slice method
For a node whose value is an array, returns the slice of its children.
Implementation
Iterable<Node>? slice({int? start, int? stop, int? step}) {
final v = value;
if (v is List) {
return sliceIndices(v.length, start, stop, step ?? 1)
.map((index) => _element(v, index));
}
return null;
}