From: acondolu <andrea.condoluci@unibo.it>
Date: Fri, 7 Jul 2017 17:16:29 +0000 (+0200)
Subject: Fixes to how arities are assigned and propagated
X-Git-Tag: weak-reduction-separation~70
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=ffece1568ae283bde759da5e146fbbd3eda66303;p=fireball-separation.git

Fixes to how arities are assigned and propagated
- added truelam to subst (useless, can be removed)
- TODO: to measure the problem, count the `fake` variables
        which are the ones with arity = min_int
---

diff --git a/ocaml/lambda4.ml b/ocaml/lambda4.ml
index acfec51..8498513 100644
--- a/ocaml/lambda4.ml
+++ b/ocaml/lambda4.ml
@@ -110,7 +110,7 @@ prerr_endline ("# INST0: " ^ string_of_var x ^ " := " ^ print ~l inst));*)
   | [] -> acc
   | t::todo_ps ->
 (*prerr_endline ("EXPAND t:" ^ print (t :> nf));*)
-     let t = subst false x inst (t :> nf) in
+     let t = subst false false x inst (t :> nf) in
 (*prerr_endline ("SUBSTITUTED t:" ^ print (t :> nf));*)
      let freshno,new_t,acc_new_ps =
       expand_match (freshno,acc_ps@`Var(max_int/3,-666)::todo_ps,acc_new_ps) t
@@ -124,7 +124,7 @@ prerr_endline ("# INST0: " ^ string_of_var x ^ " := " ^ print ~l inst));*)
    | t::todo_conv ->
 (*prerr_endline ("EXPAND t:" ^ print (t :> nf));*)
       (* try *)
-       let t = subst false x inst (t :> nf) in
+       let t = subst false false x inst (t :> nf) in
 (*prerr_endline ("SUBSTITUTED t:" ^ print (t :> nf));*)
        let freshno,new_t,acc_new_ps =
         expand_match (freshno,ps,acc_new_ps) t
@@ -137,7 +137,7 @@ prerr_endline ("# INST0: " ^ string_of_var x ^ " := " ^ print ~l inst));*)
    function
    | None -> freshno, None, acc_new_ps
    | Some t ->
-      let t = subst false x inst (t :> nf) in
+      let t = subst false false x inst (t :> nf) in
       let freshno,new_t,acc_new_ps =
        expand_match (freshno,ps,acc_new_ps) t
       in
@@ -151,7 +151,7 @@ prerr_endline ("# INST0: " ^ string_of_var x ^ " := " ^ print ~l inst));*)
          match u with
          | `N i -> acc_new_ps,i
          | _ ->
-            let ps = List.map (fun t -> cast_to_i_num_var (subst false x inst (t:> nf))) (acc_ps@acc_new_ps) in
+            let ps = List.map (fun t -> cast_to_i_num_var (subst false false x inst (t:> nf))) (acc_ps@acc_new_ps) in
             let super_simplified_ps = super_simplify_ps ps ps in
 (*prerr_endline ("CERCO u:" ^ print (fst u :> nf));
 List.iter (fun x -> prerr_endline ("IN: " ^ print (fst x :> nf))) ps;
@@ -420,16 +420,15 @@ let instantiate p x n =
    then failwithProblem p ("BOMB (" ^ string_of_nf !bomb ^ ") cannot be instantiated!"));
  let arity_of_x = max_arity_tms x (all_terms p) in
  (if arity_of_x < 0 then failwithProblem p "step on a var of negative arity");
- (* AC: FIXME compute arities correctly below! *)
- let arities = Num.compute_arities x (n+1) (all_terms p :> nf list) in
+ (* AC: Once upon a time, it was:
+    let arities = Num.compute_arities x (n+1) (all_terms p :> nf list) in *)
  (* let arities = Array.to_list (Array.make (n+1) 0) in *)
+ let arities = Array.to_list (Array.make (n+1) min_int) in
  let p,vars = make_fresh_vars p arities in
- (* let p,zero = make_fresh_var p in *)
- (* let zero = Listx.Nil zero in *)
- (* let args = if n = 0 then zero else Listx.append zero (Listx.from_list vars) in *)
  let args = Listx.from_list (vars :> nf list) in
  let bs = ref [] in
- let inst = `Lam(false,`Match(`I((0,0),Listx.map (lift 1) args),(x,arity_of_x),1,bs,[])) in
+ (* min_int, since it will be replaced anyway during subst: *)
+ let inst = `Lam(false,`Match(`I((0,n+1),Listx.map (lift 1) args),(x,min_int),1,bs,[])) in
  let p = {p with deltas=bs::p.deltas} in
  subst_in_problem x inst p
 ;;
diff --git a/ocaml/num.ml b/ocaml/num.ml
index 81bb1da..3c84f4f 100644
--- a/ocaml/num.ml
+++ b/ocaml/num.ml
@@ -169,7 +169,7 @@ let rec mk_app (h : nf) (arg : nf) =
  match h with
     `I(v,args) -> `I(v,Listx.append (Listx.Nil arg) args)
   | `Var v -> `I(v, Listx.Nil arg)
-  | `Lam(_,nf) -> subst true 0 arg (nf : nf) (* AC FIXME sanity check on arity *)
+  | `Lam(truelam,nf) -> subst truelam true 0 arg (nf : nf) (* AC FIXME sanity check on arity *)
   | `Match(t,v,lift,bs,args) -> `Match(t,v,lift,bs,List.append args [arg])
   | `N _ -> assert false (* Numbers cannot be applied *)
 (*in let l = ["v0";"v1";"v2"] in
@@ -194,10 +194,11 @@ and mk_match t (n,ar) bs_lift bs args =
         `Match (t,(n,ar),bs_lift,bs,args))
   | `I _ | `Var _ | `Match _ -> `Match(t,(n,ar),bs_lift,bs,args)
 
-and subst delift_by_one what (with_what : nf) (where : nf) =
+and subst truelam delift_by_one what (with_what : nf) (where : nf) =
  let aux_propagate_arity ar = function
- | `Lam(false,`Match(`I(v,args),(x,_),liftno,bs,args')) ->
+ | `Lam(false,`Match(`I(v,args),(x,_),liftno,bs,args')) when not delift_by_one ->
     `Lam(false,`Match(`I(v,args),(x,ar),liftno,bs,args'))
+ | `Var(i,_) -> `Var(i,ar)
  | _ as t -> t in
  let rec aux_i_num_var l =
   function
@@ -218,7 +219,7 @@ and subst delift_by_one what (with_what : nf) (where : nf) =
        let with_what' = lift l' with_what in
        (* The following line should be the identity when delift_by_one = true because we
           are assuming the ts to not contain lambda-bound variables. *)
-       bs := List.map (fun (n,t) -> n,subst false what with_what' t) !bs ;
+       bs := List.map (fun (n,t) -> n,subst truelam false what with_what' t) !bs ;
        mk_match (cast_to_i_num_var (aux_i_num_var l t)) v bs_lift bs (List.map (aux l) args)
  and aux l(*lift*) =
 (*function iii -> let res = match iii with*)
diff --git a/ocaml/num.mli b/ocaml/num.mli
index e06a821..c981cff 100644
--- a/ocaml/num.mli
+++ b/ocaml/num.mli
@@ -38,7 +38,7 @@ val mk_app : nf -> nf -> nf
 val mk_appl : nf -> nf list -> nf
 val mk_appx : nf -> nf Listx.listx -> nf
 val mk_match : nf i_num_var_ -> var -> int -> (int * nf) list ref -> nf list -> nf
-val subst : bool -> int -> nf -> nf -> nf
+val subst : bool -> bool -> int -> nf -> nf -> nf
 val parse' : string list -> nf list * string list
 val eta_compare : nf -> nf -> int
 val eta_eq : [< nf ] -> [< nf ] -> bool