Re: Namespaces on Attribute Names

james anderson (James.Anderson@mecomnet.de)
Tue, 21 Jul 1998 19:28:14 +0200


the suggested interpretation of qualified attribute names conflates two things
(inheritance and namespaces). these are better left distinct - at least on the
conceptual level on which i understood the response to have been situated.

David Megginson wrote:
> ...
> XML Excerpt
> -----------
>
> <doc id="xxx" LC:refNo="BS123.456 1998" CRTC:rating="family">
> [...]
> </doc>
>
> ...
>
> // This class is implicit.
> class MyDoc : public Doc, public LC, public CRTC
> {
> [...]
> }

do i understand the suggestion correctly, to specify that the presence of an
attribute from a given namespace denotes a dynamic subtype relation between
the containing element and an element with the same name as the prefix used
for the namespace (the correctness of applying 'LC.getRefNo' to the element).
aren't there alternative ways to expresss that? ways which would be just as
expressive, though less terse, but which would also allow permit other
denotations and which don't lead to the such quandries as the following.

if i follow your c++ example back to xml, i understand it to imply, for
example, that the possible declaration

<!ATTLIST LC LC:refno CDATA #REQUIRED >

applies to any element in which the attribute is present, but doesn't apply
when the attribute is not. !?

is this the kind of thing mr murray-rust is always alluding to when he
mentions the "rather hairy problems of validating dtds" in the presence of
qualified names?

bye,