@Override
    public FunctionNode clone() {
        FunctionNode obj = (FunctionNode)super.clone();
        if (result != null) {
            obj.result = (ResultNode)result.clone();
        }
        return obj;
    }
This abstract expression node represents a function to execute.

@author baldersheim
@author Simon Thoresen Hult
searchlib/src/main/java/com/yahoo/searchlib/expression/FunctionNode.java