1(*
2 * Copyright (c) 1997-1999 Massachusetts Institute of Technology
3 * Copyright (c) 2003, 2007-14 Matteo Frigo
4 * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
19 *
20 *)
21
22type ('a, 'b) elem =
23  | Leaf
24  | Node of int * ('a, 'b) elem * ('a, 'b) elem * ('a * 'b) list
25val empty : ('a, 'b) elem
26val lookup :
27    ('a -> int) -> ('a -> 'b -> bool) -> 'a -> ('b, 'c) elem -> 'c option
28val insert :
29    ('a -> int) -> 'a -> 'c -> ('a, 'c) elem -> ('a, 'c) elem
30