Re: [PATCH] Make display-time-mode time zone configurable

[Mark Oteiza <mvoteiza@udel.edu>]

On 16/02/16 at 09:11am, Paul Eggert wrote:
> On 02/16/2016 06:33 AM, W. Greenhouse wrote:
> > Also, as far as parts of Emacs that deal with time zones, there's also
> > `calendar-time-zone', which uses a totally different format (offset in
> > minutes, instead of zoneinfo-style names)! The calendar also seems to
> > NIH the handling of daylight saving time.
> 
> Yes, the calendar code predates the new support for time zones at the lower
> level, and it suffers because of that. For example, if you had started Emacs
> in Cancun last year at 2015-02-01 01:59, its calendar would have been messed
> up, because Cancun changed its clocks a minute later (a time zone change,
> not a daylight-saving change) and Emacs would have cached the wrong standard
> time zone. Eventually we should fix this sort of bug by having the calendar
> code use the new lower-level primitives better....
> 
> > Now that I understand the role of `display-time-string-forms', I can fix
> > the problem for myself there without Mark's proposed defcustom, but the
> > defcustom raises visibility a lot for others who might have the same
> > desired wall-clock configuration as I.
> 
> OK, how about if we wait for others to have problems that cannot be solved
> via display-time-string-forms and deal with the issues that come up then.

Seeing how display-time-string-forms is a bucket of code, I suspect there
are few problems that cannot be solved by changing it.

I would like to see this defcustom be made into something more
manageable. For instance, assimilating its large pieces into their own
functions.  I just went for a less intrusive way to implement the
ZONE feature.