Status: IN
Visitor's recursive computation capability requires two independently necessary architectural contributions: the dual class hierarchy provides structural independence (enabling stateful accumulation across heterogeneous elements sharing no common parent), while double dispatch provides type-resolution governance (enabling the recursive subsystem's OCP-inverted extensibility without fragile type-switching) — together making Visitor the uniquely capable pattern for governed stateful computation on arbitrary recursive structures.
Dual hierarchy (structural independence) and double dispatch (type governance) are jointly necessary for governed recursive computation
Depends on (SL): visitor-dual-hierarchy-enables-recursive-stateful-ops, double-dispatch-enables-governed-recursive-extensibility