xml-dev - Re: Why the Infoset?

[John Cowan <jcowan@reutershealth.com>]

Jonathan Borden wrote:

> What we mean by "high fidelity" is simply this: the *parsed* model,  what is
> also called a grove, has the capability of saving the document *exactly*,
> character for character, from what it was parsed.

Okay, this is the one that cares about the 74 occurrences of S, which Simon
insists on calling a red herring?

> But it is not hard to describe, that is my point. The XML 1.0 production
> rules create a parse tree which exactly describes the source document, down
> to the byte. This is what I would call the XML property set, and from this
> one can subset to one's desire.

Okay, I understand now.  Actually the production-rule level is *not* the
bottom parsing level, because for the most part PE-references have already
been removed.  Internal PEs are not really structural in XML;
it is a mere validity constraint that requires DTD constructs to begin
and end in the same PE, and

	<!ENTITY % element "<!ELEMENT">
	%element; FOO EMPTY>

is a well-formed though not valid external subset.

> Doesn't it make the most sense to subset from the full description, rather
> than both add to and subtract from a partial description?

IMHO no.  The correct level to aim at, when doing the job for the first
time for the benefit of the SGML-naive, is the middle useful level, what
you call "structure sensitive".  The question then remains, just what is
useful structure and what is not?  I have done my best to answer that
question.

-- 

Schlingt dreifach einen Kreis um dies! || John Cowan <jcowan@reutershealth.com>
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Denn er genoss vom Honig-Tau,           || http://www.ccil.org/~cowan
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