(*
 *  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/.
 *)

let fold_file f init fname =
  let inchan = open_in fname in
  let rec fold_lines' value =
    try 
      let line = input_line inchan in 
      fold_lines' (f value line)
    with End_of_file -> value
  in
  let res = (try fold_lines' init with e -> (close_in inchan; raise e)) in
  close_in inchan;
  res
let iter_file f = fold_file (fun _ line -> f line) ()

let hashtbl_sorted_fold f tbl init =
  let sorted_keys =
    List.sort compare (Hashtbl.fold (fun key _ keys -> key::keys) tbl [])
  in
  List.fold_left (fun acc k -> f k (Hashtbl.find tbl k) acc) init sorted_keys