Antlr4.Runtime.Atn.LL1Analyzer.GetDecisionLookahead C# (CSharp) Метод

        public virtual IntervalSet[] GetDecisionLookahead(ATNState s)
        {
            //		System.out.println("LOOK("+s.stateNumber+")");
            if (s == null)
            {
                return null;
            }
            IntervalSet[] look = new IntervalSet[s.NumberOfTransitions];
            for (int alt = 0; alt < s.NumberOfTransitions; alt++)
            {
                look[alt] = new IntervalSet();
                HashSet<ATNConfig> lookBusy = new HashSet<ATNConfig>();
                bool seeThruPreds = false;
                // fail to get lookahead upon pred
                Look(s.Transition(alt).target, null, PredictionContext.EMPTY, look[alt], lookBusy, new BitSet(), seeThruPreds, false);
                // Wipe out lookahead for this alternative if we found nothing
                // or we had a predicate when we !seeThruPreds
                if (look[alt].Count == 0 || look[alt].Contains(HitPred))
                {
                    look[alt] = null;
                }
            }
            return look;
        }

        protected virtual void ProcessParser()
        {
            g.decisionLOOK = new List<IntervalSet[]>(g.atn.NumberOfDecisions + 1);
            foreach (DecisionState s in g.atn.decisionToState)
            {
                g.tool.Log("LL1", "\nDECISION " + s.decision + " in rule " + g.GetRule(s.ruleIndex).name);
                IntervalSet[] look;
                if (s.nonGreedy)
                { // nongreedy decisions can't be LL(1)
                    look = new IntervalSet[s.NumberOfTransitions + 1];
                }
                else
                {
                    LL1Analyzer anal = new LL1Analyzer(g.atn);
                    look = anal.GetDecisionLookahead(s);
                    g.tool.Log("LL1", "look=[" + string.Join(", ", look.AsEnumerable()) + "]");
                }

                Debug.Assert(s.decision + 1 >= g.decisionLOOK.Count);
                Utils.SetSize(g.decisionLOOK, s.decision + 1);
                g.decisionLOOK[s.decision] = look;
                g.tool.Log("LL1", "LL(1)? " + Disjoint(look));
            }
        }