protected ATNConfigSet ComputeStartState(ICharStream input,
ATNState p)
{
PredictionContext initialContext = PredictionContext.EMPTY;
ATNConfigSet configs = new OrderedATNConfigSet();
for (int i = 0; i < p.NumberOfTransitions; i++)
{
ATNState target = p.Transition(i).target;
LexerATNConfig c = new LexerATNConfig(target, i + 1, initialContext);
Closure(input, c, configs, false, false, false);
}
return(configs);
}
/**
* Compute a target state for an edge in the DFA, and attempt to add the
* computed state and corresponding edge to the DFA.
*
* @param input The input stream
* @param s The current DFA state
* @param t The next input symbol
*
* @return The computed target DFA state for the given input symbol
* {@code t}. If {@code t} does not lead to a valid DFA state, this method
* returns {@link #ERROR}.
*/
protected DFAState ComputeTargetState(ICharStream input, DFAState s, int t)
{
ATNConfigSet reach = new OrderedATNConfigSet();
// if we don't find an existing DFA state
// Fill reach starting from closure, following t transitions
GetReachableConfigSet(input, s.configSet, reach, t);
if (reach.Empty)
{ // we got nowhere on t from s
if (!reach.hasSemanticContext)
{
// we got nowhere on t, don't throw out this knowledge; it'd
// cause a failover from DFA later.
AddDFAEdge(s, t, ERROR);
}
// stop when we can't match any more char
return(ERROR);
}
// Add an edge from s to target DFA found/created for reach
return(AddDFAEdge(s, t, reach));
}
