parse method

Implementation

@override
Result<Object?>? parse(State<I> state) {
  final pos = state.pos;
  final r1 = p1.fastParse(state);
  if (r1) {
    final r2 = p2.fastParse(state);
    if (r2) {
      final r3 = p3.fastParse(state);
      if (r3) {
        final r4 = p4.fastParse(state);
        if (r4) {
          return const Result(null);
        }
      }
    }
  }

  state.pos = pos;
  return null;
}