Re: 4.2 Location-source/Base address

At 12:33 PM -0800 3/4/97, Tim Bray wrote:
>4.2.a Should we formalize at all the concept of a base address?

Probably. The URL standard underway does formalize the meaning of relative
URLs, so that we could just steal that definition (but it won't help us for
fragments, of course). It works in the obvious way, actually.

>4.2.b If so, should we call it a location source or something else?

Probably BASE, as the term seems to be well known. I know that the HTML
definition was not too good, but changing the name will probably confuse
people.

>4.2.c Should we formalize the concept of the implied location source?

It seems that this concept already underlies the notion of "relative URLs".
I'm not convinced that we should include explicit location sources, even
though they have a _lot_ of power and utility. The do provide one way to
conceptualize inter-document IDREF (via ENTITY attributes) and the notion
of BASE address. If we allowed _just_ those two forms, it might not be too
pernicious. I think referred entities should be required to be well-formed
for the results to be well-defined (It is possible that we could allow any
XML entity, but then we would have to talk about "virtual" root nodes, for
those entities not enclosed in a single tag. The complexityof explanation
might be a net loss in that case.

>4.2.d If so, should the values be DOCELEM and REFERRER, defaulting to
>DOCELEM?

I never cared for those values too much. We might do better to
conceptualize this as an extension of BASE to handle entities values,
rather than as a full LOCSRC.

I'm thinking that the base attribute would be a URL if declared CDATA or
undeclared, and an entity if declared ENTITY, and there would be no other
case allowed. If not present, we get a default value of the URL used to
fetch this (DOCUMENT or ENTITY??? open issue, but document is probably
better...).

  -- David

_________________________________________
David Durand              dgd@cs.bu.edu  \  david@dynamicDiagrams.com
Boston University Computer Science        \  Sr. Analyst
http://www.cs.bu.edu/students/grads/dgd/   \  Dynamic Diagrams
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Received on Friday, 7 March 1997 10:52:47 UTC