publicwhile

Publicwhile is a hypothetical programming construct used in discussions of program semantics and formal verification. In this concept, a while loop is annotated with a visibility modifier indicating that the loop's invariants, guards, and observable effects are part of the program's public contract and must be verifiable by external observers.

Origin and terminology: The term emerges in academic discourse about transparent computation and auditable software, particularly in contexts such as secure smart contracts and safety-critical systems, where external verification of looping behavior is desirable.

Semantics and design: A publicwhile loop differs from a standard while by mandating explicit public invariants and effect logging. Verifiers enforce that for every iteration, the program state visible to the public contract remains within the invariant and that any state changes are reflectable in a public log.

Usage and benefits: Publicwhile is used in theoretical models and teaching to illustrate the relationship between loop execution and external observability, aiding formal verification, debugging, and audit readiness.

Limitations: It introduces overhead for invariant maintenance, limits privacy, and depends on language support and verification tooling; real-world applicability hinges on privacy and performance constraints.

See also: formal verification, loop invariant, auditable software, smart contract verification.