.  It's enough to point out one example of an "encouraged" Web architecture implementation that does not suffer the issues raised.  I immediately thought of the HTTPd/Apache static file module.  It provides seamless access to an arbitrarily large information space, including inter and intra-document navigation

Document root:

http://myhost/folder1/folder1.1/doc1.html

Specified subsection of document:

http://myhost/folder1/folder1.1/doc1.1.1.html#section1

Relative navigation from one document/section to another

<a href=""../../folder1.2/doc1.1.2.html#section3">...

Sure crude id/anchor is no match for the intra-document sophistication of XPath (XPointer would have helped, in theory) but that's the point entirely: XPath has the intrinsic expressiveness within the document, but is limited beyond that.  I think the elegant "/" and "#" syntax of static file servers shows that the limitation in cross-document "mobility" does not come from Web architecture.  Rather, the XPath/XSLT 1.0 language designers very sensibly kept their scope manageable by just focusing on the single document case.  It sounds as if later XPath specs just haven't got around to remedying this, but I don't think it would be so terribly hard, once it comes to it.

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