xml-dev - RE: xpath vs xql

[Joshua Allen <joshuaa@microsoft.com>]

Yeah, I was just assuming XQL was talking about the
old W3C XML-QL and ongoing work based on that.  Sorry
about the confusion!  FWIW, Dan Suciu's page at
http://www.research.att.com/~suciu/strudel/external/NodeExternal,internal.ge
noid_3.html
has alot of info about his research in XML; the
XML-QL is a very nice foundation.


> -----Original Message-----
> From: Jonathan Robie [mailto:Jonathan.Robie@SoftwareAG-USA.com]
> Sent: Tuesday, July 04, 2000 6:41 AM
> To: Christopher R. Maden; xml-dev@xml.org
> Subject: RE: xpath vs xql
> 
> 
> At 04:31 PM 7/3/00 -0700, Christopher R. Maden wrote:
> 
> >At 12:03 3-07-2000 -0500, Jonathan Robie wrote:
> >>There is very little difference between XQL'98 and the 
> abbreviated syntax 
> >>of XPath. XQL '98 may best be regarded as a predecessor of XPath.
> >
> >Can you clarify that statement?  My recollection is that work on the 
> >syntax now known as XPath began shortly after the March '98 
> meeting of the 
> >XSL WG, if not sooner.  The July '98 WD of XSL shows the 
> XPath syntax; 
> >when was XQL'98 published?  The "QL '98" workshop was in 
> December, but I 
> >can't find a pointer to XQL'98.
> 
> Work on XQL started in January, 1998, and was largely 
> finished by March, 
> 1998. It originated when I was working on the DOM and needed 
> a simple query 
> language for XML repositories. I showed the original version of the 
> language to people at Microsoft and webMethods, and we 
> started working 
> together on it, producing a significantly better language 
> than the original 
> XQL. Unfortunately, although the original intent was to publish XQL 
> quickly, it proved difficult to get all the partners to agree to this.
> 
> The people working on XSL Patterns included someone who knew 
> XQL quite 
> well, and I think that it is fairly clear that XQL influenced 
> the design of 
> XSL Patterns. XQL did not originally support functions, which 
> it adopted 
> from XSL.
> 
> The language I call XQL'98 is the language defined in the QL 
> '98 workshop 
> submission, which is identical to the language defined in the 
> drafts we 
> submitted to the XSL WG in September '98, and is referenced 
> in the XPath 
> specification. There were two other versions of XQL, the 
> original XQL from 
> January 1998 and XQL '99, which has now been abandoned in 
> favor of Quilt.
> 
> At any rate, there is *very* little difference between XQL 
> '98 and the 
> abbreviated syntax of XPath, and XQL was never blessed by a 
> standards body, 
> so most XQL implementations now use the XPath interpretation 
> where the two 
> languages differed, e.g. numbering arrays from 1 as in XPath 
> rather than 
> from 0 as in the original XQL. Some implementations say they 
> support both 
> XQL and a subset of XPath, giving them two acronyms for the 
> price of one.
> 
> Jonathan
> 
> 
> **************************************************************
> *************
> This is xml-dev, the mailing list for XML developers.
> To unsubscribe, mailto:majordomo@xml.org&BODY=unsubscribe%20xml-dev
> List archives are available at http://xml.org/archives/xml-dev/
> **************************************************************
> *************
> 

***************************************************************************
This is xml-dev, the mailing list for XML developers.
To unsubscribe, mailto:majordomo@xml.org&BODY=unsubscribe%20xml-dev
List archives are available at http://xml.org/archives/xml-dev/
***************************************************************************