toString method

Implementation

@override
String toString() {
  final out = StringBuffer();
  final pending = StringBuffer();

  for (final c in _cells) {
    if (c.isZero) continue;
    if (c.isEmpty) {
      pending.write(' ');
      continue;
    }
    if (pending.isNotEmpty) {
      out.write(pending.toString());
      pending.clear();
    }
    out.write(c.content);
  }

  return out.toString();
}