joncloud/rlx-net

Adds functional programming aspects using functions like Some, None, Ok, Error

Rlx.NET

Description

Rlx.NET provides core helper functions for abstracting null-references and errors. Rlx itself is short for Rust Language Extensions.

It was heavily inspired by the Rust programming language Option and Result types.

Licensing

Released under the MIT License. See the LICENSE file for further details.

Installation

In the Package Manager Console execute

Install-Package Rlx

Or update *.csproj to include a dependency on

<ItemGroup>
  <PackageReference Include="Rlx" Version="0.2.1-*" />
</ItemGroup>

Usage

Sample echo program:

using Rlx;

static void Main(string[] args) {
  string message = args.ElementAtOrDefault(0)
    .ToOption()
    .MapOrElse(() => "Missing Argument", msg => $"Echo: {msg}");
  
  Console.WriteLine(message);
}

Need to generically handle exceptions? Wrap up logic with TryFunctions:

using System.IO;
using static Rlx.Functions;

public class MyClass
{
  public static void Unsafe() =>
    throw new NotImplementedException();

  public static Result<Unit, Exception> Safe() =>
    Try(Unsafe);

  public static Result<Unit, IOException> IOSafe() =>
    Try(Unsafe).Catch<IOException>();
}

And also MVC helpers:

using Rlx;
using Rlx.MvcCore;
using static Rlx.Functions;

interface IDataService {
  OptionTask<Data> LoadDataAsync(Guid id);
  ResultTask<Data, string> UpdateDataAsync(Data data);
}

class DataController : Controller {
  readonly IDataService _dataService;
  public DataController(IDataService dataService) =>
    _dataService = dataService;

  public Task<IActionResult> Get(Guid id) =>
    WithErrors().AndThen(_ => _dataService.LoadDataAsync(id))
      .ToActionResult();

  public Task<IActionResult> Post([FromModel]Data data) =>
    WithErrors().AndThen(_ => _dataService.UpdateDataAsync(data))
      .ToActionResult(_ => 200, _ => 400, x => Some(x));

  Result<Unit, string> WithErrors() =>
    ModelState.ToResult().MapError(x => "Bad Request");
}

For additional usage see Tests and MVC Tests.

rlx-net's Issues

Uninitialized OptionTask<T>, Result<T, U>, ResultTask<T, U> need better messaging

Reason

Struct types cannot define behavior for parameterless constructors (private or assign default values).

Use Cases

Better understanding when

• Accidentally using new Result<int, string>()
• Mocking frameworks returning default values for unmet conditions

Add logo

Reason

Default nuget logo doesn't look very good

Define build script

Reason

It is common practice to define build.sh and build.cmd to produce build artifacts

Use Cases

Local builds
Simpler yaml

Add Unit type

Reason

Facilitate other generics to understand a zero-tuple struct

Use Cases

Returning Option<Unit> to indicate presence of a value

• Consider predefining static readonly Option<Unit> Some and None