From 640e7671fac6bebe8debe37dba052018c3b4c76f Mon Sep 17 00:00:00 2001
From: acondolu <andrea.condoluci@unibo.it>
Date: Thu, 7 Jun 2018 10:02:19 +0200
Subject: [PATCH] Removed B and C from t, stepped from problem

---
 ocaml/simple.ml | 38 +++++++++-----------------------------
 1 file changed, 9 insertions(+), 29 deletions(-)

diff --git a/ocaml/simple.ml b/ocaml/simple.ml
index e5e829a..154992d 100644
--- a/ocaml/simple.ml
+++ b/ocaml/simple.ml
@@ -11,8 +11,6 @@ type t =
  | V of var
  | A of t * t
  | L of t
- | B (* bottom *)
- | C of int
 ;;
 
 let delta = L(A(V 0, V 0));;
@@ -23,7 +21,6 @@ let eta_eq' =
   | L t1, t2 -> aux l1 (l2+1) t1 t2
   | t1, L t2 -> aux (l1+1) l2 t1 t2
   | V a, V b -> a + l1 = b + l2
-  | C a, C b -> a = b
   | A(t1,t2), A(u1,u2) -> aux l1 l2 t1 u1 && aux l1 l2 t2 u2
   | _, _ -> false
  in aux ;;
@@ -49,10 +46,8 @@ let string_of_t =
   let rec string_of_term_w_pars level = function
     | V v -> if v >= level then "`" ^ string_of_int (v-level) else
        string_of_bvar (level - v-1)
-    | C n -> "c" ^ string_of_int n
     | A _
     | L _ as t -> "(" ^ string_of_term_no_pars level t ^ ")"
-    | B -> "BOT"
   and string_of_term_no_pars_app level = function
     | 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
@@ -68,19 +63,18 @@ type problem = {
  ; div : t
  ; conv : t
  ; sigma : (var * t) list (* substitutions *)
- ; stepped : var list
  ; phase : [`One | `Two] (* :'( *)
 }
 
 let string_of_problem p =
  let lines = [
-  "[stepped] " ^ String.concat " " (List.map string_of_int p.stepped);
   "[DV] " ^ string_of_t p.div;
   "[CV] " ^ string_of_t p.conv;
  ] in
  String.concat "\n" lines
 ;;
 
+exception B;;
 exception Done of (var * t) list (* substitution *);;
 exception Fail of int * string;;
 
@@ -98,8 +92,7 @@ let rec is_inert =
  function
  | A(t,_) -> is_inert t
  | V _ -> true
- | C _
- | L _ | B -> false
+ | L _ -> false
 ;;
 
 let is_var = function V _ -> true | _ -> false;;
@@ -117,7 +110,6 @@ let rec no_leading_lambdas v n = function
  | L t -> 1 + no_leading_lambdas (v+1) n t
  | A _ as t -> let v', m = get_inert t in if v = v' then max 0 (n - m) else 0
  | V v' -> if v = v' then n else 0
- | B | C _ -> 0
 ;;
 
 let rec subst level delift sub =
@@ -128,11 +120,8 @@ let rec subst level delift sub =
   let t1 = subst level delift sub t1 in
   let t2 = subst level delift sub t2 in
   mk_app t1 t2
- | C _ as t -> t
- | B -> B
-and mk_app t1 t2 = if t2 = B || (t1 = delta && t2 = delta) then B
+and mk_app t1 t2 = if t1 = delta && t2 = delta then raise B
  else match t1 with
- | B -> B
  | L t1 -> subst 0 true (0, t2) t1
  | _ -> A (t1, t2)
 and lift n =
@@ -141,25 +130,21 @@ and lift n =
   | V m -> V (if m >= lev then m + n else m)
   | L t -> L (aux (lev+1) t)
   | A (t1, t2) -> A (aux lev t1, aux lev t2)
-  | C _ as t -> t
-  | B -> B
  in aux 0
 ;;
 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;
-  stepped=v::p.stepped;
-  sigma=sub::p.sigma}
+ let sigma = sub::p.sigma in
+ let div = try subst sub p.div with B -> raise (Done sigma) in
+ let conv = try subst sub p.conv with B -> raise (Fail(-1,"p.conv diverged")) in
+ {p with div; conv; sigma}
 ;;
 
 let get_subterm_with_head_and_args hd_var n_args =
  let rec aux lev = function
- | C _
- | V _ | B -> None
+ | V _ -> None
  | L t -> aux (lev+1) t
  | A(t1,t2) as t ->
    let hd_var', n_args' = get_inert t1 in
@@ -176,8 +161,6 @@ let rec purify = function
  | L t -> Pure.L (purify t)
  | A (t1,t2) -> Pure.A (purify t1, purify t2)
  | V n -> Pure.V n
- | C _ -> Pure.V max_int (* FIXME *)
- | B -> Pure.B
 ;;
 
 let check p sigma =
@@ -196,8 +179,6 @@ let check p sigma =
 
 let sanity p =
  print_endline (string_of_problem p); (* non cancellare *)
- if p.conv = B then problem_fail p "p.conv diverged";
- if p.div = B then raise (Done p.sigma);
  if p.phase = `Two && p.div = delta then raise (Done p.sigma);
  if not (is_inert p.div) then problem_fail p "p.div converged";
  p
@@ -244,7 +225,6 @@ let compute_max_lambdas_at hd_var j =
       else id) (max (aux hd t1) (aux hd t2))
  | L t -> aux (hd+1) t
  | V _ -> 0
- | _ -> assert false
  in aux hd_var
 ;;
 
@@ -332,7 +312,7 @@ let problem_of (label, div, convs, ps, var_names) =
  | Some div -> aux (div :> Num.nf)
  | None -> assert false in
  let varno = List.length var_names in
- let p = {orig_freshno=varno; freshno=1+varno; div; conv; sigma=[]; stepped=[]; phase=`One} in
+ let p = {orig_freshno=varno; freshno=1+varno; div; conv; sigma=[]; phase=`One} in
  (* initial sanity check *)
  sanity p
 ;;
-- 
2.39.2