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Re: List Type Delimiter?

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 06 Feb 2001 16:47:46 +0000
To: "Richard Rathmann" <Richard.Rathmann@noaa.gov>
Cc: www-xml-schema-comments@w3.org
Message-ID: <f5bu267vjv1.fsf@cogsci.ed.ac.uk>
"Richard Rathmann" <Richard.Rathmann@noaa.gov> writes:

> I recently read through the Primer CR and skimmed through parts of the
> Structures and Datatype CRs.  I then decided to attempt converting the
> XHTML 1.0 DTD to a schema to try and get some hands-on experience of how
> to use schemas myself.
> 
> One concern I came across in the process deals, in particular, with
> "MediaDesc" parameter entity content for the "media" attributes of the
> <link> and <style> elements.  The possible value space for this
> attribute is described as a "single or comma-separated list of media
> descriptors."  However, this datatype can not be represented with the
> current definition of a list composite datatype, as the atomic items in
> the list are delimited by commas rather than by whitespace.
> 
> If an optional "delimiter" attribute, which might default to whitespace,
> was added to list datatype declarations, the "MediaDesc" datatype could
> then be described with a list datatype declaration and a comma
> delimiter.

Sorry that XHTML chose to introduce a non-XML datatype (lists in XML,
in so far as they are supported at all by XML 1.0, only allow whitespace
delimeters).

The issue of microparsing, of which delimiters is an example, was
discussed at length at the end of Last Call, and the WG's decision not 
to go there was upheld by the Director.

I recommend the Last Call issues list public version [1] for more
information on this.

ht

[1] http://www.w3.org/2000/05/12-xmlschema-lcissues.html#list-sep
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Tuesday, 6 February 2001 11:47:53 GMT

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