public static bool IsCompatible(ATNState state, ParserStack stack)
{
var processResult = stack.Process(state);
if (!processResult.isValid)
{
return(false);
}
return(!state.epsilonOnlyTransitions ||
state.Transitions.Any(transition => IsCompatible(transition.target, processResult.parserStack)));
}
private void Suggest(ParserStack stack, ATNState state, int suggestionIndex)
{
var stackRes = stack.Process(state);
if (!stackRes.isValid)
{
return;
}
foreach (var transition in state.Transitions)
{
if (transition.IsEpsilon && !_alreadyPassed.Contains(transition.target.stateNumber))
{
_alreadyPassed.Add(transition.target.stateNumber);
Suggest(stackRes.parserStack, transition.target, suggestionIndex);
}
else
{
switch (transition)
{
case AtomTransition atomTransition when(_allTokens.Count == 0 || _currentIndex >= _allTokens.Count) && _currentIndex == suggestionIndex:
{
if (ParserStack.IsCompatible(transition.target, stack))
{
_suggestions.Add(atomTransition.label);
}
break;
}
case AtomTransition atomTransition:
{
var nextToken = _allTokens[_currentIndex];
if (_currentIndex == suggestionIndex && ParserStack.IsCompatible(transition.target, stack))
{
_suggestions.Add(atomTransition.label);
}
else if (nextToken.Type == atomTransition.label)
{
if (_currentIndex + 1 > _allTokens.Count)
{
return;
}
_currentIndex++;
Suggest(stackRes.parserStack, transition.target, suggestionIndex);
}
break;
}
case SetTransition setTransition when(_allTokens.Count == 0 || _currentIndex >= _allTokens.Count) && _currentIndex == suggestionIndex:
{
foreach (var tokenType in setTransition.Label.ToIntegerList())
{
if (ParserStack.IsCompatible(transition.target, stack))
{
_suggestions.Add(tokenType);
}
}
break;
}
case SetTransition setTransition:
{
var nextToken = _allTokens[_currentIndex];
foreach (var tokenType in setTransition.Label.ToIntegerList())
{
if (_currentIndex == suggestionIndex &&
ParserStack.IsCompatible(transition.target, stack))
{
_suggestions.Add(tokenType);
}
else if (nextToken.Type == tokenType)
{
if (_currentIndex + 1 > _allTokens.Count)
{
return;
}
_currentIndex++;
Suggest(stackRes.parserStack, transition.target, suggestionIndex);
}
}
break;
}
default:
throw new NotSupportedException();
}
}
}
}
