Yes. From the XSLT 1.0 spec, 12.1: -- Yes I get that part, but thats to solve the immutable problem.
My statement/question is more about document identity - outside of xpath(). XPath defines node and document identity for the purposes of that particular invocation but really skirts the whole concept of document identity in the outside world. Not that it *could* address that problem. But just to cite some interesting problems. 1) 1 URI invoked twice *could* produce different document contents. Are they the same document ?
2) 2 different URIs could refer to the same document. 3) Documents could be transient, dynamic and unnamed ... but all that is just navel gazing and worthy of intoxicated arguments at balisage :) What is more to my point is ... if we were to support a web-wide "InfoSpace" we have to more clearly define (or skirt)
the concept of indirecting URI's ... And a core concept in this thread is an issue with XML itself being "document centric", In general its assumed XML 'lives in a document'. This is very powerful but also very limiting. Its powerful because you can do things like node-uri() and doc( uri ) and fn:root() But its limiting as we start to model data which is not necessarily contained 'in a document' but put there solely for the purposes
of making XML happy.
Michael Kay's talk on Ftan was very interesting in that they resolved that issue by getting rid of node identity ... but along that so went the parent and sibling
accessors ! But maybe thats the price to pay ... RDF solves this mostly by working with a very fine grain of data ... a triple. And then wraps then in a graph which to my reading is very mutable (more like
a collection then a document). To really implement the concept of a Info Space I am feeling we need to drop the concept of "documents" much like Ftan does. But that doesn't solve accessibility and reliability ...
We don't. -------- So your opinion is that a web based InfoSpace is impossible or impractical ? ---------------------------------------- David A. Lee |