Re: A proposed solution

-----Original Message-----
From: James Clark <jjc@jclark.com>
Date: Thursday, June 15, 2000 5:35 AM


James wrote,
>In the case of external entities, the only thing that an XML processor
>needs to do with the system identifier is to fetch the resource it
>identifies.  It doesn't have to compare it for equality with other
>system identifiers.  In the case of namespace names, the namespace
>processor doesn't have to fetch the resource it identifies, but it has
>to compare it with other namespace names with possible different
>contexts, in order to determine whether attributes are unique (in
>accordance with section 5.3 of the namespaces Rec).


Following the decision that the base URI for
a URI reference in an extrenal entity is the URI of that entity, 
it is clear that an XML processor -- or at least a parser which
creates an infoset which is passed (eg through the DOM)
to an application must provide the information as to where
a relative URI came from. So external entities cannot be
expanded in place in the document tree without annotating
them with this. I guess this is obvious.  But the base URI can't
be lost.

(Of course, anything which feteches a resource in practice
does to string comparison with URIs of resources already
fetched, before fetching them again!)

>James
>
>