Vanilla Object Orientation (VOO): A Value-Semantics Approach to Classes in Tcl

I present Vanilla Object Orientation (VOO), a framework that composes classes from Tcl’s native data structures – lists and dictionaries – rather than introducing additional framework infrastructure. VOO objects are plain Tcl lists with automatic memory management through copy-on-write semantics, eliminating the destructor burden inherent in TclOO and Itcl. Benchmarks on Tcl 8.6.13 and Tcl 9.0 show VOO achieves 7–18x faster object creation and 4–6x superior memory efficiency compared to TclOO. A companion C++ migration path (VOO C++) further improves field-access speed (setter 2.3–2.6x faster) and memory (6.8–9.8x lighter than TclOO), while preserving an identical Tcl call-site API. Cross-version analysis confirms that VOO’s compositional design scales better than framework-based approaches as the interpreter evolves.