processSetValue method

TreeReference? processSetValue(SetValueAction action, TreeReference? context)

Performs a <setvalue> (port of SetValueAction.processAction).

Implementation

TreeReference? processSetValue(
  SetValueAction action,
  TreeReference? context,
) {
  final target = action.target;
  var targetRef = context == null ? target : target.contextualize(context)!;
  final ec = EvaluationContext.withContext(evaluationContext, targetRef);
  final failMessage =
      'Target of TreeReference ${target.toString(includePredicates: true)} '
      'could not be resolved!';
  final refs = ec.expandReference(targetRef)!;
  if (refs.isEmpty) {
    if (mainInstance.hasTemplatePath(target)) return null;
    throw StateError(failMessage);
  }
  if (refs.length > 1) {
    throw XPathTypeMismatchException(
      'You are trying to target a repeated field. Currently you may only '
      'target a field in a specific repeat instance.\n\nXPath nodeset has '
      'more than one node [" + references + "].',
    );
  }
  targetRef = refs.single;
  final node = ec.resolveReference(targetRef);
  if (node == null) {
    if (mainInstance.hasTemplatePath(target)) return null;
    throw StateError(failMessage);
  }
  final result = unpack(action.value.eval(mainInstance, ec));
  final wrapped = wrapData(result, node.dataType);
  setValue(
    wrapped == null ? null : castToDataType(wrapped.uncast(), node.dataType),
    targetRef,
  );
  return targetRef;
}