[FIX] Various fixes for Celeste

Lex Spoon lex at cc.gatech.edu
Wed Nov 24 09:59:15 UTC 1999


Tim Rowledge <rowledge at interval.com> wrote:
> On Tue 23 Nov, Lex Spoon wrote:
> 
> > I keep hoping someone will jump up who understands time zones and
> > calendrial calculations and such and implement something in Squeak that
> > can be easily ported around.
> Oh my, that's a _lot_ to hope for! At PPS some years ago we had a
> multi-day mailstorm about timezone stuff that generated enough hot air
> to send Branson across the Atlantic. Conclusion: it's _damn_
> complicated. Basically you need a way to read the time and your
> machine's timezone, plus a way to convert from one TZ to another.
> 
> The good news is that by now all the OS's we use have at least some
> understanding of timezones, where back then many didn't. I don't suppose
> there is a website that offers zone/time conversion ? It may well be
> simplest to pass the job off to a server somewhere.
> Some timezones have a partial hour offset.
> Some have wierd rules for daylight savings time start/stop.
> Some appear to have no 'rules' - IIRC, UK DST is set on a year by year
> basis.
> Some have many names.
> Ugh.
> 

Hmm, okay, it would be kind of a shame to have 10k lines of code
floating around the smalltalk image just to deal with this one issue. 
Though it's always nice to have things that are quietly Done Right, it's
also nice to have code proportional to the benefit you get from it.

Maybe to get started, we should simply add a "localtime" primitive to
Squeak, which returns a tuple of both the global (GMT) time, and an
offset from it to get to local time?  This would avoid a lot of
conversion messes, and constrained platforms could simply implement the
local-time offset as a constant somewhere.  There is already a basic
dateAndTimeFromSeconds: implementation in class Time, so maybe this
primitive would take us a long way.

What do ya'll think?

Lex





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