Frequently Asked Questions

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Creating a result of type Nullable<T> from a value

Q: I have a value of type int?, and I need to construct a Maybe<int> from it, where a null value creates a None result, and a non-null value creates a Success result. I would like to be able to call the Maybe<int>.FromValue method, but it won’t take a null value, only a regular int. And I could call Maybe<int?>.FromValue, but it returns a Maybe<int?>, which isn’t exactly what I need. How do I get exactly what I need without having to write too much code?

int? value;

// Does not compile:
Maybe<int> result = Maybe<int>.FromValue(value);

// Not quite what we need:
Maybe<int?> result = Maybe<int?>.FromValue(value);

// Too complicated:
Maybe<int> result = value is null
	? Maybe<int>.None
	: Maybe<int>.Success(value.Value);

A: The solution is to first create a result with a nullable value, then convert it to a result with a non-nullable value with the AsNonNullable extension method.

int? value;

// Exactly what we need in one line:
Maybe<int> result = Maybe<int?>.FromValue(value).AsNonNullable();

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