singletype
Singletype, commonly referred to as a singleton type, is a type that has exactly one possible value or inhabitant. In type theory and programming language design, singleton types are used to encode information that is guaranteed to be unique by the type system. They provide a way to represent a quantity with no variable data and can support type-level programming and formal reasoning within dependently typed languages.
In practice, the unit type is the most familiar example of a singleton type. For instance, in
Dependent type systems may parameterize singleton types by values, creating types that are inhabited only by
Related concepts include the unit type, the bottom (empty) type, and broader notions of refinement or dependent