Hallo,

I've been messing about with getting tables to display formula results
as for instance 30,00.00: two-place floating-point precision, and commas
grouping digits. I realize I can set these as the defaults in
org-calc-default-modes, but I wanted to alter the table formula format
string to allow per-field formatting.

I made a small edit to org-table.el, which you can see in the attached
patch. It assigns the key "G" to add "calc-group-digits t" to the front
of org-tbl-calc-modes.

I think it's uncovered a bug: it only works if I already have
"calc-group-digits" present in org-calc-default-modes, because of the
end of org-set-calc-mode:

#+BEGIN_SRC emacs-lisp
(if (memq var org-tbl-calc-modes)
      (setcar (cdr (memq var org-tbl-calc-modes)) value)
    (cons var (cons value org-tbl-calc-modes)))
  org-tbl-calc-modes)
#+END_SRC

If the mode is already present (with any value), it is set. If it's not,
it's consed onto org-tbl-calc-modes, the resulting new list is
jettisoned into the ether, and the original value of org-tbl-calc-modes
is returned. I think it would have to look like this to work:

#+BEGIN_SRC emacs-lisp
(if (memq var org-tbl-calc-modes)
    (progn
       (setcar (cdr (memq var org-tbl-calc-modes)) value)
       org-tbl-calc-modes)
  (cons var (cons value org-tbl-calc-modes))))
#+END_SRC

I'm not terribly confident about this, but perhaps someone could take a
look?

Thanks,
Eric