From 461dcd3dc0bf5090be9980548bc1874a423dc6cc Mon Sep 17 00:00:00 2001
From: acondolu <andrea.condoluci@unibo.it>
Date: Wed, 30 May 2018 12:36:15 +0200
Subject: [PATCH] Clean up

---
 ocaml/andrea.ml | 95 ++++++++++++++++++++++---------------------------
 1 file changed, 43 insertions(+), 52 deletions(-)

diff --git a/ocaml/andrea.ml b/ocaml/andrea.ml
index c8710f4..affdcad 100644
--- a/ocaml/andrea.ml
+++ b/ocaml/andrea.ml
@@ -35,24 +35,23 @@ type problem = {
 exception Done of (var * t) list (* substitution *);;
 exception Fail of int * string;;
 
-let string_of_t p =
-  let bound_vars = ["x"; "y"; "z"; "w"; "q"] in
+let string_of_t =
+  let string_of_bvar =
+   let bound_vars = ["x"; "y"; "z"; "w"; "q"] in
+   let bvarsno = List.length bound_vars in
+   fun nn -> if nn < bvarsno then List.nth bound_vars nn else "x" ^ (string_of_int (nn - bvarsno + 1)) in
   let rec string_of_term_w_pars level = function
     | V v -> if v >= level then "`" ^ string_of_int (v-level) else
-     let nn = level - v-1 in
-      if nn < 5 then List.nth bound_vars nn else "x" ^ (string_of_int (nn-4))
+       string_of_bvar (level - v-1)
     | A _
-    | L _ as t -> "(" ^ string_of_term_no_pars_lam level t ^ ")"
+    | L _ as t -> "(" ^ string_of_term_no_pars level t ^ ")"
     | B -> "BOT"
     | P -> "PAC"
   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)
+    | 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_lam level = function
-    | L t -> "λ" ^ string_of_term_w_pars (level+1) (V 0) ^ ". " ^ (string_of_term_no_pars_lam (level+1) t)
-    | _ as t -> string_of_term_no_pars level t
   and string_of_term_no_pars level = function
-    | L _ as t -> string_of_term_no_pars_lam level t
+    | L t -> "λ" ^ string_of_bvar level ^ ". " ^ string_of_term_no_pars (level+1) t
     | _ as t -> string_of_term_no_pars_app level t
   in string_of_term_no_pars 0
 ;;
@@ -60,8 +59,8 @@ let string_of_t p =
 let string_of_problem p =
  let lines = [
   "[stepped] " ^ String.concat " " (List.map string_of_int p.stepped);
-  "[DV] " ^ (string_of_t p p.div);
-  "[CV] " ^ (string_of_t p p.conv);
+  "[DV] " ^ string_of_t p.div;
+  "[CV] " ^ string_of_t p.conv;
  ] in
  String.concat "\n" lines
 ;;
@@ -86,15 +85,9 @@ let rec is_inert =
 let is_var = function V _ -> true | _ -> false;;
 let is_lambda = function L _ -> true | _ -> false;;
 
-let rec head_of_inert = function
- | V n -> n
- | A(t, _) -> head_of_inert t
- | _ -> assert false
-;;
-
-let rec args_no = function
- | V _ -> 0
- | A(t, _) -> 1 + args_no t
+let rec get_inert = function
+ | V n -> (n,0)
+ | A(t, _) -> let hd,args = get_inert t in hd,args+1
  | _ -> assert false
 ;;
 
@@ -105,7 +98,7 @@ let rec subst level delift sub =
  | A (t1,t2) ->
   let t1 = subst level delift sub t1 in
   let t2 = subst level delift sub t2 in
-  if t1 = B || t2 = B then B else mk_app t1 t2
+  mk_app t1 t2
  | B -> B
  | P -> P
 and mk_app t1 t2 = let t1 = if t1 = P then L P else t1 in match t1 with
@@ -113,11 +106,11 @@ and mk_app t1 t2 = let t1 = if t1 = P then L P else t1 in match t1 with
  | L t1 -> subst 0 true (0, t2) t1
  | t1 -> A (t1, t2)
 and lift n =
- let rec aux n' =
+ let rec aux lev =
   function
-  | V m -> V (if m >= n' then m + n else m)
-  | L t -> L (aux (n'+1) t)
-  | A (t1, t2) -> A (aux n' t1, aux n' t2)
+  | 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)
   | B -> B
   | P -> P
  in aux 0
@@ -125,13 +118,12 @@ and lift n =
 let subst = subst 0 false;;
 
 let subst_in_problem (sub: var * t) (p: problem) =
-print_endline ("-- SUBST " ^ string_of_t p (V (fst sub)) ^ " |-> " ^ string_of_t p (snd sub));
- let p = {p with stepped=(fst sub)::p.stepped} in
- let conv = subst sub p.conv in
- let div = subst sub p.div in
- let p = {p with div; conv} in
- (* print_endline ("after sub: \n" ^ string_of_problem p); *)
- {p with sigma=sub::p.sigma}
+print_endline ("-- SUBST " ^ string_of_t (V (fst sub)) ^ " |-> " ^ string_of_t (snd sub));
+ {p with
+  div=subst sub p.div;
+  conv=subst sub p.conv;
+  stepped=(fst sub)::p.stepped;
+  sigma=sub::p.sigma}
 ;;
 
 let get_subterm_with_head_and_args hd_var n_args =
@@ -139,7 +131,8 @@ let get_subterm_with_head_and_args hd_var n_args =
  | V _ | B | P -> None
  | L t -> aux (lev+1) t
  | A(t1,t2) as t ->
-   if head_of_inert t1 = hd_var + lev && n_args <= 1 + args_no t1 (* why `1+' ?*)
+   let hd_var', n_args' = get_inert t1 in
+   if hd_var' = hd_var + lev && n_args <= 1 + n_args'
     then Some (lift ~-lev t)
     else match aux lev t2 with
     | None -> aux lev t1
@@ -156,11 +149,9 @@ let get_subterm_with_head_and_args hd_var n_args =
 
 let sanity p =
  print_endline (string_of_problem p); (* non cancellare *)
- if p.div = B then raise (Done p.sigma);
- if not (is_inert p.div) then problem_fail p "p.div converged";
  if p.conv = B then problem_fail p "p.conv diverged";
- (* let p = if is_var p.div then simple_explode p else p in *)
- p
+ if p.div = B then raise (Done p.sigma);
+ if not (is_inert p.div) then problem_fail p "p.div converged"
 ;;
 
 let print_cmd s1 s2 = print_endline (">> " ^ s1 ^ " " ^ s2);;
@@ -169,20 +160,20 @@ let print_cmd s1 s2 = print_endline (">> " ^ s1 ^ " " ^ s2);;
  It does NOT perform any check, may fail if done unsafely *)
 let eat p =
 print_cmd "EAT" "";
- let var = head_of_inert p.div in
- let n = args_no p.div in
+ let var, n = get_inert p.div in
  let rec aux m t =
   if m = 0
    then lift n t
    else L (aux (m-1) t) in
  let subst = var, aux n B in
- sanity (subst_in_problem subst p)
+ let p = subst_in_problem subst p in
+ sanity p; p
 ;;
 
 (* step on the head of div, on the k-th argument, with n fresh vars *)
 let step k n p =
- let var = head_of_inert p.div in
- print_cmd "STEP" ("on " ^ string_of_t p (V var) ^ " (of:" ^ string_of_int n ^ ")");
+ let var, _ = get_inert p.div in
+ print_cmd "STEP" ("on " ^ string_of_t (V var) ^ " (of:" ^ string_of_int n ^ ")");
  let rec aux' p m t =
   if m < 0
    then p, t
@@ -198,7 +189,8 @@ let step k n p =
    else L (aux (m-1) t) in
  let t = aux k t in
  let subst = var, t in
- sanity (subst_in_problem subst p)
+ let p = subst_in_problem subst p in
+ sanity p; p
 ;;
 
 let parse strs =
@@ -230,7 +222,7 @@ let problem_of div conv =
    (print_endline ("after subst in problem " ^ string_of_problem p); p)
   with Not_found -> p in
  (* initial sanity check *)
- sanity p
+ sanity p; p
 ;;
 
 let exec div conv cmds =
@@ -258,7 +250,7 @@ let find_eta_difference p t n_args =
  let rec aux t u k = match t, u with
  | V _, V _ -> assert false (* div subterm of conv *)
  | A(t1,t2), A(u1,u2) ->
-    if not (eta_eq t2 u2) then (print_endline((string_of_t p t2) ^ " <> " ^ (string_of_t p u2)); k)
+    if not (eta_eq t2 u2) then (print_endline((string_of_t t2) ^ " <> " ^ (string_of_t u2)); k)
     else aux t1 u1 (k-1)
  | _, _ -> assert false
  in aux p.div t n_args
@@ -272,10 +264,10 @@ let rec no_leading_lambdas = function
 let compute_max_lambdas_at hd_var j =
  let rec aux hd = function
  | A(t1,t2) ->
-    (if head_of_inert t1 = hd && args_no t1 = j
-      then max (
-       if is_inert t2 && head_of_inert t2 = hd
-        then j - args_no t2
+    (if get_inert t1 = (hd, j)
+      then max ( (*FIXME*)
+       if is_inert t2 && let hd', j' = get_inert t2 in hd' = hd
+        then let hd', j' = get_inert t2 in j - j'
         else no_leading_lambdas t2)
       else id) (max (aux hd t1) (aux hd t2))
  | L t -> aux (hd+1) t
@@ -285,8 +277,7 @@ let compute_max_lambdas_at hd_var j =
 ;;
 
 let rec auto p =
- let hd_var = head_of_inert p.div in
- let n_args = args_no p.div in
+ let hd_var, n_args = get_inert p.div in
  match get_subterm_with_head_and_args hd_var n_args p.conv with
  | None ->
     (try problem_fail (eat p) "Auto did not complete the problem"  with Done _ -> ())
-- 
2.39.2