protected internal virtual IToken GetMissingSymbol(Parser recognizer)
{
IToken currentSymbol = recognizer.CurrentToken;
IntervalSet expecting = GetExpectedTokens(recognizer);
int expectedTokenType = expecting.GetMinElement();
// get any element
string tokenText;
if (expectedTokenType == TokenConstants.Eof)
{
tokenText = "<missing EOF>";
}
else
{
tokenText = "<missing " + recognizer.TokenNames[expectedTokenType] + ">";
}
IToken current = currentSymbol;
IToken lookback = ((ITokenStream)recognizer.InputStream).Lt(-1);
if (current.Type == TokenConstants.Eof && lookback != null)
{
current = lookback;
}
return(ConstructToken(((ITokenStream)recognizer.InputStream).TokenSource, expectedTokenType
, tokenText, current));
}
private static int OptimizeSets(ATN atn, bool preserveOrder)
{
if (preserveOrder)
{
// this optimization currently doesn't preserve edge order.
return(0);
}
int removedPaths = 0;
IList <DecisionState> decisions = atn.decisionToState;
foreach (DecisionState decision in decisions)
{
IntervalSet setTransitions = new IntervalSet();
for (int i = 0; i < decision.NumberOfOptimizedTransitions; i++)
{
Transition epsTransition = decision.GetOptimizedTransition(i);
if (!(epsTransition is EpsilonTransition))
{
continue;
}
if (epsTransition.target.NumberOfOptimizedTransitions != 1)
{
continue;
}
Transition transition = epsTransition.target.GetOptimizedTransition(0);
if (!(transition.target is BlockEndState))
{
continue;
}
if (transition is NotSetTransition)
{
// TODO: not yet implemented
continue;
}
if (transition is AtomTransition || transition is RangeTransition || transition is
SetTransition)
{
setTransitions.Add(i);
}
}
if (setTransitions.Size() <= 1)
{
continue;
}
IList <Transition> optimizedTransitions = new List <Transition>();
for (int i_1 = 0; i_1 < decision.NumberOfOptimizedTransitions; i_1++)
{
if (!setTransitions.Contains(i_1))
{
optimizedTransitions.Add(decision.GetOptimizedTransition(i_1));
}
}
ATNState blockEndState = decision.GetOptimizedTransition(setTransitions.GetMinElement
()).target.GetOptimizedTransition(0).target;
IntervalSet matchSet = new IntervalSet();
for (int i_2 = 0; i_2 < setTransitions.GetIntervals().Count; i_2++)
{
Interval interval = setTransitions.GetIntervals()[i_2];
for (int j = interval.a; j <= interval.b; j++)
{
Transition matchTransition = decision.GetOptimizedTransition(j).target.GetOptimizedTransition
(0);
if (matchTransition is NotSetTransition)
{
throw new NotSupportedException("Not yet implemented.");
}
else
{
matchSet.AddAll(matchTransition.Label);
}
}
}
Transition newTransition;
if (matchSet.GetIntervals().Count == 1)
{
if (matchSet.Size() == 1)
{
newTransition = new AtomTransition(blockEndState, matchSet.GetMinElement());
}
else
{
Interval matchInterval = matchSet.GetIntervals()[0];
newTransition = new RangeTransition(blockEndState, matchInterval.a, matchInterval
.b);
}
}
else
{
newTransition = new SetTransition(blockEndState, matchSet);
}
ATNState setOptimizedState = new BasicState();
setOptimizedState.SetRuleIndex(decision.ruleIndex);
atn.AddState(setOptimizedState);
setOptimizedState.AddTransition(newTransition);
optimizedTransitions.Add(new EpsilonTransition(setOptimizedState));
removedPaths += decision.NumberOfOptimizedTransitions - optimizedTransitions.Count;
if (decision.IsOptimized)
{
while (decision.NumberOfOptimizedTransitions > 0)
{
decision.RemoveOptimizedTransition(decision.NumberOfOptimizedTransitions - 1);
}
}
foreach (Transition transition_1 in optimizedTransitions)
{
decision.AddOptimizedTransition(transition_1);
}
}
return(removedPaths);
}
