parseAsync method

Implementation

@override
AsyncResult<String> parseAsync(State<ChunkedData<StringReader>> state) {
  final result = AsyncResult<String>();
  final input = state.input;
  final pos = state.pos;
  late AsyncResult<O1> r1;
  late AsyncResult<O2> r2;
  late AsyncResult<O3> r3;
  var action = 0;
  void parse() {
    while (true) {
      switch (action) {
        case 0:
          r1 = p1.parseAsync(state);
          action = 1;
          if (r1.ok == null) {
            r1.handler = parse;
            return;
          }

          break;
        case 1:
          if (r1.ok == false) {
            result.ok = false;
            input.handler = result.handler;
            return;
          }

          r2 = p2.parseAsync(state);
          action = 2;
          if (r2.ok == null) {
            r2.handler = parse;
            return;
          }

          break;
        case 2:
          if (r2.ok == false) {
            state.pos = pos;
            result.ok = false;
            input.handler = result.handler;
            return;
          }

          r3 = p3.parseAsync(state);
          action = 3;
          if (r3.ok == null) {
            r3.handler = parse;
            return;
          }

          break;
        case 3:
          if ((result.ok = r3.ok) == false) {
            state.pos = pos;
          } else {
            result.value =
                Result(input.data.source.substring(pos, state.pos));
          }

          input.handler = result.handler;
          action = -1;
          return;
        default:
          throw StateError('Invalid state: $action');
      }
    }
  }

  parse();
  return result;
}