public override NFAModel ConvertAlternationCharSet(AlternationCharSetExpression exp)
{
NFAState head = new NFAState();
NFAState tail = new NFAState();
//build edges
NFAModel charSetNfa = new NFAModel();
charSetNfa.AddState(head);
HashSet <int> classesSet = new HashSet <int>();
foreach (var symbol in exp.CharSet)
{
int cclass = CompactCharSetManager.GetCompactClass(symbol);
if (classesSet.Add(cclass))
{
var symbolEdge = new NFAEdge(cclass, tail);
head.AddEdge(symbolEdge);
}
}
charSetNfa.AddState(tail);
//add an empty entry edge
charSetNfa.EntryEdge = new NFAEdge(head);
charSetNfa.TailState = tail;
return(charSetNfa);
}
public override NFAModel ConvertStringLiteral(StringLiteralExpression exp)
{
NFAModel literalNfa = new NFAModel();
NFAState lastState = null;
foreach (var symbol in exp.Literal)
{
var symbolState = new NFAState();
int cclass = CompactCharSetManager.GetCompactClass(symbol);
var symbolEdge = new NFAEdge(cclass, symbolState);
if (lastState != null)
{
lastState.AddEdge(symbolEdge);
}
else
{
literalNfa.EntryEdge = symbolEdge;
}
lastState = symbolState;
literalNfa.AddState(symbolState);
}
literalNfa.TailState = lastState;
return(literalNfa);
}
public override NFAModel ConvertEmpty(EmptyExpression exp)
{
NFAState tail = new NFAState();
NFAEdge entryEdge = new NFAEdge(tail);
NFAModel emptyNfa = new NFAModel();
emptyNfa.AddState(tail);
emptyNfa.TailState = tail;
emptyNfa.EntryEdge = entryEdge;
return(emptyNfa);
}
public override NFAModel ConvertSymbol(SymbolExpression exp)
{
NFAState tail = new NFAState();
int cclass = CompactCharSetManager.GetCompactClass(exp.Symbol);
NFAEdge entryEdge = new NFAEdge(cclass, tail);
NFAModel symbolNfa = new NFAModel();
symbolNfa.AddState(tail);
symbolNfa.TailState = tail;
symbolNfa.EntryEdge = entryEdge;
return(symbolNfa);
}
public override NFAModel ConvertKleeneStar(KleeneStarExpression exp)
{
var innerNFA = Convert(exp.InnerExpression);
var newTail = new NFAState();
var entry = new NFAEdge(newTail);
innerNFA.TailState.AddEmptyEdgeTo(newTail);
newTail.AddEdge(innerNFA.EntryEdge);
var kleenStarNFA = new NFAModel();
kleenStarNFA.AddStates(innerNFA.States);
kleenStarNFA.AddState(newTail);
kleenStarNFA.EntryEdge = entry;
kleenStarNFA.TailState = newTail;
return(kleenStarNFA);
}
internal void AddEdge(NFAEdge edge)
{
CodeContract.RequiresArgumentNotNull(edge, "edge");
m_outEdges.Add(edge);
}