[Emacs-diffs] emacs/lisp/calc calc.el

[Jay Belanger]

CVSROOT:        /cvsroot/emacs
Module name:    emacs
Changes by:     Jay Belanger <jpb>      09/07/21 18:56:35

Modified files:
        lisp/calc      : calc.el 

Log message:
        (calc-undo-length): New variable.
        (calc-quit): Truncate rather than eliminate `calc-undo-list'.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/emacs/lisp/calc/calc.el?cvsroot=emacs&r1=1.126&r2=1.127

Patches:
Index: calc.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/calc/calc.el,v
retrieving revision 1.126
retrieving revision 1.127
diff -u -b -r1.126 -r1.127
--- calc.el     27 Apr 2009 23:07:21 -0000      1.126
+++ calc.el     21 Jul 2009 18:56:35 -0000      1.127
@@ -417,6 +417,12 @@
   :group 'calc
   :type 'boolean)
 
+(defcustom calc-undo-length 
+  100
+  "The number of undo steps that will be preserved when Calc is quit."
+  :group 'calc
+  :type 'integer)
+
 (defvar calc-bug-address "address@hidden"
   "Address of the maintainer of Calc, for use by `report-calc-bug'.")
 
@@ -1485,7 +1491,14 @@
       (unless (eq major-mode 'calc-mode)
         (calc-create-buffer))
       (run-hooks 'calc-end-hook)
-      (setq calc-undo-list nil calc-redo-list nil)
+      (if (integerp calc-undo-length)
+          (cond
+           ((= calc-undo-length 0)
+            (setq calc-undo-list nil calc-redo-list nil))
+           ((> calc-undo-length 0)
+            (let ((tail (nthcdr (1- calc-undo-length) calc-undo-list)))
+              (if tail (setcdr tail nil)))
+            (setq calc-redo-list nil))))
       (mapc (function (lambda (v) (set-default v (symbol-value v))))
            calc-local-var-list)
       (let ((buf (current-buffer))