Linearuse

Linearuse is a term used in theoretical computer science and programming languages to denote a discipline in which data values or resources are used exactly once. The idea arises from linear logic and has practical implications for safe resource management, memory safety, and controlled effects. In systems that enforce linearuse, values of certain types may not be copied or discarded at will; instead they must be consumed or moved, and any further use requires explicit re-creation or a new value.

The idea has its roots in linear logic and is realized in practical type systems through linear or affine types. Linear types require exact single usage, while affine types permit at most one use. Languages may expose linear function arrows or restricted ownership rules to enforce linearuse, reducing aliasing and enabling deterministic resource destruction.

Examples and implementations: In Haskell, the GHC compiler includes a linear types extension that enforces linear use of function arguments; other languages with similar ideas use ownership or borrowing mechanisms to prevent multiple active references to the same resource. Rust’s ownership model embodies comparable constraints by moving values rather than copying, ensuring single ownership. Some languages and frameworks model linearuse with session types for protocol-safe communication, ensuring that a communication channel is used in a disciplined, single-pass manner.

Applications and limitations: Linearuse supports safe resource management (file handles, memory buffers), predictable destruction, and safer concurrent programs. It can complicate code and type inference, requiring annotations or specialized tooling. Critics note that linear constraints can hinder composability and impose a learning curve, though advances in type systems and tooling aim to mitigate these costs.

See also: linear logic, linear type, affine type, session types.