Re: XPATH differences between 1.0 and 2.0

José,

I don't disagree with your principle that a spec 
should be readable by everybody who is interested 
in the subject matter and sufficiently educated 
in the domain of that spec.  However, a spec 
should not be considered to be a tutorial, a 
primer, or a text book.  It is intended to be a 
completely precise specification of some 
technology that can be implemented by people 
knowledgeable about the context in which the spec 
and its technology exist.  As in almost all 
endeavors, there are tradeoffs to be made when a 
spec is written.  When the tradeoff is between 
time of delivery, technical accuracy, and 
tutorial material (pick two), I will ALWAYS make 
the choice of being as technically accurate as 
possible with a delivery time as close to plan as 
possible.  That obviously means that I am willing 
to sacrifice the ability of a spec to be used as a tutorial.

I don't disagree that the W3C has published 
tutorial material (usually, but not always, in 
the form of Primers), and that some of them have 
been successful.  But there is at least an order 
of magnitude of difficulty, complexity, and size 
of the XQuery/XPath suite of specifications and 
the RDF/OWL suite of specs.  XQuery/XPath were 
already eight years in development.  Do you think 
that the world would have been willing to wait 
another year or two so we could write a Primer?  I don't think so.

In any case, I think that Mike Kay's book on 
XPath 2.0 is a most excellent reference on the 
subject, with considerable tutorial material, 
comparative material, and detailed 
explanations.  I recommend it highly.  For a 
shorter, higher-level introduction to XPath 2.0, 
XQuery 1.0 and other technologies, you might 
consider my book, too: "Querying XML: XQuery, 
XPath, and SQL/XML in Context" (Jim Melton and Stephen Buxton).

Hope this helps,
    Jim

At 11/27/2006 03:53 AM, José Manuel Cantera Fonseca wrote:
>Basically I don't agree that a spec should only 
>be readable by the people who wrote it.
>A well-structured and well-written spec should 
>allow anyone to read it. If a spec is not 
>readable even by technologists, it will be 
>counter-productive for the technology itself because it could not be endorsed.
>
>The W3C is full of Primer success documents, 
>such as RDF, OWL, and so on. I think there is a 
>place for W3C tutorials and for book detailed 
>tutorials with plenty of use cases.

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Jim Melton --- Editor of ISO/IEC 9075-* (SQL)     Phone: +1.801.942.0144
   Co-Chair, W3C XML Query WG; F&O (etc.) editor    Fax : +1.801.942.3345
Oracle Corporation        Oracle Email: jim dot melton at oracle dot com
1930 Viscounti Drive      Standards email: jim dot melton at acm dot org
Sandy, UT 84093-1063 USA          Personal email: jim at melton dot name
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