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Re: Fw: Section 7 (PR#139)

From: Erik Bruchez <ebruchez@orbeon.com>
Date: Wed, 24 Oct 2007 16:08:09 -0700
Message-ID: <471FD059.6050108@orbeon.com>
To: John Boyer <boyerj@ca.ibm.com>
CC: "Forms WG (new)" <public-forms@w3.org>

Thanks John, I will have a look at this.

-Erik

John Boyer wrote:
> 
> Hi Erik,
> 
> Here is a response from Michael Kay that is quite informative regarding 
> the kinds of things you would need to keep in mind while formulating a 
> fix for issue #139.
> 
> He's clearly right about missing namespace prefixes of course (I 
> basically forgot to list that, so do double-check the actual XPath 1.0 
> context definition).
> 
> Also, if I read correctly, he is pointing out that type mismatches can 
> occur, and could be viewed as static or dynamic.  The two examples of 
> type mismatches that he gave are parameters (e.g. count receiving a 
> string) and invalid caste operations (e.g. union of non-nodeset).
> 
> If the wording is done well, I think we may not have to make the 
> distinction, i.e. we do not have to care whether a particular XPath 1.0 
> implementation treats these as static or dynamic.  
> 
> I think the more careful wording should take the form of saying that at 
> all times the exception occurs *when the XPath evaluation is performed*.
> 
> Cheers,
> John M. Boyer, Ph.D.
> STSM: Lotus Forms Architect and Researcher
> Chair, W3C Forms Working Group
> Workplace, Portal and Collaboration Software
> IBM Victoria Software Lab
> E-Mail: boyerj@ca.ibm.com  
> 
> Blog: http://www.ibm.com/developerworks/blogs/page/JohnBoyer
> 
> 
> ----- Forwarded by John Boyer/CanWest/IBM on 10/24/2007 12:33 PM -----
> *"Michael Kay" <mike@saxonica.com>*
> Sent by: www-forms-editor-request@w3.org
> 
> 10/24/2007 12:29 PM
> 
> 	
> To
> 	"'John Boyer'" <xforms-issues@mn.aptest.com>
> cc
> 	<w3c-xml-query-wg@w3.org>, <www-forms-editor@w3.org>
> Subject
> 	RE: Section 7 (PR#139)
> 
> 
> 	
> 
> 
> 
> 
> 
> 
> That's fine.
> 
> Undefined namespace prefixes are another possibility, in case you are
> enumerating them.
> 
> In fact XPath 1.0 doesn't distinguish very carefully between static and
> dynamic errors, so count("xyz") is an error that can be reported either
> statically or dynamically, similarly ($x|3).
> 
> Michael Kay
> 
>  > -----Original Message-----
>  > From: John Boyer [mailto:xforms-issues@mn.aptest.com]
>  > Sent: 24 October 2007 20:00
>  > To: mike@saxonica.com
>  > Cc: w3c-xml-query-wg@w3.org; www-forms-editor@w3.org
>  > Subject: Re: Section 7 (PR#139)
>  >
>  > Hi Michael,
>  >
>  > The working group agrees that this is a problem and will fix
>  > it in the specification.  For XPath 1.0, the static errors
>  > appear to be limited to expression well-formedness, undefined
>  > variable references and undefined function references as
>  > issues with the [context node, position, size] are handled
>  > separately, i.e. their non-availability implies not executing
>  > the xpath and behaving as if empty nodeset were returned.
>  >
>  > Please let us know if you have any further concerns about this issue.
>  >
>  > Thank you,
>  > John Boyer
>  >
>  > >
>  > >
>  > >
>  > >     D. "XPath expressions that are not syntactically valid": should
>  > >     cover all static errors, not just syntax errors. (Other static
>  > >     errors include, for example, references to functions or
>  > variables
>  > >     not present in the context, and type errors detected
>  > statically).
>  > >
>  > >
>  > >
>  > >
> 
> 


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Received on Wednesday, 24 October 2007 23:08:17 UTC

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