libanvl.opt 2.2.14-rc

libanvl.Opt

A null-free optional value library for .NET.

• An optional value is represented as the struct Opt<T>

See the Examples Tests for more on how to use Opt.

Requirements

.NET 8

Releases

• NuGet packages are available on NuGet.org
  • Embedded debug symbols
  • Source Link enabled
• NuGet packages from CI builds are available on the libanvl GitHub feed

Features

• Immutable
• Use Opt<T> instead of T? for optional values
• Implicit conversion from T to Opt<T>
• Deep selection of properties in complex objects
• SomeOrDefault() for any type
• Explicitly opt-in to exceptions with Unwrap()
• Cast inner value to compatible type with Cast<U>()
• SomeOrEmpty() for string and enumerables
• Opts of IEnumerable<T> are iterable

Examples

class Car
{
	public string Driver { get; set;}
}

public void AcceptOptionalValue(Opt<Car> optCar, Opt<string> optName)
{
	if (optCar.IsSome)
	{
		optCar.Unwrap().Driver = optName.SomeOr("Default Driver");
	}

	if (optCar.IsNone)
	{
		throw new Exception();
	}

	// or use Unwrap() to throw for None

	Car bcar = optCar.Unwrap();
}

public void RunCarOperations()
{
	var acar = new Car();
	AcceptOptionalValue(acar, "Rick");

	Car? nocar = null;
	AcceptOptionalValue(Opt.From(nocar), Opt<string>.None)

	// use Select to project to an Opt of an inner property
	Opt<string> driver = acar.Select(x => x.Driver);
}