[Emacs-diffs] Changes to emacs/lisp/calculator.el,v

[Jay Belanger]

CVSROOT:        /cvsroot/emacs
Module name:    emacs
Changes by:     Jay Belanger <jpb>      07/07/04 04:17:21

Index: calculator.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/calculator.el,v
retrieving revision 1.26
retrieving revision 1.27
diff -u -b -r1.26 -r1.27
--- calculator.el       11 Feb 2007 01:14:59 -0000      1.26
+++ calculator.el       4 Jul 2007 04:17:21 -0000       1.27
@@ -278,7 +278,7 @@
     ("IC" acos (D (acos X))    x  6)
     ("IT" atan (D (atan X))    x  6)
     ("Q"  sqrt sqrt            x  7)
-    ("^"  ^    expt            2  7)
+    ("^"  ^    calculator-expt 2  7)
     ("!"  !    calculator-fact x  7)
     (";"  1/   (/ 1 X)         1  7)
     ("_"  -    -               1  8)
@@ -596,7 +596,8 @@
 `+' and `-' can be used as either binary operators or prefix unary
 operators.  Numbers can be entered with exponential notation using `e',
 except when using a non-decimal radix mode for input (in this case `e'
-will be the hexadecimal digit).
+will be the hexadecimal digit).  If the result of a calculation is too
+large (out of range for Emacs), the value of \"inf\" is returned.
 
 Here are the editing keys:
 * `RET' `='      evaluate the current expression
@@ -1779,13 +1780,43 @@
        (car calculator-last-opXY) (nth 1 calculator-last-opXY) x))
     x))
 
+(defun calculator-integer-p (x)
+  "Non-nil if X is equal to an integer."
+  (condition-case nil
+      (= x (ftruncate x))
+    (error nil)))
+
+(defun calculator-expt (x y)
+  "Compute X^Y, dealing with errors appropriately."
+  (condition-case
+      nil
+      (expt x y)
+    (domain-error 0.0e+NaN)
+    (range-error
+     (if (> y 0) 
+         (if (and
+              (< x 0)
+              (= y (truncate y))
+              (oddp (truncate y)))
+             -1.0e+INF
+           1.0e+INF)
+       0.0))
+    (error 0.0e+NaN)))
+
 (defun calculator-fact (x)
   "Simple factorial of X."
+  (if (and (>= x 0)
+           (calculator-integer-p x))
+      (if (= (calculator-expt (/ x 3.0) x) 1.0e+INF)
+          1.0e+INF
   (let ((r (if (<= x 10) 1 1.0)))
     (while (> x 0)
       (setq r (* r (truncate x)))
       (setq x (1- x)))
     (+ 0.0 r)))
+    (if (= x 1.0e+INF)
+        x
+      0.0e+NaN)))
 
 (defun calculator-truncate (n)
   "Truncate N, return 0 in case of overflow."