/// <summary>
/// creates a new PDA in normal form: for every transition is the maximum number of pushed stack-symbols 2
/// and no Epsilon-Transition does push any stack-symbols
/// </summary>
/// <param name="pda"></param>
/// <returns></returns>
public static PDA <A, StackSymbolSequence <S> > ToNormalForm(PDA <A, S> pda)
{
Assertion.Assert(pda.Deterministic, "the normal form can only be created for deterministic PDAs, but the given is not");
var res = new PDA <A, StackSymbolSequence <S> >(pda.AcceptanceCondition, true, new StackSymbolSequence <S>(pda.FirstStackSymbol), pda.InitialState.Final, new List <StackSymbolSequence <S> >()
{
});
AddStatesToPDA(pda, res);
AddTransitionsToPDA(pda, res);
CorrectEpsilonTransitions(res);
res.HasNormalForm();
return(res);
}
public void ToSDAInNormalFormTest()
{
var dpda = new PDA <char, char>(new AcceptanceCondition.EmptyStack(), true, 'Z', false, "ZA");
dpda.AddState(1, false);
dpda.HasNormalForm();
dpda.AddTransition().From(0).To(0).Read('a').Pop('Z').Push("AZ");
dpda.AddTransition().From(0).To(0).Read('a').Pop('A').Push("AA");
dpda.AddTransition().From(0).To(1).Read('b').Pop('A').Push("A");
dpda.AddTransition().From(1).To(1).Read('c').Pop('A').Push();
dpda.AddTransition().From(1).To(1).Read().Pop('Z').Push();
var symbols = new Dictionary <string, TripleStackSymbol <char> >()
{
{ "0A1", new TripleStackSymbol <char>(0, 'A', 1) },
{ "0Z1", new TripleStackSymbol <char>(0, 'Z', 1) },
{ "1A1", new TripleStackSymbol <char>(1, 'A', 1) }
};
var exp = new SDA <char, TripleStackSymbol <char> >(symbols.Values);
exp.AddTransition('a', symbols["0Z1"], new TripleStackSymbol <char>[] { symbols["0A1"] });
exp.AddTransition('a', symbols["0A1"], new TripleStackSymbol <char>[] { symbols["0A1"], symbols["1A1"] });
exp.AddTransition('b', symbols["0A1"], new TripleStackSymbol <char>[] { symbols["1A1"] });
exp.AddTransition('c', symbols["1A1"]);
var act = DPDAInNormalFormToSDAConverter <char, char> .ToSDAInNormalForm(dpda).sda;
Assert.IsTrue(exp.Equals(act));
var actPDA = act.ToPDA(symbols["0Z1"]);
actPDA.CreateRunner();
dpda.CreateRunner();
var equalityResult = new PDAEqualityResult <char, TripleStackSymbol <char> >(dpda, actPDA, "abc", 7, 300000, 3000);
Assert.IsTrue(equalityResult.AreEqual);
var actDeterminisedSDA = DeterminisedSDA <char, TripleStackSymbol <char> > .FromSDAInNormalForm(act);
actDeterminisedSDA.CalculateShortestWordsOfStackSymbols();
Assert.IsTrue(actDeterminisedSDA.ShortestWordsOfStackSymbols[symbols["1A1"]].SequenceEqual("c"));
Assert.IsTrue(actDeterminisedSDA.ShortestWordsOfStackSymbols[symbols["0A1"]].SequenceEqual("bc"));
Assert.IsTrue(actDeterminisedSDA.ShortestWordsOfStackSymbols[symbols["0Z1"]].SequenceEqual("abc"));
}