Fixed eta_compare in the case Lam vs. Bot

[fireball-separation.git] / ocaml / num.ml

diff --git a/ocaml/num.ml b/ocaml/num.ml
index 1b121efaec576a8cbd0c2ee6b3769af3902ba964..aa9338c4c8d2d777fa45c5d0b74a85c376032dc7 100644 (file)
--- a/ocaml/num.ml
+++ b/ocaml/num.ml
@@ -118,31 +118,36 @@ end
 
 (* let rec string_of_term l  = fun _ -> "";; *)
 
-let rec string_of_term l  =
- let rec string_of_term_w_pars l  = function
-  | `Var(n,ar) -> List.nth l n ^ (if debug_display_arities then ":" ^ string_of_int ar else "")
+let rec string_of_term =
+ let boundvar x = "v" ^ string_of_int x in
+ let varname lev l n =
+  if n < lev then boundvar (lev-n-1)
+   else if n < List.length l then List.nth l (n-lev)
+    else "`" ^ string_of_int (n-lev) in
+ let rec string_of_term_w_pars lev l  = function
+  | `Var(n,ar) -> varname lev l n ^ (if debug_display_arities then ":" ^ string_of_int ar else "")
   | `N n -> string_of_int n
-  | `I _ as t -> "(" ^ string_of_term_no_pars_app l t ^ ")"
+  | `I _ as t -> "(" ^ string_of_term_no_pars_app lev l t ^ ")"
   | `Lam(_,`Bottom) -> "BOMB"
-  | `Lam _ as t -> "(" ^ string_of_term_no_pars_lam l t ^ ")"
+  | `Lam _ as t -> "(" ^ string_of_term_no_pars_lam lev l t ^ ")"
   | `Match(t,(v,ar),bs_lift,bs,args) ->
-     "["^ List.nth l v ^ (if debug_display_arities then ":"^ string_of_int ar else "") ^",match " ^ string_of_term_no_pars l (t :> nf) ^
-     " with " ^ String.concat " | " (List.map (fun (n,t) -> string_of_int n ^ " => " ^ string_of_term l (lift bs_lift (t :> nf))) !bs) ^ "] " ^
+      (* assert (bs_lift = lev); *)
+     "(["^ varname lev l v ^ (if debug_display_arities then ":"^ string_of_int ar else "") ^",match " ^ string_of_term_no_pars lev l (t :> nf) ^
+     " with " ^ String.concat " | " (List.map (fun (n,t) -> string_of_int n ^ " => " ^ string_of_term l (t :> nf)) !bs) ^ "] " ^
      String.concat " " (List.map (string_of_term l) (args :> nf list)) ^ ")"
   | `Bottom -> "BOT"
   | `Pacman -> "PAC"
- and string_of_term_no_pars_app l  = function
-  | `I((n,ar), args) -> List.nth l n ^ (if debug_display_arities then ":" ^ string_of_int ar else "") ^ " " ^ String.concat " " (List.map (string_of_term_w_pars l) (Listx.to_list args :> nf list))
-  | #nf as t -> string_of_term_w_pars l t
- and string_of_term_no_pars_lam l  = function
+ and string_of_term_no_pars_app lev l  = function
+  | `I((n,ar), args) -> varname lev l n ^ (if debug_display_arities then ":" ^ string_of_int ar else "") ^ " " ^ String.concat " " (List.map (string_of_term_w_pars lev l) (Listx.to_list args :> nf list))
+  | #nf as t -> string_of_term_w_pars lev l t
+ and string_of_term_no_pars_lam lev l  = function
   | `Lam(_,`Bottom) -> "BOMB"
-  | `Lam(_,t) -> let name = "x" ^ string_of_int (List.length l) in
-     "λ" ^ name ^ ". " ^ (string_of_term_no_pars_lam (name::l) t)
-  | _ as t -> string_of_term_no_pars l t
- and string_of_term_no_pars l  = function
-  | `Lam _ as t -> string_of_term_no_pars_lam l t
-  | #nf as t -> string_of_term_no_pars_app l t
- in string_of_term_no_pars l
+  | `Lam(_,t) -> "λ" ^ boundvar lev ^ ". " ^ (string_of_term_no_pars_lam (lev+1) l t)
+  | _ as t -> string_of_term_no_pars lev l t
+ and string_of_term_no_pars lev l = function
+  | `Lam _ as t -> string_of_term_no_pars_lam lev l t
+  | #nf as t -> string_of_term_no_pars_app lev l t
+ in string_of_term_no_pars 0
 ;;
 
 let print ?(l=[]) = string_of_term l;;
@@ -245,6 +250,9 @@ and subst truelam delift_by_one what (with_what : nf(*_nob*)) (where : nf) =
    | `N _ as x -> x
    | `Match(t,v,bs_lift,bs,args) ->
        let bs_lift = bs_lift + if delift_by_one then -1 else 0 in
+       (* Warning! It now applies again the substitution in branches of matches.
+          But careful, it does it many times, for every occurrence of
+          the match. This is okay because what does not occur in with_what. *)
        let l' = l - bs_lift  in
        let with_what' = lift l' (with_what :> nf) in
        (* The following line should be the identity when delift_by_one = true because we
@@ -287,8 +295,8 @@ let eta_compare x y =
   | `Pacman, `Pacman -> 0
   | `Lam _, `N _ -> -1
   | `N _, `Lam _ -> 1
-  | `Bottom, `Lam _
-  | `Lam _, `Bottom -> assert false (* TO BE UNDERSTOOD *)
+  | `Bottom, `Lam(_,t) -> -1
+  | `Lam(_,t), `Bottom ->  1
   | `Lam(_,t1), `Lam(_,t2) -> aux t1 t2
   | `Lam(_,t1), t2 -> - aux t1 (mk_app (lift 1 t2) (`Var(0,-666)))
   | t2, `Lam(_,t1) ->   aux t1 (mk_app (lift 1 t2) (`Var(0,-666)))