scan.cs

 public IEnumerable<Token> Scan(IEnumerable<char> source)
        {
            var currentState = StatesTable.States[StatesTable.InitialState];
            string currentValue = "";
            var enumerator = source.GetEnumerator();

            bool @continue = enumerator.MoveNext();
            while (@continue)
            {
                var c = enumerator.Current;
                if (currentState.GoTo.ContainsKey(c))
                {
                    currentState = StatesTable.States[currentState.GoTo[c]];
                    currentValue += c;
                    @continue = enumerator.MoveNext();
                    if (!@continue)
                    {
                        if (currentState.ResultingTokenId != null)
                        {
                            var result = new Token(currentState.ResultingTokenId, currentValue);
                            yield return result;
                            currentState = StatesTable.States[StatesTable.InitialState];
                            currentValue = "";
                        }
                        else
                        {
                            throw new ArgumentException("Invalid source", "source");
                        }
                    }
                }
                else if (currentState.ResultingTokenId != null)
                {
                    var result = new Token(currentState.ResultingTokenId, currentValue);
                    yield return result;
                    currentState = StatesTable.States[StatesTable.InitialState];
                    currentValue = "";
                }
                else
                {
                    throw new ArgumentException("Invalid source", "source");
                }
            }
        }