OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help



   Re: [xml-dev] XSLT and XQuery

[ Lists Home | Date Index | Thread Index ]

At 01:45 AM 1/8/2002 -0500, Mike Champion wrote:

>So, XQuery -- as currently defined -- could easily take a year or more to 
>sort out
>before they get to a Candidate Recommendation, especially if they add updates
>(as many are pleading).

I think that basic project management is required for standards as well as 
for software projects. If adding new requirements would result in a delay 
of one year, and you have a product or a standard that is useful and has a 
market without the meeting the new requirements, you have to have a *very* 
good reason for accepting the new requirements.

Obviously, standards projects, like software projects, can slip for a 
variety of reasons. If there were a compelling reason to push back our 
schedule another year, we would have to do so. I haven't seen that reason yet.

>I think it's basically:
>- Unify the XSLT/XPath/XQuery data model.  This may be more or less done

I think it is. It took a year, but it is more or less done now, and was 
worth doing.

>- Make sure that queries can be defined to return schema-valid results

This is an area where we have an enormous amount of work done by brilliant 
people. Not all aspects of XML Schema are modeled, for obvious reasons, and 
I think we need to sort out some aspects of substitutability and named 
typing. But we have done a huge amount of work on this, it is very 
important to some members of the Working Group, and I think that at this 
point it would be more work to rip it out than to finish what we have.

>- Sort out/Respond to feedback on the latest draft, including
>     Strong typing as a requirement in XQuery; is there enough gain for 
> the pain?

I do not speak for the XML Query Working Group, but I think that most 
members strongly believe that there is. And adding strong typing or support 
for datatypes to a later version of XQuery would cause significant 
compatibility problems if it were not there in XQuery 1.0.

Certainly our requirements have said we had to support at least datatypes 
ever since January, 2000, and we have invited public comment on these for 
two years now

>3.3.2 Datatypes
>The XML Query Data Model MUST represent both XML 1.0 character data and 
>the simple and complex types of the XML Schema specification.

The requirement does not say whether operations should be strongly or 
weakly typed, or whether static typing is necessary. To me, static typing 
should be optional - implementations need not implement it, and users can 
still do queries that do not pass the conservative static typecheck.

So far, discussion on XML-DEV has not centered on these questions, but on 
the question of whether the XML Schema datatypes should be supported at all.

>     The use of quasi-XML syntax in the XQuery element/attribute constructors

This is more a matter of differing opinions than a difficult work item that 
should take a year to resolve. We could take it out of the BNF today if the 
Working Group decided to do so.

>     The XQueryX pure XML syntax -- is it needed? Should it be more XSLT-like?

Personally, I would be quite happy to drop XQueryX. I don't think it should 
be more XSLT-like. The best XSLT-like language is XSLT.

>     Updates - should they hold up the spec to put in updates.

So far, nobody has commented on the proposal in Patrick's thesis:


Is this more or less what people are looking for? At any rate, I don't 
think I've seen clear consensus on this list that the XQuery spec should be 
held up until updates are supported. I've seen opinions on both sides.



News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 2001 XML.org. This site is hosted by OASIS