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Re: B.2 DTD required or optional?



At 03:05 PM 10/12/96 CDT, Michael Sperberg-McQueen wrote:

>B.2 Should XML require each document instance to have a DTD or not
>(7.1)?

One concept is that the XML spec should define two separate characteristics
that a document can have, well-formedness and validity.

A. A "Well-Formed XML Document" has 

1. syntactically distinguishable elements, attributes, comments, and PI's
2. one root element
3. all elements properly nested within each other
4. no text outside the root element

Such a document may or may not contain markup declarations.  If it does,
well-formedness also allows

5. empty elements, if they're declared
6. entity references, if they're declared

B. A "Valid XML document" means there's a full DTD and it's been validated
   in the familiar SGML sense.


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


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