Implementing entanglement of terms

FIXME usage of flags b' in subst and mk_app
 must be understood and fixed!

diff --git a/ocaml/simple.ml b/ocaml/simple.ml
index a7a8d7ab1ccf2bffb1b68dc5b2f8f7e09450ce82..5764c3ca60e5a7fab41722ec9f1c3c0b958c4557 100644 (file)
--- a/ocaml/simple.ml
+++ b/ocaml/simple.ml
@@ -9,14 +9,19 @@ open Pure
 type var = int;;\r
 type t =\r
  | V of var\r
- | A of bool * t * t\r
+ | A of (bool ref) * t * t\r
  | L of (bool * t)\r
 ;;\r
 \r
-let rec measure_of_t = function\r
- | V _ -> 0\r
- | A(b,t1,t2) -> (if b then 1 else 0) + measure_of_t t1 + measure_of_t t2\r
- | L(b,t) -> if b then measure_of_t t else 0\r
+let measure_of_t =\r
+ let rec aux acc = function\r
+ | V _ -> acc, 0\r
+ | A(b,t1,t2) ->\r
+   let acc, m1 = aux acc t1 in\r
+   let acc, m2 = aux acc t2 in\r
+   if not (List.memq b acc) && !b then b::acc, 1 + m1 + m2 else acc, m1 + m2\r
+ | L(b,t) -> if b then aux acc t else acc, 0\r
+ in snd ++ (aux [])\r
 ;;\r
 \r
 let string_of_t =\r
@@ -30,7 +35,7 @@ let string_of_t =
     | A _\r
     | L _ as t -> "(" ^ string_of_term_no_pars level t ^ ")"\r
   and string_of_term_no_pars_app level = function\r
-    | A(b,t1,t2) -> string_of_term_no_pars_app level t1 ^ (if b then "," else " ") ^ string_of_term_w_pars level t2\r
+    | A(b,t1,t2) -> string_of_term_no_pars_app level t1 ^ (if !b then "," else " ") ^ string_of_term_w_pars level t2\r
     | _ as t -> string_of_term_w_pars level t\r
   and string_of_term_no_pars level = function\r
     | L(_,t) -> "λ" ^ string_of_bvar level ^ ". " ^ string_of_term_no_pars (level+1) t\r
@@ -39,7 +44,7 @@ let string_of_t =
 ;;\r
 \r
 \r
-let delta = L(true,A(true,V 0, V 0));;\r
+let delta = L(true,A(ref true,V 0, V 0));;\r
 \r
 (* does NOT lift the argument *)\r
 let mk_lams = fold_nat (fun x _ -> L(false,x)) ;;\r
@@ -105,13 +110,13 @@ let rec subst b' level delift sub =
  function\r
  | V v -> if v = level + fst sub then lift level (snd sub) else V (if delift && v > level then v-1 else v)\r
  | L(b,t) -> L(b, subst b' (level + 1) delift sub t)\r
- | A(_,t1,(V v as t2)) when b' && v = level + fst sub ->\r
+ | A(_,t1,(V v as t2)) when !b' && v = level + fst sub ->\r
     mk_app b' (subst b' level delift sub t1) (subst b' level delift sub t2)\r
  | A(b,t1,t2) ->\r
     mk_app b (subst b' level delift sub t1) (subst b' level delift sub t2)\r
 and mk_app b' t1 t2 = if t1 = delta && t2 = delta then raise B\r
  else match t1 with\r
- | L(b,t1) -> subst (b' && not b) 0 true (0, t2) t1\r
+ | L(b,t1) -> subst (ref (!b' && not b)) 0 true (0, t2) t1\r
  | _ -> A (b', t1, t2)\r
 and lift n =\r
  let rec aux lev =\r
@@ -121,14 +126,14 @@ and lift n =
   | A (b,t1, t2) -> A (b,aux lev t1, aux lev t2)\r
  in aux 0\r
 ;;\r
-let subst = subst false 0 false;;\r
-let mk_app = mk_app true;;\r
+let subst = subst (ref false) 0 false;;\r
+let mk_app = mk_app (ref true);;\r
 \r
 let eta_eq =\r
  let rec aux t1 t2 = match t1, t2 with\r
   | L(_,t1), L(_,t2) -> aux t1 t2\r
-  | L(_,t1), t2 -> aux t1 (A(true,lift 1 t2,V 0))\r
-  | t1, L(_,t2) -> aux (A(true,lift 1 t1,V 0)) t2\r
+  | L(_,t1), t2 -> aux t1 (A(ref true,lift 1 t2,V 0))\r
+  | t1, L(_,t2) -> aux (A(ref true,lift 1 t1,V 0)) t2\r
   | V a, V b -> a = b\r
   | A(_,t1,t2), A(_,u1,u2) -> aux t1 u1 && aux t2 u2\r
   | _, _ -> false\r
@@ -244,36 +249,6 @@ let compute_max_lambdas_at hd_var j =
 \r
 let print_cmd s1 s2 = print_endline (">> " ^ s1 ^ " " ^ s2);;\r
 \r
-(* eat the arguments of the divergent and explode.\r
- It does NOT perform any check, may fail if done unsafely *)\r
-let eat p =\r
-print_cmd "EAT" "";\r
- let var, k = get_inert p.div in\r
- let phase = p.phase in\r
- let p =\r
-  match phase with\r
-  | `One ->\r
-      let n = 1 + max\r
-       (compute_max_lambdas_at var (k-1) p.div)\r
-       (compute_max_lambdas_at var (k-1) p.conv) in\r
-      (* apply fresh vars *)\r
-      let p, t = fold_nat (fun (p, t) _ ->\r
-        let p, v = freshvar p in\r
-        p, A(false, t, V (v + k))\r
-      ) (p, V 0) n in\r
-      let p = {p with phase=`Two} in\r
-      let t = A(false, t, delta) in\r
-      let t = fold_nat (fun t m -> A(false, t, V (k-m))) t (k-1) in\r
-      let subst = var, mk_lams t k in\r
-      let p = subst_in_problem subst p in\r
-      let _, args = get_inert p.div in\r
-      {p with div = inert_cut_at (args-k) p.div}\r
-  | `Two ->\r
-      let subst = var, mk_lams delta k in\r
-      subst_in_problem subst p in\r
- sanity p\r
-;;\r
-\r
 (* step on the head of div, on the k-th argument, with n fresh vars *)\r
 let step k n p =\r
  let var, _ = get_inert p.div in\r
@@ -281,10 +256,10 @@ print_cmd "STEP" ("on " ^ string_of_t (V var) ^ " (of:" ^ string_of_int n ^ ")")
  let p, t = (* apply fresh vars *)\r
   fold_nat (fun (p, t) _ ->\r
     let p, v = freshvar p in\r
-    p, A(false, t, V (v + k + 1))\r
+    p, A(ref false, t, V (v + k + 1))\r
   ) (p, V 0) n in\r
  let t = (* apply bound variables V_k..V_0 *)\r
-  fold_nat (fun t m -> A(false, t, V (k-m+1))) t (k+1) in\r
+  fold_nat (fun t m -> A(ref false, 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