execute method

@override List execute(List results, Map<String, dynamic> passed)

The iterable, nested function that evaluates the entire FHIRPath expression one object at a time

Implementation

@override
List execute(List results, Map<String, dynamic> passed) {
  final executedBefore = before.execute(results.toList(), passed);
  final executedAfter = after.execute(results.toList(), passed);
  if (executedBefore.isEmpty || executedAfter.isEmpty) {
    return [];
  } else if (executedBefore.length != 1 || executedAfter.length != 1) {
    throw FhirPathEvaluationException(
      'Math Operators require each operand to result in a '
      'single object. The "*" operator was passed the following:\n'
      'Operand 1: $executedBefore\n'
      'Operand 2: $executedAfter',
      operation: '*',
      collection: results,
    );
  } else if (executedBefore.first is num && executedAfter.first is num) {
    return [(executedBefore.first as num) * (executedAfter.first as num)];
  } else if (executedBefore.first is ValidatedQuantity &&
      executedAfter.first is ValidatedQuantity) {
    return [
      (executedBefore.first as ValidatedQuantity) *
          (executedAfter.first as ValidatedQuantity),
    ];
  } else {
    throw FhirPathEvaluationException(
      'The "*" operator only accepts Integers, Decimals and '
      'Quantities, but was passed the following:\n'
      'Operand 1: ${executedBefore.first} (${executedBefore.first.runtimeType})\n'
      'Operand 2: ${executedAfter.first} (${executedAfter.first.runtimeType})',
      operation: '*',
      collection: results,
    );
  }
}