public IAcceptWord Reverse() {
var pdat = new PDATransform();
string[] names = new string[this.StatesCount + 1];
//array pointer old to new state
uint[] newstate = new uint[this.StatesCount];
for (uint i = 0; i < newstate.Length; i++) {
newstate[i] = this.StatesCount - i;
names[i + 1] = (newstate[i] - 1).ToString();
}
names[0] = "new";
//turn and add each transform
foreach (var dt in this.Transforms.Reverse())
foreach (var dtv in dt.Value)
pdat.AddM(newstate[dtv.qNext], dt.Key.ci, dt.Key.cw, dtv.cw2, newstate[dt.Key.q]);
//start state is qe, which leads to every old accepted state
for (int i = 0; i < this.AcceptedStates.Length; i++)
pdat.AddM(0, null, null, null, newstate[this.AcceptedStates[i]]);
if (this is StatePDA)
return new StatePDA($"Reverse({Name})", names, this.Alphabet, this.WorkAlphabet, pdat, 0, this.StartSymbol, new uint[] { this.StatesCount });
else if (this is StackPDA)
return new StackPDA($"Reverse({Name})", names, this.Alphabet, this.WorkAlphabet, pdat, 0, this.StartSymbol);
else
throw new System.NotImplementedException();
}
public override IAutomat PurgeStates()
{
(uint[] translate, string[] names, _) = base.RemovedStateTranslateTables();
var newT = new PDATransform();
foreach (var t2 in Transforms)
{
if (translate.Contains(t2.Key.q))
{
foreach (var v in t2.Value)
{
if (translate.Contains(v.qNext))
{
newT.AddM(translate.ArrayIndex(t2.Key.q), t2.Key.ci, t2.Key.cw, v.cw2, translate.ArrayIndex(v.qNext));
}
}
}
}
return(new StackPDA($"{Name}_purged", names, Alphabet, WorkAlphabet, newT, translate.ArrayIndex(StartState), StartSymbol));
}
public static StackPDA GenerateRandom()
{
const byte MAX_STATES = 20;
const byte MAX_CHAR = 7;
var rnd = Uni.Utils.RND;
var t = new PDATransform();
int stateCount = rnd.Next(1, MAX_STATES);
char[] inputAlphabet = new char[rnd.Next(1, MAX_CHAR)];
for (int i = 0; i < inputAlphabet.Length; i++)
{
inputAlphabet[i] = (char)rnd.Next('a', 'z');
}
inputAlphabet = inputAlphabet.Distinct().ToArray();
char[] workAlphabet = new char[rnd.Next(1, MAX_CHAR)];
for (int i = 1; i < workAlphabet.Length; i++)
{
workAlphabet[i] = (char)rnd.Next('a', 'z');
}
workAlphabet[0] = START;
workAlphabet = workAlphabet.Distinct().ToArray();
for (uint i = 0; i < stateCount; i++)
{
int transformsRnd = rnd.Next(0, inputAlphabet.Length);
for (int j = 0; j < transformsRnd; j++)
{
t.AddM(i, inputAlphabet.RndElement(), workAlphabet.RndElement(), workAlphabet.RndElement().ToString(), (uint)rnd.Next(0, stateCount));
}
}
var ret = new StackPDA("SPDA_Random", (uint)stateCount, inputAlphabet, workAlphabet, t, (uint)rnd.Next(0, stateCount), START);
ret.Name = $"SPDA_Random_{ret.GetHashCode()}";
return(ret);
}
public StatePDA(string name, uint StatesCount, char[] InputAlphabet, char[] Workalphabet, PDATransform Transform, uint StartState, char?Startstacksymbol, params uint[] AcceptedStates)
: base(name, StatesCount, InputAlphabet, Workalphabet, Transform, StartState, Startstacksymbol, AcceptedStates)
{
}
public StatePDA(string name, string[] names, char[] InputAlphabet, char[] Workalphabet, PDATransform Transform, uint StartState, params uint[] AcceptedStates)
: base(name, names, InputAlphabet, Workalphabet, Transform, StartState, null, AcceptedStates)
{
}
protected PDA(string name, string[] states, char[] inputAlphabet, char[] workalphabet, PDATransform transform, uint startState, char? startStackSymbol, uint[] acceptedStates)
: base(name, states, inputAlphabet, startState, acceptedStates) {
this.WorkAlphabet = workalphabet;
if (startStackSymbol.HasValue && !workalphabet.Contains(startStackSymbol.Value))
this.WorkAlphabet = this.WorkAlphabet.Append(startStackSymbol.Value).ToArray();
this.Transforms = transform;
this.StartSymbol = startStackSymbol;
CheckConstraints();
}
IAcceptWord JoinConcatUnion(IAcceptWord automat, JoinConcatUnionKind kind) {
if (!(automat is PDA pda2))
throw new System.NotSupportedException();
if (kind != JoinConcatUnionKind.Join && !(automat is StatePDA))
throw new System.NotSupportedException();
if (this is StackPDA || automat is StackPDA)
throw new System.NotImplementedException();
// TODO: investigate more, State PDA is perfect Stack PDA seems complicated
// TODO: what if A1 or A2 has a StackStartsymbol set, should it be transformed
// to a transform or applied
uint offsetA1 = 0; // first state of A2
uint offsetA2 = this.StatesCount; // first state of A2
if (kind == JoinConcatUnionKind.Union) {
offsetA1 = 1;
offsetA2++;
}
char[] inputAlphabet = this.Alphabet.Union(pda2.Alphabet).ToArray();
char[] workAlphabet = this.WorkAlphabet.Union(pda2.WorkAlphabet).ToArray();
var pdat = new PDATransform();
uint startState;
// Union: add new start state, with e to both starts
if (kind == JoinConcatUnionKind.Union) {
startState = 0;
pdat.Add(0, null, null, null, this.StartState + offsetA1);
pdat.AddM(0, null, null, null, pda2.StartState + offsetA2);
} else
startState = this.StartState;
// add each D1 transform + offset of A1
foreach (var item in this.Transforms)
foreach (var val in item.Value)
pdat.AddM(item.Key.q + offsetA1, item.Key.ci, item.Key.cw, val.cw2, val.qNext + offsetA1);
// add each D1 transform, + offset of A2
foreach (var item in pda2.Transforms)
foreach (var val in item.Value)
pdat.AddM(item.Key.q + offsetA2, item.Key.ci, item.Key.cw, val.cw2, val.qNext + offsetA2);
uint[] accStates;
if (kind == JoinConcatUnionKind.Concat)
// Concat: has only accepted states from A2
accStates = new uint[pda2.AcceptedStates.Length];
else
// Join, Union has A1, A2 accpted states
accStates = new uint[this.AcceptedStates.Length + pda2.AcceptedStates.Length];
int i = 0; // store where D1 acc ends
// iterate A1 acc
for (; i < this.AcceptedStates.Length; i++)
if (kind == JoinConcatUnionKind.Concat)
// Concat: lead accepted states from A1 to A2 start
pdat.AddM(this.AcceptedStates[i] + offsetA1, null, null, null, pda2.StartState + offsetA2);
else
// Join, Union: states from A1 are normal accepted
accStates[i] = this.AcceptedStates[i] + offsetA1;
if (kind == JoinConcatUnionKind.Concat)
i = 0;
// iterate A2 acs and + offsetA2
for (int j = 0; j < pda2.AcceptedStates.Length; j++)
accStates[i + j] = (pda2.AcceptedStates[j] + offsetA2);
if (this is StatePDA)
return new StatePDA($"{kind.ToString()}({Name}+{pda2.Name})", this.StatesCount + pda2.StatesCount + offsetA1, inputAlphabet, workAlphabet, pdat, startState, pda2.StartSymbol, accStates);
else if (this is StackPDA)
return new StackPDA($"{kind.ToString()}({Name}+{pda2.Name})", this.StatesCount + pda2.StatesCount + offsetA1, inputAlphabet, workAlphabet, pdat, startState, pda2.StartSymbol);
else
throw new System.NotImplementedException();
}
public StackPDA(string name, string[] states, char[] InputAlphabet, char[] Workalphabet, PDATransform Transform, uint StartState)
: base(name, states, InputAlphabet, Workalphabet, Transform, StartState, null, new uint[] { })
{
}
/// <summary>
/// Create PDA which accepts by empty stack
/// </summary>
/// <param name="StatesCount">How many states</param>
/// <param name="InputAlphabet">Input Alphabet for Word processing</param>
/// <param name="Workalphabet">Work Alphabet for Stack</param>
/// <param name="Transform"></param>
/// <param name="StartState">State from which to start</param>
/// <param name="Startsymbol">Inital Stack Population</param>
public StackPDA(string name, uint StatesCount, char[] InputAlphabet, char[] Workalphabet, PDATransform Transform, uint StartState, char?Startsymbol)
: base(name, StatesCount, InputAlphabet, Workalphabet, Transform, StartState, Startsymbol, new uint[] { })
{
}
