Odin.System.Result 0.9.37

About Odin.System.Result

Odin.System.Result, part of the OrDinary INfrastructure libraries, provides several 'Result' classes, which all encapsulate the outcome of an operation, together with a list of messages.

Result is the simplest concept.

ResultValue of TValue adds a generic Value property.

Result of TMessage and ResultValue of TValue, TMessage add support for the Messages list to be of any type.

ResultEx and ResultValueEx of TValue come with a TMessage type that is aligned with logging failure issues.

Getting Started

1 - Result: Success() and Failure()

    public class HeartOfGoldService
    {
        public Result WarpSpeedToMilliways()
        {
            if (_eddie.IsOK()) return Result.Success();
            return Result.Failure(["Zaphod, that is not possible...", "Error 42"])
        }
    }

2 - Result: IsSuccess and Messages properties

    Result outcome = _heartOfGold.WarpSpeedToMilliways()
    if (!outcome.IsSuccess)
    {
        outcome.Messages.ForEach(m => _logger.LogWarning(m));
    }    
    

3 - ResultValue:

Adds a generic Value property to Result.

    public class ZaphodMemoryFetcherService
    {
        public ResultValue<IReadonlyList<MemSnippet>> 
            FetchMemoriesFor(Source source, DateOnly day)
        {
            var results = new List<MemSnippet>();
            ...
            ...
            // On success...
            return ResultValue<IReadonlyList<MemSnippet>>.Success(results);

            // On failure...
            return ResultValue<IReadonlyList<MemSnippet>>.Failure("Tampering detected!")
        }
    }

4 - ResultValue: IsSuccess, Value and Messages properties

    ResultValue<IReadonlyList<MemSnippet>> outcome = 
        _zaphod.FetchMemoriesFor(_milliwaysDinner, DateOnly.MaxValue)
    if (outcome.IsSuccess)
    {
        var memories = outcome.Value;
    }
    else
    {
        outcome.Messages.ForEach(m => _logger.LogWarning(m));
    }    
    

5 - Result & ResultValue Messages can also be of type TMessage, as opposed to just string.

    public record MyMessage(int EventId, string Message)
    Result<MyMessage> result = Result<MyMessage>.Failure(
        new MyMessage(134, "Some message"));
    ...
    result.Messages.ForEach(m => _logger.LogWarning(m.EventId, m.Message));

6 - ResultEx & ResultValueEx

Uses a message type that is aligned with logging...

    ResultEx result = ResultEx.Failure(LogLevel.Critical, 
        "Zaphod has broken the improbability drive", unhandledWarpExceptionCaught);
    ...
    MessageEx message =  result.Messages[0];
    _logger.Log(message.Severity, message.Error, message.Message);