Re: Making decoded-times and calendar dates compatible?

[Richard Stallman <rms@gnu.org>]

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  > If we changed them to use a format like, say,
  >   (YEAR MONTH DAY)
  > and 
  >   (YEAR MONTH DAY DOW HOUR MINUTE SECOND DST TZ)
  > respectively, changing the relevant accessors, then calendar arithmetic
  > functions could also work effortlessly with [the date part of] decoded
  > times,

In principle it sounds like a good idea, but I think that the
incompatibility might be a big pain to fix.  Doesn't some user code
have to operate on those formats?

I wonder also if calendar.el was designed to be compatible with
something in Unix that existed before GNU Emacs.  But I wasn't the
one who wrote it, so I wouldn't know.

One possible way to make the incompatible change less of a pain to
cope with would be to use a list like

  (calendar YEAR MONTH DAY)

in caledar.el.  The presence of the synbol `calendar' would say "this
date uses the new format", thus avoiding ambiguity of the datum.
There would still need to be a lot of change, but at least it would be
easier to be sure you found all the places that had to be changed.

-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)