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Re: C.4 Undeclared entities?



On Fri, 18 Oct 96 22:35:35 EDT, lee@sq.com wrote:

>Charles Goldfarb argued:
>> Questions like this are more easily analyzed if we avoid the confusing term
>> "optional DTD".
>> A missing DTD is really an implied DTD (like SGML's implied SGML
>> Declaration) in which all element types have mixed content consisting of
>> "(#pcdata | any element type)*" and all attributes are CDATA #REQUIRED
>> (except for special conventions for ID, etc. that we might adopt).
>
>I am not sure where this comes from -- are you saying that this is the
>current state of ISO8879, or that you would like to propose this for XML?

I thought that was what was being proposed for XML. I'm not proposing it, just
trying to put it in context. Sorry for the confusion.

>> So there is always a DTD. Now the question is: what does a parser do with
>> references to undeclared entities?
>> There is no reason to do anything different
>> from what is done in SGML.
>
>This is invidious, but fallacious, reasoning.
>That there is always a DTD does not mean that there is always a
>user-supplied DTD.
>
>If your implied DTD declares all the elements, it could also declare
>all the entities just as easily.

I guess you are right on that point, which to me shows the fallacy of implying a
DTD.

>
>> As for declaring entities automatically, I assume that means there will be a
>> piece of public text containing the "automatic" declarations that is
>> considered to be referenced by all DTDs (including the implied one).
>
>It is sufficient to specify an algorithm by which such entities cn
>be constructed.

Unfortunately, not in 8879 as it exists today. WG8 has proposed something
similar for character references in SGML97.

>> Or, to put it another way, all DTDs are partial; the "automatic"
>> entity declarations are the other part.
>
>I for one would find it helpful if you could mark proposals as that,
>and statements of how ISO8879 works today as such -- I recognise
>that this is a weakness in my understanding of SGML, but I didn't
>understand ISO8879 as specifying anything about implied DTDs.

It doesn't. I was trying to characterize what I thought was a proposal for XML
(non-existent DTDs) in terms of SGML.

>But you cannopt possibly be talking about XML, because no consensus has
>been reached about implied or partial DTDs, so one cannot say of
>XML that `all DTDs are partial'.

I was referring to a proposal for XML which would have the effect of making all
DTDs partial.

>Or are you hoping we will accept your proposal as a fact and not
>question it??  that can't be right, sorry.   I'm missing something.

As I said above, I was referring to a proposal made on this list. It is not my
proposal. In fact, I don't like it at all, Lee. Your note has revealed even more
problems with it.
--
Charles F. Goldfarb * Information Management Consulting * +1(408)867-5553
           13075 Paramount Drive * Saratoga CA 95070 * USA
  International Standards Editor * ISO 8879 SGML * ISO/IEC 10744 HyTime
 Prentice-Hall Series Editor * CFG Series on Open Information Management
--


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