Stacket

Stacket is a term used in computer science and software engineering to denote a hybrid data structure or programming concept that blends characteristics of a stack with additional features to support reversible or layered operations. The word is a portmanteau of "stack" and, in some usages, "packet" or "ticket," but it is informal and not part of a formal standard.

Definition and core features

A stacket primarily behaves as a stack, providing push and pop operations that add and remove elements in last-in, first-out order. In addition, it typically supports operations to checkpoint, snapshot, or bookmark the current state, and to rollback to a previous checkpoint. Some definitions include a notion of layered contexts, where each push carries a context or ownership tag, enabling selective rollback or grouped operations. In persistent implementations, a stacket may offer immutability and versioning, allowing historical states to be retrieved.

Implementation notes

Stacket implementations vary; common approaches include maintaining a separate log of operations, using persistent data structures, or integrating with transactional memory to ensure atomicity of multi-operation sequences. Performance characteristics depend on whether persistence or rollback features are enabled, but basic push/pop remain amortized O(1) in many designs.

Applications

Stacket concepts appear in educational materials to illustrate state management, undo/redo systems, transactional programming, interpreters, and reversible computation. They are also used in software projects that require safe rollback of complex operation sequences or layered configuration changes.

Etymology and usage

The term is informal and not part of a formal standard. It appears in tutorials and discussions as a convenient shorthand for stack-like structures with extra features.

See also

Stack, persistent data structure, undo stack, versioned data structure.