X-Schema syntax

Mark Birbeck Mark.Birbeck at iedigital.net
Tue Jun 29 09:09:12 BST 1999


Paul Prescod wrote:
> Mark Birbeck wrote:
> 
> > Also, I assumed that the students you referred to were
> > programmers. Anyway, the question still remains, why is it better to
> > learn two syntaxes (XML and DTD) than just one?
> 
> This is one of my favorite paradoxes. I can't count how many 
> speeches and tutorials I've seen that started along the lines of: "XML
schemas are
> great because they don't require you to learn a new syntax" and then
> continued along the lines of: "Now let's spend an hour 
> talking about the syntax."

I agree with you, but that was not the substance of my argument - in
fact it was mentioned only in passing. You didn't actually address my
main point, which was ...

Productivity gains from XML are in part achieved by being able to
represent many forms of information in a consistent way. For example, if
you develop a tool that can transform data of one type, it can also be
used to transform information of thousands of other types. An editor
that can edit data of one type - and enforce data types, enumerated
values, and so on - can be used to edit data of another type. Tools that
transfer, store, compress, parse, validate, and so on, data of one type
can be used to do the same to data of other types. I see no reason why
XML grammars themselves should not benefit from the productivity gains
of XML. Why shouldn't I be able to use the same indexing techniques so
that I can search for all grammars that have a delivery address element?
Why shouldn't I be able to transform one grammar into another grammar
using XSLT, say in German instead of English? Or use XSLF to produce
help files?

IMVHO, there are a number of problems with XML that have been bouncing
around for a while that cannot be solved at the level of
meta-information, and must be looked at on the plane of
meta-meta-information. Take the oft-discussed question of searching
documents that may have common data but were produced with different
DTDs - the old <author>, <written-by>, <created-by> and <auteur>
problem. The solution often offered is to impose a common DTD on
everyone - pretty unlikely to ever happen, and even if it does in the
future there would be legacy data to contend with. However, we could
begin to solve this by dealing with the schemas themselves - using the
same tools we are already using - provided that we express
meta-meta-information as meta-information. Search engines of the future
might then pick up documents and their related schema from your server,
as well as a transform file that describes how to convert the elements
in your schema to some agreed standard words.

Best regards,

Mark

Mark.Birbeck at iedigital.net
http://www.iedigital.net/

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