Creation

The factory methods that build an Option<T>.

Option.Some

Option<T> Option.Some<T>(T value)

Wraps a value. The result is always Some.

Option<string> some = Option.Some("Hello Bees!");

On null: throws ArgumentNullException. T is constrained notnull, and the constructor enforces it. A default value is fine — Option.Some(0) is a Some holding zero.

Option.None

Option<T> Option.None<T>()

The empty case. You supply the type parameter because there is no value to infer it from.

Option<string> none = Option.None<string>();

Option.FromNullable

Option<T> Option.FromNullable<T>(T? value)

Some when the value is not null, None when it is. Use it at the edge of your code, where the shape is not yours to choose.

Option.Try

Option<T> Option.Try<T>(Func<T> factory)

Runs a factory that might throw, and asks one question: did it hand back a value you can work with?

Option<Adventurer> maybeAdventurer = Option.Try(() => GetCurrentAdventurer());

On a throw: the exception is caught, sent to your configured exception logger, and you get None.

On null: you get None, because a Some cannot hold one. Nothing is logged, because nothing threw. Option.Try(() => 0) gives you Some(0) — only null is rejected.

A cancellation is not caught. Try and TryAsync let an OperationCanceledException propagate, so a cancelled operation throws rather than becoming a None. Cancelling is you asking the work to stop, not the work failing. See Configuration to get the pre-6.0.0 behaviour back.

Do not pass an async factory to Try. It compiles, gives you an Option<Task<T>>, and catches nothing. Use TryAsync. WM1011 reports every occurrence.

Option.TryAsync

ValueTask<Option<T>> Option.TryAsync<T>(Func<Task<T>> asyncFactory)

The same, for a factory that returns a Task. See Async.

Passing state to the factory

Try and TryAsync each take an optional first argument that they hand to your factory. Use it to keep the factory from capturing:

Option<int> parsed = Option.Try(text, static value => int.Parse(value));

See State overloads for why this matters.