usewhile

Usewhile is a proposed or experimental control-flow construct designed to combine a while-style loop with automatic resource management. In languages that explore this idea, usewhile aims to ensure that resources acquired during each iteration are reliably released when that iteration completes, even if the loop exits early due to a break or an exception.

The common form is usewhile (condition) { … } where the body contains the work for the current iteration. Some variants allow declaring a resource in the condition or at the start of the body, such as usewhile (r := acquireResource()) { … }. The exact syntax varies by language, but the core semantics are that a per-iteration resource scope is entered at the start of each iteration and disposed at its end.

Semantically, usewhile maintains that the loop continues while the condition holds, and at the end of each iteration, any resources created within that iteration are automatically finalized or released. This provides deterministic cleanup without requiring explicit finally blocks or manual disposal code in every iteration. If a loop iteration is interrupted, the language runtime or compiler ensures the corresponding cleanup still occurs.

Use cases for usewhile include streaming I/O, per-iteration processing of data items, and patterns where resources are expensive or fragile and must be released promptly. Because usewhile is not part of mainstream languages, support is limited and semantics can differ between designs. Potential drawbacks include added complexity for readers unfamiliar with the construct and performance considerations from per-iteration resource management.

See also: while loop, context manager, resource management, deterministic finalization, try-with-resources.