The model

Argon distinguishes values from individuals. A value is data — an integer, a string, a record (struct), a variant of an enum. Two values are equal when their contents are equal. An individual is an entity with identity — a person, a lease, a shipment. It keeps that identity as its data changes, and two individuals may carry identical data and remain distinct. Values are compared by structure, individuals by identity, and the type system tracks which a given position holds.