From 7f2867ee172be351c32c9ff959be8c0079d0f0dc Mon Sep 17 00:00:00 2001
From: acondolu <andrea.condoluci@unibo.it>
Date: Fri, 1 Jun 2018 10:18:20 +0200
Subject: [PATCH] More comments and better variable names

---
 ocaml/simple.ml | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/ocaml/simple.ml b/ocaml/simple.ml
index 8e4f619..35874b6 100644
--- a/ocaml/simple.ml
+++ b/ocaml/simple.ml
@@ -111,10 +111,12 @@ let rec get_inert = function
  | _ -> assert false
 ;;
 
-let rec no_leading_lambdas hd_var j = function
- | L t -> 1 + no_leading_lambdas (hd_var+1) j t
- | A _ as t -> let hd_var', n = get_inert t in if hd_var = hd_var' then max 0 (j - n) else 0
- | V n -> if n = hd_var then j else 0
+(* 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
+ | 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
 ;;
 
@@ -145,12 +147,12 @@ and lift n =
 ;;
 let subst = subst 0 false;;
 
-let subst_in_problem sub p =
-print_endline ("-- SUBST " ^ string_of_t (V (fst sub)) ^ " |-> " ^ string_of_t (snd sub));
+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=(fst sub)::p.stepped;
+  stepped=v::p.stepped;
   sigma=sub::p.sigma}
 ;;
 
@@ -162,6 +164,7 @@ let get_subterm_with_head_and_args hd_var n_args =
  | A(t1,t2) as t ->
    let hd_var', n_args' = get_inert t1 in
    if hd_var' = hd_var + lev && n_args <= 1 + n_args'
+    (* the `+1` above is because of t2 *)
     then Some (lift ~-lev t)
     else match aux lev t2 with
     | None -> aux lev t1
@@ -182,7 +185,7 @@ let check p sigma =
  let div = purify p.div in
  let conv = purify p.conv in
  let sigma = List.map (fun (v,t) -> v, purify t) sigma in
- let freshno = List.fold_right (fun (x,_) -> max x) sigma 0 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.";
@@ -201,6 +204,8 @@ let sanity p =
 ;;
 
 (* drops the arguments of t after the n-th *)
+(* FIXME! E' usato in modo improprio contando sul fatto
+   errato che ritorna un inerte lungo esattamente n *)
 let inert_cut_at n t =
  let rec aux t =
   match t with
@@ -213,6 +218,7 @@ let inert_cut_at n t =
  in snd (aux t)
 ;;
 
+(* FIXME! eta_difference dovrebbe restituire un int partendo da 0 *)
 let find_eta_difference p t n_args =
  let t = inert_cut_at n_args t in
  let rec aux t u k = match t, u with
-- 
2.39.2