private static IEnumerable <Tuple <bool[], TLetter, bool[]> > GetPWSTransitionsWithLetter <TLetter>(
int n, EpsilonDFA <int, TLetter> epsNFA, TLetter letter)
{
bool[][] reachable = new bool[n][];
for (int i = 0; i < n; i++)
{
var states = epsNFA.ReachableStates(i, letter);
reachable[i] = new bool[n];
foreach (var endState in states)
{
reachable[i][endState] = true;
}
}
foreach (var powerSet in AllStates(n))
{
bool[] endPowerSet = new bool[n];
for (int i = 0; i < n; i++)
{
if (powerSet[i])
{
for (int j = 0; j < n; j++)
{
endPowerSet[j] |= reachable[i][j];//So many things can go wrong here.
}
}
}
yield return(Tuple.Create(powerSet, letter, endPowerSet));
}
}
public static EpsilonDFA <TState, TLetter> KleeneClosure(
EpsilonDFA <TState, TLetter> toRepeat,
Func <TState> getNewState)
{
var onlyNew = getNewState();
var epsilonTransitions =
toRepeat.epsilonTransitions.Concat(
Tuple.Create(onlyNew, toRepeat.startState),
Tuple.Create(toRepeat.finalState, onlyNew));
return(new EpsilonDFA <TState, TLetter>(toRepeat.transitions, epsilonTransitions, onlyNew, onlyNew));
}
public static EpsilonDFA <TState, TLetter> Concatenation(
EpsilonDFA <TState, TLetter> first,
EpsilonDFA <TState, TLetter> second,
Func <TState> getNewState)
{
var epsilonTransitions =
first.epsilonTransitions.Concat(
second.epsilonTransitions).Concat(
Tuple.Create(first.finalState, second.startState));
var transitions = first.transitions.Concat(second.transitions);
return(new EpsilonDFA <TState, TLetter>(transitions, epsilonTransitions,
first.startState, second.finalState));
}
private static EpsilonDFA <TState, TLetter> GetNFA <TState, TLetter>(
IRegExExpressionTree <TLetter> exp, Func <TState> getNewState)
{
switch (exp.Type)
{
case RegExNodeTypes.Letter:
return(EpsilonDFA <TState, TLetter> .Letter(
((Letter <TLetter>)exp).LetterToMatch,
getNewState));
case RegExNodeTypes.EmptyWord:
return(EpsilonDFA <TState, TLetter> .EmptyWord(getNewState));
case RegExNodeTypes.Empty:
return(EpsilonDFA <TState, TLetter> .Empty(getNewState));
case RegExNodeTypes.KleeneClosure:
return(EpsilonDFA <TState, TLetter> .KleeneClosure(
GetNFA(exp.GetChildren().First(), getNewState),
getNewState));
case RegExNodeTypes.Choise:
return(EpsilonDFA <TState, TLetter> .Choise(
GetNFA(exp.GetChildren().First(), getNewState),
GetNFA(exp.GetChildren().Last(), getNewState),
getNewState));
case RegExNodeTypes.Concatenation:
return(EpsilonDFA <TState, TLetter> .Concatenation(
GetNFA(exp.GetChildren().First(), getNewState),
GetNFA(exp.GetChildren().Last(), getNewState),
getNewState));
default:
throw new ArgumentException();
}
}
