substanceeither

Substanceeither is a theoretical data construct used to model a value that embodies two exclusive states: an actual substance instance or an alternate representation of that substance, such as a substitution record or a witness. The term blends the concept of substance from ontology with the logical idea of "either," signaling a disjoint union of two possibilities.

In formal terms, SubstanceEither A is a sum type with two constructors: Substance carrying a value of type A, and Substitute carrying a value of type A that represents an alternative or provisional form. In a Haskell-like syntax, one might write: data SubstanceEither a = Substance a | Substitute a. This structure supports standard decompositions and transformations that preserve the dual-state semantics, enabling functions to operate on the contained A regardless of which constructor was used, while allowing callers to distinguish the two cases.

Common use cases include modeling processes where a substance is either confirmed as present or recorded as a substitute pending confirmation, or representing data provenance flows that can carry either an original substance or a substitute record. The approach clarifies intent and can improve pattern matching and error handling by making the distinction explicit.

Substanceeither is not a widely standardized term; it appears mostly in theoretical discussions, education examples, or speculative design work. It is related to established concepts like the Either and Maybe types, sum types, and other algebraic data types, as well as philosophical discussions of substance and property.