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diff --git a/helm/ocaml/library/coercGraph.ml b/helm/ocaml/library/coercGraph.ml
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+(* Copyright (C) 2000, HELM Team.
+ * 
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ * 
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA  02111-1307, USA.
+ * 
+ * For details, see the HELM World-Wide-Web page,
+ * http://cs.unibo.it/helm/.
+ *)
+
+(* $Id$ *)
+
+open Printf;;
+
+type coercion_search_result = 
+  | SomeCoercion of Cic.term
+  | NoCoercion
+  | NotMetaClosed
+  | NotHandled of string Lazy.t
+
+let debug = false
+let debug_print s = if debug then prerr_endline (Lazy.force s) else ()
+
+(* searches a coercion fron src to tgt in the !coercions list *)
+let look_for_coercion src tgt =
+  try 
+    let l = 
+      CoercDb.find_coercion 
+        (fun (s,t) -> CoercDb.eq_carr s src && CoercDb.eq_carr t tgt) 
+    in
+    match l with
+    | [] -> 
+        debug_print 
+          (lazy 
+            (sprintf ":-( coercion non trovata da %s a %s" 
+              (CoercDb.name_of_carr src) 
+              (CoercDb.name_of_carr tgt)));
+        NoCoercion
+    | [u] -> 
+        debug_print (lazy (
+          sprintf ":-) TROVATA 1 coercion da %s a %s: %s" 
+            (CoercDb.name_of_carr src) 
+            (CoercDb.name_of_carr tgt)
+            (UriManager.name_of_uri u)));
+        SomeCoercion (CicUtil.term_of_uri u)
+    | u::_ -> 
+        debug_print (lazy (
+          sprintf ":-/ TROVATE %d coercion(s) da %s a %s, prendo la prima: %s" 
+            (List.length l)
+            (CoercDb.name_of_carr src) 
+            (CoercDb.name_of_carr tgt)
+            (UriManager.name_of_uri u)));
+        SomeCoercion (CicUtil.term_of_uri u)
+  with
+    | CoercDb.EqCarrNotImplemented s -> NotHandled s
+    | CoercDb.EqCarrOnNonMetaClosed -> NotMetaClosed
+;;
+
+let look_for_coercion src tgt = 
+  let src_uri = CoercDb.coerc_carr_of_term src in
+  let tgt_uri = CoercDb.coerc_carr_of_term tgt in
+  look_for_coercion src_uri tgt_uri
+
+let is_a_coercion t = 
+  try
+    let uri = CicUtil.uri_of_term t in
+    CoercDb.is_a_coercion uri
+  with Invalid_argument _ -> false
+
+let source_of t = 
+  try
+    let uri = CicUtil.uri_of_term t in
+    CoercDb.term_of_carr (fst (CoercDb.get_carr uri))
+  with Invalid_argument _ -> assert false (* t must be a coercion *)
+  
+let target_of t =
+  try
+    let uri = CicUtil.uri_of_term t in
+    CoercDb.term_of_carr (snd (CoercDb.get_carr uri))
+  with Invalid_argument _ -> assert false (* t must be a coercion *)
+    
+(* EOF *)