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Re: <time> values in HTML5

From: Liam R E Quin <liam@w3.org>
Date: Tue, 22 Nov 2011 14:02:11 -0500
To: John Cowan <cowan@mercury.ccil.org>
Cc: tantek@cs.stanford.edu, Jeni Tennison <jeni@jenitennison.com>, www-xml-schema-comments@w3.org, HTML Data Task Force WG <public-html-data-tf@w3.org>, RDFa WG <public-rdfa-wg@w3.org>, public-html-xml@w3.org
Message-ID: <1321988531.15817.95.camel@desktop.barefootcomputing.com>
On Tue, 2011-11-22 at 12:48 -0500, John Cowan wrote:
> Liam R E Quin scripsit:
> 
> > XSD already has date/time types; sometimes an increase in
> > interoperability (here by specifying an additional mapping from a
> > lexical form, probbably) is worth while even at CR.
> 
> I don't think you can add year-and-week just as an additional mapping;
> it is not commensurable with any existing XSD types.

Year-Week-Day can easily map into an existing type, of course, as can
Year-Week, if one takes just the first day of the week as the point to
map.  This loses the intensional information, but XSD does that with
value mappings already. Having said that I agree (having looked more
closely) that a new type would make most sense, and is out of scope for
XSD 1.1.

> > I think adding intensional time would be a significant change, and Mike
> > Kay's idea of a separate document makes sense there.
> 
> >From what I understand, this is not the issue: the issue is that there
> is no XSD type corresponding to a bare time zone offset.  This could be
> treated as an integer type with a range of -24*60 to +24*60.
Yes (again losing information of course).

The bigger aspect is that if the "time" element is there to do iCal-like
work, it needs to represent things like recurring events, and XSD lacks
that concept, and so do the other specs using XSD for their type system,
by and large - not only XPath, XQuery, XSLT, XQueryX, but also various
work in the RDF world, and work outside the w3C such as RelaxNG.

But, even though XSD is at CR, and it's too late to add features such as
new ways of looking at or representing time intervals, that doesn't mean
there is necessarily no useful change to XSD possible, given words and
resources.  One such change might be to have the XSD spec link to a
public registry a bit like the XPointer registry, but for new Schema
types.

This also raises the question, long term, of what to do about future
change requests to XSD after the current WG has closed.

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
Received on Tuesday, 22 November 2011 19:03:51 GMT

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