SomeNone

SomeNone is a term used in discussions of optional value types in programming languages. It is not a formal language feature, but a shorthand used by educators and theorists to describe the two possibilities that an optional value can take: a present value (Some) or the absence of a value (None). The concept is particularly associated with languages that implement an option or Maybe type with explicit constructors for these cases.

In practical use, SomeNone serves as a conceptual tool for reasoning about functions and data flows that may or may not produce a value. It emphasizes the need for handling both outcomes explicitly, which in turn supports safer error handling, exhaustive pattern matching, and clearer type signatures. Some literature uses SomeNone when contrasting successful results with missing data, or when teaching the idea of total functions that account for all input cases.

Common examples arise in languages with a strongly typed option type. For instance, a function that searches a collection might have a type that returns Some x when a match is found and None otherwise. This framing helps programmers design APIs that require explicit handling of the absence of a value, rather than relying on nullable or undefined states.

See also: Optional type, Maybe, Option, Null safety, Pattern matching.