1 files changed, 17 insertions, 16 deletions
diff --git a/gcd.lisp b/gcd.lisp
index 4bf5840..8899491 100644
--- a/gcd.lisp
+++ b/gcd.lisp
@@ -1,29 +1,30 @@
 ; SYNOPSIS:
 ; # clisp gcd.lisp 11 22 33 121
+; # ecl --shell gcd.lisp  121 22 33
+; # gcl -f gcd.lisp 121 22 33
 ; # sbcl --script gcd.lisp 121 22 33
-;
 
 (defun gcd2 (a b)
-  (if (= b 0)
-    a 
-    (gcd2 b (mod a b))))
+  (loop while (/= b 0) do
+    (psetq a b b (mod a b))
+    finally (return a)))
 
-(defun gcdn (&rest numbers)
-  (reduce #'gcd2 (rest numbers)
-          :initial-value (first numbers)))
+(defun gcdn (n &rest ns)
+  (reduce #'gcd2 ns :initial-value n))
 
-; Command line access is different on different Lisps
 (defun program-args ()
   (or
-   #+SBCL (rest *posix-argv*)
    #+CLISP *args*
-   ;#+ECL (ext:command-args)
-   ;#+CMU extensions:*command-line-words*
-   ;#+LISPWORKS system:*line-arguments-list*
+   #+ECL   (cdr ext:*unprocessed-ecl-command-args*)
+   #+GCL   (cdr si::*command-args*)
+   #+SBCL  (cdr *posix-argv*)
    nil))
 
-(write (apply #'gcdn 
-              (map 'list #'parse-integer (program-args))
-              ))
-(fresh-line)
+(defun numbers ()
+  (mapcar #'parse-integer (program-args)))
+
+(let ((ns (numbers)))
+  (when ns
+    (write (apply #'gcdn ns))
+    (fresh-line)))