public RegExpr ParseRegex()
{
var re = new RegExpr();
var follow = new HashSet<TokenType>()
{TokenType.EOF, TokenType.CLOSEGROUP};
do
{
re.Alternatives.Add(ParseAlternative());
} while (SkipIf(TokenType.ALTERNATIVE));
if (!follow.Contains(_ts.Peek().Type))
throw new ParseException();
if (_ts.Peek().Type == TokenType.EOF)
_ts.NextToken();
return re;
}
private void InstantiateFromRegex(RegExpr re)
{
_startState = NewState();
_finishState.Add(NewState());
foreach (var alt in re.Alternatives)
{
var altnfa = new NFAGraph(alt);
CopyInto(altnfa);
var nsl = new NFALink();
var nfl = new NFALink();
nsl.IsEmpty = true;
nfl.IsEmpty = true;
nsl.Target = altnfa._startState;
nfl.Target = _finishState.Single();
_adjList[_startState].Add(nsl);
_adjList[altnfa._finishState.Single()].Add(nfl);
}
}
public NFAGraph(RegExpr reParseTree)
{
InstantiateFromRegex(reParseTree);
}
public Group(RegExpr innerRegExpr)
{
InnerRegExpr = innerRegExpr;
}