public RegExp(string regex)
{
RegExp regExp = String2Regex(new RegExp(), regex);
Operator = regExp.Operator;
Terminals = regExp.Terminals;
Left = regExp.Left;
Right = regExp.Right;
}
public RegExp Dot(RegExp e2)
{
RegExp result = new RegExp();
result.Operator = OperatorEnum.Dot;
result.Left = this;
result.Right = e2;
return(result);
}
public static void Execute(RegExp regExp)
{
// Convert regex to ndfa
Console.WriteLine();
Console.WriteLine("----- Converting regex to ndfa -----");
Automaat <string> ndfa = ThompsonConstruction.ConvertRegExp(regExp);
foreach (Transition <string> transition in ndfa.Transitions)
{
Console.WriteLine(transition.ToString());
}
Console.WriteLine("Printing image");
GraphVizParser.PrintGraph(ndfa, "ndfa");
Console.WriteLine("Image saved as ndfa.jpg");
// Convert ndfa to dfa
Console.WriteLine();
Console.WriteLine("----- Converting ndfa to dfa -----");
Automaat <string> dfa = NdfaToDfaConverter.Convert(ndfa);
foreach (Transition <string> transition in dfa.Transitions)
{
Console.WriteLine(transition.ToString());
}
Console.WriteLine("Printing image");
GraphVizParser.PrintGraph(dfa, "dfa");
Console.WriteLine("Image saved as dfa.jpg");
// Optimizing dfa Brzozowski
Console.WriteLine();
Console.WriteLine("----- Optimizing dfa: Brzozowski's algorithm -----");
Automaat <string> brzozowskiDfa = NdfaToDfaConverter.OptimizeDfa(dfa);
foreach (Transition <string> transition in brzozowskiDfa.Transitions)
{
Console.WriteLine(transition.ToString());
}
Console.WriteLine("Printing image");
GraphVizParser.PrintGraph(brzozowskiDfa, "BrzozowskiDfa");
Console.WriteLine("Image saved as BrzozowskiDfa.jpg");
// Optimize dfa Hopcroft
Console.WriteLine();
Console.WriteLine("----- Optimizing dfa: Hopcroft's algorithm -----");
Automaat <string> hopcroftDfa = HopcroftAlgorithm.MinimizeDfa(dfa);
foreach (Transition <string> transition in hopcroftDfa.Transitions)
{
Console.WriteLine(transition.ToString());
}
Console.WriteLine("Printing image");
GraphVizParser.PrintGraph(hopcroftDfa, "HopcroftDfa");
Console.WriteLine("Image saved as HopcroftDfa.jpg");
}
public static void Plus(RegExp regExp, ref Automaat <string> automaat, ref int stateCounter, int leftState, int rightState)
{
int stateTwo = stateCounter;
int stateThree = stateCounter + 1;
stateCounter = stateCounter + 2;
automaat.AddTransition(new Transition <string>(leftState.ToString(), '$', stateTwo.ToString()));
automaat.AddTransition(new Transition <string>(stateThree.ToString(), '$', stateTwo.ToString()));
automaat.AddTransition(new Transition <string>(stateThree.ToString(), '$', rightState.ToString()));
Convert(regExp.Left, ref automaat, ref stateCounter, stateTwo, stateThree);
}
public static Automaat <string> ConvertRegExp(RegExp regExp)
{
Automaat <string> automaat = new Automaat <string>();
automaat.DefineAsStartState("0");
automaat.DefineAsFinalState("1");
int stateCounter = 2;
Convert(regExp, ref automaat, ref stateCounter, 0, 1);
automaat.Symbols = new SortedSet <char>(automaat.Transitions.Distinct().Select(e => e.Symbol).ToList());
//Epsilon should not be in alphabet
automaat.Symbols.Remove('$');
return(automaat);
}
public static void Or(RegExp regExp, ref Automaat <string> automaat, ref int stateCounter, int leftState, int rightState)
{
int state2 = stateCounter;
int state3 = stateCounter + 1;
int state4 = stateCounter + 2;
int state5 = stateCounter + 3;
stateCounter = stateCounter + 4;
automaat.AddTransition(new Transition <string>(leftState.ToString(), '$', state2.ToString()));
automaat.AddTransition(new Transition <string>(leftState.ToString(), '$', state4.ToString()));
automaat.AddTransition(new Transition <string>(state3.ToString(), '$', rightState.ToString()));
automaat.AddTransition(new Transition <string>(state5.ToString(), '$', rightState.ToString()));
Convert(regExp.Left, ref automaat, ref stateCounter, state2, state3);
Convert(regExp.Right, ref automaat, ref stateCounter, state4, state5);
}
public RegExp String2Regex(RegExp regex, string stringToRegex)
{
for (int index = 0; index < stringToRegex.Length; index++)
{
char currentChar = stringToRegex[index];
if (currentChar == '(')
{
int closingBracketPosition = -1;
int bracketCount = 0;
for (int i = index + 1; i < stringToRegex.Length; i++)
{
if (stringToRegex[i] == '(')
{
bracketCount++;
}
if (stringToRegex[i] == ')' && bracketCount == 0)
{
closingBracketPosition = i;
break;
}
if (stringToRegex[i] == ')' && bracketCount != 0)
{
bracketCount--;
}
}
string between = stringToRegex.Substring(index + 1, closingBracketPosition - 1 - index);
RegExp regExp = String2Regex(new RegExp(), between);
if (closingBracketPosition + 1 < stringToRegex.Length)
{
index = closingBracketPosition + 1;
currentChar = stringToRegex[index];
if (currentChar == '+')
{
regExp = regExp.Plus();
}
else if (currentChar == '*')
{
regExp = regExp.Star();
}
}
if (regex.Terminals == "" && regex.Operator == RegExp.OperatorEnum.One)
{
regex = regExp;
}
else
{
regex = regex.Dot(regExp);
}
}
else if (currentChar == '+')
{
regex = regex.Plus();
}
else if (currentChar == '*')
{
regex = regex.Star();
}
else if (currentChar == '|')
{
regex = regex.Or(new RegExp(stringToRegex[index + 1].ToString()));
index++;
}
else
{
if (regex.Terminals == "" && regex.Operator == RegExp.OperatorEnum.One)
{
regex.Terminals = currentChar.ToString();
}
else
{
regex = regex.Dot(new RegExp(currentChar.ToString()));
}
}
}
return(regex);
}
