+let empty_db = DB.empty,DB.empty
+
+class status =
+ object
+ val db = empty_db
+ method coerc_db = db
+ method set_coerc_db v = {< db = v >}
+ method set_coercion_status
+ : 'status. < coerc_db : db; .. > as 'status -> 'self
+ = fun o -> {< db = o#coerc_db >}
+ end
+
+let index_coercion status c src tgt arity arg =
+ let db_src,db_tgt = status#coerc_db in