public void Remove(String str)
 {
     if (namedTokens.Keys.Contains(str) && !(namedTokens[str].constant || IsReservedWord(str)))
     {
         FunctionDefiner.RemoveFromList(str);
         var t = namedTokens[str];
         namedTokens.Remove(str);
         t.token.TokenName = "";
     }
 }
 public void RemoveAll()
 {
     foreach (string str in namedTokens.Keys)
     {
         if (!(IsConstant(str) || IsReservedWord(str)))
         {
             FunctionDefiner.RemoveFromList(str);
         }
     }
     foreach (var t in namedTokens)
     {
         t.Value.token.TokenName = "";
     }
     namedTokens.Clear();
     SetConstants();
     AddToken(new Token(TokenType.Vector, "ans", new double[] { double.NaN }), false);
 }