ErgodicMage.Result 0.5.0

ErgodicMage Result

A simple implementations of the Result Pattern, Guard Clauses and using Result to reduce exceptions.

Result Types

public readonly record struct Result (bool Success, string ErrorMessage, Exception? Exception)
public readonly record struct Result<T> (bool Success, string ErrorMessage, Exception? Exception, T Value)

Example

private readonly record struct Workflow(string Name, int Jobs);

public async Task<Result<string>> DoWorkflow(string? workflow, CancellationToken token = default)
{
    Result result = GuardClause.NullOrWhiteSpace(workflow);
    if (!result.Success) return result;

    Result<Workflow> resultWorkflow = await GetWorkflow(workflow!, token);
    if (!resultWorkflow.Success) return Result.Error($"Workflow {workflow} not found");

    return await Result<string>.TryAsync(async (Workflow workflow, CancellationToken token) =>
    {
        return await DoWork(workflow, token);
    },
    resultWorkflow.Value, token);
}

private static async Task<Result<Workflow>> GetWorkflow(string workflow, CancellationToken? token = default)
    => new Workflow(workflow, 1);

private static async Task<Result<string>> DoWork(Workflow workflow, CancellationToken? token = default)
{
    Result result = GuardClause.Null(workflow);
    if (!result.Success) return result;
    await Task.Delay(1000);
    return workflow.Name;
}

Guard Clauses

Null and empty string guard clauses

public static Result Null(object? input, string? parameterName = null, string? message = null)
public static Result Null(this Result result, object? input, string? parameterName = null, string? message = null)
public static Result NullOrEmpty(string? input, string? parameterName = null, string? message = null)
public static Result NullOrEmpty(this Result result, string? input, string? parameterName = null, string? message = null)
public static Result NullOrWhiteSpace(string? input, string? parameterName = null,  string? message = null)

Minumum and Maximum for any IComparable. Built in type provided: short, int, long, float, double and decimal.

public static Result Minimum<T>(T input, T minimum, string? parameterName = null, string? message = null) where T : struct, IComparable
public static Result Minimum<T>(this Result result, T input, T maximum, string? parameterName = null, string? message = null) where T : struct, IComparable
public static Result Maximum<T>(T input, T maximum, [CallerArgumentExpression(nameof(input))] string? parameterName = null, string? message = null) where T : struct, IComparable
public static Result Maximum<T>(this Result result, T input, T maximum, string? parameterName = null, string? message = null) where T : struct, IComparable

Result exception handlers