Calendar style: no yyyy/mm/dd variant ? (enhancement request)

[Edward Welbourne]

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In GNU Emacs 21.2.1 (i386-debian-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2002-03-22 on raven, modified by Debian
configured using `configure  i386-debian-linux-gnu --prefix=/usr 
--sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib 
--infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes --with-x=yes 
--with-x-toolkit=athena --without-gif'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

The info on calendar style tells me about the default American style
(in which the most and least significant digits are in the middle and
adjacent to one another) and the optional European style (with a
sawtooth pattern of variation of significance of digits) but not the
style where the significance of digits varies monotonically with
position - as used by the Japanese (and the ISO date format ?) and
anyone who wants to use dates in filenames and have ls list them in
chronological order - year, month, day !

Since adding a japanese-calendar-style variable to set t would merely
create confusion when someone manages to have both it and
european-calendar-style set, might I humbly suggest a new variable
called calendar-date-style (or just date-style, since it'd ideally be
honoured by other things than calendar and diary - maybe even dired
mode ;-) whose value is:

  * "USA" for USA date style
  * "Europe" for European date style
  * "Japan" (and "ISO" if my memory is right) for yyyy mon dd
  * nil (its default value) for fallback; will be "Europe" if
    european-calendar-style is set, else "USA" (for compatibility with
    status quo)

oh, and test case-insensitively !  For bonus marks, allow values
consisting of the three letters M, D and Y (once each) to specify
arbitrary order; "MDY" = "USA", "DMY" = "Europe", "YMD" = "Japan",
etc. - but perhaps that's a little ambitious; and, besides, that's
half the *possible* variants already :^>

Then again, maybe it implies a nice implementation ?

Recent input:
n <tab> <return> M-> M-{ M-{ C-n C-k C-k C-k ( C-x 
o C-s e u r o p C-s C-s C-s M-b C-SPC M-f M-f M-f C-b 
M-w C-x o s e t q SPC C-y C-h v <return> SPC t ) C-x 
C-e M-b M-b C-h v <return> C-x o C-x k <return> C-x 
o C-x C-s C-x o u u u u l q C-h C-v C-h C-v C-h v e 
u r <tab> c a l <tab> s <tab> <return> C-x o C-x k 
<return> C-x o M-x r e p o <tab> r <tab> <return>

Recent messages:
Type C-x 4 b RET to restore the other window.  C-M-v to scroll the help.
t
Wrote /home/eddy/.sys/elisp/init.el
unzipping emacs-21.gz...done
unzipping emacs-1.gz...done
unzipping emacs.gz...done
unzipping emacs-1.gz...done
Type C-x 4 b RET to restore the other window.  C-M-v to scroll the help.
Making completion list...
Loading emacsbug...done