propertieswhile

Propertieswhile is a theoretical programming construct used to express and enforce invariants inside a while loop. The idea is to attach a set of declarative properties to the loop that must hold during every iteration, in addition to the loop’s ordinary condition. Propertieswhile aims to support formal reasoning about loop behavior, improve correctness, and guide automated verification.

Propertieswhile typically allows specification of invariants, monotonicity constraints, and bounds on resources. Invariants describe conditions that remain true across iterations, while monotonicity constrains how variables may change. The construct can also express allowed relationships between variables at various points of the loop. Implementations may perform runtime checks by inserting assertions or contribute information to a static verifier.

Example: propertieswhile (i >= 0 and sum >= 0) while (i < n) { ... } This fictional syntax asserts that i never becomes negative and sum never becomes negative during the loop’s execution.

Semantics and tooling: The properties are intended to be preserved by each iteration. A compiler or verifier may instrument the loop to check the properties at entry and exit of the loop body, or use them as input to formal verification tools.

Relation to other concepts: Propertieswhile relates to Hoare logic loop invariants and contract programming. It is primarily discussed in theoretical contexts and experimental languages, and is not widely adopted in mainstream languages as of now.