private NDFA <string> Dot(RegEx expression, NDFA <string> automata, ref int stateCounter)
{
Convert(expression.leftExp, automata, ref stateCounter);
Convert(expression.rightExp, automata, ref stateCounter);
return(automata);
}
private NDFA <string> Or(RegEx expression, NDFA <string> automata, ref int stateCounter)
{
int firstState = stateCounter + 1;
int secondState = stateCounter + 2;
int startState = stateCounter;
stateCounter++;
automata.addTransition(new Transition <string>(startState.ToString(), '$', stateCounter.ToString()));
Convert(expression.leftExp, automata, ref stateCounter);
int endFirst = stateCounter;
stateCounter++;
automata.addTransition(new Transition <string>(startState.ToString(), '$', stateCounter.ToString()));
Convert(expression.rightExp, automata, ref stateCounter);
int endSecond = stateCounter;
stateCounter++;
automata.addTransition(new Transition <string>(endFirst.ToString(), '$', stateCounter.ToString()));
automata.addTransition(new Transition <string>(endSecond.ToString(), '$', stateCounter.ToString()));
return(automata);
}
public RegEx Star()
{
RegEx result = new RegEx();
result.op = Operator.STAR;
result.leftExp = this;
return(result);
}
public RegEx Plus()
{
RegEx result = new RegEx();
result.op = Operator.PLUS;
result.leftExp = this;
return(result);
}
public static RegEx getExample1() //aaa of bba
{
RegEx exp1 = new RegEx("aaa");
RegEx exp2 = new RegEx("bba");
RegEx exp3 = exp1.Or(exp2);
return(exp3);
}
public static RegEx getExample4()
{
RegEx exp1 = new RegEx("aaa");
RegEx exp2 = new RegEx("bba");
RegEx exp3 = exp1.Dot(exp2.Star());
return(exp3);
}
public RegEx Dot(RegEx exp2)
{
RegEx result = new RegEx();
result.op = Operator.DOT;
result.leftExp = this;
result.rightExp = exp2;
return(result);
}
private NDFA <string> One(RegEx expression, NDFA <string> automata, ref int stateCounter)
{
foreach (char characther in expression.exp)
{
automata.addTransition(new Transition <string>(stateCounter.ToString(), characther, (stateCounter + 1).ToString()));
stateCounter++;
}
return(automata);
}
public static RegEx getExample2() //begind met bbaba of een of meerdere keren aa gevolgd 0 of meerdere keren bba
{
RegEx exp1 = new RegEx("bbaba");
RegEx exp2 = new RegEx("aa");
RegEx exp3 = new RegEx("bba");
RegEx exp4 = exp1.Or(exp2.Plus());
RegEx exp5 = exp4.Dot(exp4.Star());
return(exp5);
}
public static RegEx getExample3()
{
RegEx exp1 = new RegEx("ababa");
RegEx exp2 = new RegEx("baba");
RegEx exp3 = exp1.Dot(exp2);
RegEx exp4 = new RegEx("aaa");
RegEx exp5 = new RegEx("bb");
RegEx exp6 = exp4.Or(exp3.Plus());
RegEx exp7 = exp6.Dot(exp6.Plus());
return(exp7);
}
public bool Equals(RegEx other)
{
if (other == null)
{
return(false);
}
else if (this.ToString() == other.ToString() && this.exp == other.exp && this.op == other.op && this.leftExp == other.leftExp && this.rightExp == other.rightExp)
{
return(true);
}
else
{
return(false);
}
}
private NDFA <string> Plus(RegEx expression, NDFA <string> automata, ref int stateCounter)
{
int startState = stateCounter;
stateCounter++;
int secondState = stateCounter;
automata.addTransition(new Transition <string>(startState.ToString(), '$', secondState.ToString()));
Convert(expression.leftExp, automata, ref stateCounter);
automata.addTransition(new Transition <string>(stateCounter.ToString(), '$', secondState.ToString()));
automata.addTransition(new Transition <string>(stateCounter.ToString(), '$', (stateCounter + 1).ToString()));
stateCounter++;
return(automata);
}
private NDFA <string> Convert(RegEx expression, NDFA <string> automata, ref int stateCounter)
{
switch (expression.op)
{
case Operator.ONE:
return(One(expression, automata, ref stateCounter));
case Operator.OR:
return(Or(expression, automata, ref stateCounter));
case Operator.DOT:
return(Dot(expression, automata, ref stateCounter));
case Operator.STAR:
return(Star(expression, automata, ref stateCounter));
case Operator.PLUS:
return(Plus(expression, automata, ref stateCounter));
}
return(null);
}