(* 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://www.cs.unibo.it/helm/.
 *)

open Dbconn;;
open Utility;;

let cat l1 l2 =
    if l1 > l2 then 
        l2 @ l1
    else
        l1 @ l2
;;

let rec pattern_ex l =
  match l with
     [] -> []
   | s::tl -> let result = 
             let c = pgc () in
             let qq = "select uri from registry where uri ~ '" ^ s ^ "' order by registry.uri asc" in
             let res = c#exec (qq) in
             List.map (function uri -> (uri,[])) (pgresult_to_string_list res)
             in
	     cat result (pattern_ex tl)
;;