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 executedValue = value.execute(results.toList(), passed);
  return results.isEmpty
      ? []
      : results.length > 1
          ? throw _requiresList('.substring()', results)
          : (results.first is! String)
              ? throw _requiresString('.substring()', results)
              : executedValue.isNotEmpty &&
                      executedValue.first is int &&
                      (((executedValue.first as int) >=
                              (results.first as String).length) ||
                          (executedValue.first as int) < 0)
                  ? []
                  : executedValue.length == 1 && executedValue.first is int
                      ? [
                          results.first
                              .toString()
                              .substring(executedValue.first as int)
                        ]
                      : executedValue.length == 2 &&
                              executedValue.first is int &&
                              executedValue.last is int
                          ? [
                              results.first.toString().substring(
                                    executedValue.first as int,
                                    ((executedValue.first as int) +
                                                (executedValue.last as int)) >
                                            results.first.toString().length
                                        ? results.first.toString().length
                                        : ((executedValue.first as int) +
                                            (executedValue.last as int)),
                                  )
                            ]
                          : throw FhirPathEvaluationException(
                              'The function .substring() was not provided the '
                              ' proper parameters.',
                              operation: '.substring()',
                              collection: results,
                              arguments: executedValue);
}