treedel example: a few renamings

type point -> loc
predicate tree -> istree
post-condition: t -> t'

examples/verifythis_fm2012_treedel.mlw

@@ -12,7 +12,7 @@ Iterative deletion in a binary search tree - 90 minutes
 VERIFICATION TASK
 -----------------
 
-Given: a pointer t to the root of a non-empty binary search tree (not
+Given: a loc t to the root of a non-empty binary search tree (not
 necessarily balanced). Verify that the following procedure removes the
 node with the minimal key from the tree. After removal, the data
 structure should again be a binary search tree.
@@ -38,30 +38,30 @@ Note: When implementing in a garbage-collected language, the call to
 dispose() is superfluous.
 *)
 
-(* Why3 has no pointer data structures, so we model the heap *)
+(* Why3 has no loc data structures, so we model the heap *)
 module Memory
 
   use export map.Map
   use export ref.Ref
 
-  type pointer
-  constant null: pointer
-  type node = { left: pointer; right: pointer; data: int; }
-  type memory = map pointer node
+  type loc
+  constant null: loc
+  type node = { left: loc; right: loc; data: int; }
+  type memory = map loc node
 
   (* the global variable mem contains the current state of the memory *)
   val mem: ref memory
 
-  (* accessor functions to ensure safety i.e. no null pointer dereference *)
-  let get_left (p: pointer) : pointer =
+  (* accessor functions to ensure safety i.e. no null loc dereference *)
+  let get_left (p: loc) : loc =
     requires { p <> null }
     ensures  { result = !mem[p].left }
     !mem[p].left
-  let get_right (p: pointer) : pointer =
+  let get_right (p: loc) : loc =
     requires { p <> null }
     ensures  { result = !mem[p].right }
     !mem[p].right
-  let get_data (p: pointer) : int =
+  let get_data (p: loc) : int =
     requires { p <> null }
     ensures  { result = !mem[p].data }
     !mem[p].data
@@ -76,14 +76,14 @@ module Treedel
   use import list.Distinct
 
   (* there is a binary tree t rooted at p in memory m *)
-  inductive tree (m: memory) (p: pointer) (t: tree pointer) =
+  inductive istree (m: memory) (p: loc) (t: tree loc) =
     | leaf: forall m: memory.
-        tree m null Empty
-    | node: forall m: memory, p: pointer, l r: tree pointer.
+        istree m null Empty
+    | node: forall m: memory, p: loc, l r: tree loc.
         p <> null ->
-        tree m m[p].left l ->
-        tree m m[p].right r ->
-        tree m p (Node l p r)
+        istree m m[p].left l ->
+        istree m m[p].right r ->
+        istree m p (Node l p r)
 
   (* degenerated zipper for a left descent (= list of pairs) *)
   type zipper 'a =
@@ -99,32 +99,32 @@ module Treedel
      forall z "induction": zipper 'a, x: 'a, l r: tree 'a.
      inorder (zip (Node l x r) z) = inorder l ++ Cons x (inorder (zip r z))
 
-  let ghost left (t: tree pointer) =
+  let ghost left (t: tree loc) =
      requires { t <> Empty }
      ensures  { match t with Empty -> false | Node l _ _ -> result = l end }
      match t with Empty -> absurd | Node l _ _ -> l end
 
-  let ghost right (t: tree pointer) =
+  let ghost right (t: tree loc) =
      requires { t <> Empty }
      ensures  { match t with Empty -> false | Node _ _ r -> result = r end }
      match t with Empty -> absurd | Node _ _ r -> r end
 
   lemma main_lemma:
-    forall m: memory, t pp p: pointer, ppr pr: tree pointer, z: zipper pointer.
+    forall m: memory, t pp p: loc, ppr pr: tree loc, z: zipper loc.
     let it = zip (Node (Node Empty p pr) pp ppr) z in
-    tree m t it -> distinct (inorder it) ->
+    istree m t it -> distinct (inorder it) ->
     let m' = m[pp <- { m[pp] with left = m[p].right }] in
-    tree m' t (zip (Node pr pp ppr) z)
+    istree m' t (zip (Node pr pp ppr) z)
 
-  (* specification is as follows: if t is a tree and its list of pointers
+  (* specification is as follows: if t is a tree and its list of locs
      is x::l then, at the end of execution, its list is l and m = x.data *)
   let search_tree_delete_min
-    (t: pointer) (ghost it: tree pointer) (ghost ot: ref (tree pointer))
-    : (pointer, int)
+    (t: loc) (ghost it: tree loc) (ghost ot: ref (tree loc))
+    : (loc, int)
     requires { t <> null }
-    requires { tree !mem t it }
+    requires { istree !mem t it }
     requires { distinct (inorder it) }
-    ensures  { let (t, m) = result in tree !mem t !ot /\
+    ensures  { let (t', m) = result in istree !mem t' !ot /\
                match inorder it with
                | Nil -> false
                | Cons p l -> m = !mem[p].data /\ inorder !ot = l end }
@@ -146,8 +146,8 @@ module Treedel
         invariant { !pp <> null /\ !mem[!pp].left = !p }
         invariant { !p <> null /\ !mem[!p].left = !tt }
         invariant { let pt = Node !subtree !pp !ppr in
-                    tree !mem !pp pt /\ zip pt !zipper = it }
-        assert { tree !mem !p !subtree };
+                    istree !mem !pp pt /\ zip pt !zipper = it }
+        assert { istree !mem !p !subtree };
         ghost zipper := Left !zipper !pp !ppr;
         ghost ppr := right !subtree;
         ghost subtree := left !subtree;
@@ -155,7 +155,7 @@ module Treedel
         p := !tt;
         tt := get_left !p
       done;
-      assert { tree !mem !p !subtree };
+      assert { istree !mem !p !subtree };
       assert { !pp <> !p };
       let m = get_data !p in
       tt := get_right !p;

examples/verifythis_fm2012_treedel/verifythis_fm2012_treedel_Treedel_WP_parameter_search_tree_delete_min_2.v

@@ -21,15 +21,15 @@ Definition contents {a:Type} {a_WT:WhyType a} (v:(ref a)): a :=
   | (mk_ref x) => x
   end.
 
-Axiom pointer : Type.
-Parameter pointer_WhyType : WhyType pointer.
-Existing Instance pointer_WhyType.
+Axiom loc : Type.
+Parameter loc_WhyType : WhyType loc.
+Existing Instance loc_WhyType.
 
-Parameter null: pointer.
+Parameter null: loc.
 
 (* Why3 assumption *)
 Inductive node :=
-  | mk_node : pointer -> pointer -> Z -> node.
+  | mk_node : loc -> loc -> Z -> node.
 Axiom node_WhyType : WhyType node.
 Existing Instance node_WhyType.
 
@@ -39,19 +39,19 @@ Definition data (v:node): Z := match v with
   end.
 
 (* Why3 assumption *)
-Definition right1 (v:node): pointer :=
+Definition right1 (v:node): loc :=
   match v with
   | (mk_node x x1 x2) => x1
   end.
 
 (* Why3 assumption *)
-Definition left1 (v:node): pointer :=
+Definition left1 (v:node): loc :=
   match v with
   | (mk_node x x1 x2) => x
   end.
 
 (* Why3 assumption *)
-Definition memory := (map.Map.map pointer node).
+Definition memory := (map.Map.map loc node).
 
 (* Why3 assumption *)
 Inductive tree
@@ -140,12 +140,12 @@ Axiom distinct_append : forall {a:Type} {a_WT:WhyType a}, forall (l1:(list
   x l1) -> ~ (mem x l2)) -> (distinct (infix_plpl l1 l2)))).
 
 (* Why3 assumption *)
-Inductive tree1 : (map.Map.map pointer node) -> pointer -> (tree
-  pointer) -> Prop :=
-  | leaf : forall (m:(map.Map.map pointer node)), (tree1 m null (Empty :(tree
-      pointer)))
-  | node1 : forall (m:(map.Map.map pointer node)) (p:pointer) (l:(tree
-      pointer)) (r:(tree pointer)), (~ (p = null)) -> ((tree1 m
+Inductive tree1 : (map.Map.map loc node) -> loc -> (tree
+  loc) -> Prop :=
+  | leaf : forall (m:(map.Map.map loc node)), (tree1 m null (Empty :(tree
+      loc)))
+  | node1 : forall (m:(map.Map.map loc node)) (p:loc) (l:(tree
+      loc)) (r:(tree loc)), (~ (p = null)) -> ((tree1 m
       (left1 (map.Map.get m p)) l) -> ((tree1 m (right1 (map.Map.get m p))
       r) -> (tree1 m p (Node l p r)))).
 
@@ -171,9 +171,9 @@ Axiom inorder_zip : forall {a:Type} {a_WT:WhyType a}, forall (z:(zipper a))
   (x:a) (l:(tree a)) (r:(tree a)), ((inorder (zip (Node l x r)
   z)) = (infix_plpl (inorder l) (Cons x (inorder (zip r z))))).
 
-Axiom main_lemma : forall (m:(map.Map.map pointer node)) (t:pointer)
-  (pp:pointer) (p:pointer) (ppr:(tree pointer)) (pr:(tree pointer))
-  (z:(zipper pointer)), let it := (zip (Node (Node (Empty :(tree pointer)) p
+Axiom main_lemma : forall (m:(map.Map.map loc node)) (t:loc)
+  (pp:loc) (p:loc) (ppr:(tree loc)) (pr:(tree loc))
+  (z:(zipper loc)), let it := (zip (Node (Node (Empty :(tree loc)) p
   pr) pp ppr) z) in ((tree1 m t it) -> ((distinct (inorder it)) -> (tree1
   (map.Map.set m pp (mk_node (right1 (map.Map.get m p))
   (right1 (map.Map.get m pp)) (data (map.Map.get m pp)))) t (zip (Node pr pp
@@ -182,39 +182,39 @@ Axiom main_lemma : forall (m:(map.Map.map pointer node)) (t:pointer)
 Require Import Why3. Ltac ae := why3 "alt-ergo" timelimit 3.
 
 (* Why3 goal *)
-Theorem WP_parameter_search_tree_delete_min : forall (t:pointer) (it:(tree
-  pointer)), forall (mem1:(map.Map.map pointer node)), (((~ (t = null)) /\
+Theorem WP_parameter_search_tree_delete_min : forall (t:loc) (it:(tree
+  loc)), forall (mem1:(map.Map.map loc node)), (((~ (t = null)) /\
   (tree1 mem1 t it)) /\ (distinct (inorder it))) -> ((~ (t = null)) ->
   ((~ ((left1 (map.Map.get mem1 t)) = null)) -> ((~ ((left1 (map.Map.get mem1
-  t)) = null)) -> ((~ (it = (Empty :(tree pointer)))) -> forall (o:(tree
-  pointer)), match it with
+  t)) = null)) -> ((~ (it = (Empty :(tree loc)))) -> forall (o:(tree
+  loc)), match it with
   | Empty => False
   | (Node _ _ r) => (o = r)
-  end -> ((~ (it = (Empty :(tree pointer)))) -> forall (o1:(tree pointer)),
+  end -> ((~ (it = (Empty :(tree loc)))) -> forall (o1:(tree loc)),
   match it with
   | Empty => False
   | (Node l _ _) => (o1 = l)
-  end -> forall (subtree:(tree pointer)) (ppr:(tree pointer))
-  (zipper1:(zipper pointer)) (tt:pointer) (pp:pointer) (p:pointer),
+  end -> forall (subtree:(tree loc)) (ppr:(tree loc))
+  (zipper1:(zipper loc)) (tt:loc) (pp:loc) (p:loc),
   ((((~ (pp = null)) /\ ((left1 (map.Map.get mem1 pp)) = p)) /\
   ((~ (p = null)) /\ ((left1 (map.Map.get mem1 p)) = tt))) /\ let pt :=
   (Node subtree pp ppr) in ((tree1 mem1 pp pt) /\ ((zip pt
   zipper1) = it))) -> ((tt = null) -> ((tree1 mem1 p subtree) ->
   ((~ (pp = p)) -> ((~ (p = null)) -> ((~ (p = null)) ->
-  forall (tt1:pointer), (tt1 = (right1 (map.Map.get mem1 p))) ->
-  forall (mem2:(map.Map.map pointer node)), (mem2 = (map.Map.set mem1 pp
+  forall (tt1:loc), (tt1 = (right1 (map.Map.get mem1 p))) ->
+  forall (mem2:(map.Map.map loc node)), (mem2 = (map.Map.set mem1 pp
   (mk_node tt1 (right1 (map.Map.get mem1 pp)) (data (map.Map.get mem1
-  pp))))) -> ((~ (subtree = (Empty :(tree pointer)))) -> forall (pl:(tree
-  pointer)),
+  pp))))) -> ((~ (subtree = (Empty :(tree loc)))) -> forall (pl:(tree
+  loc)),
   match subtree with
   | Empty => False
   | (Node l _ _) => (pl = l)
-  end -> ((pl = (Empty :(tree pointer))) -> ((~ (subtree = (Empty :(tree
-  pointer)))) -> forall (o2:(tree pointer)),
+  end -> ((pl = (Empty :(tree loc))) -> ((~ (subtree = (Empty :(tree
+  loc)))) -> forall (o2:(tree loc)),
   match subtree with
   | Empty => False
   | (Node _ _ r) => (o2 = r)
-  end -> forall (ot:(tree pointer)), (ot = (zip o2 (Left zipper1 pp ppr))) ->
+  end -> forall (ot:(tree loc)), (ot = (zip o2 (Left zipper1 pp ppr))) ->
   match (inorder it) with
   | Nil => True
   | (Cons p1 l) => ((inorder ot) = l)