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Re: C.4 Undeclared entities?

From: Charles F. Goldfarb <Charles@SGMLsource.com>
Date: Fri, 18 Oct 1996 12:01:20 GMT
To: Michael Sperberg-McQueen <U35395@UICVM.CC.UIC.EDU>
Cc: W3C SGML Working Group <w3c-sgml-wg@w3.org>
Message-ID: <326e6f07.11560658@mail.alink.net>
On Thu, 17 Oct 96 13:20:13 CDT, Michael Sperberg-McQueen
<U35395@UICVM.CC.UIC.EDU> wrote:

>On 23 October 1996, the ERB will vote to decide the following
>question.  A straw poll indicates the ERB is leaning to declaring
>only lt, gt, and amp automatically and making references to
>undeclared entities be a reportable error.
>C.4 if XML makes DTDs optional and allows partial DTDs, what must or
>may a parser do when it encounters references to undeclared entities
>(9.4)?  Should XML declare any set of entities automatically?

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).

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.

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). Or, to put it another
way, all DTDs are partial; the "automatic" entity declarations are the other
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
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Received on Friday, 18 October 1996 08:01:11 UTC

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