Factorial macro example.

resources/examples/factorial_macro.c3

@@ -0,0 +1,16 @@
+macro int factorial($n)
+{
+    $if ($n == 0):
+        return 1;
+    $else:
+        return $n * @factorial($n - 1);
+    $endif;
+}
+
+extern func void printf(char *fmt, ...);
+
+func void main()
+{
+    int x = @factorial(12);
+    printf("12! = %d\n", x);
+}