Antlr4.Runtime.Atn.LexerATNSimulator.Closure C# (CSharp) Method

        protected bool Closure(ICharStream input, LexerATNConfig config, ATNConfigSet configs, bool currentAltReachedAcceptState, bool speculative, bool treatEofAsEpsilon)
        {
            if (debug)
            {
                Console.WriteLine("closure(" + config.ToString(recog, true) + ")");
            }

            if (config.state is RuleStopState)
            {
                if (debug)
                {
                    if (recog != null)
                    {
                        Console.WriteLine("closure at " + recog.RuleNames[config.state.ruleIndex] + " rule stop " + config);
                    }
                    else {
                        Console.WriteLine("closure at rule stop " + config);
                    }
                }

                if (config.context == null || config.context.HasEmptyPath)
                {
                    if (config.context == null || config.context.IsEmpty)
                    {
                        configs.Add(config);
                        return true;
                    }
                    else {
                        configs.Add(new LexerATNConfig(config, config.state, PredictionContext.EMPTY));
                        currentAltReachedAcceptState = true;
                    }
                }

                if (config.context != null && !config.context.IsEmpty)
                {
                    for (int i = 0; i < config.context.Size; i++)
                    {
                        if (config.context.GetReturnState(i) != PredictionContext.EMPTY_RETURN_STATE)
                        {
                            PredictionContext newContext = config.context.GetParent(i); // "pop" return state
                            ATNState returnState = atn.states[config.context.GetReturnState(i)];
                            LexerATNConfig c = new LexerATNConfig(config, returnState, newContext);
                            currentAltReachedAcceptState = Closure(input, c, configs, currentAltReachedAcceptState, speculative, treatEofAsEpsilon);
                        }
                    }
                }

                return currentAltReachedAcceptState;
            }

            // optimization
            if (!config.state.OnlyHasEpsilonTransitions)
            {
                if (!currentAltReachedAcceptState || !config.hasPassedThroughNonGreedyDecision())
                {
                    configs.Add(config);
                }
            }

            ATNState p = config.state;
            for (int i = 0; i < p.NumberOfTransitions; i++)
            {
                Transition t = p.Transition(i);
                LexerATNConfig c = GetEpsilonTarget(input, config, t, configs, speculative, treatEofAsEpsilon);
                if (c != null)
                {
                    currentAltReachedAcceptState = Closure(input, c, configs, currentAltReachedAcceptState, speculative, treatEofAsEpsilon);
                }
            }

            return currentAltReachedAcceptState;
        }