From Undecidability Require Import TM.Util.Prelim TM.Util.TM_facts.
From Undecidability.TM Require Import Lifting.LiftTapes CodeTM ChangeAlphabet.
Ltac modpon' H :=
simpl_surject;
once lazymatch type of H with
| forall (i : Fin.t _), ?P => idtac
| forall (x : ?X), ?P =>
once lazymatch type of X with
| Prop =>
tryif spec_assert H by
(simpl_surject;
solve [ eauto
| contains_ext
| isVoid_mono
]
)
then idtac ;
modpon' H
else (spec_assert H;
[ idtac
| modpon' H
]
)
| _ =>
let x' := fresh "x" in
evar (x' : X); specialize (H x'); subst x';
modpon' H
end
| ?X /\ ?Y =>
let H' := fresh H in
destruct H as [H H']; modpon' H; modpon' H'
| _ => idtac
end.
Ltac modpon H := progress (modpon' H).
Ltac dec_pos P := let H := fresh in destruct (Dec P) as [_ | H]; [ | now contradiction H].
Ltac dec_neg P := let H := fresh in destruct (Dec P) as [H | _]; [now contradiction H | ].
Ltac simpl_dec :=
match goal with
| [ H : context [ Dec (?x = ?x) ] |- _ ] => dec_pos (x=x)
| [ |- context [ Dec (?x = ?x) ]] => dec_pos (x=x)
| [ _ : ?H |- context [ Dec ?H ]] => dec_pos H
| [ _ : ~ ?H |- context [ Dec ?H ]] => dec_neg H
| [ _ : ?H, _ : context [ Dec ?H ] |- _] => dec_pos H
| [ _ : ~ ?H, _ : context [ Dec ?H ] |- _] => dec_neg H
| _ => fail "could not match goal"
end.
Section test.
Variable P : Prop.
Variable dec_P : dec P.
Goal if Dec (1 = 1) then True else False.
Proof.
intros. deq 1. tauto.
Qed.
Goal P -> if (Dec P) then True else False.
Proof.
intros. simpl_dec. tauto.
Qed.
Goal ~ P -> if (Dec P) then False else True.
Proof.
intros. simpl_dec. tauto.
Qed.
Goal P -> (if (Dec P) then False else True) -> False.
Proof.
intros. simpl_dec. tauto.
Qed.
Goal ~ P -> (if (Dec P) then True else False) -> False.
Proof.
intros. simpl_dec. tauto.
Qed.
End test.
Ltac inv_pair :=
once lazymatch goal with
| [ H : (_, _) = (_, _) |- _] => inv H
| [ |- (_, _) = (_, _) ] => f_equal
end.
Ltac destruct_param_tape_pair :=
once lazymatch goal with
| [ x : _ * tapes _ _ |- _] =>
let ymid := fresh "ymid" in
let tmid := fresh "tmid" in
destruct x as (ymid&tmid)
end.
Ltac destruct_unit :=
repeat once lazymatch goal with
| [ x : unit |- _ ] => destruct x
end.
Ltac TMSimp_goal :=
repeat multimatch goal with
| [ H : ?X = _ |- _ ] => rewrite H
end.
Fixpoint all_vec {X:Type} {n:nat} {struct n}: (Vector.t X n -> Prop) -> Prop :=
match n with
0 => fun A => A (@Vector.nil _)
| S n => fun A => forall x, all_vec (fun xs => A (x:::xs))
end.
Lemma all_vec_correct {X:Type} {n:nat} (P : Vector.t X n -> Prop):
all_vec P -> forall xs, P xs.
Proof.
revert P. induction n;cbn;intros. now apply Vector.case0.
intros. apply Vector.caseS'. intro. now eapply IHn.
Qed.
Lemma all_vec_correct2 {X:Type} {n:nat} (P : Vector.t X n -> Prop):
(forall xs, P xs) -> all_vec P.
Proof.
revert P. induction n;cbn;intros. now apply Vector.case0. eauto.
Qed.
Tactic Notation "vector_destruct" hyp(tin) :=
let rec introT n :=
once lazymatch n with
| S ?n =>
let x := fresh tin "_0" in
intro x;introT n
| 0 => try clear tin
| _ => simple apply all_vec_correct2;try clear tin;let tin' := fresh tin in intros tin'
end
in
let tac n := revert dependent tin; refine (all_vec_correct _);
cbn [all_vec];introT n;cbn [Vector.nth Vector.caseS];intros
in
once lazymatch type of tin with
tapes _ ?n => tac n
| Vector.t _ ?n => tac n
end.
Lemma eq_nth_iff' X n (v w : Vector.t X n):
(forall i : Fin.t n, v[@i] = w[@i]) -> v = w.
Proof. intros. eapply Vector.eq_nth_iff. now intros ? ? ->. Qed.
Ltac TMSimp1 T :=
try destruct_param_tape_pair; destruct_unit;
simpl_not_in;
cbn in *;
repeat match goal with
| [ H : ?x = _ |- _ ] => is_var x;move x at bottom;subst x
| [ H : _ = ?x |- _ ] => is_var x;move x at bottom;symmetry in H;subst x
| [ H : (forall i : Fin.t _, _[@i] = _[@i]) |- _ ] => apply eq_nth_iff' in H
end;
unfold finType_CS in *;
try T;
repeat
once lazymatch goal with
| [ x : unit |- _ ] => destruct x
| [ H : _ ::: _ = [| |] |- _ ] => discriminate H
| [ H : [| |] = _ ::: _ |- _ ] => discriminate H
| [ H : _ ::: _ = _ ::: _ |- _ ] => apply VectorSpec.cons_inj in H
| [ H : _ :: _ = [] |- _ ] => discriminate H
| [ H : [] = _ :: _ |- _ ] => discriminate H
| [ H : _ :: _ = _ :: _ |- _ ] => inv H
| [ H : Some _ = Some _ |- _ ] => inv H
| [ H : None = Some _ |- _ ] => discriminate H
| [ H : Some _ = None |- _ ] => discriminate H
| [ H : _ /\ _ |- _] => destruct H
| [ H : @ex ?A ?P |- _] =>
once lazymatch A with
| tapes _ _ =>
let tmid := fresh "tmid" in
destruct H as (tmid&H)
| _ =>
let ymid := fresh "ymid" in
destruct H as (ymid&H)
end
| [ x : _ * _ |- _ ] => destruct x
end.
Ltac TMSimp2 :=
let tac ts n :=
once lazymatch n with
S _ => vector_destruct ts
end
in
once match goal with
| [ ts: tapes _ ?n|- _ ] => tac ts n
| [ ts: Vector.t _ ?n|- _ ] => tac ts n
| [H : @Vector.nil _ = @Vector.nil _ |-_ ] => clear H
end.
Tactic Notation "TMSimp" tactic(T) :=
repeat progress (repeat progress TMSimp1 T; repeat TMSimp2; unlock all).
Tactic Notation "TMSimp" := TMSimp idtac.
Tactic Notation "TMBranche" :=
(
match goal with
| [ H : context [ match ?x with _ => _ end ] |- _ ] => let E := fresh "E" in destruct x eqn:E
| [ |- context [ match ?x with _ => _ end ] ] => let E := fresh "E" in destruct x eqn:E
| [ H : _ \/ _ |- _] => destruct H
| [ IH : ?P -> ?Q |- _] =>
match type of P with
| Prop => spec_assert IH; [ clear IH | ]
end
| [ x : bool |- _ ] => destruct x
| [ x : option _ |- _ ] => destruct x
| [ |- ex ?P ] => eexists
| [ H : _ \/ _ |- _] => destruct H
end
).
Tactic Notation "TMSolve" int_or_var(k) :=
repeat progress first [
match goal with
| [ |- (_ ::: _) = (_ ::: _) ] => f_equal
| [ |- Some _ = Some _ ] => f_equal
| [ |- _ /\ _ ] => split
end
|| congruence
|| eauto k
].
Tactic Notation "TMCrush" tactic(T) :=
repeat progress
(
TMSimp T;
try TMBranche
).
Tactic Notation "TMCrush" :=
repeat progress
(
TMSimp;
try TMBranche
).
From Undecidability.TM Require Import Lifting.LiftTapes CodeTM ChangeAlphabet.
Ltac modpon' H :=
simpl_surject;
once lazymatch type of H with
| forall (i : Fin.t _), ?P => idtac
| forall (x : ?X), ?P =>
once lazymatch type of X with
| Prop =>
tryif spec_assert H by
(simpl_surject;
solve [ eauto
| contains_ext
| isVoid_mono
]
)
then idtac ;
modpon' H
else (spec_assert H;
[ idtac
| modpon' H
]
)
| _ =>
let x' := fresh "x" in
evar (x' : X); specialize (H x'); subst x';
modpon' H
end
| ?X /\ ?Y =>
let H' := fresh H in
destruct H as [H H']; modpon' H; modpon' H'
| _ => idtac
end.
Ltac modpon H := progress (modpon' H).
Ltac dec_pos P := let H := fresh in destruct (Dec P) as [_ | H]; [ | now contradiction H].
Ltac dec_neg P := let H := fresh in destruct (Dec P) as [H | _]; [now contradiction H | ].
Ltac simpl_dec :=
match goal with
| [ H : context [ Dec (?x = ?x) ] |- _ ] => dec_pos (x=x)
| [ |- context [ Dec (?x = ?x) ]] => dec_pos (x=x)
| [ _ : ?H |- context [ Dec ?H ]] => dec_pos H
| [ _ : ~ ?H |- context [ Dec ?H ]] => dec_neg H
| [ _ : ?H, _ : context [ Dec ?H ] |- _] => dec_pos H
| [ _ : ~ ?H, _ : context [ Dec ?H ] |- _] => dec_neg H
| _ => fail "could not match goal"
end.
Section test.
Variable P : Prop.
Variable dec_P : dec P.
Goal if Dec (1 = 1) then True else False.
Proof.
intros. deq 1. tauto.
Qed.
Goal P -> if (Dec P) then True else False.
Proof.
intros. simpl_dec. tauto.
Qed.
Goal ~ P -> if (Dec P) then False else True.
Proof.
intros. simpl_dec. tauto.
Qed.
Goal P -> (if (Dec P) then False else True) -> False.
Proof.
intros. simpl_dec. tauto.
Qed.
Goal ~ P -> (if (Dec P) then True else False) -> False.
Proof.
intros. simpl_dec. tauto.
Qed.
End test.
Ltac inv_pair :=
once lazymatch goal with
| [ H : (_, _) = (_, _) |- _] => inv H
| [ |- (_, _) = (_, _) ] => f_equal
end.
Ltac destruct_param_tape_pair :=
once lazymatch goal with
| [ x : _ * tapes _ _ |- _] =>
let ymid := fresh "ymid" in
let tmid := fresh "tmid" in
destruct x as (ymid&tmid)
end.
Ltac destruct_unit :=
repeat once lazymatch goal with
| [ x : unit |- _ ] => destruct x
end.
Ltac TMSimp_goal :=
repeat multimatch goal with
| [ H : ?X = _ |- _ ] => rewrite H
end.
Fixpoint all_vec {X:Type} {n:nat} {struct n}: (Vector.t X n -> Prop) -> Prop :=
match n with
0 => fun A => A (@Vector.nil _)
| S n => fun A => forall x, all_vec (fun xs => A (x:::xs))
end.
Lemma all_vec_correct {X:Type} {n:nat} (P : Vector.t X n -> Prop):
all_vec P -> forall xs, P xs.
Proof.
revert P. induction n;cbn;intros. now apply Vector.case0.
intros. apply Vector.caseS'. intro. now eapply IHn.
Qed.
Lemma all_vec_correct2 {X:Type} {n:nat} (P : Vector.t X n -> Prop):
(forall xs, P xs) -> all_vec P.
Proof.
revert P. induction n;cbn;intros. now apply Vector.case0. eauto.
Qed.
Tactic Notation "vector_destruct" hyp(tin) :=
let rec introT n :=
once lazymatch n with
| S ?n =>
let x := fresh tin "_0" in
intro x;introT n
| 0 => try clear tin
| _ => simple apply all_vec_correct2;try clear tin;let tin' := fresh tin in intros tin'
end
in
let tac n := revert dependent tin; refine (all_vec_correct _);
cbn [all_vec];introT n;cbn [Vector.nth Vector.caseS];intros
in
once lazymatch type of tin with
tapes _ ?n => tac n
| Vector.t _ ?n => tac n
end.
Lemma eq_nth_iff' X n (v w : Vector.t X n):
(forall i : Fin.t n, v[@i] = w[@i]) -> v = w.
Proof. intros. eapply Vector.eq_nth_iff. now intros ? ? ->. Qed.
Ltac TMSimp1 T :=
try destruct_param_tape_pair; destruct_unit;
simpl_not_in;
cbn in *;
repeat match goal with
| [ H : ?x = _ |- _ ] => is_var x;move x at bottom;subst x
| [ H : _ = ?x |- _ ] => is_var x;move x at bottom;symmetry in H;subst x
| [ H : (forall i : Fin.t _, _[@i] = _[@i]) |- _ ] => apply eq_nth_iff' in H
end;
unfold finType_CS in *;
try T;
repeat
once lazymatch goal with
| [ x : unit |- _ ] => destruct x
| [ H : _ ::: _ = [| |] |- _ ] => discriminate H
| [ H : [| |] = _ ::: _ |- _ ] => discriminate H
| [ H : _ ::: _ = _ ::: _ |- _ ] => apply VectorSpec.cons_inj in H
| [ H : _ :: _ = [] |- _ ] => discriminate H
| [ H : [] = _ :: _ |- _ ] => discriminate H
| [ H : _ :: _ = _ :: _ |- _ ] => inv H
| [ H : Some _ = Some _ |- _ ] => inv H
| [ H : None = Some _ |- _ ] => discriminate H
| [ H : Some _ = None |- _ ] => discriminate H
| [ H : _ /\ _ |- _] => destruct H
| [ H : @ex ?A ?P |- _] =>
once lazymatch A with
| tapes _ _ =>
let tmid := fresh "tmid" in
destruct H as (tmid&H)
| _ =>
let ymid := fresh "ymid" in
destruct H as (ymid&H)
end
| [ x : _ * _ |- _ ] => destruct x
end.
Ltac TMSimp2 :=
let tac ts n :=
once lazymatch n with
S _ => vector_destruct ts
end
in
once match goal with
| [ ts: tapes _ ?n|- _ ] => tac ts n
| [ ts: Vector.t _ ?n|- _ ] => tac ts n
| [H : @Vector.nil _ = @Vector.nil _ |-_ ] => clear H
end.
Tactic Notation "TMSimp" tactic(T) :=
repeat progress (repeat progress TMSimp1 T; repeat TMSimp2; unlock all).
Tactic Notation "TMSimp" := TMSimp idtac.
Tactic Notation "TMBranche" :=
(
match goal with
| [ H : context [ match ?x with _ => _ end ] |- _ ] => let E := fresh "E" in destruct x eqn:E
| [ |- context [ match ?x with _ => _ end ] ] => let E := fresh "E" in destruct x eqn:E
| [ H : _ \/ _ |- _] => destruct H
| [ IH : ?P -> ?Q |- _] =>
match type of P with
| Prop => spec_assert IH; [ clear IH | ]
end
| [ x : bool |- _ ] => destruct x
| [ x : option _ |- _ ] => destruct x
| [ |- ex ?P ] => eexists
| [ H : _ \/ _ |- _] => destruct H
end
).
Tactic Notation "TMSolve" int_or_var(k) :=
repeat progress first [
match goal with
| [ |- (_ ::: _) = (_ ::: _) ] => f_equal
| [ |- Some _ = Some _ ] => f_equal
| [ |- _ /\ _ ] => split
end
|| congruence
|| eauto k
].
Tactic Notation "TMCrush" tactic(T) :=
repeat progress
(
TMSimp T;
try TMBranche
).
Tactic Notation "TMCrush" :=
repeat progress
(
TMSimp;
try TMBranche
).