;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001
;;        David J. Biesack

;; This file is not part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; sum up the values in a column of integers

;; Author: David Biesack (David.Biesack@sas.com  or biesack@mindspring.com)
;; Last Modified By: biesack@mindspring.com
;; Last Modified: Thu Mar 15 17:42:16 2001

(defvar *column-sum* 0 "Result of last \\[column-sum]")

(defun column-sum (start end arg)
  "Compute and print in minibuffer the sum of the numbers
in the column delimited by START and END. Result is stored
in the elisp variable *column-sum*. With an ARG, the
result is inserted into the buffer."
  (interactive "r\nP")
  (copy-rectangle-to-register ?S start end)
  (let ((sum (get-buffer-create " *Column-Sum*")))
    (save-excursion
      (set-buffer sum)
      (erase-buffer)
      (insert "(setq *column-sum* \(+ \n")
      (insert-register ?S)
      (end-of-buffer)
      (insert "\)\)")
      (eval-last-sexp 1))
    (and arg (insert " (" (int-to-string *column-sum*) ") "))
    (message "Sum: %d" *column-sum*)))

; 1
; 2
; 23
; 3
; 23
; 43
; -43
; 43