X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=ocaml%2Fsimple.ml;h=079774e5ac67e5c53feaa53eca9e7e622dd77c76;hb=b0ecd3e4062bb9012ea9623237d0b379bd7646f2;hp=897d6b68a4b736952774d4127e109020f2fb7618;hpb=69f44e4fb3d56f89adcc952514707914886fdd79;p=fireball-separation.git

diff --git a/ocaml/simple.ml b/ocaml/simple.ml
index 897d6b6..079774e 100644
--- a/ocaml/simple.ml
+++ b/ocaml/simple.ml
@@ -10,11 +10,11 @@ type var = int;;
 type t =
  | V of var
  | A of t * t
- | L of t
+ | L of (t * t list (*garbage*))
  | C (* constant *)
 ;;
 
-let delta = L(A(V 0, V 0));;
+let delta = L(A(V 0, V 0),[]);;
 
 let rec is_stuck = function
  | C -> true
@@ -25,9 +25,9 @@ let rec is_stuck = function
 let eta_eq' =
  let rec aux l1 l2 t1 t2 = match t1, t2 with
   | _, _ when is_stuck t1 || is_stuck t2 -> true
-  | L t1, L t2 -> aux l1 l2 t1 t2
-  | L t1, t2 -> aux l1 (l2+1) t1 t2
-  | t1, L t2 -> aux (l1+1) l2 t1 t2
+  | L t1, L t2 -> aux l1 l2 (fst t1) (fst t2)
+  | L t1, t2 -> aux l1 (l2+1) (fst t1) t2
+  | t1, L t2 -> aux (l1+1) l2 t1 (fst t2)
   | V a, V b -> a + l1 = b + l2
   | A(t1,t2), A(u1,u2) -> aux l1 l2 t1 u1 && aux l1 l2 t2 u2
   | _, _ -> false
@@ -37,14 +37,14 @@ let eta_eq = eta_eq' 0 0;;
 (* is arg1 eta-subterm of arg2 ? *)
 let eta_subterm u =
  let rec aux lev t = if t = C then false else (eta_eq' lev 0 u t || match t with
- | L t -> aux (lev+1) t
+ | L(t,g) -> List.exists (aux (lev+1)) (t::g)
  | A(t1, t2) -> aux lev t1 || aux lev t2
  | _ -> false) in
  aux 0
 ;;
 
 (* does NOT lift the argument *)
-let mk_lams = fold_nat (fun x _ -> L x) ;;
+let mk_lams = fold_nat (fun x _ -> L(x,[])) ;;
 
 let string_of_t =
   let string_of_bvar =
@@ -61,7 +61,8 @@ let string_of_t =
     | A(t1,t2) -> string_of_term_no_pars_app level t1 ^ " " ^ string_of_term_w_pars level t2
     | _ as t -> string_of_term_w_pars level t
   and string_of_term_no_pars level = function
-    | L t -> "λ" ^ string_of_bvar level ^ ". " ^ string_of_term_no_pars (level+1) t
+    | L(t,g) -> "λ" ^ string_of_bvar level ^ ". " ^ string_of_term_no_pars (level+1) t
+       ^ (if g = [] then "" else String.concat ", " ("" :: List.map (string_of_term_w_pars (level+1)) g))
     | _ as t -> string_of_term_no_pars_app level t
   in string_of_term_no_pars 0
 ;;
@@ -69,6 +70,7 @@ let string_of_t =
 type problem = {
    orig_freshno: int
  ; freshno : int
+ ; label : string
  ; div : t
  ; conv : t
  ; sigma : (var * t) list (* substitutions *)
@@ -84,12 +86,18 @@ let string_of_problem p =
 
 exception B;;
 exception Done of (var * t) list (* substitution *);;
-exception Fail of int * string;;
+exception Unseparable of string;;
+exception Backtrack of string;;
+
+let rec try_all label f = function
+ | x::xs -> (try f x with Backtrack _ -> try_all label f xs)
+ | [] -> raise (Backtrack label)
+;;
 
 let problem_fail p reason =
  print_endline "!!!!!!!!!!!!!!! FAIL !!!!!!!!!!!!!!!";
  print_endline (string_of_problem p);
- raise (Fail (-1, reason))
+ failwith reason
 ;;
 
 let freshvar ({freshno} as p) =
@@ -111,7 +119,7 @@ let rec is_constant =
     C -> true
   | V _ -> false
   | A(t,_)
-  | L t -> is_constant t
+  | L(t,_) -> is_constant t
 ;;
 
 let rec get_inert = function
@@ -133,7 +141,7 @@ let args_of_inert =
 (* 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
- | L t -> 1 + no_leading_lambdas (v+1) n t
+ | L(t,_) -> 1 + no_leading_lambdas (v+1) n t
  | A _ as t -> let v', m = get_inert t in if V v = v' then max 0 (n - m) else 0
  | V v' -> if v = v' then n else 0
  | C -> 0
@@ -141,22 +149,29 @@ let rec no_leading_lambdas v n = function
 
 let rec subst level delift sub =
  function
- | V v -> if v = level + fst sub then lift level (snd sub) else V (if delift && v > level then v-1 else v)
- | L t -> let t = subst (level + 1) delift sub t in if t = B then B else L t
+ | V v -> (if v = level + fst sub then lift level (snd sub) else V (if delift && v > level then v-1 else v)), []
+ | L x -> let t, g = subst_in_lam (level+1) delift sub x in L(t, g), []
  | A (t1,t2) ->
-  let t1 = subst level delift sub t1 in
-  let t2 = subst level delift sub t2 in
-  mk_app t1 t2
- | C -> C
+  let t1, g1 = subst level delift sub t1 in
+  let t2, g2 = subst level delift sub t2 in
+  let t3, g3 = mk_app t1 t2 in
+  t3, g1 @ g2 @ g3
+ | C -> C, []
+and subst_in_lam level delift sub (t, g) =
+  let t', g' = subst level delift sub t in
+  let g'' = List.fold_left
+   (fun xs t ->
+     let x,y = subst level delift sub t in
+     (x :: y @ xs)) g' g in t', g''
 and mk_app t1 t2 = if t1 = delta && t2 = delta then raise B
  else match t1 with
- | L t1 -> subst 0 true (0, t2) t1
- | _ -> A (t1, t2)
+ | L x -> subst_in_lam 0 true (0, t2) x
+ | _ -> A (t1, t2), []
 and lift n =
  let rec aux lev =
   function
   | V m -> V (if m >= lev then m + n else m)
-  | L t -> L (aux (lev+1) t)
+  | L(t,g) -> L (aux (lev+1) t, List.map (aux (lev+1)) g)
   | A (t1, t2) -> A (aux lev t1, aux lev t2)
   | C -> C
  in aux 0
@@ -165,29 +180,36 @@ let subst = subst 0 false;;
 
 let subst_in_problem ((v, t) as sub) p =
 print_endline ("-- SUBST " ^ string_of_t (V v) ^ " |-> " ^ string_of_t t);
- {p with
-  div=subst sub p.div;
-  conv=subst sub p.conv;
-  sigma=sub::p.sigma}
+ let sigma = sub :: p.sigma in
+ let div, g = try subst sub p.div with B -> raise (Done sigma) in
+ assert (g = []);
+ let conv, f = try subst sub p.conv with B -> raise (Backtrack "p.conv diverged") in
+ assert (g = []);
+ {p with div; conv; sigma}
 ;;
 
 let get_subterms_with_head hd_var =
- let rec aux lev inert_done = function
- | L t -> aux (lev+1) false t
- | C | V _ -> []
+ let rec aux lev inert_done g = function
+ | L(t,g') -> List.fold_left (aux (lev+1) false) g (t::g')
+ | C | V _ -> g
  | A(t1,t2) as t ->
    let hd_var', n_args' = get_inert t1 in
    if not inert_done && hd_var' = V (hd_var + lev)
-    then lift ~-lev t :: aux lev true t1 @ aux lev false t2
-    else aux lev true t1 @ aux lev false t2
- in aux 0 false
+    then lift ~-lev t :: aux lev false (aux lev true g t1) t2
+    else                 aux lev false (aux lev true g t1) t2
+ in aux 0 false []
 ;;
 
-let rec purify = function
- | L t -> Pure.L (purify t)
- | A (t1,t2) -> Pure.A (purify t1, purify t2)
- | V n -> Pure.V n
+let purify =
+ let rec aux = function
+ | L(t,g) ->
+    let t = aux (lift (List.length g) t) in
+    let t = List.fold_left (fun t g -> Pure.A(Pure.L t, aux g)) t g in
+    Pure.L t
+ | A (t1,t2) -> Pure.A (aux t1, aux t2)
+ | V n -> Pure.V (n)
  | C -> Pure.V (min_int/2)
+ in aux
 ;;
 
 let check p sigma =
@@ -197,16 +219,18 @@ let check p sigma =
  let sigma = List.map (fun (v,t) -> v, purify t) sigma in
  let freshno = List.fold_right (max ++ fst) sigma 0 in
  let env = Pure.env_of_sigma freshno sigma in
- assert (Pure.diverged (Pure.mwhd (env,div,[])));
- print_endline " D diverged.";
- assert (not (Pure.diverged (Pure.mwhd (env,conv,[]))));
- print_endline " C converged.";
+ (if not (Pure.diverged (Pure.mwhd (env,div,[])))
+  then failwith "D converged in Pure");
+ print_endline "- D diverged.";
+ (if Pure.diverged (Pure.mwhd (env,conv,[]))
+  then failwith "C diverged in Pure");
+ print_endline "- C converged.";
  ()
 ;;
 
 let sanity p =
  print_endline (string_of_problem p); (* non cancellare *)
- if not (is_inert p.div) then problem_fail p "p.div converged";
+ if not (is_inert p.div) then raise (Backtrack "p.div converged");
  (* Trailing constant args can be removed because do not contribute to eta-diff *)
  let rec remove_trailing_constant_args = function
  | A(t1, t2) when is_constant t2 -> remove_trailing_constant_args t1
@@ -233,9 +257,11 @@ let inert_cut_at n t =
 let find_eta_difference p t =
  let divargs = args_of_inert p.div in
  let conargs = args_of_inert t in
+ let rec range i j =
+  if j = -1 then [] else i :: range (i+1) (j-1) in
  let rec aux k divargs conargs =
   match divargs,conargs with
-     [],_ -> []
+     [],conargs -> range k (List.length conargs)
    | _::_,[] -> [k]
    | t1::divargs,t2::conargs ->
       (if not (eta_eq t1 t2) then [k] else []) @ aux (k+1) divargs conargs
@@ -252,7 +278,7 @@ let compute_max_lambdas_at hd_var j =
         then let hd', j' = get_inert t2 in j - j'
         else no_leading_lambdas hd_var j t2)
       else id) (max (aux hd t1) (aux hd t2))
- | L t -> aux (hd+1) t
+ | L(t,_) -> aux (hd+1) t
  | V _ | C -> 0
  in aux hd_var
 ;;
@@ -296,7 +322,7 @@ let finish p =
  let compute_max_arity =
    let rec aux n = function
    | A(t1,t2) -> max (aux (n+1) t1) (aux 0 t2)
-   | L t -> max n (aux 0 t)
+   | L(t,g) -> List.fold_right (max ++ (aux 0)) (t::g) 0
    | _ -> n
  in aux 0 in
 print_cmd "FINISH" "";
@@ -338,24 +364,16 @@ let auto p =
  if List.exists (fun t -> snd (get_inert t) >= n_args) tms
   then (
     (* let tms = List.sort (fun t1 t2 -> - compare (snd (get_inert t1)) (snd (get_inert t2))) tms in *)
-    List.iter (fun t -> try
+    try_all "no similar terms" (fun t ->
       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
-       List.iter
+       try_all "no eta difference"
         (fun j ->
-         try
           let k = 1 + max
            (compute_max_lambdas_at hd_var j p.div)
             (compute_max_lambdas_at hd_var j p.conv) in
-          ignore (aux (step j k p))
-         with Fail(_, s) ->
-          print_endline ("Backtracking (eta_diff) because: " ^ s)) js;
-       raise (Fail(-1, "no eta difference"))
-      with Fail(_, s) ->
-       print_endline ("Backtracking (get_subterms) because: " ^ s)) tms;
-     raise (Fail(-1, "no similar terms"))
+          aux (step j k p)) js) tms
    )
   else
     problem_fail (finish p) "Finish did not complete the problem"
@@ -368,7 +386,7 @@ let auto p =
 let problem_of (label, div, convs, ps, var_names) =
  print_hline ();
  let rec aux lev = function
- | `Lam(_, t) -> L (aux (lev+1) t, [])
+ | `Lam(_, t, g) -> L (aux (lev+1) t, List.map (aux (lev+1)) g)
  | `I (v, args) -> Listx.fold_left (fun x y -> fst (mk_app x (aux lev y))) (aux lev (`Var v)) args
  | `Var(v,_) -> if v >= lev && List.nth var_names (v-lev) = "C" then C else V v
  | `N _ | `Match _ -> assert false in
@@ -380,15 +398,26 @@ let problem_of (label, div, convs, ps, var_names) =
  | Some div -> aux 0 (div :> Num.nf)
  | None -> assert false in
  let varno = List.length var_names in
- {orig_freshno=varno; freshno=1+varno; div; conv; sigma=[]}
+ {orig_freshno=varno; freshno=1+varno; div; conv; sigma=[]; label}
 ;;
 
 let solve p =
- if is_constant p.div
-  then print_endline "!!! div is stuck. Problem was not run !!!"
- else if eta_subterm p.div p.conv
-  then print_endline "!!! div is subterm of conv. Problem was not run !!!"
-  else let p = sanity p (* initial sanity check *) in check p (auto p)
+ let c = if String.length p.label > 0 then String.sub (p.label) 0 1 else "" in
+ let module M = struct exception Okay end in
+ try
+  if eta_subterm p.div p.conv
+  then raise (Unseparable "div is subterm of conv")
+  else
+   let p = sanity p (* initial sanity check *) in
+   check p (auto p);
+   raise M.Okay
+ with
+  | M.Okay -> if c = "?" then
+    failwith "The problem succeeded, but was supposed to be unseparable"
+  | e when c = "!" ->
+    failwith ("The problem was supposed to be separable, but: "^Printexc.to_string e)
+  | e ->
+    print_endline ("The problem failed, as expected ("^Printexc.to_string e^")")
 ;;
 
 Problems.main (solve ++ problem_of);