- From: Paul Prescod <papresco@calum.csclub.uwaterloo.ca>
- Date: Thu, 12 Sep 1996 20:24:16 -0400 (EDT)
- To: Michael Sperberg-McQueen <U35395@UICVM.CC.UIC.EDU>
- Cc: Martin Bryan <mtbryan@sgml.u-net.com>, W3C SGML Working Group <w3c-sgml-wg@w3.org>
At 02:37 PM 9/12/96 CDT, Michael Sperberg-McQueen wrote:
>It's also easily thinkable that XML processing tools could provide all
>the functionality that make Bob Streich want to keep marked sections.
>We might want to have marked sections in XML, I don't know. But we
>don't *have* to have them, just because they currently provide essential
>function. It's the function that's essential, not the construct of the
>marked section. If we can find another way of providing that essential
>function, we don't need the marked section.
Do people really need conditional markup? Or are they really interested in
conditionally _displayed_ markup. If the latter, style sheets could be used.
For instance, here's a graceful mechanism for migrating tables into an
HTML-like XML instance:
<TABLES.DEFINED><TABLE>...</TABLE></TABLES.DEFINED>
<NO.TABLES.DEFINED><PRE>...</PRE>
In a style sheet (in a bizarre syntax similar to my current programming
language), you could have something like:
TABLES.DEFINED(){
if (!FEATURE_SUPPORTED(<TABLE>) )
return NULL;
else
return process_children();
}
NO.TABLES.DEFINED(){
if( FEATURE_SUPPORTED( <TABLE> ) )
return NULL;
else
return process_children();
}
Personally, I have never needed to use marked sections in instances for
anything other than conditional display. I do use them often in DTDs,
however. Maybe that's an argument against having DTDs be SGML instances.
Would "XML DTD-instances" themselves have a modifiable DTD that would allow
me to introduce these sorts of conditionals?
Paul Prescod
Received on Thursday, 12 September 1996 20:25:40 UTC