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Syntax of XML markup declarations



At 09:51 PM 23/09/96 -0900, W. Eliot Kimber wrote:

>I see no reason to try to define a new notation for declarations at this
>time. It is a *non trivial* exercise to define a document type or
>architecture for declarations, partly because the additional expressive
>power of SGML gives you a lot more options.  Having spent quite a few hours
>putting together a DTD for DTDs that attempts to provide some useful
>features beyond simply reflecting the productions, I know that such an
>effort will either be unsatisfactory or take a long time (or both): it will
>either be a brain-dead transliteration of the productions (not useful, in
>my opinion) or it will be a time-consuming document type
>design-by-committee effort of the sort many of us have been involved with
>(and about which Eve has written an excellent book).
>
>I say no. The declaration syntax is understood and easy to teach. It's not
>hard to parse and it's compact.

I disagree strongly.  It seems to me a huge gain, in writing the spec,
in reading the spec, and in implementing the system, to have one syntax
for data and metadata to the extent possible.  Eliot is right to say
that writing the meta-DTD is hard (I did one); and that most of it is
a straightforward mapping from DTD syntax into SGML; and that DTD
syntax is more compact than SGML for this purpose.  I disagree, however, 
that it would be unsatisfactory or brain-dead.  As for the design-by-committee
problem, we have that one anyhow, like it or not.

Of course I am biased in favour of the metalanguage unification because
I went through all the work of doing it, in MGML.

Cheers, Tim Bray
tbray@textuality.com http://www.textuality.com/ +1-604-488-1167