Framewhile

Framewhile is a control-flow construct described in some programming texts and experimental languages as a hybrid of frame-based execution and a while loop. It is designed to separate state into isolated frames while continuing iteration as long as a condition holds. In practice, a framewhile loop repeatedly executes a body in the context of a new or refreshed frame, allowing partial results to be accumulated without leaking frame-local state into subsequent iterations.

Semantics: Each iteration operates within a frame that captures its local variables, inputs, and partial results. Frames may be created at the start of the iteration or on demand inside the body and may be discarded at the end or preserved for the next iteration. The loop condition is evaluated against the current frame, and the loop continues while the condition is true. Some designs support pausing and resuming frames to enable cooperative multitasking or backtracking.

Syntax: A common form is framewhile (condition) { body } where condition is evaluated in the frame’s context. Some variants offer frame bindings or explicit frame transitions, such as frame { ... } framewhile (condition) { ... } or using keywords like frame, yield, or next to control frame lifecycle.

Example: framewhile (morePages) { page = fetchNextPage(); process(page); if (needsMore) { extendFrame(); } }

Relation and applications: It is related to while loops, coroutines, and frame-based languages; useful in streaming data, incremental computations, and backtracking algorithms. Limitations include increased complexity and portability concerns across implementations.

History and status: The term framewhile does not denote a widely adopted standard; it appears primarily in discussions of frame-based programming, experimental languages, or niche DSLs. Real-world implementations vary in framing semantics and lifecycle control.

See also: frame, while, coroutines, dataflow languages.