{"id":"command-undo-engineering-triad","text":"Command's undo mechanism requires engineering discipline along three independent concerns: hysteresis prevention (using Memento to avoid state drift from repeated undo/redo cycles), meaningless-undo filtering (Reversible() method to skip trivial operations like font-color changes to current color), and state-varying copy management (copying commands before history insertion when state differs across invocations).","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["command-hysteresis-use-memento","command-reversible-prevents-meaningless-undo","command-undo-requires-copy-if-state-varies"],"outlist":[],"label":"Three independent engineering concerns form a complete undo discipline"}],"dependents":["command-fully-engineered-compositional-pattern","state-atomicity-and-command-undo-complementary-temporal-safety"],"metadata":{"source_type":"derived","review_result":"pass"},"created_at":"2026-06-17T23:28:16+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":"command-undo-engineering-triad","truth_value":"IN","reason":"SL justification valid","antecedents":["command-hysteresis-use-memento","command-reversible-prevents-meaningless-undo","command-undo-requires-copy-if-state-varies"],"label":"Three independent engineering concerns form a complete undo discipline"},{"node":"command-hysteresis-use-memento","truth_value":"IN","reason":"premise"},{"node":"command-reversible-prevents-meaningless-undo","truth_value":"IN","reason":"premise"},{"node":"command-undo-requires-copy-if-state-varies","truth_value":"IN","reason":"premise"}]}}