only.rb in facets-3.0.0

- old
+ new

@@ -15,12 +15,23 @@
   #
   # CREDIT: Gavin Sinclair, Noah Gibbs
 
   def only
     unless size == 1
-      raise IndexError, "Array#only called on non-single-element array"
+      raise IndexError, "not the only element of array"
     end
     first
   end
 
+  # Does this Array have only one element?
+  # 
+  # TODO: While clearly this goes along with the regular #only method,
+  # the name doesn't seem quite right. Perhaps rename to #lonely.
+  #
+  # CREDIT: Lavir the Whiolet
+  #
+  def only?
+    size == 1
+  end
+ 
 end
 