On Sat, Nov 9, 2024 at 6:36 PM Arthur A. Gleckler <xxxxxx@speechcode.com> wrote:

> This brings to mind a question of representation I have been pondering.  I have a personal calendar written in Scheme that I use to track all my appointments, daily activities, etc.  It allows me to specify an event's time zone, and does the proper translation based on where I am at the moment.  However, sometimes I want an event to happen at, for example, 9pm no matter where in the world I happen to be.  That means that the appropriate time zone is a variable, not a constant.  Is there a standard way to represent such a time?

ISO-8601 calls this a "local time", and, of course, defines a syntax
for it. An example of local time in ISO-8601 syntax is: "21:00"

Other kind of times in 8601 are UTC times, example: "21:00Z";
and times with a time zone attached, example: "21:00-05"

I would recommend a system compatible with ISO-8601 (terminologically,
syntatically, and philosophically)

Cheers