Alt-ergo has no input syntax for triggers on existential quantifiers

parent 56135b10
* marks an incompatible change
o fixed Alt-ergo output: no triggers for "exists" quantifier
o [IDE] tool "Replay" works
o [IDE] does not use Threads anymore, thanks to Call_provers.query_call
o VC gen produces explanations in a suitable form for IDE
......
(* Floyd's ``the tortoise and the hare'' algorithm. *)
module TortoiseHare
use import int.Int
(* We consider a function f over an abstract type t *)
type t
logic f t : t
(* Given some x0 in t, we consider the sequence of the repeated calls
to f starting from x0. *)
logic x int : t
axiom xdef: forall n:int. n >= 0 -> x (n+1) = f (x n)
logic x0 : t = x 0
(* If t is finite, this sequence will eventually end up on a cycle.
Let us simply assume the existence of this cycle, that is
x (i + lambda) = x i, for some lambda > 0 and i large enough. *)
logic mu : int
axiom mu: mu >= 0
logic lambda : int
axiom lambda: lambda >= 1
axiom cycle: forall i:int. mu <= i -> x (i + lambda) = x i
lemma cycle_gen:
forall i:int. mu <= i -> forall k:int. 0 <= k -> x (i + lambda * k) = x i
(* The challenge is to prove that the recursive function
let rec run x1 x2 = if x1 <> x2 then run (f x1) (f (f x2))
terminates when called on x0 and (f x0).
*)
logic dist int int : int
axiom dist_def1:
forall n m: int. 0 <= n <= m ->
x (n + dist n m) = x m
axiom dist_def2:
forall n m: int. 0 <= n <= m ->
forall k: int. x (n + k) = x m -> dist n m <= k
logic r (x12 : (t, t)) (x'12 : (t, t)) =
let x1, x2 = x12 in
let x'1, x'2 = x'12 in
exists m:int.
x1 = x (m+1) and x2 = x (2*m+2) and x'1 = x m and x'2 = x (2*m) and
m < mu or (mu <= m and dist (m+1) (2*m+2) < dist m (2*m))
let rec run x1 x2 variant { (x1, x2) } with r =
{ exists m:int [x m]. x1 = x m and x2 = x (2*m) }
if x1 <> x2 then
run (f x1) (f (f x2))
{ }
end
(*
Local Variables:
compile-command: "unset LANG; make -C ../.. examples/programs/tortoise_hare.gui"
End:
*)
......@@ -102,8 +102,11 @@ let rec print_fmla info fmt f = match f.f_node with
(print_list comma (print_term info)) tl
end
| Fquant (q, fq) ->
let q = match q with Fforall -> "forall" | Fexists -> "exists" in
let vl, tl, f = f_open_quant fq in
let q, tl = match q with
| Fforall -> "forall", tl
| Fexists -> "exists", [] (* Alt-ergo has no triggers for exists *)
in
let forall fmt v =
fprintf fmt "%s %a:%a" q print_ident v.vs_name (print_type info) v.vs_ty
in
......@@ -141,8 +144,7 @@ and print_triggers info fmt tl =
| Term _ -> true
| Fmla {f_node = Fapp (ps,_)} -> not (ls_equal ps ps_equ)
| _ -> false in
let tl = List.map (List.filter filter)
tl in
let tl = List.map (List.filter filter) tl in
let tl = List.filter (function [] -> false | _::_ -> true) tl in
if tl = [] then () else fprintf fmt "@ [%a]"
(print_list alt (print_list comma (print_expr info))) tl
......
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