Timezones
tblanchard at mac.com
tblanchard at mac.com
Mon May 5 16:25:47 UTC 2003
On Monday, May 5, 2003, at 04:33 AM, Daniel Vainsencher wrote:
>> My personal pet desire is to get some kind of date/time/timezone thing
>> in there so you could have a couple squeaks on machines in different
>> locations and still have coordinated time. The ansi fixes on squeak
>> map provide a fairly simple mechanism - I'd like to see them adopted.
>> The timezone database is probably a more complete solution, but the
>> current Timestamp that downloads with SqueakMap is not solution at all
>> because its naive about time zones.
> A review of all the different solutions by someone interested,
> explaining the trade offs about adding them to the image vs. keeping
> them as packages, would probably help. Note that we do have an
> add-to-the-image-aversion, since we'd rather be making it smaller, not
> bigger, but something might get in IF it is the simplest solution that
> could possibly work, and the current solutions is really just broken
> (whether most of us notice or not).
>
Yeah, I've done quite a lot of looking at solutions (I want to write a
program that *schedules* things and thus this is kind of a core need
for me.
Of the solutions I know of we have:
1) Timestamp (you get it with SqueakMap and maybe Seaside, and some
other things). It is a class that is simply a date/time pair. It has
no concept of timezone/UTC. Thus I find it inadequate.
2) TimezoneDatabase - this is amazingly complete - it reads the unix
timezone database - can pull it into memory, understands daylight
savings time shifts and compensates. The primary date/time class is
PointInTime. Its pretty elaborate - but potentially large.
3) TimezoneDatabase with TimeStamp is the code in 2 - plus the
timestamp in 1 reimplemented in terms of 2.
4) ANSI package on SM provides DateAndTime which has a notion of a
single timezone with offset from UTC and some info (that you have to
give it for initialization) on when to switch from daylight time to
standard time. It is probably the simplest that that could possibly
work and if ansi-fication is any kind of goal, probably the best choice.
I hope this is useful.
-Todd Blanchard
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