Re: Picking the Tools -- Marrying processing models to data models

[Al Snell <alaric@alaric-snell.com>]

On Wed, 23 May 2001, W. E. Perry wrote:

> This is usually the other case, where the original form is identified by
> structure. Please bear with me if I stress once again how the structure or
> datatype of that original form does not govern the form in which data is
> instantiated for local processing.

Well, that's a common feature of data representations, that they don't
force you to process it in any way. Streamed formats like XML
force a serial parsing, admittedly, while more advanced ones allow you to
seek around the data as needed, but that's just the input stage; no data
format "forces" the form in which data is instantiated for local
processing...

> The original form is simply an
> identification which allows selection of the input side of the transformation
> or other process which instantiates locally useful data.

Yes. Indexing by "structure or name" isn't a significant difference, as
you make out, really; XML and CSV are both structured, it's just a matter
of whether you walk that structure by explicit names (what's called
"foo" in the file) or by implicit numbers (third element in).

> that input? It can be identified either by its label or its form. If the local
> process concludes that it is unlabeled, or that its label is incomprehensible,
> then, yes, it might be identified by its form. Even when it matches no form
> previously known to this process, it may be identifiable by something like the
> brute-force method you describe:

The label, however, is really identified by the namespace declaration more
than the XML elements. You could drop the element/attribute names and use
numbers, and have the schema/DTD/informal spec explain what each number
means, and the XML would be no less expressive (the same information would
be there, albeit now more oriented towards machine processing than human
processing).

> view of the local process is congruent--*via the transform or other process
> required to instantiate the local data*--to some equally abstract label by
> which the local process identifies its own required input data form:  'order'
> as you might use the term in Djakarta to 'order' as I use the term in New
> York, for example.

Yep, I agree with you there :-)

> Respectfully,
> 
> Walter Perry

ABS

-- 
                               Alaric B. Snell
 http://www.alaric-snell.com/  http://RFC.net/  http://www.warhead.org.uk/
   Any sufficiently advanced technology can be emulated in software