public void Concat(NFA second)
{
Finish.Translations.Add(new Translation(second.Initial, Translation.Eps)); // Соединяем первый финиш и второе начало по ε
Finish = second.Finish; // Сохраняем новый финиш
Size = UpdateStates(); // Обновляем номера состояний
}
public void Alter(NFA second)
{
State newFinish = new State(1, new List <Translation>()); // Создаем новый финиш
Finish.Translations.Add(new Translation(newFinish, Translation.Eps)); // Добавляем старому финишу первого автомата переход в новый
second.Finish.Translations.Add(new Translation(newFinish, Translation.Eps)); // Добавляем старому финишу второго автомата переход в новый
Finish = newFinish; // Сохраняем новый финиш на место старого
State oldInit = Initial; // Сохраняем старое начало
Initial = new State(0, new List <Translation>()
{
new Translation(oldInit, Translation.Eps),
new Translation(second.Initial, Translation.Eps)
}); // Создаем новое начало с двумя ε переходами в данные автоматы
Size = UpdateStates(); // Обновляем номера состояний
}
public static NFA ToNFA(string postfix)
{
Stack <NFA> nfas = new Stack <NFA>();
CharEnumerator c = postfix.GetEnumerator();
while (c.MoveNext())
{
if (char.IsLetterOrDigit(c.Current))
{
nfas.Push(new NFA(c.Current));
}
else if (c.Current == '.')
{
NFA b = nfas.Pop();
NFA a = nfas.Pop();
a.Concat(b);
nfas.Push(a);
}
else if (c.Current == '|')
{
NFA b = nfas.Pop();
NFA a = nfas.Pop();
a.Alter(b);
nfas.Push(a);
}
else if (c.Current == '*')
{
nfas.Peek().Star();
}
else if (c.Current == '+')
{
nfas.Peek().Plus();
}
}
return(nfas.Pop());
}
public static void Main(string[] args)
{
//List<char> alphabet = Enumerable.Range('a', 'z' - 'a' + 1).Select(i => (Char) i).ToList();
List <char> alphabet = Enumerable.Range('a', 'b' - 'a' + 1).Select(i => (Char)i).ToList();
//alphabet = alphabet.Concat(Enumerable.Range('0', '9' - '0' + 1).Select(i => (Char) i)).ToList();
List <char> epsAlphabet = alphabet.Concat(new char[] { 'ε' }.ToList()).ToList();
GraphVizBuilder graphViz = new GraphVizBuilder();
// Read valid regexp
Console.WriteLine("Enter RegExp to build FA:");
string regexp = Console.ReadLine();
// Preprocess regexp (adding dots where concatenating)
string processedRegexp = Preprocess(regexp);
// Process regexp to postfix
string postfixRegexp = ToPostfix(processedRegexp);
// Building NFA in graph from postfix regexp
NFA nfa = ToNFA(postfixRegexp);
var nfaTable = nfa.BuildTable(epsAlphabet); // Building NFA in table from graph
// Draw NFA
string graphNFA = graphViz.BuildString(epsAlphabet, nfaTable, nfa.Initial.S, new List <int>()
{
nfa.Finish.S
});
graphViz.CreateGraph(graphNFA, "nfa.png");
// Building DFA from NFA
DFA dfa = new DFA(nfaTable, alphabet, epsAlphabet.IndexOf(Translation.Eps), nfa.Initial.S, nfa.Finish.S);
string graphDFA = graphViz.BuildString(alphabet, dfa.DFATable, dfa.Initial, dfa.Finish);
graphViz.CreateGraph(graphDFA, "dfa.png");
//R
dfa.Reverse();
string graphDFAr = graphViz.BuildString(dfa.Alphabet, dfa.DFATable, dfa.Initial, dfa.Finish);
graphViz.CreateGraph(graphDFAr, "dfa_r.png");
//RD
dfa.MakeDfa();
string graphDFArd = graphViz.BuildString(dfa.Alphabet, dfa.DFATable, dfa.Initial, dfa.Finish);
graphViz.CreateGraph(graphDFArd, "dfa_rd.png");
//RDR
dfa.Reverse();
string graphDFArdr = graphViz.BuildString(dfa.Alphabet, dfa.DFATable, dfa.Initial, dfa.Finish);
graphViz.CreateGraph(graphDFArdr, "dfa_rdr.png");
//RDRD
dfa.MakeDfa();
string graphDFArdrd = graphViz.BuildString(dfa.Alphabet, dfa.DFATable, dfa.Initial, dfa.Finish);
graphViz.CreateGraph(graphDFArdrd, "dfa_rdrd.png");
while (true)
{
Console.WriteLine("Enter word to check allowness:");
string word = Console.ReadLine();
if (word == "`")
{
break;
}
// Model FA for given word
bool res = dfa.Model(word, alphabet);
Console.WriteLine($"Result: {res}\n");
}
}
