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Re: ERB decision, 31 October 1996

From: Charles F. Goldfarb <Charles@SGMLsource.com>
Date: Fri, 01 Nov 1996 02:05:33 GMT
To: Tim Bray <tbray@textuality.com>
Cc: w3c-sgml-wg@w3.org
Message-ID: <327b57a9.3221529@mail.alink.net>
On Thu, 31 Oct 1996 17:12:52 -0800, Tim Bray <tbray@textuality.com> wrote:


>Right.  And we didn't rule that out.  We just said that you don't *have to*
>read external text entities unless you're validating.  Which, as you
>suggest, a downstream browser likely isn't.  As for nuking external
>text entities altogether, we thought that over seriously; there are just
>too many people who see them as a sine qua non of a worthwhile authoring
>system.

But in SGML they are always accessed and parsed, and the resulting ESIS is
always the same. (Yes, I know that 8879 doesn't mention ESIS by name, but the
SGML conformance testing standard certainly does.)

Lazy parsing needn't be inconsistent with 8879 conformance, as early postings
have demonstrated, as long as the external text entity doesn't change the state
of the parse. (I still question whether XML can enforce this constraint.)

The real problem is with entities whose text changes each time they are
accessed, thereby yielding a different ESIS on each parse. Valid XML should
require that external text entities be constants. Generated files should be
accessed through attributes, where there is a chance to identify the governing
semantics of the reference.
--
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, 1 November 1996 02:16:45 EST

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