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Re: Link-4: Extended Linking Group Indirection

From: Peter Murray-Rust <Peter@ursus.demon.co.uk>
Date: Tue, 20 May 1997 10:52:23 GMT
Message-Id: <6909@ursus.demon.co.uk>
To: w3c-sgml-wg@w3.org
In message <1.5.4.32.19970520082238.0069acc0@mail.u-net.com> Martin Bryan writes:
> At 23:31 19/5/97 GMT, Peter Murray-Rust wrote:
> 
> ></CONSEQUENCE>
> >
> >If this analysis is right, we need a NULL attribute for SHOW and we no longer
> >need GROUP and DOCUMENT.  If labels are required, then we can either
> >search for EXTENDED SHOW="NULL" or use ROLE.
> 
> Actually a more correct keyword would be "CACHE". Group is designed to tell

Thanks Martin,
	I think this highlights the very important need to bring the implied
semantics into the open.  This use of GROUP had not occurred to me at all -
a warning to the pre-application that it would be getting a series of 
EXTENDED links later.  Rather like an orange signal on the UK rail system.

I had already thought about CACHE, but in a different context - a page has
been displayed and this is a hint to the processor that it shouldn't destroy
it.  For example SHOW="REPLACE" cause JUMBO to trash the first back and
going 'back' requires it to be recreated.  (This is because the JavaVM
would soon run out of memory).  NULL is different from cache, because it
says that the page will never bee displayed.  (I omitted to say that NULL
would only make sense in the context of AUTO - USER-ACTUATEable buttons
on an invisible component aren't much use.)

> you what files you need to call into cache memory before displaying text
> with AUTO includes, or to avoid delays when a user calls a file that has to
> be called at some point in processing the file. It will normally be a
> precursor to any Extended and Simple links that reference the same files.

We must still remember that GROUP doesn't (yet) have any XML-required
semantics.  Therefore (a) this use will not occur to everyone (b) other
people will overload GROUP with different semantics.  So at present GROUP
is simply a handle, nothing more.

	P.

> ----
> Martin Bryan, The SGML Centre, Churchdown, Glos. GL3 2PU, UK 
> Phone/Fax: +44 1452 714029   WWW home page: http://www.sgml.u-net.com/
> 
> 
> 

-- 
Peter Murray-Rust, domestic net connection
Virtual School of Molecular Sciences
http://www.vsms.nottingham.ac.uk/
Received on Tuesday, 20 May 1997 06:31:01 UTC

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