Re: [relax-ng] Re: DOM Abstract Schemas revisited

[Eric van der Vlist <vdv@dyomedea.com>]

James Clark wrote:
>>I may have missed something, but I have not understood the AS spec in
>>this way :) ...
>>
>>I think that when they write about editing AS schemas, they mean "editing
>>(AS schemas)" ie an API to edit a new kind of beast called an AS schema
>>and do not pretend to provide an abstract API to edit any kind of schema.
>>
> 
> I disagree.  The DOM has requirements for editing DTDs and XML Schemas not 
> some new kinf of beast.  The WD says:
> 
> "In the October 9, 1997 DOM requirements document, the following appeared: 
> "There will be a way to determine the presence of a DTD. There will be a 
> way to add, remove, and change declarations in the underlying DTD (if 
> available). There will be a way to test conformance of all or part of the 
> given document against a DTD (if available)." In later discussions, the 
> following was added, "There will be a way to query element/attribute (and 
> maybe other) declarations in the underlying DTD (if available)," 
> supplementing the primitive support for these in Level 1.

DOM AS does allow to change the declarations in the underlying DTD (or 
WXS) after it has been read as a AS and it does allow to save the 
changes as an updated AS, but not as a DTD (or WXS) and this is conform 
to this paragraph (or at least with one possible interpretation of this 
paragraph).

> That work was deferred past Level 2, in the hope that XML Schemas would be 
> addressed as well. It is anticipated that lowest common denominator general 
> APIs generated in this chapter can support both DTDs and XML Schemas, and 
> other XML abstract schemas down the road."

Again, I read this one as "we expect to be able to read at least DTDs 
and WXS as AS" but I don't see where it says that there is a requirement 
to save an AS back as a DTD or a WXS. Looking further at the WG, I think 
that this would be impossible with the limited amount of information 
required. I think that this is the reason why they speak of "lowest 
common denominator".

I think that the editors had also in mind the support of RDBMS schemas.

> If they were trying to create such a beast, they would have a lot more work 
> to do.  For a start, they would have to define the semantics of their 
> schema language, which I see no attempt at in the WD.

No, they have kept to the API only and it's up to the implementation to 
define the algorithm needed to answer to an application using AS.

Note that there is no need for the saved AS to be interoperable between 
implementations.

> 
>>These are 2 different beasts and both are needed!
>>
> 
> I don't think there is any requirement for the kind of thing you are 
> suggesting. I believe that what users need is the ability to edit DTDs and 
> XML Schemas (and RELAX NG).

It's a comment that should rather be addressed to the DOM WG :=) ... I 
am not wanting to judge if it's useful or not but just mentioning that 
it's a work in progress which might support RELAX NG!

Eric

> James
-- 
See you in Seattle.
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Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
http://xsltunit.org      http://4xt.org           http://examplotron.org
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