Daylight Savings Time

[Ken Ray]

> This works well for me:
> 
> function DaylightSavingsTimeIsActive
>    local tCurDate,tRefDate
>    -----
>    put the short date into tCurDate
>    convert tCurDate from short date to dateItems
>    put tCurDate into tRefDate
>    repeat with i = 2 to 3
>      put 1 into item i of tRefDate
>      -- January first
>    end repeat
>    convert tRefDate from dateItems to dateItems
>    -- updates last item of dateItems value
>    convert tCurDate from dateItems to seconds
>    convert tRefDate from dateItems to seconds
>    return (tRefDate - tCurDate) mod 86400 = 0
> end DaylightSavingsTimeIsActive

The only trouble with this is that there are some places in the world where
DST is not an hour, but is sometimes 30 minutes or 90 minutes; also, there
are parts of the US, for example, that do not observe DST even though the
rest of the US does - Arizona is an example, so I don't know how this would
run there.

Unfortunately  there isn't a comprehensive way to know if DST is in effect
without knowing *where* the person is who's executing the code (AFAICT).

And of course it gets worse when you're asking for DST in effect for a
specific date and place...

Ken Ray
Sons of Thunder Software, Inc.
Email: kray at sonsothunder.com
Web Site: http://www.sonsothunder.com/