RE: XSD 1.1 issue: when did timezones cease being durations?

Sorry, the word "stored" was used unintentionally.  Shd have used "represented".

All the best, Ashok
 

> -----Original Message-----
> From: Dave Peterson [mailto:davep@iit.edu] 
> Sent: Tuesday, March 01, 2005 12:52 PM
> To: C. M. Sperberg-McQueen
> Cc: Ashok Malhotra; W3C XML Schema Comments list; W3C XML Schema IG
> Subject: RE: XSD 1.1 issue: when did timezones cease being durations?
> 
> At 3:25 PM -0500 050301, C. M. Sperberg-McQueen wrote:
> 
> >  > If that means you've stored one integer that is a multiple of 60 
> > between
> >>  -50400 and 50400, rather than storing one integer between 
> -840 and 
> >> 840,  then we're quite close--I don't see that it matters 
> much.  But 
> >> a  dayTimeDuration value is not an integer, it's a pair of 
> integers.  
> >> Is  that really what you want to store?
> >
> >Who's talking about storage?
> 
> RTFM.  At 11:22 AM -0800 050301, Ashok Malhotra wrote:
> 
> >2.  F&O changed it behavior as of this morning.  The 
> timezone component 
> >is now stored as a dayTimeDuration e.g.  PT5h30m.
> 
> Returning to your msg:
> 
> >You mention a bug found earlier in the idea that timezone 
> information 
> >is a duration; at the risk of replowing well known ground, can you 
> >remind the rest of us of what it was?
> 
> RTFM again, dammit!
> 
> At 2:10 PM -0500 050301, I wrote:
> 
> >THE REASON THEY WERE CHANGED IS SIMPLE:  TIMEZONES ARE NOT 
> THE SAME AS 
> >DURATIONS--THEY DON'T BEHAVE THE SAME WAY.  CALLING THEM 
> DURATIONS JUST 
> >BECAUSE THEY ARE SIMILAR TO DURATIONS IS WISHFUL THINKING.  
> TIMEZONES 
> >ARE NO MORE DURATIONS THAN FLOATS ARE DECIMALS.
> >
> >There are four things critical to timezones:  the lexical 
> mapping, the 
> >canonical mapping, the value itself, and the algorithm for 
> adding them 
> >to and subtracting them from dateTime values.
> >
> >Of these, the only thing that they *can* have in common with is the 
> >value.  Since timezones aren't really durations, what point 
> is there in 
> >replacing an integer-valued property with one whose value is 
> a pair of 
> >integers, one of which is required to be zero?
> >
> >Pretending a timezone is a duration will--obviously--not 
> confuse people 
> >into thinking that you use duration lexical representations for 
> >timezones.  People know better.  But it will confuse 
> implementers who 
> >will think that they can get correct results using the duration 
> >addition-to-dateTimes algorithm.
> >
> >This error was discovered early in the development of the 7-property 
> >model, and was corrected a long time ago by ceasing to pretend that 
> >timezones are duration.
> >
> >Must we replow this ground?
> 
> --
> Dave Peterson
> SGMLWorks!
> 
> davep@iit.edu
> 
>

Received on Tuesday, 1 March 2005 21:20:13 UTC