Result.Core 1.0.0

Result.Core

A lightweight, dependency-free functional Result<T, E> library for modern .NET. It is inspired by Rust's Result while staying idiomatic to C# with structured failure metadata and reusable templates.

Why use it?

• Replace exceptions in normal control flow with explicit successes and failures.
• Keep domain logic clear in application services, APIs, authentication flows, and data access layers.
• Share consistent error templates across bounded contexts.

Features

• Result<T, E> success/failure wrapper with implicit conversions.
• Structured failures: Failure, FailureCode, FailureTemplate, and CommonFailureTypes.
• Helpers for Match, Map, Bind, Unwrap, and TryUnwrap.
• Zero runtime dependencies with XML docs, SourceLink, and full unit test coverage.

Installation

Use the package name Result.Core:

 dotnet add package Result.Core

Or via PackageReference:

<ItemGroup>
  <PackageReference Include="Result.Core" Version="1.0.0" />
</ItemGroup>

Quick start

using Result.Core;

Result<int, Failure> Divide(int a, int b)
{
    if (b == 0)
        return CommonFailureTypes.ValidationError.CreateWithMessage("Division by zero.");

    return a / b; // implicit conversion to Result<int, Failure>
}

var result = Divide(10, 2);

int value = result.Match(
    onSuccess: v => v,
    onFailure: e => throw new InvalidOperationException(e.Message));

Transform results

using Result.Core;

var userResult = Result<int, Failure>.Success(1)
    .Bind(id => id == 1
        ? "Ruffallow"
        : CommonFailureTypes.NoDataFound.CreateWithArgs(id))
    .Map(name => name.ToUpperInvariant());

if (userResult.TryUnwrap(out var user, out _))
    Console.WriteLine(user);

Failure model

• FailureCode: numeric ID + string code (e.g. 300, "COMMON.NO_DATA_FOUND").
• FailureTemplate: reusable definition with a message template.
• Failure: concrete error instance used as E in Result<T, E>.
• CommonFailureTypes: shared templates for validation, auth, data, network, and business errors.

Creating failures:

var failure = CommonFailureTypes.NotAuthorized.Create();
Console.WriteLine(failure.Code.Code);   // COMMON.NOT_AUTHORIZED
Console.WriteLine(failure.Message);     // You are not authorized to perform this action.

Categories in CommonFailureTypes

• 1–99 General: Unknown, InternalError, OperationFailed
• 100–199 Validation: ValidationError, InvalidFormat, ValueOutOfRange, RequiredFieldMissing, InvalidEnumValue
• 200–299 Authentication/Authorization: NotAuthorized, NotAuthenticated, Forbidden, TokenExpired, InvalidCredentials
• 300–399 Data/Storage: NoDataFound, ParameterNotFound, ConcurrencyConflict, AlreadyExists, NotUnique, DataCorrupted
• 400–499 External/Network: ExternalServiceUnavailable, ExternalCallFailed, Timeout, NetworkError
• 500–599 Business: ActionAlreadyPerformed, PreconditionsNotMet, InvalidState, ResourceLocked

Project structure

Result.Core/
  src/Result.Core/           # Library project
  tests/Result.Core.Tests/   # xUnit test project
  LICENSE
  README.md
  Result.Core.sln

Contributing

Issues and pull requests are welcome.

Support

If you find this library useful, please star the repository — it helps others discover the project and motivates further improvements.