public virtual int AdaptivePredict(ITokenStream input, int decision,
ParserRuleContext outerContext)
{
if (debug || debug_list_atn_decisions)
{
Console.WriteLine("adaptivePredict decision " + decision +
" exec LA(1)==" + GetLookaheadName(input) +
" line " + input.LT(1).Line + ":" + input.LT(1).Column);
}
this.input = input;
startIndex = input.Index;
context = outerContext;
DFA dfa = decisionToDFA[decision];
thisDfa = dfa;
int m = input.Mark();
int index = startIndex;
// Now we are certain to have a specific decision's DFA
// But, do we still need an initial state?
try
{
DFAState s0;
if (dfa.IsPrecedenceDfa)
{
// the start state for a precedence DFA depends on the current
// parser precedence, and is provided by a DFA method.
s0 = dfa.GetPrecedenceStartState(parser.Precedence);
}
else {
// the start state for a "regular" DFA is just s0
s0 = dfa.s0;
}
if (s0 == null)
{
if (outerContext == null) outerContext = ParserRuleContext.EmptyContext;
if (debug || debug_list_atn_decisions)
{
Console.WriteLine("predictATN decision " + dfa.decision +
" exec LA(1)==" + GetLookaheadName(input) +
", outerContext=" + outerContext.ToString(parser));
}
bool fullCtx = false;
ATNConfigSet s0_closure =
ComputeStartState(dfa.atnStartState,
ParserRuleContext.EmptyContext,
fullCtx);
if (dfa.IsPrecedenceDfa)
{
/* If this is a precedence DFA, we use applyPrecedenceFilter
* to convert the computed start state to a precedence start
* state. We then use DFA.setPrecedenceStartState to set the
* appropriate start state for the precedence level rather
* than simply setting DFA.s0.
*/
dfa.s0.configSet = s0_closure; // not used for prediction but useful to know start configs anyway
s0_closure = ApplyPrecedenceFilter(s0_closure);
s0 = AddDFAState(dfa, new DFAState(s0_closure));
dfa.SetPrecedenceStartState(parser.Precedence, s0);
}
else {
s0 = AddDFAState(dfa, new DFAState(s0_closure));
dfa.s0 = s0;
}
}
int alt = ExecATN(dfa, s0, input, index, outerContext);
if (debug)
Console.WriteLine("DFA after predictATN: " + dfa.ToString(parser.Vocabulary));
return alt;
}
finally
{
mergeCache = null; // wack cache after each prediction
thisDfa = null;
input.Seek(index);
input.Release(m);
}
}
