Over the past couple of days I've partially implemented an export function to produce Leigh's XDELTA documents (as a simple example of a possible XML format) for the data in Lucid keys.

Would it be possible to see this code, or at least the resulting XML files? I'd like to put a lengthier example in with the XDELTA documentation than I currently have.

Note that some of the verbosity in XDELTA (i.e. the length of the tag names) was derived from the requirement to make the format as 'readable' as possible. So that it wasn't opaque to a user how their data was stored, and also potentially allowing hand-authoring.

what could we do with such data as XML that we couldn't do with the data as a simple structured file as above?

At the basic data level I'd say nothing. A data format is a data format. You could put the whole thing into a complicated CSV (comma separated value) format if you wanted.

Apart from the lauded benefits of interoperability and the other XML hype, I see one of the big advantages of XML is that because so much of the information is explicitly tagged you are able to add additional layers above that of processing the plain data.

For example an RDF application layer might allow one to make inferences about a data set (or sets) that would be otherwise difficult with a format that is more context based.

There are also advantages regarding extensibility (and again this is just a personal view). Take the DELTA comment structure. It includes all sorts of different information and has been used to encode different types of information during the lifetime of the format. When it comes to processing that data the application needs to be much more aware of this type of legacy usage. Explicitly tagging data mitigates some of these problems (but not all, XML isn't a magic bullet by any means).

As a user of an application it wouldn't matter to me whether my data is in XML or some other format. Until I decide to use another application. Can it use this format? Will I lose any data? Can my colleague use my data in his/her application? Has all my data been rendered obsolete because the latest version of this package has changed the file format (i.e. the Microsoft Word syndrome). I believe careful application of XML can help in these cases.

But you're right to question it at this stage - the initial focus needs to be on design and data modelling...

A final point. It seems to me that the discussion so far has been dominated by computer nuts (no offence intended, we need you!)

...which I hope to be able to help with, as well as providing any XML and/or programming support. I'm really keen to hear from the domain experts out there who can provide hard usage facts.

I'll duck back into my shell now! :)

Cheers,

L.