Append the eaten arg + leftmost order in find_eta_difference

simple.evil example works.

diff --git a/ocaml/simple.ml b/ocaml/simple.ml
index 9de1f2a7c12444f2b651628d7d499e7e8497871b..aa91996027a513fc5f8eaface109bdd8d0bf9600 100644 (file)
--- a/ocaml/simple.ml
+++ b/ocaml/simple.ml
@@ -206,12 +206,17 @@ let inert_cut_at n t =
 let find_eta_difference p t argsno =\r
  let t = inert_cut_at argsno t in\r
  let rec aux t u k = match t, u with\r
- | V _, V _ -> problem_fail p "no eta difference found (div subterm of conv?)"\r
+ | V _, V _ -> None\r
  | A(t1,t2), A(u1,u2) ->\r
-    if not (eta_eq t2 u2) then (k-1)\r
-    else aux t1 u1 (k-1)\r
+    (match aux t1 u1 (k-1) with\r
+    | None ->\r
+      if not (eta_eq t2 u2) then Some (k-1)\r
+      else None\r
+    | Some j -> Some j)\r
  | _, _ -> assert false\r
- in aux p.div t argsno\r
+ in match aux p.div t argsno with\r
+ | None -> problem_fail p "no eta difference found (div subterm of conv?)"\r
+ | Some j -> j\r
 ;;\r
 \r
 let compute_max_lambdas_at hd_var j =\r
@@ -269,8 +274,8 @@ print_cmd "STEP" ("on " ^ string_of_t (V var) ^ " (of:" ^ string_of_int n ^ ")")
     let p, v = freshvar p in\r
     p, A(t, V (v + k + 1))\r
   ) (p, V 0) n in\r
- let t = (* apply unused bound variables V_{k-1}..V_1 *)\r
-  fold_nat (fun t m -> A(t, V (k-m+1))) t k in\r
+ let t = (* apply bound variables V_k..V_0 *)\r
+  fold_nat (fun t m -> A(t, V (k-m+1))) t (k+1) in\r
  let t = mk_lams t (k+1) in (* make leading lambdas *)\r
  let subst = var, t in\r
  let p = subst_in_problem subst p in\r