{"id":"visitor-dual-hierarchy-enables-structural-independence","text":"Visitor's dual class hierarchy design (one for elements, one for visitors) is the structural mechanism enabling computation across elements that share no common parent class: because the visitor hierarchy is orthogonal to the element hierarchy, visitors can traverse and accumulate state across structurally unrelated objects that merely implement Accept.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["gof-visitor-two-class-hierarchies","gof-visitor-no-common-parent-required"],"outlist":[],"label":"Dual hierarchy architecture directly enables the no-common-parent capability"}],"dependents":["visitor-dual-hierarchy-enables-recursive-stateful-ops","visitor-dual-hierarchy-grounds-ocp-inversion-mechanism"],"metadata":{"source_type":"derived","review_result":"pass"},"created_at":"2026-06-18T00:02:15+00:00","updated_at":"2026-06-18T06:15:08+00:00","reviewed_at":"2026-06-18T06:15:08+00:00","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"visitor-dual-hierarchy-enables-structural-independence","truth_value":"IN","reason":"SL justification valid","antecedents":["gof-visitor-two-class-hierarchies","gof-visitor-no-common-parent-required"],"label":"Dual hierarchy architecture directly enables the no-common-parent capability"},{"node":"gof-visitor-two-class-hierarchies","truth_value":"IN","reason":"premise"},{"node":"gof-visitor-no-common-parent-required","truth_value":"IN","reason":"premise"}]}}