Status: OUT
Visitor's doubly-extensible recursive computation (stateful accumulation across elements, extensible along both type and operation axes via bidirectional OCP) is bounded by Visitor's encapsulation cost: element classes must expose enough internal state for visitors to operate, meaning recursive computation extensibility trades off against information hiding — a tension inherent in OCP axis inversion.
Doubly-extensible recursive computation is powerful but requires elements to expose state
Depends on (SL): visitor-recursive-stateful-operations, composite-visitor-dual-ocp-coverage
Unless: gof-visitor-breaks-encapsulation