From: acondolu <andrea.condoluci@unibo.it>
Date: Mon, 10 Jul 2017 12:06:55 +0000 (+0200)
Subject: new_arity = old_arity + 1
X-Git-Tag: weak-reduction-separation~69
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=6895644003c1c199f1a43d300b04a975959024e8;p=fireball-separation.git

new_arity = old_arity + 1
---

diff --git a/ocaml/lambda4.ml b/ocaml/lambda4.ml
index 8498513..304df8a 100644
--- a/ocaml/lambda4.ml
+++ b/ocaml/lambda4.ml
@@ -419,7 +419,9 @@ let instantiate p x n =
  (if hd_of_i_var (cast_to_i_var !bomb) = x
    then failwithProblem p ("BOMB (" ^ string_of_nf !bomb ^ ") cannot be instantiated!"));
  let arity_of_x = max_arity_tms x (all_terms p) in
- (if arity_of_x < 0 then failwithProblem p "step on a var of negative arity");
+ (if arity_of_x = None then failwithProblem p "step on var non occurring in problem");
+ (if Util.option_get(arity_of_x) = min_int then failwithProblem p "step on fake variable");
+ (if Util.option_get(arity_of_x) <= 0 then failwithProblem p "step on var of non-positive arity");
  (* AC: Once upon a time, it was:
     let arities = Num.compute_arities x (n+1) (all_terms p :> nf list) in *)
  (* let arities = Array.to_list (Array.make (n+1) 0) in *)
@@ -427,8 +429,8 @@ let instantiate p x n =
  let p,vars = make_fresh_vars p arities in
  let args = Listx.from_list (vars :> nf list) in
  let bs = ref [] in
- (* min_int, since it will be replaced anyway during subst: *)
- let inst = `Lam(false,`Match(`I((0,n+1),Listx.map (lift 1) args),(x,min_int),1,bs,[])) in
+ (* 666, since it will be replaced anyway during subst: *)
+ let inst = `Lam(false,`Match(`I((0,n+2),Listx.map (lift 1) args),(x,666),1,bs,[])) in
  let p = {p with deltas=bs::p.deltas} in
  subst_in_problem x inst p
 ;;
diff --git a/ocaml/num.ml b/ocaml/num.ml
index 3c84f4f..d59d07f 100644
--- a/ocaml/num.ml
+++ b/ocaml/num.ml
@@ -161,9 +161,11 @@ let set_arity arity = function
 | `Var(n,_) -> `Var(n,arity)
 | `Lam(false, `N _)
 | `Lam(false, `Lam _) as t -> t
-| `Lam(false, `Match(t,(n,ar),bs_lift,bs,args)) -> `Lam(false, `Match(t,(n,arity),bs_lift,bs,args))
+| `Lam(false, `Match(t,(n,_),bs_lift,bs,args)) -> `Lam(false, `Match(t,(n,arity),bs_lift,bs,args))
 | _ -> assert false
 
+let minus1 n = if n = min_int then n else n - 1;;
+
 let rec mk_app (h : nf) (arg : nf) =
 (*let res =*)
  match h with
@@ -187,7 +189,7 @@ and mk_match t (n,ar) bs_lift bs args =
     `N m ->
       (try
         let h = List.assoc m !bs in
-        let h = set_arity (ar-1) h in
+        let h = set_arity (minus1 ar) h in
         let h = lift bs_lift h in
         mk_appl h args
        with Not_found ->
@@ -236,12 +238,12 @@ prerr_endline ("subst l:" ^ string_of_int l ^ " delift_by_one:" ^ string_of_bool
 
 let parse' strs =
   let fix_arity = function
-  | `I((n,_),args) -> `I((n,Listx.length args),args)
+  | `I((n,_),args) -> `I((n,1+Listx.length args),args)
   | _ -> assert false in
   let rec aux = function
   | Parser.Lam t -> `Lam (true, aux t)
   | Parser.App (t1, t2) -> fix_arity (mk_app (aux t1) (aux t2))
-  | Parser.Var v -> `Var(v,0) in
+  | Parser.Var v -> `Var(v,1) in
   let (tms, free) = Parser.parse_many strs in
   List.map aux tms, free
 ;;
@@ -305,15 +307,20 @@ let eta_subterm (#nf as x) (#nf as y) = eta_subterm x y;;
 
 
 let max_arity_tms n =
- let aux_var l (m,a) = if n + l = m then a else -1 in
+ let max a b = match a, b with
+  | None, None -> None
+  | None, Some x
+  | Some x, None -> Some x
+  | Some x, Some y -> Some (Pervasives.max x y) in
+ let aux_var l (m,a) = if n + l = m then Some a else None in
  let rec aux l = function
   | `Var v -> aux_var l v
   | `I(v,tms) -> max (aux_var l v) (aux_tms l (Listx.to_list tms))
   | `Lam(_,t) -> aux (l+1) t
   | `Match(u,_,_,bs,args) -> max (max (aux l (u :> nf)) (aux_tms l args)) (aux_tms l (List.map snd !bs))
-  | `N _ -> -1
+  | `N _ -> None
  and aux_tms l =
-  List.fold_left (fun acc t -> Pervasives.max acc (aux l t)) ~-1 in
+  List.fold_left (fun acc t -> Pervasives.max acc (aux l t)) None in
  fun tms -> aux_tms 0 (tms :> nf list)
 ;;
 
@@ -333,7 +340,7 @@ let compute_arities m =
    then []
    else
     let tms = Util.filter_map (function `Lam(_,t) -> Some t | _ -> None ) tms in
-    let arity = max 0 (max_arity_tms (m-n) tms) in (* FIXME: 0 or -1 ??? *)
+    let arity = match max_arity_tms (m-n) tms with None -> -666 | Some x -> x in
      arity :: (aux (n-1) tms)
  in fun tms -> List.rev (aux m tms)
 ;;
diff --git a/ocaml/num.mli b/ocaml/num.mli
index c981cff..ca99e44 100644
--- a/ocaml/num.mli
+++ b/ocaml/num.mli
@@ -43,5 +43,5 @@ val parse' : string list -> nf list * string list
 val eta_compare : nf -> nf -> int
 val eta_eq : [< nf ] -> [< nf ] -> bool
 val eta_subterm : [< nf ] -> [< nf ] -> bool
-val max_arity_tms : int -> [< nf] list -> int
+val max_arity_tms : int -> [< nf] list -> int option
 val compute_arities : int -> int -> nf list -> int list
diff --git a/ocaml/util.ml b/ocaml/util.ml
index a4af2dd..a87b96f 100644
--- a/ocaml/util.ml
+++ b/ocaml/util.ml
@@ -14,6 +14,11 @@ let option_map f = function
  | Some x -> Some (f x)
 ;;
 
+let option_get = function
+ | Some x -> x
+ | None -> failwith "option_get: None"
+;;
+
 let rec find_opt f =
  function
     [] -> None
diff --git a/ocaml/util.mli b/ocaml/util.mli
index 751225a..96f03ed 100644
--- a/ocaml/util.mli
+++ b/ocaml/util.mli
@@ -1,6 +1,7 @@
 val ( ++ ) : ('a -> 'b) -> ('c -> 'a) -> 'c -> 'b
 val findi : ('a -> bool) -> 'a list -> (int * 'a)
 val option_map : ('a -> 'b) -> 'a option -> 'b option
+val option_get : ('a option) -> 'a
 val find_opt : ('a -> 'b option) -> 'a list -> 'b option
 val index_of : ?eq:('a -> 'a -> bool) -> 'a -> 'a list -> int
 val index_of_opt : ?eq:('a -> 'a -> bool) -> 'a list -> 'a -> int option