X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_refiner%2FnCicMetaSubst.ml;h=26dc85cacebadc948661b90ae084159a7499ba78;hb=c22f39a5d5afc0ef55beb221e00e2e6703b13d90;hp=94cfe669036143734c56d3c4e5d5992fe0977256;hpb=f094694e53cfeea2c33e8c2aa2abac6dd7e44138;p=helm.git

diff --git a/helm/software/components/ng_refiner/nCicMetaSubst.ml b/helm/software/components/ng_refiner/nCicMetaSubst.ml
index 94cfe6690..26dc85cac 100644
--- a/helm/software/components/ng_refiner/nCicMetaSubst.ml
+++ b/helm/software/components/ng_refiner/nCicMetaSubst.ml
@@ -14,9 +14,10 @@
 exception MetaSubstFailure of string Lazy.t
 exception Uncertain of string Lazy.t
 
-let newmeta = 
+let newmeta,maxmeta = 
   let maxmeta = ref 0 in
-  fun () -> incr maxmeta; !maxmeta
+  (fun () -> incr maxmeta; !maxmeta),
+  (fun () -> !maxmeta)
 ;;
 
 exception NotInTheList;;
@@ -220,6 +221,8 @@ let int_of_out_scope_tag tag =
 ;;
 
 
+exception Found;;
+
 (* INVARIANT: we suppose that t is not another occurrence of Meta(n,_), 
    otherwise the occur check does not make sense in case of unification
    of ?n with ?n *)
@@ -232,26 +235,44 @@ let delift ~unify metasenv subst context n l t =
         with NCicUtils.Subst_not_found _ -> false)
     | _ -> false
   in
-  let unify_list in_scope = 
+  let contains_in_scope subst t = 
+    let rec aux _ () = function
+      | NCic.Meta _ as t ->
+          if is_in_scope_meta subst t then raise Found
+          else ()
+      | t -> 
+          if is_in_scope_meta subst t then raise Found
+          else NCicUtils.fold (fun _ () -> ()) () aux () t
+    in
+    try aux () () t; false with Found -> true
+  in
+  let unify_list ~alpha in_scope = 
     match l with
     | _, NCic.Irl _ -> fun _ _ _ _ _ -> None
     | shift, NCic.Ctx l -> fun metasenv subst context k t ->
-       if flexible_arg subst t || is_in_scope_meta subst t then None else
+       if flexible_arg subst t || contains_in_scope subst t then None else
          let lb = List.map (fun t -> t, flexible_arg subst t) l in
          HExtlib.list_findopt
           (fun (li,flexible) i ->
             if flexible || i < in_scope then None else
              let li = NCicSubstitution.lift (k+shift) li in
-             match unify metasenv subst context li t with
-             | Some (metasenv,subst) -> 
-                 Some ((metasenv, subst), NCic.Rel (i+1+k))
-             | None -> None)
+              if alpha then
+               if NCicReduction.alpha_eq metasenv subst context li t then
+                Some ((metasenv,subst), NCic.Rel (i+1+k))
+               else
+                None
+              else
+               match unify metasenv subst context li t with
+               | Some (metasenv,subst) -> 
+                   Some ((metasenv, subst), NCic.Rel (i+1+k))
+               | None -> None)
           lb
   in
   let rec aux (context,k,in_scope) (metasenv, subst as ms) t = 
-   match unify_list in_scope metasenv subst context k t with
+   match unify_list ~alpha:true in_scope metasenv subst context k t with
    | Some x -> x
    | None -> 
+   try
     match t with 
     | NCic.Rel n as t when n <= k -> ms, t
     | NCic.Rel n -> 
@@ -382,6 +403,10 @@ let delift ~unify metasenv subst context n l t =
     | t -> 
         NCicUntrusted.map_term_fold_a 
           (fun e (c,k,s) -> (e::c,k+1,s)) (context,k,in_scope) aux ms t
+   with NotInTheList ->
+    match unify_list ~alpha:false in_scope metasenv subst context k t with
+    | Some x -> x
+    | None -> raise NotInTheList
   in
    try aux (context,0,0) (metasenv,subst) t
    with NotInTheList ->
@@ -400,10 +425,7 @@ let delift ~unify metasenv subst context n l t =
       let lc = NCicUtils.expand_local_context lc in
       let l = List.map (NCicSubstitution.lift shift) lc in
        if
-         List.exists
-          (fun t -> 
-                  NCicUntrusted.metas_of_term subst context t = [])
-            l
+        List.exists (fun t-> NCicUntrusted.metas_of_term subst context t = []) l
        then
         raise (Uncertain msg)
        else