Re: [xml-dev] IDs without DTD/Schema , Is there a way ?

[Elliotte Rusty Harold <elharo@metalab.unc.edu>]

At 10:18 AM -0500 10/29/01, Daniel Veillard wrote:


>  Well if foo have an ID attribute on an element of value "Chapter12"
>then of course foo#Chapter12 will have the expected semandtic with the existing
>version of XPointer (and I think all the previous ones too !).

Yes, but the problem is that foo can't have an ID attribute if the document does not have a DTD.

>  The problem at stake if I understand correctly is to actually 
>always be able to find the fact that this attribute is an ID, even
>if case of:
>    - absence of DTD

No, if the document does not have a DTD, then no attribute can have type ID; i.e. there are no ID type attributes without a DTD.

>    - the parser is not validating

Yes.

>    - you don't want to trust a remote DTD but just the XML instance
> for example.
>

If you don't trust the DTD, then you've got bigger problems; but yes, the proposal would address this problem as well. 

> I have myself advocated getting xml:id been integrated in the XML spec
>because that's the only clean way to get reliable linking even in the absence
>of Dtd or Schemas validation without trying to use structure/XPath based
>naming schemes.
>

I don't think we need to change XML 1.0 to make this happen. Tim Bray's xml:id or ID namespace would allow us to define a second space of unique element identifiers encoded in attributes that are separate from the normal ID type attributes of the document. These attributes might even have type CDATA in documents without DTDs, just like all other attributes in such documents. Nonetheless, they could have all the characteristics we need for reliable, name-based linking. 
-- 

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| Elliotte Rusty Harold | elharo@metalab.unc.edu | Writer/Programmer |
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