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RE: ISSUE-126 (Revisit Datatypes): A new proposal for the real <-> float <-> double conundrum

From: Dave Peterson <davep@iit.edu>
Date: Sun, 6 Jul 2008 09:51:57 -0400
Message-Id: <a06240816c4967c3ee258@[192.168.1.100]>
To: Michael Kay <mike@saxonica.com>, "'Alan Ruttenberg'" <alanruttenberg@gmail.com>, "'Rob Shearer'" <rob.shearer@comlab.ox.ac.uk>
Cc: public-webont-comments@w3.org, public-owl-wg@w3.org, www-xml-schema-comments@w3.org

At 10:13 AM +0100 2008-07-06, Michael Kay wrote:
>  >
>>  I don't see that moments in time, segments of time, and
>>  repeating intervals make up a sensible datatype.  That's my
>>  particular problem with the idea. 
>
>Well, one can certainly conceive of a generalization of these types that is
>a three-dimensional space whose axes are the start instant (perhaps
>unknown), the duration (perhaps zero), and the interval between repeats
>(perhaps infinite). Alternatively, and perhaps more conveniently, you can
>think of it as a seven-dimensional space containing year, month, day, hour,
>minute, second, and timezone-offset, allowing components at either end to be
>omitted, where the absence of a high-order component indicates a repeating
>interval and the absence of a low-order component indicates a time span.
>
>E.g., how does one define order?  Is 14:00:00 less than or equal to 1997?
>
>You could define an ordering (if you wanted to) by filling in the gaps,
>treating 14:00:00 as say 0000-01-01T14:00:00 and 1997 as
>1997-01-01T00:00:00. Or you could say that the new primitive type is
>unordered, only the subtypes are ordered, as we do with the two duration
>subtypes.
>>
>>  I'm curious how the simplification would be effected for QT.
>
>Difficult to do retrospectively, but with such a type, instead of XSLT
>defining three functions format-date, format-time, and format-dateTime, it
>could have defined a single function which would work perfectly well on all
>eight types, as well as on other logically-consistent subtypes like
>gHourMinute.

Good ideas all.  Fodder for Schema 2.0, I'd say.  It takes time to
think these things out; equality didn't diverge from identity in 1.0
because we didn't have time to think out the ramifications.  Sigh--
even standards creation is a publish-or-perish world, and if a version
of the standard doesn't get out the door in a reasonable time, even
if the possible improvements haven't been thought out yet, the
creating standards group finds its resources gone and no standard
at all gets out.

One does the best one can, and hopes one hasn't closed off too many
useful possibilities for the next round--or left things totally
screwed up by not closing up some loopholes that leave the standard
useless.  A fine balancing act.

(This, of course, is preaching to the choir WRT Mike Kay himself;
he's been involved in the production of at least several standards.)
-- 
Dave Peterson
SGMLWorks!

davep@iit.edu
Received on Sunday, 6 July 2008 13:52:49 GMT

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