Re: New/old pattern syntax, why can't we have both ?

James K. Tauber wrote:
> 
> I'm interested in exploring the possibility of expanding both to form a
> superset tree addressing language.
> 
> What might make this difficult is that:
> 
> 1. XSL patterns are generally interested in a class of nodes (eg "all the
> elements of type 'emph'") whereas XPointers are generally interested in a
> specific node.

So we're talking about a function that returns one node or one or more.
Clearly the first is just a superset of the second. XPointers could be
merely constrained from resulting in a result set of more than one node.
 
> 2. The processing models are likely quite different. XPointers are used to
> find nodes in a document whereas with XSL, you start with a node and try to
> find the pattern that matches with the greatest specificity.

That's just one way to look at it. You could think of XSL dividing up all
nodes into a sets (the result of queries). One node can reside in multiple
query result sets. The set that most specifically describes the node is
the one that wins.
 
> I don't think XPointers are sufficient but I don't think it would take much
> to make them so.

I agree. This is an important harmonization project. Addressing, filtering
and querying are different views of the same thing, and should share a
syntax and data model.

 Paul Prescod  - http://itrc.uwaterloo.ca/~papresco

"You have the wrong number."
"Eh? Isn't that the Odeon?"
"No, this is the Great Theater of Life. Admission is free, but the 
taxation is mortal. You come when you can, and leave when you must. The 
show is continuous. Good-night." -- Robertson Davies, "The Cunning Man"


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