/// <summary>
/// Checks whether the ATNState is compatiple with the given stack.
/// </summary>
/// <param name="state"></param>
/// <param name="parserStack"></param>
/// <returns></returns>
public static bool IsCompatibleWith(ATNState state, ParserStack parserStack)
{
var res = parserStack.Process(state);
if (!res.Item1)
{
return(false);
}
if (state.epsilonOnlyTransitions)
{
return(state.Transitions.Any(it => IsCompatibleWith(it.target, res.Item2)));
}
else
{
return(true);
}
}
private void Process(ATNState state, MyTokenStream tokens, ICollection <Suggestion> collector, ParserStack parserStack, HashSet <int> alreadyPassed)
{
var atCaret = tokens.AtCaret();
var stackRes = parserStack.Process(state);
if (!stackRes.Item1)
{
return;
}
foreach (var it in state.Transitions)
{
if (it.IsEpsilon)
{
var stateNo = it.target.StateNumber;
if (!alreadyPassed.Contains(stateNo))
{
Process(it.target, tokens, collector, stackRes.Item2, alreadyPassed);
alreadyPassed.Add(stateNo);
}
}
else if (it is AtomTransition)
{
var atomTransition = it as AtomTransition;
var nextToken = tokens.Next();
if (atCaret)
{
if (ParserStack.IsCompatibleWith(it.target, parserStack))
{
AddSymbol(collector, parserStack, atomTransition.label, nextToken);
}
}
else
{
if (nextToken.Type == atomTransition.label)
{
Process(it.target, tokens.Move(), collector, stackRes.Item2, new HashSet <int>());
}
}
}
else if (it is SetTransition)
{
var setTransition = it as SetTransition;
var nextToken = tokens.Next();
foreach (var sym in setTransition.Label.ToList())
{
if (atCaret)
{
if (ParserStack.IsCompatibleWith(it.target, parserStack))
{
AddSymbol(collector, parserStack, sym, nextToken);
}
}
else
{
if (nextToken.Type == sym)
{
Process(it.target, tokens.Move(), collector, stackRes.Item2, new HashSet <int>());
}
}
}
}
else
{
throw new InvalidOperationException(it.GetType().FullName);
}
}
}