calc-mode.el (calc-set-simplify-mode): Use `cond' instead of nested `if's.

lisp/ChangeLog

+2012-08-01  Jay Belanger  <jay.p.belanger@gmail.com>
+
+	* calc/calc-mode.el (calc-set-simplify-mode): Use `cond' instead
+	of nested `if's.
+
 2012-08-01  Glenn Morris  <rgm@gnu.org>
 	* progmodes/autoconf.el (autoconf-definition-regexp):

lisp/calc/calc-mode.el

@@ -497,11 +497,11 @@
 
 (defun calc-set-simplify-mode (mode arg msg)
   (calc-change-mode 'calc-simplify-mode
-		    (if arg
-			(and (> (prefix-numeric-value arg) 0)
-			     mode)
-		      (and (not (eq calc-simplify-mode mode))
-			   mode)))
+                    (cond
+                     (arg mode)
+                     ((eq calc-simplify-mode mode)
+                      'alg)
+                     (t mode)))
   (message "%s" (if (eq calc-simplify-mode mode)
 	       msg
 	     "Algebraic simplification occurs by default")))