Arithmetic operations on dates ?

[SimPLsol at aol.com]

Sorry Michael,
     Your dateItems script is logical - it just will not work reliably with 
Revolution - because... 
Some days in Rev. start at 1 am, most start at 2 am, and even 3 am. This is 
again related to the crazy way Rev. handles daylight saving time. Also Rev. 
does not convert 2005,2,29, etc. to 2005,3,1 etc.
     There are requests in Revzilla for almost two years now to get some kind 
of usable date and time functions. Personally I'd settle for "absolute 
seconds" where every day has 86400 seconds. So far no word from the Mother Ship. I'm 
sure that these anomalies are causing problems for programmers who would 
never consider that the length of a day varies because of how local time is 
displayed - and there is nothing in the documentation to warn them.
     I have a script which will give accurate past and future dates but the 
original question concerned things like "the last 17 hours" - I don't know how 
to do that reliably in Revolution.
Sincerely,
Paul Looney