XML-LINK

[Peter Murray-Rust]

Many thanks indeed Eliot,

	This is extremely useful and I think I follow everything you have 
put forward.  [It's taken me several months to get to that stage, so
it's clear that for webhackers, rather than rocket scientists there is a
longish learning curve - at least until real applications become common].

I will some back to some of the detalied points shortly.  Eliot's reply 
confirmed my suspicion that there could be different interpretations of
the role of XML-LINK ('structure' and 'annotation').  If this is not realised
then it would easy to create software for XML-LINK which was inappropriate 
in the wrong context, and it could be very confusing for newcomers.  
There is also the strong likelihood that *some* XML-LINK processors will be 
tightly bound to particular applications (browsers, database engines, etc.).  
The converse may be that a general XML-LINK engine (covering both approaches 
above) might be described in language sufficiently abstract that newcomers 
to XML might fail to understand its purpose and value.

It would be extremely useful to see where XML-DEV readers see a link-processor
in the XML architecture.  From Eliot's reply I see it as a browser-independent
engine which answers queries about links regardless of what use they are
to be put to.  (It presumably *holds* the traversal information, but simply 
hands it to the querying engine.)  So JUMBO should be independent of the 
link processor.  When JUMBO was acting as a generic browser and a node was 
actuated/processed/arrived_at, etc. JUMBO would query the link processor as 
to whether it had information about this node.  If so, it would decide whether
to act upon it.  However I assume an application could instruct JUMBO that
certain Nodes (or collections of nodes) required information from the link
processor, such as whether they were part of a DAG, linked list or
whatever.  Then it could extract the whole structure independently of 
behaviour (haven't thought this through in detail :-).

So I am extremely wary of starting to code anything more in this area until
its limits become clear.  It's clearly venturing into rocket science
territory.  By comparison XML-LINK=SIMPLE is relatively straightforward.
Therefore I suspect there will be implementers (like myself) who find that
full XML-LINK implementation is too difficult/expensive/undefined, whilst
SIMPLE is useful and doable.

IMO it will be valuable to have an application-independent link processor for
XML-LINK.  Is this likely to happen?  Or is this only really conceivable 
in very large organisations?

	Once again many thanks

	P.


-- 
Peter Murray-Rust, domestic net connection
Virtual School of Molecular Sciences
http://www.vsms.nottingham.ac.uk/

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