// Returns the list of all accepting states of an automaton.
private static List <DfaState <TSymbol> > GetAllAcceptingStates(Dfa <TSymbol> dfa)
{
var result = new List <DfaState <TSymbol> >();
var queue = new Queue <DfaState <TSymbol> >();
var visited = new HashSet <DfaState <TSymbol> >();
visited.Add(dfa.Start);
queue.Enqueue(dfa.Start);
while (queue.Count > 0)
{
var state = queue.Dequeue();
if (state.Accepting > 0)
{
result.Add(state);
}
foreach (var kv in state.Transitions)
{
var nextState = kv.Value;
if (!visited.Contains(nextState))
{
visited.Add(nextState);
queue.Enqueue(nextState);
}
}
}
return(result);
}
public Grammar(TSymbol start, IDictionary <TSymbol, IProduction <TSymbol>[]> productions)
{
Start = start;
Productions = productions;
WhichProduction = new Dictionary <uint, IProduction <TSymbol> >();
Automatons = new Dictionary <TSymbol, Dfa <TSymbol> >();
// Here we prepare automatons for each symbol.
uint productionMarker = 1;
foreach (var symbolProductions in Productions)
{
var automatons = new List <Lexer.DfaUtils.MinimizedDfa <TSymbol> >();
foreach (var production in symbolProductions.Value)
{
automatons.Add(Dfa <TSymbol> .RegexDfa(production.Rhs, productionMarker));
WhichProduction[productionMarker] = production;
productionMarker++;
}
Automatons[symbolProductions.Key] = Dfa <TSymbol> .ProductDfa(automatons.ToArray());
}
Nullable = GrammarUtils <TSymbol> .ComputeNullable(Automatons);
First = GrammarUtils <TSymbol> .ComputeFirst(Automatons, Nullable);
Follow = GrammarUtils <TSymbol> .ComputeFollow(Automatons, Nullable, First);
SymbolListLeftRecursion = GrammarUtils <TSymbol> .HasLeftRecursion(Automatons, Nullable);
TargetStatesDictionary = GrammarUtils <TSymbol> .computeTargetStatesDictionary(Automatons);
AccStateOwnerDictionary = GrammarUtils <TSymbol> .computeAccStateOwnerDictionary(Automatons);
}
