Library OracleLanguages.Imp.Oracles.RefactorCommonBranchRemainder
Require Import Common.
Require Import Imp.Lang.
Require Import ProgrammingLanguage.
Require Import OracleLanguage.
Require Import OracleHelpers.
Module Make
(Var_as_DT : UsualDecidableTypeOrig)
(Import Lang : ImpProgrammingLanguage Var_as_DT)
(Import OracleHelpers : ImpOracleHelpers Var_as_DT Lang).
Inductive mod :=
| Refactor.
Inductive _cont_mod := .
Definition _genv := unit.
Inductive _state : Type :=
| Stuck : state → state → _state
| State : state → state → list (cont_mod mod _cont_mod) → _state.
Definition perform_n_steps
(n : nat) (S₁ S₂ : state)
(km' : list (cont_mod mod _cont_mod)) : option _state :=
match step υ S₁, step υ S₂ with
| None, None ⇒
None
| _, _ ⇒
match nsteps' υ n S₁, nsteps' υ n S₂ with
| (S₁', 0), (S₂', 0) ⇒
Some (State S₁' S₂' km')
| (S₁', S _), (S₂', S _) ⇒
Some (Stuck S₁' S₂')
| _, _ ⇒
None
end
end.
Definition _step (_ : _genv) (S : _state) : option _state :=
match S with
| Stuck S₁ S₂ ⇒
None
| State S₁ S₂ km ⇒
match step_helper S₁ S₂ km with
| None ⇒
None
| Some StuckStep ⇒
None
| Some (GenericStep S₁' S₂' km') ⇒
Some (State S₁' S₂' km')
| Some (SpecialCmdStep _ km') ⇒
perform_n_steps 2 S₁ S₂ (CmdMod Id::CmdMod Id::km')
| Some (SpecialContStep _ km') ⇒
None
end
end.
Definition _left_state (S : _state) : ProgrammingLanguage.state imp_language :=
match S with
| Stuck S₁ _ | State S₁ _ _ ⇒
S₁
end.
Definition _right_state (S : _state) : ProgrammingLanguage.state imp_language :=
match S with
| Stuck _ S₂ | State _ S₂ _ ⇒
S₂
end.
Definition refactor_common_trailer c :=
match c with
| ITE b (Seq c₁₁ c₁₂) (Seq c₂₁ c₂₂) ⇒
if cmd_eq_dec c₁₂ c₂₂ then
ret (Seq (ITE b c₁₁ c₂₁) c₁₂)
else
None
| _ ⇒ None
end.
Fixpoint apply_cmd_mod c m :=
match m with
| Id ⇒ Some c
| RecMod m₁ m₂ ⇒
match c with
| Seq c₁ c₂ ⇒
apply_cmd_mod c₁ m₁ >>= λ c₁',
apply_cmd_mod c₂ m₂ >>= λ c₂',
Some (Seq c₁' c₂')
| ITE b c₁ c₂ ⇒
apply_cmd_mod c₁ m₁ >>= λ c₁',
apply_cmd_mod c₂ m₂ >>= λ c₂',
Some (ITE b c₁' c₂')
| While b c ⇒
apply_cmd_mod c m₁ >>= λ c',
Some (While b c')
| Skip | Assign _ _ | Assert _ ⇒
None
end
| LeafMod Refactor ⇒ refactor_common_trailer c
end.
Lemma apply_cmd_mod_id:
∀ c, apply_cmd_mod c Id = Some c.
Inductive km_invariant : list (cont_mod mod _cont_mod) → cont → cont → Prop :=
| empty_cont_mod : km_invariant [] [] []
| cmd_cont : ∀ c c' m km k₁ k₂,
apply_cmd_mod c m = Some c' →
km_invariant km k₁ k₂ →
km_invariant (CmdMod m::km) (c::k₁) (c'::k₂).
Definition _invariant (_ : _genv) (S : _state) : Prop :=
match S with
| Stuck S₁ S₂ ⇒ step υ S₁ = None ∧ step υ S₂ = None
| State (k₁, s₁) (k₂, s₂) km ⇒
km_invariant km k₁ k₂ ∧ M.Equal s₁ s₂
end.
Lemma _invariant_1:
∀ genv os os',
_invariant genv os →
_step genv os = Some os' →
_invariant genv os'.
Lemma _prediction_soundness :
∀ genv os os',
_invariant genv os →
_step genv os = Some os' →
∃ n₁ n₂,
opt_state_eq (nsteps υ n₁ (_left_state os))
(Some (_left_state os'))
∧ opt_state_eq (nsteps υ n₂ (_right_state os))
(Some (_right_state os'))
∧ n₁ + n₂ > 0.
Lemma _prediction_completeness :
∀ genv os,
_invariant genv os →
_step genv os = None →
step υ (_left_state os) = None
∧ step υ (_right_state os) = None.
Definition refactor_common_branch_trailer_oracle
: oracle_language imp_language imp_language :=
{|
oracle_state := _state;
oracle_genv := unit;
oracle_step := _step;
left_state := _left_state;
right_state := _right_state;
left_genv := λ _, υ;
right_genv := λ _, υ;
invariant := _invariant;
invariant_1 := _invariant_1;
prediction_soundness := _prediction_soundness;
prediction_completeness := _prediction_completeness
|}.
End Make.