From: Enrico Tassi <enrico.tassi@inria.fr>
Date: Wed, 23 Apr 2008 16:41:37 +0000 (+0000)
Subject: ported the instantiate-left-params-to-calculate-rec-args patch from the old to the... 
X-Git-Tag: make_still_working~5292
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=3928102abd95778d390e2790fdb7ac2ae3567813;p=helm.git

ported the instantiate-left-params-to-calculate-rec-args patch from the old to the new kernel,
to test the patch properly some steps of substitution inside a possibly blocked fix are performed,
this should be in general avoided without good checks (still to understand)
---

diff --git a/helm/software/components/ng_kernel/nCicTypeChecker.ml b/helm/software/components/ng_kernel/nCicTypeChecker.ml
index e96169e3e..6dceca87f 100644
--- a/helm/software/components/ng_kernel/nCicTypeChecker.ml
+++ b/helm/software/components/ng_kernel/nCicTypeChecker.ml
@@ -26,9 +26,9 @@ let shift_k e (c,rf,x,safes) =
   e::c,List.map (fun (k,v) -> k+1,v) rf,x+1,List.map ((+)1) safes
 ;;
 
-(* $Id: cicTypeChecker.ml 8213 2008-03-13 18:48:26Z sacerdot $ *)
-
-
+let shift_k_add_1_safe e (c,rf,x,safes) =
+  e::c,List.map (fun (k,v) -> k+1,v) rf,x+1,1::List.map ((+)1) safes
+;;
 
 (*
 (* the boolean h means already protected *)
@@ -294,7 +294,7 @@ let rec split_prods ~subst context n te =
    | (_, _) -> raise (AssertFailure (lazy "split_prods"))
 ;;
 
-let debruijn ?(cb=fun _ _ -> ()) uri number_of_types = 
+let debruijn ?(cb=fun _ _ -> ()) uri number_of_types context = 
  let rec aux k t =
   let res =
    match t with
@@ -309,7 +309,7 @@ let debruijn ?(cb=fun _ _ -> ()) uri number_of_types =
   in
    cb t res; res
  in
-  aux 0
+  aux (List.length context)
 ;;
 
 let sort_of_prod ~metasenv ~subst context (name,s) (t1, t2) =
@@ -371,20 +371,44 @@ let eat_prods ~subst ~metasenv context he ty_he args_with_ty =
     aux ty_he args_with_ty
 ;;
 
-let fix_lefts_in_constrs ~subst uri paramsno tyl i =
-  let len = List.length tyl in
-  let _,_,arity,cl = List.nth tyl i in
-  let tys = List.map (fun (_,n,ty,_) -> n,C.Decl ty) tyl in
-  let cl' =
-   List.map
-    (fun (_,id,ty) ->
-      let debruijnedty = debruijn uri len ty in
-      id, snd (split_prods ~subst tys paramsno ty),
-       snd (split_prods ~subst tys paramsno debruijnedty))
-    cl 
+(* instantiate_parameters ps (x1:T1)...(xn:Tn)C                             *)
+(* returns ((x_|ps|:T_|ps|)...(xn:Tn)C){ps_1 / x1 ; ... ; ps_|ps| / x_|ps|} *)
+let rec instantiate_parameters params c =
+  match c, params with
+  | c,[] -> c
+  | C.Prod (_,_,ta), he::tl -> instantiate_parameters tl (S.subst he ta)
+  | t,l -> raise (AssertFailure (lazy "1"))
+;;
+
+let specialize_inductive_type ~subst context ty_term =
+  match R.whd ~subst context ty_term with
+  | C.Const (Ref.Ref (_,uri,Ref.Ind i) as ref)  
+  | C.Appl (C.Const (Ref.Ref (_,uri,Ref.Ind i) as ref) :: _ ) as ty ->
+      let args = match ty with C.Appl (_::tl) -> tl | _ -> [] in
+      let is_ind, leftno, itl, attrs, i = E.get_checked_indtys ref in
+      let left_args,_ = HExtlib.split_nth leftno args in
+      let itl =
+        List.map (fun (rel, name, arity, cl) ->
+          let arity = instantiate_parameters left_args arity in
+          let cl = 
+            List.map (fun (rel, name, ty) -> 
+              rel, name, instantiate_parameters left_args ty)
+              cl
+          in
+            rel, name, arity, cl)
+          itl
+      in
+        is_ind, leftno, itl, attrs, i
+  | _ -> assert false
+;;
+
+let fix_lefts_in_constrs ~subst r_uri r_len context ty_term =
+  let _,_,itl,_,i = specialize_inductive_type ~subst context ty_term in
+  let _,_,_,cl = List.nth itl i in  
+  let cl =
+    List.map (fun (_,id,ty) -> id, debruijn r_uri r_len context ty) cl 
   in
-  let lefts = fst (split_prods ~subst [] paramsno arity) in
-  lefts@tys, len, cl'
+  List.map (fun (_,name,arity,_) -> name, C.Decl arity) itl, cl
 ;;
 
 exception DoesOccur;;
@@ -445,14 +469,6 @@ let rec weakly_positive ~subst context n nn uri te =
    | _ ->
      raise (TypeCheckerFailure (lazy "Malformed inductive constructor type"))
 
-(* instantiate_parameters ps (x1:T1)...(xn:Tn)C                             *)
-(* returns ((x_|ps|:T_|ps|)...(xn:Tn)C){ps_1 / x1 ; ... ; ps_|ps| / x_|ps|} *)
-and instantiate_parameters params c =
-  match c, params with
-  | c,[] -> c
-  | C.Prod (_,_,ta), he::tl -> instantiate_parameters tl (S.subst he ta)
-  | t,l -> raise (AssertFailure (lazy "1"))
-
 and strictly_positive ~subst context n nn te =
   match R.whd context te with
    | t when does_not_occur ~subst context n nn t -> true
@@ -864,7 +880,7 @@ and check_mutual_inductive_defs uri ~metasenv ~subst is_ind leftno tyl =
     (fun (_,_,_,cl) i ->
        List.iter
          (fun (_,name,te) -> 
-           let debruijnedte = debruijn uri len te in
+           let debruijnedte = debruijn uri len [] te in
            ignore (typeof ~subst ~metasenv tys debruijnedte);
            (* let's check also the positivity conditions *)
            if 
@@ -888,9 +904,13 @@ and eat_lambdas ~subst ~metasenv context n te =
       raise (AssertFailure (lazy (Printf.sprintf "9 (%d, %s)" n 
         (NCicPp.ppterm ~subst ~metasenv ~context te))))
 
-and guarded_by_destructors ~subst ~metasenv context recfuns t = 
+and guarded_by_destructors r_uri r_len ~subst ~metasenv context recfuns t = 
  let recursor f k t = NCicUtils.fold shift_k k (fun k () -> f k) () t in
  let rec aux (context, recfuns, x, safes as k) t = 
+(*
+   prerr_endline ("GB: " ^ NCicPp.ppterm ~metasenv ~subst ~context t
+     ^ "        " ^ String.concat "," (List.map (fun i -> NCicPp.ppterm ~metasenv ~subst ~context (C.Rel i)) safes));
+ *)
   match R.whd ~subst context t with (* TODO: use ~delta:false as mush as poss*)
   | C.Rel m as t when List.mem_assoc m recfuns -> 
       raise (NotGuarded (lazy 
@@ -908,31 +928,52 @@ and guarded_by_destructors ~subst ~metasenv context recfuns t =
          " is a partial application of a fix")))
      else
        let rec_arg = List.nth tl rec_no in
-       if not (is_really_smaller ~subst ~metasenv k rec_arg) then 
-         raise (NotGuarded (lazy 
-           (NCicPp.ppterm ~context ~subst ~metasenv rec_arg ^ " not smaller")));
+       if not (is_really_smaller r_uri r_len ~subst ~metasenv k rec_arg) then 
+         raise (NotGuarded (lazy (Printf.sprintf ("Recursive call %s, %s is not"
+          ^^ " smaller.\ncontext:\n%s") (NCicPp.ppterm ~context ~subst ~metasenv
+          t) (NCicPp.ppterm ~context ~subst ~metasenv rec_arg)
+          (NCicPp.ppcontext ~subst ~metasenv context))));
        List.iter (aux k) tl
-       (*
-  | C.Appl (C.Const ((Ref.Ref (_,_,Ref.Fix (i,j))) as r)::args) ->
-      List.iter (aux k) args;
-      let fixes,_,_ = E.get_checked_fixes r in
-      let _,_,_,_,bo = List.nth fixes i in
-      let bo_wout_lam, context = eat_lambdas ~subst ~metasenv context j in
-      (* debruijna body..... *) assert false
-*)
+  | C.Appl (C.Const ((Ref.Ref (_,uri,Ref.Fix (i,j))) as r)::args) 
+    when List.length args > j 
+     (* TODO: extra check really usueful?? *)      
+    && List.exists (fun (k,_) -> List.exists (fun t -> not (does_not_occur ~subst context k (k+1) t)) args) recfuns
+    && is_really_smaller r_uri r_len ~subst ~metasenv k (List.nth args j) ->
+      let fl,_,_ = E.get_checked_fixes r in
+      let ctx_tys, bos = 
+        List.split (List.map (fun (_,name,_,ty,bo) -> (name, C.Decl ty), bo) fl)
+      in
+      let bo = List.nth bos i in
+      let bo = debruijn uri (List.length fl) context bo in
+      let args, rest = HExtlib.split_nth j args in  
+      let bo = 
+        (* TODO: here we should check which args are passed around ... *)
+        if j > 0 then R.head_beta_reduce ~upto:j (C.Appl (bo::args)) else bo 
+      in
+      let bo, context_rec = eat_lambdas ~subst ~metasenv context 1 bo in
+      let bo = 
+        if rest = [] then  bo else
+        let rest = List.tl rest in if rest <> [] then C.Appl (bo::rest) else bo
+      in
+      let k = context@ctx_tys, recfuns, x, safes in
+      aux (shift_k_add_1_safe (List.hd context_rec) k) bo
   | C.Match (Ref.Ref (_,uri,_) as ref,outtype,term,pl) as t ->
      (match R.whd ~subst context term with
      | C.Rel m | C.Appl (C.Rel m :: _ ) as t when List.mem m safes || m = x ->
-        let isinductive, paramsno, tl, _, i = E.get_checked_indtys ref in
+        (* TODO: add CoInd to references so that this call is useless *)
+        let isinductive, _, _, _, _ = E.get_checked_indtys ref in
         if not isinductive then recursor aux k t
         else
-         let c_ctx,len,cl = fix_lefts_in_constrs ~subst uri paramsno tl i in
+         let ty = typeof ~subst ~metasenv context term in
+         let itl_ctx,cl = fix_lefts_in_constrs ~subst r_uri r_len context ty in
          let args = match t with C.Appl (_::tl) -> tl | _ -> [] in
+         let dc_ctx = context @ itl_ctx in
+         let start, stop = List.length context, List.length context + r_len in
          aux k outtype; 
          List.iter (aux k) args; 
          List.iter2
-           (fun p (_,_,bruijnedc) ->
-             let rl = recursive_args ~subst ~metasenv c_ctx 0 len bruijnedc in
+           (fun p (_,dc) ->
+             let rl = recursive_args ~subst ~metasenv dc_ctx start stop dc in
              let p, k = get_new_safes ~subst k p rl in
              aux k p) 
            pl cl
@@ -988,6 +1029,10 @@ and recursive_args ~subst ~metasenv context n nn te =
   match R.whd context te with
   | C.Rel _ | C.Appl _ -> []
   | C.Prod (name,so,de) ->
+(*
+      prerr_endline ("RA: " ^ NCicPp.ppterm ~subst ~metasenv ~context so
+       ^ " == " ^ string_of_bool (not (does_not_occur ~subst context n nn so)));
+ *)
      (not (does_not_occur ~subst context n nn so)) ::
       (recursive_args ~subst ~metasenv 
         ((name,(C.Decl so))::context) (n+1) (nn + 1) de)
@@ -1001,7 +1046,13 @@ and get_new_safes ~subst (context, recfuns, x, safes as k) p rl =
       let safes = (if b then [0] else []) @ safes in
       get_new_safes ~subst 
         (shift_k (name,(C.Decl so)) (context, recfuns, x, safes)) ta tl
-  | C.Meta _ as e, _ | e, [] -> e, k
+  | C.Meta _ as e, _ | e, [] -> 
+(*
+      prerr_endline ("GNS: " ^ String.concat ","
+        (List.map (fun i -> 
+          NCicPp.ppterm ~subst ~metasenv:[] ~context (C.Rel i)) safes));
+ *)
+      e, k
   | _ -> raise (AssertFailure (lazy "Ill formed pattern"))
 
 and split_prods ~subst context n te =
@@ -1011,13 +1062,15 @@ and split_prods ~subst context n te =
        split_prods ~subst ((name,(C.Decl so))::context) (n - 1) ta
   | _ -> raise (AssertFailure (lazy "split_prods"))
 
-and is_really_smaller ~subst ~metasenv (context, recfuns, x, safes as k) te =
+and is_really_smaller 
+  r_uri r_len ~subst ~metasenv (context, recfuns, x, safes as k) te 
+=
  match R.whd ~subst context te with
  | C.Rel m when List.mem m safes -> true
  | C.Lambda (name, s, t) ->
-     is_really_smaller ~subst ~metasenv (shift_k (name, C.Decl s) k) t
+    is_really_smaller r_uri r_len ~subst ~metasenv (shift_k (name,C.Decl s) k) t
  | C.Appl (he::_) ->
-     is_really_smaller ~subst ~metasenv k he
+    is_really_smaller r_uri r_len ~subst ~metasenv k he
  | C.Appl _
  | C.Rel _ 
  | C.Const (Ref.Ref (_,_,Ref.Con _)) -> false
@@ -1044,18 +1097,22 @@ and is_really_smaller ~subst ~metasenv (context, recfuns, x, safes as k) te =
  | C.Match (Ref.Ref (_,uri,_) as ref,outtype,term,pl) ->
     (match term with
     | C.Rel m | C.Appl (C.Rel m :: _ ) when List.mem m safes || m = x ->
-        let isinductive, paramsno, tl, _, i = E.get_checked_indtys ref in
+        (* TODO: add CoInd to references so that this call is useless *)
+        let isinductive, _, _, _, _ = E.get_checked_indtys ref in
         if not isinductive then
-          List.for_all (is_really_smaller ~subst ~metasenv k) pl
+          List.for_all (is_really_smaller r_uri r_len ~subst ~metasenv k) pl
         else
-          let c_ctx,len,cl = fix_lefts_in_constrs ~subst uri paramsno tl i in
+          let ty = typeof ~subst ~metasenv context term in
+          let itl_ctx,dcl= fix_lefts_in_constrs ~subst r_uri r_len context ty in
+          let start, stop = List.length context, List.length context + r_len in
+          let dc_ctx = context @ itl_ctx in
           List.for_all2
-           (fun p (_,_,debruijnedte) -> 
-             let rl'=recursive_args ~subst ~metasenv c_ctx 0 len debruijnedte in
-             let e, k = get_new_safes ~subst k p rl' in
-             is_really_smaller ~subst ~metasenv k e)
-           pl cl
-    | _ -> List.for_all (is_really_smaller ~subst ~metasenv k) pl)
+           (fun p (_,dc) -> 
+             let rl = recursive_args ~subst ~metasenv dc_ctx start stop dc in
+             let e, k = get_new_safes ~subst k p rl in
+             is_really_smaller r_uri r_len ~subst ~metasenv k e)
+           pl dcl
+    | _ -> List.for_all (is_really_smaller r_uri r_len ~subst ~metasenv k) pl)
  | _ -> assert false
 
 and returns_a_coinductive ~subst context ty =
@@ -1116,33 +1173,44 @@ and check_obj_well_typed (uri,height,metasenv,subst,kind) =
             ((name,(C.Decl (S.lift len ty)))::types, k::kl,len+1)
          ) ([],[],0) fl
       in
-        List.iter (fun (_,name,x,ty,bo) ->
-         let bo = debruijn uri len bo in
-         let ty_bo = typeof ~subst ~metasenv types bo in
-         if not (R.are_convertible ~subst ~metasenv types ty_bo (S.lift len ty))
-         then raise (TypeCheckerFailure (lazy ("(Co)Fix: ill-typed bodies")))
-         else
-          if inductive then begin
-            let m, context = eat_lambdas ~subst ~metasenv types (x + 1) bo in
-            (* guarded by destructors conditions D{f,k,x,M} *)
-            let rec enum_from k = 
-              function [] -> [] | v::tl -> (k,v)::enum_from (k+1) tl 
+      List.iter (fun (_,name,x,ty,bo) ->
+       let bo = debruijn uri len [] bo in
+       let ty_bo = typeof ~subst ~metasenv types bo in
+       if not (R.are_convertible ~subst ~metasenv types ty_bo (S.lift len ty))
+       then raise (TypeCheckerFailure (lazy ("(Co)Fix: ill-typed bodies")))
+       else
+        if inductive then begin
+          let m, context = eat_lambdas ~subst ~metasenv types (x + 1) bo in
+          let r_uri, r_len =
+            let he =
+             match List.hd context with _,C.Decl t -> t | _ -> assert false
             in
-            guarded_by_destructors 
-             ~subst ~metasenv context (enum_from (x+2) kl) m
-          end else
-           match returns_a_coinductive ~subst [] ty with
-            | None ->
+            match R.whd ~subst (List.tl context) he with
+            | C.Const (Ref.Ref (_,uri,Ref.Ind _) as ref)
+            | C.Appl (C.Const (Ref.Ref (_,uri,Ref.Ind _) as ref) :: _) ->
+                let _,_,itl,_,_ = E.get_checked_indtys ref in
+                  uri, List.length itl
+            | _ -> assert false
+          in
+          (* guarded by destructors conditions D{f,k,x,M} *)
+          let rec enum_from k = 
+            function [] -> [] | v::tl -> (k,v)::enum_from (k+1) tl 
+          in
+          guarded_by_destructors r_uri r_len 
+           ~subst ~metasenv context (enum_from (x+2) kl) m
+        end else
+         match returns_a_coinductive ~subst [] ty with
+          | None ->
+              raise (TypeCheckerFailure
+                (lazy "CoFix: does not return a coinductive type"))
+          | Some uri ->
+              (* guarded by constructors conditions C{f,M} *)
+              if not (guarded_by_constructors ~subst ~metasenv
+                  types 0 len false bo [] uri)
+              then
                 raise (TypeCheckerFailure
-                  (lazy "CoFix: does not return a coinductive type"))
-            | Some uri ->
-                (* guarded by constructors conditions C{f,M} *)
-                if not (guarded_by_constructors ~subst ~metasenv
-                    types 0 len false bo [] uri)
-                then
-                  raise (TypeCheckerFailure
-                   (lazy "CoFix: not guarded by constructors"))
-          ) fl
+                 (lazy "CoFix: not guarded by constructors"))
+        ) fl
 
 let typecheck_obj = check_obj_well_typed;;