bug#13411: 24.2.91; Sorting in Buffer Menu Mode

[Aaron S. Hawley]

The old Buffer Menu Mode would sort only on 4 columns:

 M-x buffer-menu -- sort by display time
 M-2 M-x Buffer-menu-sort -- sort by name
 M-3 M-x Buffer-menu-sort -- sort by size (ascending)
 M-4 M-x Buffer-menu-sort -- sort by mode
 M-5 M-x Buffer-menu-sort -- sort by file name
 M-x Buffer-menu-sort -- go back to sorting by display time

The new Bufer Menu Mode can sort on 7 fields:

 M-x buffer-menu -- sort by display time
 M-0 M-x Buffer-menu-sort -- sort by current buffer (there is none!)
 M-1 M-x Buffer-menu-sort -- sort by read-only
 M-2 M-x Buffer-menu-sort -- sort by modification flag
 M-3 M-x Buffer-menu-sort -- sort by name
 M-4 M-x Buffer-menu-sort -- sort by size (descending)
 M-5 M-x Buffer-menu-sort -- sort by mode
 M-6 M-x Buffer-menu-sort -- sort by file name
 M-x Buffer-menu-sort -- sort by the column at point

Repeating any of these twice reverses the order.  If sorting by size
descending, then sorting by size again switches to ascending.

I can live with these changes except for one:  How do I disable
sorting so that it goes back to the default order of buffer-list?  The
only way to do is to kill the buffer for Buffer Menu and run C-x C-b
to reopen it.

 M-x buffer-menu -- update the list, but keep the sort
 C-x k RET M-x buffer-menu -- go back to sorting by display time

Maybe it could with the M-0 argument since it's not being used.  Or
maybe a M-- argument since negative columns don't exist?  Although,
with 7 columns to remember now, maybe sorting the second to last
column with M-- M-2 should be available.

Otherwise looking forward to Emacs 24.3!
aaron

-- 
In general, we reserve the right to have a poor
memory--the computer, however, is supposed to
remember!  Poor computer.  -- Guy Lewis Steele Jr.