Standardise Guile simple example

Changes so that it works the same as other language modules

Examples/guile/simple/example.c

@@ -1,21 +1,18 @@
-/* Simple example from documentation */
 /* File : example.c */
 
-#include <time.h>
+/* A global variable */
+double Foo = 3.0;
 
-double My_variable = 3.0;
-
-int fact(int n) {
-  if (n <= 1) return 1;
-  else return n*fact(n-1);
+/* Compute the greatest common divisor of positive integers */
+int gcd(int x, int y) {
+  int g;
+  g = y;
+  while (x > 0) {
+    g = x;
+    x = y % x;
+    y = g;
+  }
+  return g;
 }
 
-int mod(int n, int m) {
-  return (n % m);
-}
 
-char *get_time() {
-  long ltime;
-  time(&ltime);
-  return ctime(&ltime);
-}

Examples/guile/simple/example.i

@@ -5,10 +5,8 @@
 %}
 
 %inline %{
-extern double My_variable;
-extern int    fact(int);
-extern int    mod(int n, int m);
-extern char  *get_time();
+extern int    gcd(int x, int y);
+extern double Foo;
 %}
 
 %include guile/guilemain.i

Examples/guile/simple/runme.scm

@@ -3,24 +3,20 @@
   (for-each display args)
   (newline))
 
-(mdisplay-newline (get-time) "My variable = " (My-variable))
+; Call our gcd() function
 
-(do ((i 0 (1+ i)))
-    ((= 14 i))
-  (mdisplay-newline i " factorial is " (fact i)))
+(define x 42)
+(define y 105)
+(define g (gcd x y))
+(mdisplay-newline "The gcd of " x " and " y " is " g)
 
-(define (mods i imax j jmax)
-  (if (< i imax)
-      (if (< j jmax)
-          (begin
-            (My-variable (+ (My-variable) (mod i j)))
-            (mods i imax (+ j 1) jmax))
-          (mods (+ i 1) imax 1 jmax))))
+; Manipulate the Foo global variable
 
-(mods 1 150 1 150)
+; Output its current value
+(mdisplay-newline "Foo = " (Foo))
 
-(mdisplay-newline "My-variable = " (My-variable))
-
-(exit (and (= 1932053504 (fact 13))
-           (= 745470.0 (My-variable))))
+; Change its value
+(Foo 3.1415926)
 
+; See if the change took effect
+(mdisplay-newline "Foo = " (Foo))