xml-dev - Re: Does DTD validation work with namespaces?

[tpassin@home.com]

Norman Walsh commented on my previous post (qutoed by Winchel 'Todd'
Vincent, III) -

> | Presumably, it would mean "If this fragment had been embedded in a valid
> | structure according to its own DTD, this fragment would not cause the
whole
> | structure to be invalid."
> |
> | This sounds like a tall order for a processor to understand, and also a
tall
> | order to describe in a DTD.  It's funny, though, isn't it? All us humans
> | know pretty well what it would mean:  e.g., if we put in an <html:h2>
> | element, we want a processor to display an h2 heading at that point **as
> | if** it were an html document.  It's the formal aspect that's tough.
>
> I don't, in fact, agree that it's easy for humans to understand. Given:
>
>   <bookinfo>
>   <author><firstname>Norman</firstname>
>     <html:h2>Is a Big Fat Idiot</html:h2>
>     <surname>Walsh</surname>
>   </author>
>   </bookinfo>
>
> I have no idea what that H2 means. It doesn't mean display an H2 heading,
> it *can't* mean that because the author isn't displayed at all, it's
> just metadata that's associated with the document. Now I have a document
> with unintelligable metadata. I'm totally confused.
>
I see I simplified too much to try to make a point.  Let me try again.
Seems to me that the only reasons to include elements from other namespaces
in a document are 1) to reuse the same element names, like <h2>, but flag
them as having some different meaning - which is a matter for the processor
to handle -, or 2) to use some properties that usually belong to that other
namespace.  Ideally, perhaps, those properties would be semantics, but in a
real XML document, all we can really get is the syntax.

If I insert an h2 element from the html namespace, presumably I want some
html property - probably processor behavior - to accompany it.  Otherwise I
wouldn't bother.  For the example of including, say, contract elements
within a civil pleading (as some people have been talking about), I
presumably want to bring in the exact agreed-on semantics that go along with
the "contracts" vocabulary.  This is really a matter of semantics (or
ontology, if you like to look at it that way), but in xml, semantics is a
matter for the processor, not the parser.  If we get the syntax right,
perhaps there is some hope that the semantics are appropriate as well.

So is a namespace really a glorified processing instruction that has a
scope? Anyone care to tackle that one?

Cheers,

Tom Passin