[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XPath 1.5? (was RE: typing and markup)
At 07:21 PM 5/8/2002 +1000, Rick Jelliffe wrote: >From: "Jonathan Robie" <jonathan.robie@d...> > > > >The idea that a query system can optimise away, or generate errors on, > > >queries like aaa/bbb if the schema specifies that aaa has no bbb children > > >is also very worrying. > > > > Indeed. > > > > Whether or not that is an error is currently an open issue in XQuery. My > > own view is that it should be neither a static nor a dynamic error, but > > that it should evaluate to an empty sequence. > >Is that right? There is no way to say "Tell me what is in the document" >if some schema has deemed something impossible. How the hell can >anyone validate documents-in-progress (which may well be invalid) >using that? You are agreeing with my view, I believe. Also, queries may operate on collections of documents, some of which do have a given element, and some of which do not. > > >How could one write schematron in Xpath2 if it > > >needs to find exactly such cases and report errors? Xpath1 was designed > > >to work on documents that specified a DTD but were invalid, not only > > >well formed documents that did not specify a DTD. Is the same really > > >true of Xpath2 wrt schema? > > > > This question has not been answered, it is an open issue. My own view is > > that if the validation fails, XPath 2.0 and XQuery 1.0 should have > > undefined behavior. > >So you are saying an XPath 2.0 can never be used to positively locate errors? >What happened to the basic well-formedness versus valid distinction which >allows manipulation and rectification of XML even when it is not valid >using the same tools as when it is valid? What I suggest would allow you to query the document as well formed, but not to validate the PSVI of the document. I want to avoid querying a PSVI that could only be constructed partially. >Startled >Rick Jellffe Are you still started? If so, I'm still listening... Jonathan
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