[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: fundamental facets - inquiry from the XMLSchemaWorking Gro
On Sat, 2003-10-11 at 12:56, Liam Quin wrote: > Rick mentioned dates and durations, so I'll say a bit more > about them to show how tricky they are... yes, if you > subtract 20th June, 1837 from 20th July 1837, yuo get either > "a month" or you get 30 days. no - you get 30 days. implicit in specifying the day of the month. it's only a coincidence that they're the same day. this is part of the point i'm trying to make. subtract dates and you get days. now july 1837 - june 1837 is one month. you're subtracting months - these aren't dates. > > If you then add the resulting duration to 30th January, 2003, > you get either 30th February 2003 (probably an error) or you > get nd March 2003, which might or might not be what you wanted. > now there's no error. 30th january + 30 days may or may not be the 29th february (might be 1st march); january 1837 + 1 (month) is february 1837. 30th january + 1 (month) is not defined; but 20th january + 1 (month) is = 20th february. but then we could say + 1month = last day of month if the new month doesn't have enough days. equally for - 1 (month) so with domains we have to be able to be specific - it behaves like a group; it is defined by these rules; by observation for this user exceptions are handled this way... etc rick
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|