main.cs

if (first == "op")
            {
                Expression initialVar = OperationExpression;
                // We have UI access at hand. Assemble the entire access chain.
                foreach (var piece in pieces.Skip(1))
                {
                    var number = -1;
                    try
                    {
                        number = int.Parse(piece);
                        initialVar = Expression.MakeIndex(initialVar, typeof(List<Object>).GetProperty("Item"), new[] { Expression.Constant(number) });
                    }
                    catch (FormatException)
                    {
                        initialVar = Expression.PropertyOrField(initialVar, piece);
                    }
                }
                return initialVar;
            }
            else
            {
                throw new Exception(String.Format("Unkown variable {0}", first));
            }