XOM API for Processing XML with Java

["Michael Kay" <mike AT saxonica.com>]

I think the xml:id spec actually says that all the errors can be ignored if
you want, so you have to make a decision on this.

It's a moot point (in the British sense!) whether an XPath 1.0
implementation should allow the id() function to recognize xml:id
attributes. Common sense says it's probably OK to do so (who's going to
complain?), but one could argue about the fine print of what the XPath 1.0
spec actually says.

Michael Kay
http://www.saxonica.com/ 



> -----Original Message-----
> From: xom-interest-bounces AT lists.ibiblio.org 
> [mailto:xom-interest-bounces AT lists.ibiblio.org] On Behalf Of 
> John Cowan
> Sent: 20 January 2005 13:19
> To: xom-interest AT lists.ibiblio.org
> Subject: [XOM-interest] XOM 1.1 proposal: xml:id
> 
> The new xml:id spec is just about to become a Candidate Recommendation
> of the W3C.  I am proposing that XOM 1.1 include support for it.
> See http://www.w3.org/TR/xml-id for what is currently the Last Call WD
> but will soon be the CR draft.
> 
> The idea of xml:id is that it is an attribute which is always of type
> ID even in the absence of a DTD declaration.  By using it, 
> documents can
> gain the advantages of IDs without having to carry the burden 
> of a DTD;
> this is especially important because XSLT can generate 
> references to an
> external DTD but cannot create an internal one.
> 
> It's an error to have an xml:id attribute declared other than 
> as type ID.
> (It's implicitly tolerated to have it declared of type CDATA, because
> SAX doesn't report the difference between a CDATA declaration and no
> declaration at all.)  It's also an error for the value to be other
> than an NCName, or for two xml:id attributes to have the same value.
> 
> In any case, though, every xml:id attribute gets leading and trailing
> whitespace removed, internal whitespace collapsed to a single space,
> and its type set to ID.
> 
> I proposed privately to ERH to add a mutator to Document that 
> would fix
> up the document.  He replied (and encouraged me to post to this list):
> 
> > I would prefer it to be more subtle; i.e. not add any new
> > methods but change the behavior of existing methods, 
> including XPath and
> > XInclude, to match this, so that it works automatically without
> > requiring an extra method call or cluttering up the interface of
> > Document.
> 
> I'm not clear why XPath and XInclude are specially relevant; I'd think
> it was Attribute.setType and Attribute.setValue that need to change in
> order to make this work automatically.  The xml:id recommendation
> does not require the uniqueness check (it's a SHOULD not a MUST),
> so that check could be omitted in XOM or provided externally.  
> 
> What do people think?
> 
> -- 
> The experiences of the past show                John Cowan
> that there has always been a discrepancy        
> jcowan AT reutershealth.com
> between plans and performance.                  
> http://www.reutershealth.com
>         --Emperor Hirohito, August 1945         
> http://www.ccil.org/~cowan
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