Re: A8 and A17: entities, conditional inclusion, what's XML for?
On Wed, 09 Oct 96 16:34:31 CDT, Michael Sperberg-McQueen
>The discussions of entities and conditional inclusion seem to me to
>suggest we may need clarification of some issues, raised by questions A8
>We might disagree over these because of different views on whether
>entities, or conditional inclusion, are needed or desirable for XML as a
>mechanism for publication on wide-area networks.
>We might disagree because of different views on whether they are
>essential for document management in production work on any reasonably
>large body of documents.
>Or we might disagree because of different views on whether XML's task is
>solely to support network distribution and publication of documents, or
>to support, as far as possible, production work in managing those
Actually, these views can be reconciled once we accept the idea that XML is a
conforming subset of SGML We have seen that this goal is possible if we:
1. Specity some unambiguous rule for RE handling that is a reasonable
interpretation of the standard (i.e., one that would be a viable candidate for
2. Define a simplified, but conforming, declaration syntax.
If XML is a conformance level of SGML ("core SGML") then it doesn't need
conditional DTDs because full SGML is available for that. Derived DTDs will be
sufficient for casual editing of instances. No DTDs should be needed just to
read the instances (but there must be a DTD available and identified in the
As for entities, James Clark's suggestion that internal entities be limited to a
single character is a good one, as it provides a mnemonic capability for
I believe the question of external data entities -- the only other potentially
necessary entity category -- should be deferred to the discussion of linking
mechanisms, as that is what they are. (At present, I favor having them.)
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