X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Flibrary%2FcoercDb.ml;h=3a4dac726783e0e6584a8a772efc8d7f1c7aaaa4;hb=62f814b9b8c255abbdfcbf12d96f3a3b4e74d477;hp=8b7982ea0576645c531fc82e5c599633ffcf39b2;hpb=9ff32d2a3efcf850ea52fe0223a5152f8777aee5;p=helm.git

diff --git a/helm/software/components/library/coercDb.ml b/helm/software/components/library/coercDb.ml
index 8b7982ea0..3a4dac726 100644
--- a/helm/software/components/library/coercDb.ml
+++ b/helm/software/components/library/coercDb.ml
@@ -41,6 +41,10 @@ let coerc_carr_of_term t =
   Term t
 ;;
 
+let uri_of_carr = function
+  | Uri u -> Some u
+  | _ -> None
+
 let rec name_of_carr = function
   | Uri u -> UriManager.name_of_uri u
   | Sort s -> CicPp.ppsort s
@@ -72,28 +76,51 @@ let eq_carr src tgt =
 let to_list () =
   !db
 
-let add_coercion c =
-  db := c :: !db
-
-let remove_coercion p = 
-  db := List.filter (fun u -> not(p u)) !db
+let rec myfilter p = function
+  | [] -> []
+  | (s,t,l)::tl ->
+      let l = List.filter (fun u -> not (p (s,t,u))) l in
+      if l = [] then myfilter p tl else (s,t,l)::myfilter p tl
+;;
+  
+let remove_coercion p = db := myfilter p !db;;
 
 let find_coercion f =
-  List.map (fun (_,_,x) -> x) (List.filter (fun (s,t,_) -> f (s,t)) !db)
+  List.flatten 
+    (List.map 
+      (fun (_,_,x) -> x) 
+      (List.filter (fun (s,t,_) -> f (s,t)) !db))
+;;
 
-let is_a_coercion u =
-  List.exists (fun (_,_,x) -> UriManager.eq x u) !db
+let is_a_coercion u = 
+  List.exists (fun (_,_,xl) -> List.exists (UriManager.eq u) xl) !db
+;;
 
 let get_carr uri =
   try
-    let src, tgt, _ = List.find (fun (_,_,x) -> UriManager.eq x uri) !db in
+    let src, tgt, _ = 
+      List.find (fun (_,_,xl) -> List.exists (UriManager.eq uri) xl) !db 
+    in
     src, tgt
   with Not_found -> assert false (* uri must be a coercion *)
+;;
 
 let term_of_carr = function
   | Uri u -> CicUtil.term_of_uri u
   | Sort s -> Cic.Sort s
   | Term _ -> assert false
+;;
   
+let add_coercion (src,tgt,u) =
+  let f s t = eq_carr s src && eq_carr t tgt in
+  let where = List.filter (fun (s,t,_) -> f s t) !db in
+  let rest = List.filter (fun (s,t,_) -> not (f s t)) !db in
+  match where with
+  | [] -> db := (src,tgt,[u]) :: !db
+  | (src,tgt,l)::tl ->
+      assert (tl = []); (* not sure, this may be a feature *)
+      db := (src,tgt,u::l)::tl @ rest
+;;
+