/// <summary>
/// Builds an automaton equivalent to the regex s[0]s[1] ... s[r.Length-1],
/// returns the automaton accepting only the empty word when s is empty.
/// </summary>
public Automaton <S> MkSeq(params S[] s)
{
if (s.Length == 0)
{
return(MkEmptyWord());
}
bool start = isBeg;
bool end = isEnd;
//sequence of characters
//string sequence = node._str;
int count = s.Length;
//bool ignoreCase = ((node._options & RegexOptions.IgnoreCase) != 0);
int initialstate = nodeId;
nodeId = nodeId + count + 1;
int finalstate = initialstate + count;
int[] finalstates = new int[] { finalstate };
var moves = new List <Move <S> >();
for (int i = 0; i < count; i++)
{
moves.Add(Move <S> .Create(initialstate + i, initialstate + i + 1, s[i]));
}
Automaton <S> res = Automaton <S> .Create(this.solver, initialstate, finalstates, moves);
res.isDeterministic = true;
if (start) //may start with any characters
{
res.AddMove(Move <S> .Create(initialstate, initialstate, solver.True));
res.isDeterministic = false;
}
if (end) //may end with any characters
{
res.AddMove(Move <S> .Create(finalstate, finalstate, solver.True));
}
res.isEpsilonFree = true;
return(res);
}
private Automaton <S> MakeKleeneClosure(Automaton <S> sfa)
{
if (sfa.IsEmpty || sfa.IsEpsilon)
{
return(this.epsilon);
}
if (sfa.IsKleeneClosure())
{
return(sfa);
}
if (sfa.DoesNotContainWordBoundaries && sfa.InitialStateIsSource && sfa.HasSingleFinalSink)
{
//common case, avoid epsilons in this case
//just destructively make the final state to be the initial state
sfa.RenameInitialState(sfa.FinalState);
return(sfa);
}
int origInitState = sfa.InitialState;
if (!sfa.IsFinalState(sfa.InitialState))//the initial state is not final
{
if (sfa.InitialStateIsSource)
{
//make the current initial state final
sfa.MakeInitialStateFinal();
}
else
{
//add a new initial state that is also final
sfa.AddNewInitialStateThatIsFinal(this.MkStateId());
}
}
//add epsilon transitions from final states to the original initial state
foreach (int state in sfa.GetFinalStates())
{
if (state != sfa.InitialState && state != origInitState)
{
sfa.AddMove(Move <S> .Epsilon(state, origInitState));
}
}
//epsilon loops might have been created, remove them
var sfa1 = sfa.RemoveEpsilonLoops();
if (!sfa.DoesNotContainWordBoundaries)
{
sfa1.AddWordBoundaries(sfa.EnumerateWordBoundaries());
}
return(sfa1);
}
