public static GroupedState GetEpsilonClosureFromState(Automata automata, State targetState, GroupedState aggregatedState = null)
{
if (targetState is GroupedState)
{
return(GetAggregatedEpsilonClosureFromStates(
automata, ((GroupedState)targetState).GetSubStates().ToList()
));
}
else
{
// spontaneous transitions from target state
var transitionsFromState = automata.GetTransitionsFromState(
automata.GetStateLike(targetState), Automata.SYMBOL_SPONTANEOUS_TRANSITION
);
// spontaneously (directly) reachable states from target state
var reachableStates = transitionsFromState.Select(x => x.To).ToList();
// epsilon closure includes current state
reachableStates.Add(targetState);
// aggregate spontaneously reachable states to a single state
if (aggregatedState == null)
{
aggregatedState = new GroupedState(reachableStates);
}
else
{
aggregatedState.AddSubStates(reachableStates);
}
// aggregate spontaneously reachable
// child states to our state recursively
if (reachableStates.Count > 1)
{
reachableStates.ForEach(
x => {
if (x != targetState)
{
aggregatedState.AddSubState(
GetEpsilonClosureFromState(
automata, x, aggregatedState
)
);
}
}
);
}
return(aggregatedState);
}
}
public static State DeepCloneState(State state)
{
State clonedState = null;
if (state is GroupedState)
{
clonedState = new GroupedState(
((GroupedState)state).GetSubStates()
);
}
else
{
clonedState = new State(state.Name, state.IsFinal);
}
return(clonedState);
}
public static GroupedState GetAggregatedEpsilonClosureFromStates(Automata automata, List <State> targetStates)
{
GroupedState aggregatedState = null;
targetStates.ForEach(
x => {
var epsilon = GetEpsilonClosureFromState(automata, x);
if (aggregatedState == null)
{
aggregatedState = new GroupedState(epsilon.GetSubStates());
}
else
{
aggregatedState.AddSubStates(epsilon.GetSubStates());
}
}
);
return(aggregatedState);
}
public static Tuple <List <GroupedState>, List <Transition> > GetEpsilonTuple(
Automata automata,
State currentState = null,
GroupedState currentEpsilon = null,
Tuple <List <GroupedState>, List <Transition> > aggregatedValues = null
)
{
// init our tuple
if (aggregatedValues == null)
{
aggregatedValues = new Tuple <List <GroupedState>, List <Transition> >(
new List <GroupedState>(),
new List <Transition>()
);
}
var aggregatedStates = aggregatedValues.Item1;
var aggregatedTransitions = aggregatedValues.Item2;
// defining first state
if (currentState == null)
{
currentState = automata.GetInitialState();
}
// defining the current epsilon
if (currentEpsilon == null)
{
currentEpsilon = GetEpsilonClosureFromState(
automata, currentState
);
}
// aggregate initial epsilon
if (aggregatedStates == null)
{
aggregatedStates = new List <GroupedState>();
}
if (!AggregatedStateListContainsStateLike(aggregatedStates, currentEpsilon))
{
aggregatedStates.Add(currentEpsilon);
// find more epsilons and aggregate them recursively
foreach (var symbol in automata.GetSymbols())
{
var epsilonCandidates = new List <State>();
// get all states found consuming the symbol
// from every subState in our epsilon
currentEpsilon.GetSubStates().ToList().ForEach(
x => epsilonCandidates.AddRange(
automata.GetTransitionsFromState(
x, symbol
).Select(t => t.To)
)
);
if (epsilonCandidates.Count > 0)
{
var aggregatedCandidates = new GroupedState(epsilonCandidates);
var aggregationEpsilon = GetEpsilonClosureFromState(
automata, aggregatedCandidates
);
aggregatedTransitions.Add(new Transition(
currentEpsilon, symbol, aggregationEpsilon
));
// aggregate new epsilons recursively
GetEpsilonTuple(
automata,
aggregatedCandidates,
aggregationEpsilon,
aggregatedValues
);
}
}
}
return(aggregatedValues);
}
