closureCheckingStopState method

void closureCheckingStopState(ATNConfig config, ATNConfigSet configs, Set<ATNConfig> closureBusy, bool collectPredicates, bool fullCtx, int depth, bool treatEofAsEpsilon,)

Implementation

void closureCheckingStopState(
    ATNConfig config,
    ATNConfigSet configs,
    Set<ATNConfig> closureBusy,
    bool collectPredicates,
    bool fullCtx,
    int depth,
    bool treatEofAsEpsilon) {
  if (debug) log('closure(' + config.toString(parser, true) + ')');

  assert(config.context != null);

  final configContext = config.context!;

  if (config.state is RuleStopState) {
    // We hit rule end. If we have context info, use it
    // run thru all possible stack tops in ctx
    if (!configContext.isEmpty) {
      for (var i = 0; i < configContext.length; i++) {
        if (configContext.getReturnState(i) ==
            PredictionContext.EMPTY_RETURN_STATE) {
          if (fullCtx) {
            configs.add(
                ATNConfig.dup(
                  config,
                  state: config.state,
                  context: EmptyPredictionContext.Instance,
                ),
                mergeCache);
            continue;
          } else {
            // we have no context info, just chase follow links (if greedy)
            if (debug) {
              log('FALLING off rule ' + getRuleName(config.state.ruleIndex));
            }
            closure_(
              config,
              configs,
              closureBusy,
              collectPredicates,
              fullCtx,
              depth,
              treatEofAsEpsilon,
            );
          }
          continue;
        }
        final returnState = atn.states[configContext.getReturnState(i)]!;
        final newContext = configContext.getParent(i); // "pop" return state
        final c = ATNConfig(
          returnState,
          config.alt,
          newContext,
          config.semanticContext,
        );
        // While we have context to pop back from, we may have
        // gotten that context AFTER having falling off a rule.
        // Make sure we track that we are now out of context.
        //
        // This assignment also propagates the
        // isPrecedenceFilterSuppressed() value to the new
        // configuration.
        c.reachesIntoOuterContext = config.reachesIntoOuterContext;
//          assert(depth > int.MIN_VALUE);
        closureCheckingStopState(c, configs, closureBusy, collectPredicates,
            fullCtx, depth - 1, treatEofAsEpsilon);
      }
      return;
    } else if (fullCtx) {
      // reached end of start rule
      configs.add(config, mergeCache);
      return;
    } else {
      // else if we have no context info, just chase follow links (if greedy)
      if (debug) {
        log('FALLING off rule ' + getRuleName(config.state.ruleIndex));
      }
    }
  }

  closure_(
    config,
    configs,
    closureBusy,
    collectPredicates,
    fullCtx,
    depth,
    treatEofAsEpsilon,
  );
}