Commit 60012749 authored by Andrei Paskevich's avatar Andrei Paskevich

Eliminate_epsilon: factorize canonical closures (\ x1...xn . f x1...xn)

We do not want to generate distinct liftings for every single
partial application of a function or predicate symbol. Canonical
closures have an easily recognizable shape, thus we can detect
them and replace them with a unique constant "f_closure".
parent abeaa94b
...@@ -13,25 +13,84 @@ open Ident ...@@ -13,25 +13,84 @@ open Ident
open Term open Term
open Decl open Decl
let rec lift_f acc t = match t.t_node with let is_canonical x f =
let vl,_,f = match f.t_node with
| Tquant (Tforall,b) -> t_open_quant b
| _ -> [],[],f in
let hd,e = match f.t_node with
| Tapp (ls, [hd; t]) when ls_equal ls ps_equ -> hd,t
| Tbinop (Tiff, {t_node = Tapp (ls, [hd; t])}, f)
when ls_equal ls ps_equ && t_equal t t_bool_true -> hd,f
| _ -> raise Exit in
let check_arg v t = match t.t_node with
| Tvar u when vs_equal u v -> ()
| _ -> raise Exit in
let ls = match e.t_node with
| Tapp (ls,tl) -> List.iter2 check_arg vl tl; ls
| _ -> raise Exit in
let rec check_head hd vl = match hd.t_node, vl with
| Tapp (ls, [hd; {t_node = Tvar u}]), v :: vl
when ls_equal ls fs_func_app && vs_equal u v -> check_head hd vl
| Tvar y, [] when vs_equal y x -> ()
| _ -> raise Exit in
check_head hd (List.rev vl);
ls
let is_canonical x f =
try Some (is_canonical x f)
with Exit | Invalid_argument _ -> None
let get_canonical ls =
let ty = Opt.get_def Ty.ty_bool ls.ls_value in
let ty = List.fold_right Ty.ty_func ls.ls_args ty in
let nm = ls.ls_name.id_string ^ "_closure" in
let cs = create_fsymbol (id_derive nm ls.ls_name) [] ty in
let mk_vs ty = create_vsymbol (id_fresh "y") ty in
let vl = List.map mk_vs ls.ls_args in
let tl = List.map t_var vl in
let t = List.fold_left t_func_app (fs_app cs [] ty) tl in
let e = t_app ls tl ls.ls_value in
let f = if ls.ls_value = None
then t_iff (t_equ t t_bool_true) e else t_equ t e in
let nm = ls.ls_name.id_string ^ "_closure_def" in
let pr = create_prsymbol (id_derive nm ls.ls_name) in
let ax = create_prop_decl Paxiom pr (t_forall_close vl [] f) in
create_param_decl cs, ax, cs
let get_canonical =
let ht = Hls.create 3 in fun ls ->
try Hls.find ht ls with Not_found ->
let res = get_canonical ls in
Hls.add ht ls res; res
let rec lift_f acc t0 = match t0.t_node with
| (Tapp (ps, [t1; {t_node = Teps fb}]) | (Tapp (ps, [t1; {t_node = Teps fb}])
| Tapp (ps, [{t_node = Teps fb}; t1])) | Tapp (ps, [{t_node = Teps fb}; t1]))
when ls_equal ps ps_equ -> when ls_equal ps ps_equ ->
let vs, f = t_open_bound fb in let vs, f = t_open_bound fb in
lift_f acc (t_let_close_simp vs t1 f) let f = t_let_close_simp vs t1 f in
lift_f acc (t_label_copy t0 f)
| Teps fb -> | Teps fb ->
let vl = Mvs.keys (t_vars t) in let vl = Mvs.keys (t_vars t0) in
let vs, f = t_open_bound fb in let vs, f = t_open_bound fb in
let (abst,axml), f = lift_f acc f in let acc, t = match is_canonical vs f with
let tyl = List.map (fun x -> x.vs_ty) vl in | Some ls ->
let ls = create_fsymbol (id_clone vs.vs_name) tyl vs.vs_ty in let abst, axml = acc in
let t = t_app ls (List.map t_var vl) t.t_ty in let ld, ax, cs = get_canonical ls in
let f = t_forall_close_merge vl (t_subst_single vs t f) in (ld :: abst, ax :: axml), fs_app cs [] vs.vs_ty
let id = id_derive (vs.vs_name.id_string ^ "_def") vs.vs_name in | None ->
let ax = create_prop_decl Paxiom (create_prsymbol id) f in let (abst,axml), f = lift_f acc f in
(create_param_decl ls :: abst, ax :: axml), t let tyl = List.map (fun x -> x.vs_ty) vl in
let ls = create_fsymbol (id_clone vs.vs_name) tyl vs.vs_ty in
let t = fs_app ls (List.map t_var vl) vs.vs_ty in
let f = t_forall_close_merge vl (t_subst_single vs t f) in
let id = id_derive (vs.vs_name.id_string ^ "_def") vs.vs_name in
let ax = create_prop_decl Paxiom (create_prsymbol id) f in
(create_param_decl ls :: abst, ax :: axml), t
in
acc, t_label_copy t0 t
| _ -> | _ ->
t_map_fold lift_f acc t t_map_fold lift_f acc t0
let lift_l (acc,dl) (ls,ld) = let lift_l (acc,dl) (ls,ld) =
let vl, t, close = open_ls_defn_cb ld in let vl, t, close = open_ls_defn_cb ld in
......
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