lib/cartesian.rb in Cartesian-0.2.3 vs lib/cartesian.rb in Cartesian-0.3.0

@@ -136,15 +136,22 @@
   #   1,1,1
   #
   # It also works with Range objects.
   #
   def **(fixnum)
-    return self if fixnum <= 1
-    iter = CartesianIterator.new(self, self)
-    (fixnum-2).times do
-      iter.x(self)
+    if fixnum < 0
+      raise ArgumentError, "power must be non-negative"
+    elsif fixnum == 0
+      return []
+    elsif fixnum == 1
+      return self
+    else
+      iter = CartesianIterator.new(self, self)
+      (fixnum-2).times do
+        iter.x(self)
+      end
+      iter
     end
-    iter
   end
   alias :power! :**
 end
 
 class Array