X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=helm%2Fsoftware%2Fcomponents%2Fcic_proof_checking%2FcicSubstitution.ml;h=8d1dad9e2c2af09ccded670260c3b9c0b8971927;hb=233836d11a41951f0197523c75a317d1070d7c6e;hp=a30a036cb42dc7726c1720906d706f903b0fcf30;hpb=55b82bd235d82ff7f0a40d980effe1efde1f5073;p=helm.git

diff --git a/helm/software/components/cic_proof_checking/cicSubstitution.ml b/helm/software/components/cic_proof_checking/cicSubstitution.ml
index a30a036cb..8d1dad9e2 100644
--- a/helm/software/components/cic_proof_checking/cicSubstitution.ml
+++ b/helm/software/components/cic_proof_checking/cicSubstitution.ml
@@ -62,7 +62,8 @@ let lift_from k n =
     | C.Cast (te,ty) -> C.Cast (liftaux k te, liftaux k ty)
     | C.Prod (n,s,t) -> C.Prod (n, liftaux k s, liftaux (k+1) t)
     | C.Lambda (n,s,t) -> C.Lambda (n, liftaux k s, liftaux (k+1) t)
-    | C.LetIn (n,s,t) -> C.LetIn (n, liftaux k s, liftaux (k+1) t)
+    | C.LetIn (n,s,ty,t) ->
+       C.LetIn (n, liftaux k s, liftaux k ty, liftaux (k+1) t)
     | C.Appl l -> C.Appl (List.map (liftaux k) l)
     | C.Const (uri,exp_named_subst) ->
        let exp_named_subst' = 
@@ -108,7 +109,12 @@ let lift n t =
    lift_from 1 n t
 ;;
 
-let subst arg =
+(* subst t1 t2                                                         *)
+(* substitutes [t1] for [Rel 1] in [t2]                                *)
+(* if avoid_beta_redexes is true (default: false) no new beta redexes  *)
+(* are generated. WARNING: the substitution can diverge when t2 is not *)
+(* well typed and avoid_beta_redexes is true.                          *)
+let rec subst ?(avoid_beta_redexes=false) arg =
  let rec substaux k =
   let module C = Cic in
    function
@@ -137,13 +143,20 @@ let subst arg =
     | C.Cast (te,ty) -> C.Cast (substaux k te, substaux k ty)
     | C.Prod (n,s,t) -> C.Prod (n, substaux k s, substaux (k + 1) t)
     | C.Lambda (n,s,t) -> C.Lambda (n, substaux k s, substaux (k + 1) t)
-    | C.LetIn (n,s,t) -> C.LetIn (n, substaux k s, substaux (k + 1) t)
+    | C.LetIn (n,s,ty,t) ->
+       C.LetIn (n, substaux k s, substaux k ty, substaux (k + 1) t)
     | C.Appl (he::tl) ->
        (* Invariant: no Appl applied to another Appl *)
        let tl' = List.map (substaux k) tl in
         begin
          match substaux k he with
             C.Appl l -> C.Appl (l@tl')
+            (* Experimental *)
+          | C.Lambda (_,_,bo) when avoid_beta_redexes ->
+             (match tl' with
+                 [] -> assert false
+               | [he] -> subst ~avoid_beta_redexes he bo
+               | he::tl -> C.Appl (subst he bo::tl))
           | _ as he' -> C.Appl (he'::tl')
         end
     | C.Appl _ -> assert false
@@ -246,7 +259,8 @@ debug_print (lazy "---- END\n\n ") ;
     | C.Cast (te,ty) -> C.Cast (substaux k te, substaux k ty)
     | C.Prod (n,s,t) -> C.Prod (n, substaux k s, substaux (k + 1) t)
     | C.Lambda (n,s,t) -> C.Lambda (n, substaux k s, substaux (k + 1) t)
-    | C.LetIn (n,s,t) -> C.LetIn (n, substaux k s, substaux (k + 1) t)
+    | C.LetIn (n,s,ty,t) ->
+       C.LetIn (n, substaux k s, substaux k ty, substaux (k + 1) t)
     | C.Appl (he::tl) ->
        (* Invariant: no Appl applied to another Appl *)
        let tl' = List.map (substaux k) tl in
@@ -387,7 +401,7 @@ let subst_meta l t =
     | C.Cast (te,ty) -> C.Cast (aux k te, aux k ty) (*CSC ??? *)
     | C.Prod (n,s,t) -> C.Prod (n, aux k s, aux (k + 1) t)
     | C.Lambda (n,s,t) -> C.Lambda (n, aux k s, aux (k + 1) t)
-    | C.LetIn (n,s,t) -> C.LetIn (n, aux k s, aux (k + 1) t)
+    | C.LetIn (n,s,ty,t) -> C.LetIn (n, aux k s, aux k ty, aux (k + 1) t)
     | C.Appl l -> C.Appl (List.map (aux k) l)
     | C.Const (uri,exp_named_subst) ->
        let exp_named_subst' =
@@ -426,3 +440,4 @@ let subst_meta l t =
   aux 0 t          
 ;;
 
+Deannotate.lift := lift;;