- From: Michael Kay <mike@saxonica.com>
- Date: Sun, 6 Jul 2008 10:13:35 +0100
- To: "'Dave Peterson'" <davep@iit.edu>, "'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>
> > 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. Michael Kay http://www.saxonica.com/
Received on Sunday, 6 July 2008 09:14:14 UTC