splitSequence method

Iterable<Iterable<T>> splitSequence(Iterable<T> separator, { bool comparer(T separator, T element)?, bool keepSeparator = false, })

Splits the is iterable into multiple iterables on elements that match the separator.

Optionally a comparer can be provided to determine if an element is equal to the separator.

If keepSeparator is true, the returned iterables will be interleaved with the value of the separator. Otherwise, the separator elements will be omitted from the output.

Implementation

Iterable<Iterable<T>> splitSequence(
  Iterable<T> separator, {
  bool Function(T separator, T element)? comparer,
  bool keepSeparator = false,
}) sync* {
  final separatorList = separator.toList(growable: false);
  var index = 0;
  var buffer = <T>[];

  comparer ??= EqualityComparer.forType<T>().compare;

  for (final o in this) {
    if (comparer(separatorList[index], o)) {
      index++;

      if (index >= separatorList.length) {
        yield List.unmodifiable(buffer);
        if (keepSeparator) yield separatorList;
        index = 0;
        buffer = <T>[];
      }
    } else {
      if (index > 0) buffer.addAll(separatorList.take(index));
      buffer.add(o);
      index = 0;
    }
  }

  if (index > 0) {
    buffer.addAll(separatorList.take(index));
  }

  if (buffer.isNotEmpty) {
    yield List.unmodifiable(buffer);
  }
}