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Re: NOTATIONS and DATA TYPES (was: Update on namespaces)

From: len bullard <cbullard@hiwaay.net>
Date: Wed, 11 Jun 1997 22:19:58 -0500
Message-ID: <339F6ADE.5B38@hiwaay.net>
To: Joe English <jenglish@crl.com>
CC: w3c-sgml-wg@w3.org
Joe English wrote:
 
> That was the original intent as I understand it,
> but I've never seen <!NOTATION...> actually used that way,
> and it would make very little sense to do so, at least
> for general SGML.

Actually, that is precisely how the MID specification 
indicates a "known" processor which the preparer of 
the document is indicating will work.  It was convenient.
 
> The idea that there is *one* application capable of doing all
> possible processing on a data entity, and moreover that the
> location of that application should be hardwired into the DTD,
> is in direct contradiction to the principles of data reuse and
> system independence.

Hmm.  It is an odd place to put it, I grant you.  Would you 
preferred it to have been in the instance?  If you wanted 
to move the information/data naming the processor or processor 
type, and you don't have MIME, how would you do it?

> The situation might be different for XML; since we're assuming
> a Web-based environment it *might* make sense to specify the URI
> of a Java applet -- all that's missing is an API with which
> the applet can interact with the application -- but that would
> leave Perl, Python, Tcl, et cetera-based XML processors out of
> the picture.  IMO Internet Media Types (MIME types) would make
> much more sense as notations' SYSTEM identifiers in XML.

It indicates the type of a processor/handler.  End of story.
How does that get registered? IOW, VRML/JAVA have CLASSPATH:
will XML have some equivalent for that?
 
> > If my understanding of NOTATION is correct (from section 4.6 in the
> > working draft at
> > http://www.textuality.com/sgml-erb/WD-xml-lang.html#sec4.6), then a
> > NOTATION in effect says "I don't know how to deal with this external
> > resource, but here is the identifier of some processor that does."  Data
> > types would be saying "This is a number (date, time, etc.) I make no
> > recommendations regarding processing."
> 
> The XML draft does lend itself to that interpretation.
> In full SGML though -- where NOTATIONs can be associated with
> external CDATA entities (which XML lacks) and elements --
> they are often used to indicate data types in the sense
> you describe.

They do both, but they don't indicate data types, but name a 
document that defines the data types.  Correct?  So in that 
sense, they are in situ, only names.  One is the name of a 
document; the other is presumably the name of a processor 
that the DTD emitter *says* handles whatever that document defines.

How useful is that pair of names in that form?

len
Received on Wednesday, 11 June 1997 23:24:48 EDT

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