X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=ocaml%2Fsimple.ml;h=44b9aa2a871d74619fdcbe88599580ce4c7b2d70;hb=484254ec5f3e94aa86ffdc2bf7c07c46e42be8d7;hp=bac3ddf98a532784a587fa90cd9cbd67ca1f1e0a;hpb=2b941d27823cb7d06bbf83353c21779c866f3161;p=fireball-separation.git

diff --git a/ocaml/simple.ml b/ocaml/simple.ml
index bac3ddf..44b9aa2 100644
--- a/ocaml/simple.ml
+++ b/ocaml/simple.ml
@@ -100,6 +100,8 @@ let freshvar ({freshno} as p) =
  {p with freshno=freshno+1}, freshno+1
 ;;
 
+(* CSC: rename? is an applied C an inert?
+   is_inert and get_inert work inconsistently *)
 let rec is_inert =
  function
  | A(t,_) -> is_inert t
@@ -108,12 +110,31 @@ let rec is_inert =
  | L _ | B -> false
 ;;
 
+let rec is_constant =
+ function
+    C -> true
+  | V _ -> false
+  | B -> assert false
+  | A(t,_)
+  | L t -> is_constant t
+;;
+
 let rec get_inert = function
  | V _ | C as t -> (t,0)
  | A(t, _) -> let hd,args = get_inert t in hd,args+1
  | _ -> assert false
 ;;
 
+let args_of_inert =
+ let rec aux acc =
+  function
+   | V _ | C -> acc
+   | A(t, a) -> aux (a::acc) t
+   | _ -> assert false
+ in
+  aux []
+;;
+
 (* precomputes the number of leading lambdas in a term,
    after replacing _v_ w/ a term starting with n lambdas *)
 let rec no_leading_lambdas v n = function
@@ -201,8 +222,6 @@ let sanity p =
 ;;
 
 (* drops the arguments of t after the n-th *)
-(* FIXME! E' usato in modo improprio contando sul fatto
-   errato che ritorna un inerte lungo esattamente n *)
 let inert_cut_at n t =
  let rec aux t =
   match t with
@@ -216,19 +235,18 @@ let inert_cut_at n t =
 ;;
 
 (* return the index of the first argument with a difference
-   (the first argument is 0)
-   precondition: p.div and t have n+1 arguments
-   *)
-let find_eta_difference p t argsno =
- let t = inert_cut_at argsno t in
- let rec aux t u k = match t, u with
- | V _, V _ -> []
- | A(t1,t2), A(u1,u2) ->
-    print_endline (string_of_t t2 ^ " vs " ^ string_of_t u2);
-    if not (eta_eq t2 u2) then (k-1)::aux t1 u1 (k-1)
-    else aux t1 u1 (k-1)
- | _, _ -> assert false
- in aux p.div t argsno
+   (the first argument is 0) *)
+let find_eta_difference p t =
+ let divargs = args_of_inert p.div in
+ let conargs = args_of_inert t in
+ let rec aux k divargs conargs =
+  match divargs,conargs with
+     [],_ -> []
+   | _::_,[] -> [k]
+   | t1::divargs,t2::conargs ->
+      (if not (eta_eq t1 t2) then [k] else []) @ aux (k+1) divargs conargs
+ in
+  aux 0 divargs conargs
 ;;
 
 let compute_max_lambdas_at hd_var j =
@@ -248,6 +266,18 @@ let compute_max_lambdas_at hd_var j =
 
 let print_cmd s1 s2 = print_endline (">> " ^ s1 ^ " " ^ s2);;
 
+(* returns Some i if i is the smallest integer s.t. p holds for the i-th
+   element of the list in input *)
+let smallest_such_that p =
+ let rec aux i =
+  function
+     [] -> None
+   | hd::_ when (print_endline (string_of_t hd) ; p hd) -> Some i
+   | _::tl -> aux (i+1) tl
+ in
+  aux 0
+;;
+
 (* eat the arguments of the divergent and explode.
  It does NOT perform any check, may fail if done unsafely *)
 let eat p =
@@ -260,17 +290,21 @@ print_cmd "EAT" "";
  let p =
   match phase with
   | `One ->
+      let i =
+       match smallest_such_that (fun x -> not (is_constant x)) (args_of_inert p.div) with
+          Some i -> i
+        | None -> assert false (*CSC: backtrack? *) in
       let n = 1 + max
-       (compute_max_lambdas_at var (k-1) p.div)
-       (compute_max_lambdas_at var (k-1) p.conv) in
+       (compute_max_lambdas_at var (k-i-1) p.div)
+       (compute_max_lambdas_at var (k-i-1) p.conv) in
       (* apply fresh vars *)
       let p, t = fold_nat (fun (p, t) _ ->
         let p, v = freshvar p in
         p, A(t, V (v + k))
-      ) (p, V 0) n in
+      ) (p, V (k-1-i)) n in
       let p = {p with phase=`Two} in
       let t = A(t, delta) in
-      let t = fold_nat (fun t m -> A(t, V (k-m))) t (k-1) in
+      let t = fold_nat (fun t m -> if k-m = i then t else  A(t, V (k-m))) t k in
       let subst = var, mk_lams t k in
       let p = subst_in_problem subst p in
       let _, args = get_inert p.div in
@@ -312,7 +346,7 @@ let auto p =
   then (
     (* let tms = List.sort (fun t1 t2 -> - compare (snd (get_inert t1)) (snd (get_inert t2))) tms in *)
     List.iter (fun t -> try
-      let js = find_eta_difference p t n_args in
+      let js = find_eta_difference p t in
       (* print_endline (String.concat ", " (List.map string_of_int js)); *)
       if js = [] then problem_fail p "no eta difference found (div subterm of conv?)";
       let js = List.rev js in