namespaces and document structure [Re: Next Round]

james anderson James.Anderson at
Fri Jan 22 14:30:44 GMT 1999

Tyler Baker wrote:
> james anderson wrote:
> > yes, but...
> ...
> > Neither the prefix nor the qualified name have the same permanence as the
> > local name, the namespace and the expanded name. One could well collect all
> > prefixes in connection with which as symbol appeared, but the values are of no
> > use as the bindings have dynamic extent.
> > the prefix and the qualified name need to be handled separately, through an
> > interface which combines symbols (here called names) with a dynamic parsing or
> > serialization  context.
> >
> > The other additions have to be modified accordingly: as the prefix has no
> > meaning outside of the parser's dynamic context, those interfaces have no purpose.
> Very true, but sometimes applications (or even the DOM) may want to preserve the exact
> document structure in memory and be able to write out that exact document structure as
> well.  That is the only reason for providing the prefix and qualified name methods.

The prefixes bear no relation to document structure. **Strictly speaking**
neither they nor even the URI's have anything to do with content. They simply
aid in identifying the names which figure in the content. That the prefixes
appear in bindings which appear as attributes is a (regrettable) anomoly, but
it does not change their nature.

(When I hear of application which process *prefixes* I'll take this back.)

As "mr. Bray's" algorithm makes clear, a given document actually is an
instance of an infinately large equivalence class in which the same "content"
appears in varying encodings, each of which employs difference prefixes to
bind respectively identical namespaces. The particular prefixes in one
encoding have no bearing on the ability to write out the same document
structure. To the extent that they affect the ability to duplicate the
*encoding* they do so as a consequence of the relation between prefixes and
*namespaces*, not as a consequence of the relation between prefixes and
individual *names*. 

> I agree, it is just that there may be reasons I cannot ascertain that an application
> may want the exact document structure presented to the application.  Perhaps an XML
> tree viewer for example or as I said before the DOM.  Calling
> getTypeByQualifiedName(String qualifiedName) would function pretty much exactly as
> things are defined now.  In other words, if an XML document does not implement
> namespaces, then using this method may be your cup of tea.

See above...

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