On Mon, Jan 13, 2003 at 01:00:54PM -0800, Yitzchak Scott-Thoennes wrote: > On Mon, 13 Jan 2003 13:55:17 -0600 (CST), [EMAIL PROTECTED] wrote: > > > >> So, this sounds like something very high level, which shouldn't be > >> considered part of the base object. But.. it is needed for really > >> low-level operations, like ->add(). For example: > >> > >> 19700328T233000 + 4 hours = ?? > >> > >> You'd think 19700329T033000. And you'd be right most of the time, > >> but not if that time was a Europe/Amsterdam time. Then, it'd > >> be 19700329T043000. > > > >The base object will need to _have_ a DateTime::TimeZone object. It will > >not _be_ one. > > > >> So, I think we need to either put all of this inside the base object, > >> or make the base object do UTC only. > > > >The base object will probably do UTC only for all math and so on, and the > >internal representation should probably be fixed to UTC. > > > >Then the data-returning methods can adjust the returned value based on the > >timezone object that the base object has. > > The base object should have the option of not being tied to any > particular timezone, even UTC, so that the data-returning methods do > no adjustment. For instance, if I take my wife out to dinner at 7PM > on our anniversary every year, I do so at that local time whether we > are in Seattle or Baltimore. > One of the flaws of Date::ICal has been > that it has a particular timezone and can't represent this kind of > date (pun intended). The iCalendar spec calls this a "floating" time > and differentiates it from a UTC time or a time w/timezone (or a date > without a time). Actually, I recently discovered that Date::ICal _does_ support this. if you do $date->ical (localtime => 1) it prints the time adjusted for the local timezone.
Floating time *still* has a timezone. It is just variable. But, since your computer can be in only one spot, it is never ambiguous which timezone it is in. The only time you need this floating timezone is when storing your date (to disk, in a VEVENT, whatever). So Date::ICal doesn't really do anything wrong, it just could be a bit more friendly about it. Like remembering if this was entered as a floating time. Martijn
