DTDs aren't allowed to change document syntax - the use of tags for elements
and attributes, the use of '&' for general entities, etc. The same rules
apply in this representation, as I will state more explicitly. This
representation would, however, allow _additional_ rules - with data schemas
the first issue to be addressed. This really isn't that difficult.
>Is there any good reason that the ability to change the parse tree should
>be conflated with the responsibility for verifying schema-compliance as
>they are in DTDs. Is there any good reason to perpetuate this conflation
>in your proposed replacement for DTDs?
I'd like to see a structure that's:
a) easily interpreted, edited, and stored, without the need for multiple
toolsets
b) capable of containing a complete set of information about a document,
including structure and data
What's so difficult about that? I can't think of any good reason (besides
SGML compatibility) to oppose either of those goals. Why on earth would I
want to keep multiple sets of document descriptions (schemas, whatever) around
that share the task of defining the same document set? It seems like a
management mess, a processing mess, a waste of bandwidth and storage because
of redundant information, and just generally a nuisance.
Making DTDs extensible is a good way, in my view, to address this issue, and
several others.
Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer / Cookies