| (* SKC-LISP-WORLD: Rollback — Generation Recovery *) | |
| Require Import Coq.Init.Prelude. | |
| Require Import Coq.Lists.List. | |
| Require Import Coq.Arith.Arith. | |
| Require Import Coq.Strings.String. | |
| Require Import World.ObjectKinds. | |
| Require Import Machine.State. | |
| Require Import Mutation.Event. | |
| Require Import Mutation.Journal. | |
| (* Rollback preconditions *) | |
| Definition rollback_precondition_met (state : MachineState) (target_gen : nat) : Prop := | |
| target_gen < generation state. | |
| (* Rollback to generation *) | |
| Definition rollback_to_generation (state : MachineState) (target_gen : nat) : MachineState := | |
| Build_MachineState (pc state) (current_code state) (value_stack state) | |
| (frame_stack state) (environment state) (status state) target_gen. | |
| (* Rebuild world at generation *) | |
| Definition rebuild_world_at_generation (base : MachineState) (journal : mutation_journal) (target_gen : nat) : MachineState := | |
| rollback_to_generation base target_gen. | |
| (* Validate rollback correctness *) | |
| Definition validate_rollback_correctness (original : MachineState) (rolled_back : MachineState) (target_gen : nat) : Prop := | |
| generation rolled_back = target_gen /\ | |
| target_gen < generation original. | |
| (* Theorem T18: Rollback Correctness *) | |
| Lemma rollback_correctness : forall state target_gen, | |
| rollback_precondition_met state target_gen -> | |
| generation (rollback_to_generation state target_gen) = target_gen. | |
| Proof. | |
| intros state target_gen Hpre. | |
| unfold rollback_to_generation. | |
| reflexivity. | |
| Qed. | |
| (* Rollback preserves well-formedness *) | |
| Lemma rollback_preserves_wellformedness : forall state target_gen, | |
| well_formed_state state -> | |
| rollback_precondition_met state target_gen -> | |
| well_formed_state (rollback_to_generation state target_gen). | |
| Proof. | |
| intros state target_gen Hwf Hpre. | |
| unfold rollback_to_generation. | |
| exact Hwf. | |
| Qed. | |
| (* Generation monotonicity after rollback *) | |
| Lemma rollback_respects_monotonicity : forall state gen1 gen2, | |
| gen1 < gen2 -> | |
| generation (rollback_to_generation state gen1) < | |
| generation (rollback_to_generation state gen2). | |
| Proof. | |
| intros state gen1 gen2 Hlt. | |
| unfold rollback_to_generation. | |
| exact Hlt. | |
| Qed. | |