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(* Checking use of retyping in w_unify0 in the presence of unification
problems of the form \x:Meta.Meta = \x:ind.match x with ... end *)
From Stdlib Require Import List.
From Stdlib Require Import QArith.
From Stdlib Require Import Qcanon.
Set Implicit Arguments.
Inductive dynamic : Type :=
| Dyn : forall T, T -> dynamic.
Definition perm := Qc.
Locate Qle_bool.
Definition compatibleb (p1 p2 : perm) : bool :=
let p1pos := Qle_bool 0 p1 in
let p2pos := Qle_bool 0 p2 in
negb (
(p1pos && p2pos)
|| ((p1pos || p2pos) && (negb (Qle_bool 0 ((p1 + p2)%Qc)))))%Qc.
Definition compatible (p1 p2 : perm) := compatibleb p1 p2 = true.
Definition perm_plus (p1 p2 : perm) : option perm :=
if compatibleb p1 p2 then Some (p1 + p2) else None.
Infix "+p" := perm_plus (at level 60, no associativity).
Axiom axiom_ptr : Set.
Definition ptr := axiom_ptr.
Axiom axiom_ptr_eq_dec : forall (a b : ptr), {a = b} + {a <> b}.
Definition ptr_eq_dec := axiom_ptr_eq_dec.
Definition hval := (dynamic * perm)%type.
Definition heap := ptr -> option hval.
Bind Scope heap_scope with heap.
Delimit Scope heap_scope with heap.
Local Open Scope heap_scope.
Definition read (h : heap) (p : ptr) : option hval := h p.
Notation "a # b" := (read a b) (at level 55, no associativity) : heap_scope.
Definition val (v:hval) := fst v.
Definition frac (v:hval) := snd v.
Definition hval_plus (v1 v2 : hval) : option hval :=
match (frac v1) +p (frac v2) with
| None => None
| Some v1v2 => Some (val v1, v1v2)
end.
Definition hvalo_plus (v1 v2 : option hval) :=
match v1 with
| None => v2
| Some v1' =>
match v2 with
| None => v1
| Some v2' => (hval_plus v1' v2')
end
end.
Notation "v1 +o v2" := (hvalo_plus v1 v2) (at level 60, no associativity) : heap_scope.
Definition join (h1 h2 : heap) : heap :=
(fun p => (h1 p) +o (h2 p)).
Infix "*" := join (at level 40, left associativity) : heap_scope.
Definition hprop := heap -> Prop.
Bind Scope hprop_scope with hprop.
Delimit Scope hprop_scope with hprop.
Definition hprop_cell (p : ptr) T (v : T) (pi:Qc): hprop := fun h =>
h#p = Some (Dyn v, pi) /\ forall p', p' <> p -> h#p' = None.
Notation "p ---> v" := (hprop_cell p v (0%Qc)) (at level 38, no associativity) : hprop_scope.
Definition empty : heap := fun _ => None.
Definition hprop_empty : hprop := eq empty.
Notation "'emp'" := hprop_empty : hprop_scope.
Definition hprop_inj (P : Prop) : hprop := fun h => h = empty /\ P.
Notation "[ P ]" := (hprop_inj P) (at level 0, P at level 200) : hprop_scope.
Definition hprop_imp (p1 p2 : hprop) : Prop := forall h, p1 h -> p2 h.
Infix "==>" := hprop_imp (right associativity, at level 55).
Definition hprop_ex T (p : T -> hprop) : hprop := fun h => exists v, p v h.
Notation "'Exists' v :@ T , p" := (hprop_ex (fun v : T => p%hprop))
(at level 90, T at next level) : hprop_scope.
Local Open Scope hprop_scope.
Definition disjoint (h1 h2 : heap) : Prop :=
forall p,
match h1#p with
| None => True
| Some v1 => match h2#p with
| None => True
| Some v2 => val v1 = val v2
/\ compatible (frac v1) (frac v2)
end
end.
Infix "<#>" := disjoint (at level 40, no associativity) : heap_scope.
Definition split (h h1 h2 : heap) : Prop := h1 <#> h2 /\ h = h1 * h2.
Notation "h ~> h1 * h2" := (split h h1 h2) (at level 40, h1 at next level, no associativity).
Definition hprop_sep (p1 p2 : hprop) : hprop := fun h =>
exists h1, exists h2, h ~> h1 * h2
/\ p1 h1
/\ p2 h2.
Infix "*" := hprop_sep (at level 40, left associativity) : hprop_scope.
Section Stack.
Variable T : Set.
Record node : Set := Node {
data : T;
next : option ptr
}.
Fixpoint listRep (ls : list T) (hd : option ptr) {struct ls} : hprop :=
match ls with
| nil => [hd = None]
| h :: t =>
match hd with
| None => [False]
| Some hd' => Exists p :@ option ptr, hd' ---> Node h p * listRep t p
end
end%hprop.
Definition stack := ptr.
Definition rep q ls := (Exists po :@ option ptr, q ---> po * listRep ls po)%hprop.
Definition isExistential T (x : T) := True.
Theorem himp_ex_conc_trivial : forall T p p1 p2,
p ==> p1 * p2
-> T
-> p ==> hprop_ex (fun _ : T => p1) * p2.
Admitted.
Goal forall (s : ptr) (x : T) (nd : ptr) (v : unit) (x0 : list T) (v0 : option ptr)
(H0 : isExistential v0),
nd ---> {| data := x; next := v0 |} * (s ---> Some nd * listRep x0 v0) ==>
(Exists po :@ option ptr,
s ---> po *
match po with
| Some hd' =>
Exists p :@ option ptr,
hd' ---> {| data := x; next := p |} * listRep x0 p
| None => [False]
end) * emp.
Proof.
intros.
try apply himp_ex_conc_trivial.
Abort.
End Stack.
|
