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

[Paul Prescod <papresco@xxxxxxxxxxxxxxxx>]

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

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