/// <summary>
 /// Initialization
 /// </summary>
 protected void Init()
 {
     update = () =>
     {
         foreach (FormulaMeasurement m in measurements)
         {
             m.Update();
         }
     };
     creator = VariableDetector.GetCreator(this);
 }
        IOperationAcceptor IVariableDetector.Detect(MathSymbol sym)
        {
            string key = sym.String;

            if (key.Length > 1)
            {
                return(null);
            }
            if (!(sym is SimpleSymbol))
            {
                return(null);
            }
            SimpleSymbol ss = sym as SimpleSymbol;

            if (!ss.Italic)
            {
                return(null);
            }
            if (acc.ContainsKey(key))
            {
                return(acc[key]);
            }
            return(VariableDetector.Detect(sym, acc));
        }