diff --git a/source/Commands/CommandObjectExpression.h b/source/Commands/CommandObjectExpression.h
index 5ddb0db..fcf308a 100644
--- a/source/Commands/CommandObjectExpression.h
+++ b/source/Commands/CommandObjectExpression.h
@@ -29,7 +29,7 @@
     {
     public:
 
-        CommandOptions ();
+        CommandOptions (CommandInterpreter &interpreter);
 
         virtual
         ~CommandOptions ();