diff --git a/alib2common/src/abstraction/OperationAbstraction.hpp b/alib2common/src/abstraction/OperationAbstraction.hpp
index 26cfb5468f8a8da1d6a81cbf546b3110c0548998..c52a7e2e368e6f29909e1416b13ab8734dbf8743 100644
--- a/alib2common/src/abstraction/OperationAbstraction.hpp
+++ b/alib2common/src/abstraction/OperationAbstraction.hpp
@@ -28,6 +28,7 @@ public:
 	virtual bool eval ( ) = 0;
 	virtual unsigned numberOfParams ( ) const = 0;
 	virtual bool cached ( ) const = 0;
+	virtual bool isReady ( ) const = 0;
 
 	virtual ext::type_index getParamTypeIndex ( unsigned index ) const = 0;
 	virtual ext::type_index getReturnTypeIndex ( ) const = 0;
diff --git a/alib2common/src/abstraction/ValueOperationAbstraction.hpp b/alib2common/src/abstraction/ValueOperationAbstraction.hpp
index 1b14620b4771f7fadcec6b41ef9e8c61cba3472c..a08d007f278c202ee55b96b32a1a724a1e461fdf 100644
--- a/alib2common/src/abstraction/ValueOperationAbstraction.hpp
+++ b/alib2common/src/abstraction/ValueOperationAbstraction.hpp
@@ -289,7 +289,7 @@ public:
 		callback ( std::get < Indexes > ( inputs )->getValue ( std::get < Indexes > ( moves ) ) ... );
 	}
 
-	virtual bool isReady ( ) const {
+	virtual bool isReady ( ) const override {
 		return true;
 	}