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Re: CR-49: XPath subset: Use subset not full XPath for Key and KeyRef

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 21 Feb 2001 10:01:15 +0000
To: "Andy Clark" <andyclar@us.ibm.com>
Cc: Jim Trezzo <jim.trezzo@oracle.com>, www-xml-schema-comments@w3.org, "Trezzo,Jim" <JTREZZO@US.ORACLE.COM>
Message-ID: <f5bn1bge4no.fsf@cogsci.ed.ac.uk>
"Andy Clark" <andyclar@us.ibm.com> writes:

> > SOrry for the confusion -- yes, the _only_ proposed allowed use is .//x
> 
> Thanks for the clarification.
> 
> >> But they have different types and it's unclear which type
> >> should be used for the value space comparison. How can you
> >> [...]
> >
> > One implementation strategy would be to simply collect pairs of
> > [string,type], and to compare equal iff
> 
> Okay, I can see how this could work but it seems counter-
> intuitive to me to have a collection of field values whose
> types can change.

How change?  Each result of a field query has whatever type it has.
Note this is a very marginal case, in that using a path expr to define 
a field that actually may resolve to two different elements/attribute
with the same name is pretty unlikely.

> P.S. What was the use case for ancestor::x/@?

See the example in the spec. itself -- when you actually want
reference into multiple scopes, you'll need a property of the scoping
element to distinguish one scope from another.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Wednesday, 21 February 2001 05:01:25 GMT

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