val return_ (a:Type u#a)
            (x:a)
            (opened_invariants:inames)
            (#[@@@ framing_implicit] p:a -> vprop)
  : repr a true opened_invariants Unobservable
         (return_pre (p x)) p
         True
         (fun v -> v == x)
let return_ (a:Type u#a)
            (x:a)
            (opened_invariants:inames)
            (#[@@@ framing_implicit] p:a -> vprop)
  : repr a true opened_invariants Unobservable
         (return_pre (p x)) p
         True
         (fun v -> v == x)
  = weaken_repr (SEA.return_ a x opened_invariants #p) () ()
val return_ (a:Type u#a)
            (x:a)
            (opened_invariants:inames)
            (#[@@@ framing_implicit] p:a -> vprop)
  : repr a true opened_invariants Unobservable
         (return_pre (p x)) p
         True
         (fun v -> v == x)
let return_
      (a: Type u#a)
      (x: a)
      (opened_invariants: inames)
      (#[@@@ framing_implicit]p: (a -> vprop))
    : repr a true opened_invariants Unobservable (return_pre (p x)) p True (fun v -> v == x) =
weaken_repr (SEA.return_ a x opened_invariants #p) () ()
Steel.ST.Effect.AtomicAndGhost.fst.checked
Steel.ST.Effect.fst.checked Steel.Memory.fsti.checked Steel.Effect.Common.fsti.checked Steel.Effect.Atomic.fst.checked Steel.Effect.fsti.checked prims.fst.checked FStar.Tactics.fst.checked FStar.Set.fsti.checked FStar.Pervasives.fsti.checked FStar.Monotonic.Pure.fst.checked FStar.Classical.Sugar.fsti.checked
Steel.ST.Effect.AtomicAndGhost.fst
Steel.Memory.inames Steel.Effect.Common.vprop Steel.ST.Effect.AtomicAndGhost.weaken_repr Steel.Effect.Common.Unobservable Steel.Effect.Common.return_pre Steel.Effect.Atomic.return_req Steel.Effect.Common.rmem Prims.l_True Steel.Effect.Atomic.return_ens Prims.eq2 Steel.Effect.Atomic.return_ Steel.ST.Effect.AtomicAndGhost.repr
(*
   Copyright 2020 Microsoft Research

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*)

module Steel.ST.Effect.AtomicAndGhost
friend Steel.Effect.Atomic
friend Steel.ST.Effect
module C = Steel.Effect.Common
open Steel.Memory
module T = FStar.Tactics
module STF = Steel.ST.Effect
module SEA = Steel.Effect.Atomic
open Steel.Effect.Atomic

/// This module defines atomic and ghost variants of the Steel effect

#set-options "--warn_error -330 --ide_id_info_off"  //turn off the experimental feature warning

let repr (a:Type u#a)
         (already_framed:bool)
         (opened_invariants:inames)
         (g:observability)
         (pre:pre_t)
         (post:post_t a)
         (req:Type0)
         (ens:a -> Type0)
  : Type u#(max a 2)
  = SEA.repr a already_framed opened_invariants g pre post
             (fun _ -> req)
             (fun _ x _ -> ens x)



let equiv_star_emp_r (p:vprop)
  : Lemma ((p `star` emp) `equiv` p)
  = cm_identity p;
    assert ((emp `star` p) `equiv` p);
    star_commutative p emp;
    equiv_trans (p `star` emp) (emp `star` p) p

let weaken_repr #a #framed #o #g
                (#pre:pre_t)
                (#post:post_t a)
                (#req #req':req_t pre)
                (#ens #ens':ens_t pre a post)
                ($f:SEA.repr a framed o g pre post req ens)
                (_:squash (forall (h0:hmem pre).
                            req' (mk_rmem _ h0) ==>
                            req (mk_rmem _ h0)))
                (_:squash (forall (h0:hmem pre) x (h1:hmem (post x)).
                            ens (mk_rmem _ h0)
                                x
                                (mk_rmem _ h1) ==>
                            ens' (mk_rmem _ h0) x (mk_rmem _ h1)))
  : Tot (SEA.repr a framed o g pre post req' ens')
  = let focus_rmem_refl (r:vprop) (h:rmem r)
      : Lemma (ensures focus_rmem #r h r == h)
              [SMTPat (focus_rmem #r h r)]
      = focus_rmem_refl r h
    in
    let equiv_trans (x y z:vprop) : Lemma
      (requires equiv x y /\ equiv y z)
      (ensures equiv x z)
      [SMTPat (equiv x z);
       SMTPat (equiv x y)]
     = equiv_trans x y z
    in
    let cbs (p:vprop)
      : Lemma (p `can_be_split` (p `star` emp))
              [SMTPat (p `can_be_split` (p `star` emp))]
      = star_commutative p emp;
        cm_identity p;
        equiv_sym (p `star` emp) p;
        equiv_can_be_split p (p `star` emp)
    in
    let epost ()
      : Lemma (equiv_forall post (fun x -> star (post x) emp))
      = introduce forall x. post x `equiv` (post x `star` emp)
        with (
          equiv_star_emp_r (post x);
          equiv_sym (post x `star` emp) (post x)
        );
        equiv_forall_elim post (fun x -> star (post x) emp)
    in
    epost ();
    SEA.subcomp_opaque a o g g #framed #framed
                         #pre #post
                         #req #ens
                         #pre #post
                         #req' #ens'
                         #emp
                         #True
                         #()
                         #()
                         #()
                         f

let return_ (a:Type u#a)
            (x:a)
            (opened_invariants:inames)
            (#[@@@ framing_implicit] p:a -> vprop)
  : repr a true opened_invariants Unobservable
         (return_pre (p x)) p
         True
val return_ (a:Type u#a)
            (x:a)
            (opened_invariants:inames)
            (#[@@@ framing_implicit] p:a -> vprop)
  : repr a true opened_invariants Unobservable
         (return_pre (p x)) p
         True
         (fun v -> v == x)
a: Type -> x: a -> opened_invariants: Steel.Memory.inames
  -> Steel.ST.Effect.AtomicAndGhost.repr a
      true
      opened_invariants
      Steel.Effect.Common.Unobservable
      (Steel.Effect.Common.return_pre (p x))
      p
      Prims.l_True
      (fun v -> v == x)