executeComparisons function

  1. @override
List executeComparisons(
  1. List results,
  2. ParserList before,
  3. ParserList after,
  4. Map<String, dynamic> passed,
  5. Comparator comparator, {
  6. bool where = false,
})

Implementation

@override
List executeComparisons(List results, ParserList before, ParserList after,
    Map<String, dynamic> passed, Comparator comparator,
    {bool where = false}) {
  // TODO(Dokotela): Currently, this is going to assume that if a String is being compared
  // with a Date, DateTime, or Time, and the String is a valid format of a Time
  // or DateTime, then they should still be compared
  // another type, for instance:
  // Patient.birthDate = "1981-09-18"
  // today() = Date("2022-04-15")
  // this will throw an error, despite the fact that they should be comparable
  // could consider testing it, e.g.
  //  if (param1 is! String || param2 is! String) {
  //    if(param)}

  bool stringGt(String param1, String param2) {
    final runes1 = param1.runes.toList();
    final runes2 = param2.runes.toList();
    if (runes1.length < runes2.length) {
      return false;
    }
    for (var i = 0; i < runes1.length; i++) {
      if (runes2[i] > runes1[i]) {
        return false;
      } else if (runes2[i] < runes1[i]) {
        return true;
      }
    }
    return false;
  }

  bool? makeComparison(Comparator comparator, dynamic param1, dynamic param2) {
    try {
      switch (comparator) {
        case Comparator.gt:
          return param1 > param2 as bool?;
        case Comparator.gte:
          return param1 >= param2 as bool?;
        case Comparator.lt:
          return param1 < param2 as bool?;
        case Comparator.lte:
          return param1 <= param2 as bool?;
      }
    } catch (e) {
      if (e is UnequalPrecision) {
        return null;
      } else {
        rethrow;
      }
    }
  }

  Exception cannotCompareException(dynamic param1, dynamic param2) =>
      FhirPathEvaluationException(
          'The comparator $comparator was not passed types that can be '
          'compared.\n'
          'Param1: $param1 - ${param1.runtimeType}\n'
          'Param1: $param2 - ${param2.runtimeType}\n');

  Exception invalidException(dynamic param1, dynamic param2) =>
      FhirPathEvaluationException(
          'The comparator $comparator was not passed two valid types.\n'
          'Param1: $param1 - ${param1.runtimeType} - Valid? ${param1.isValid}\n'
          'Param1: $param2 - ${param2.runtimeType} - Valid? ${param2.isValid}\n');

  bool? compare(Comparator comparator, dynamic lhs, dynamic rhs) {
    switch (lhs.runtimeType) {
      case num:
        return rhs is num
            ? makeComparison(comparator, lhs, rhs)
            : rhs is FhirNumber && rhs.isValid
                ? makeComparison(comparator, lhs, rhs.valueNumber)
                : rhs is String && num.tryParse(rhs) != null
                    ? makeComparison(comparator, lhs, num.parse(rhs))
                    : throw cannotCompareException(lhs, rhs);
      case int:
        return rhs is num
            ? makeComparison(comparator, lhs, rhs)
            : rhs is FhirNumber && rhs.isValid
                ? makeComparison(comparator, lhs, rhs.valueNumber)
                : rhs is String && num.tryParse(rhs) != null
                    ? makeComparison(comparator, lhs, num.parse(rhs))
                    : throw cannotCompareException(lhs, rhs);
      case double:
        return rhs is num
            ? makeComparison(comparator, lhs, rhs)
            : rhs is FhirNumber && rhs.isValid
                ? makeComparison(comparator, lhs, rhs.valueNumber)
                : rhs is String && num.tryParse(rhs) != null
                    ? makeComparison(comparator, lhs, num.parse(rhs))
                    : throw cannotCompareException(lhs, rhs);
      case FhirDate:
        return rhs is FhirDateTimeBase
            ? (lhs as FhirDate).isValid && rhs.isValid
                ? makeComparison(comparator, lhs, rhs)
                : throw invalidException(lhs, rhs)
            : rhs is String && FhirDateTime(rhs).isValid
                ? makeComparison(comparator, lhs, rhs)
                : throw cannotCompareException(lhs, rhs);
      case DateTime:
        return (rhs is FhirDateTimeBase && rhs.isValid)
            ? makeComparison(comparator, FhirDateTime(lhs), rhs)
            : rhs is DateTime
                ? makeComparison(
                    comparator, FhirDateTime(lhs), FhirDateTime(rhs))
                : rhs is String && FhirDateTime(rhs).isValid
                    ? makeComparison(
                        comparator, FhirDateTime(lhs), FhirDateTime(rhs))
                    : throw cannotCompareException(lhs, rhs);
      case FhirDateTime:
        return rhs is FhirDateTimeBase
            ? (lhs as FhirDateTime).isValid && rhs.isValid
                ? makeComparison(comparator, lhs, rhs)
                : throw invalidException(lhs, rhs)
            : rhs is String && FhirDateTime(rhs).isValid
                ? makeComparison(comparator, lhs, FhirDateTime(rhs))
                : throw cannotCompareException(lhs, rhs);
      case FhirTime:
        return rhs is FhirTime
            ? (lhs as FhirTime).isValid && rhs.isValid
                ? makeComparison(comparator, lhs, rhs)
                : throw invalidException(lhs, rhs)
            : rhs is String && FhirTime(rhs).isValid
                ? makeComparison(comparator, lhs, FhirTime(rhs))
                : throw cannotCompareException(lhs, rhs);
      case ValidatedQuantity:
        return rhs is ValidatedQuantity
            ? makeComparison(comparator, lhs, rhs)
            : rhs is String
                ? makeComparison(
                    comparator, lhs, ValidatedQuantity.fromString(rhs))
                : throw cannotCompareException(lhs, rhs);

      /// Default should be when lhs is a String
      default:
        {
          if (lhs is String && rhs is String) {
            return (comparator == Comparator.gt || comparator == Comparator.lt)
                ? lhs == rhs
                    ? false
                    : comparator == Comparator.gt
                        ? stringGt(lhs, rhs)
                        : !stringGt(lhs, rhs)
                : lhs == rhs
                    ? true
                    : comparator == Comparator.gte
                        ? stringGt(lhs, rhs)
                        : !stringGt(lhs, rhs);
          } else if (rhs is FhirTime && FhirTime(lhs).isValid) {
            return makeComparison(comparator, FhirTime(lhs), rhs);
          } else if ((rhs is FhirDate || rhs is FhirDateTime)) {
            if (lhs is String && FhirDateTime(lhs).isValid) {
              return makeComparison(comparator, FhirDateTime(lhs), rhs);
            } else if (lhs is DateTime && FhirDateTime(lhs).isValid) {
              return makeComparison(comparator, FhirDateTime(lhs), rhs);
            } else if (lhs is FhirDateTimeBase && lhs.isValid) {
              return makeComparison(comparator, lhs, rhs);
            }
          }
          throw FhirPathEvaluationException(
            'Can only compare Strings to other Strings',
            operation: '$comparator',
            arguments: [lhs, rhs],
          );
        }
    }
  }

  final lhs = SingletonEvaluation.toSingleton(
      before.execute(results.toList(), passed),
      name: 'left-hand side',
      operation: comparator.toString(),
      collection: results);
  final rhs = SingletonEvaluation.toSingleton(
      after.execute(results.toList(), passed),
      name: 'right-hand side',
      operation: comparator.toString(),
      collection: results);

  if (lhs.isEmpty || rhs.isEmpty) {
    return [];
  } else if (lhs.length != 1 || rhs.length != 1) {
    throw _wrongArgLength(
      comparator.toString(),
      ['Left-hand side: $lhs', 'Right-hand side: $rhs'],
    );
  }
  {
    if (!_allowedTypes.contains(lhs.first.runtimeType) ||
        !_allowedTypes.contains(rhs.first.runtimeType)) {
      final functionName = comparator == Comparator.gt
          ? '>'
          : comparator == Comparator.gte
              ? '>='
              : comparator == Comparator.lt
                  ? '<'
                  : '<=';
      throw FhirPathEvaluationException(
          'The comparator $functionName cannot work with the types '
          'passed.\n'
          'LHS: $lhs\n'
          'RHS: $rhs',
          operation: functionName,
          arguments: [before, after]);
    } else if (where) {
      results.retainWhere((element) =>
          compare(comparator, element[lhs.first], rhs.first) ?? false);
      return results;
    } else {
      final newResult = compare(comparator, lhs.first, rhs.first);
      return newResult == null ? [] : [newResult];
    }
  }
}