childInstanceRefOf method

TreeReference? childInstanceRefOf(List<FormElement> elements, List<int> multiplicities)

The instance reference of the last of elements, with the repeat instances given by multiplicities (other steps at multiplicity 0); null if the controls and binds are inconsistent.

Implementation

TreeReference? childInstanceRefOf(
  List<FormElement> elements,
  List<int> multiplicities,
) {
  if (elements.isEmpty) return null;
  var ref = elements.last.bind!;
  for (var i = 0; i < ref.size; i++) {
    if (ref.multiplicityAt(i) != TreeReference.indexAttribute) {
      ref = ref.withMultiplicity(i, 0);
    }
  }
  for (var i = 0; i < elements.length; i++) {
    final element = elements[i];
    if (element is GroupDef && element.isRepeat) {
      final repeatRef = element.bind!;
      if (!repeatRef.isAncestorOf(ref)) return null;
      ref = ref.withMultiplicity(repeatRef.size - 1, multiplicities[i]);
    }
  }
  return ref;
}