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Re: C.4 Undeclared entities?



At 03:36 AM 10/25/96 GMT, Charles F. Goldfarb wrote:

>O.K. It is now clear that in XML a document "without a DTD" means literally
>that, and not just "parsable without reference to  its DTD". I think this is
>unfortunate because I believe it will render XML a non-starter in the
>marketplace.
...
>XML without a DTD is no different from HTML extended by the ability to "add tags

Here's the problem.  Our design goals say that you ought to be able to
*process* an XML instance without a DTD.  I think in these webful days, 
almost everyone agrees that this is useful and not intrinsically harmful.

Given this, from the point of view of certain applications, the existence of
the DTD becomes moot.  If I am a browser and I want to display without
parsing, and the <?XML RMD='none'> says that I don't need any of the DTD
to produce the correct ESIS, then I really don't care about the contents of
the external or internal subset.  If it didn't exist, I wouldn't notice.

Whether in fact there is much, other than display, that you can usefully do to 
an SGML document without having a DTD, is something that only the market will 
decide.  Since XML offers DTDs and validation, it is clearly more than "HTML 
with extra tags".  Whether the market decides to use it mostly as SGML-- or 
HTML++ is a prediction I'm way too battle-scarred to even consider making.
I am, however, pretty sure that it's probably wise to write the spec in such
a way as to leave that choice up to the market.

What we have to decide for now is what (if anything) we need to say in the XML 
spec to guide the actions of a browser or suchlike app that doesn't happen to be 
using a DTD.

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


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