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comparison src/list_util.sml @ 5:258261a53842

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author Adam Chlipala <adamc@hcoop.net>
date Sat, 26 Jan 2008 16:02:47 -0500
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children 38bf996e1c2e
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4:5c3cc348e9e6 5:258261a53842
1 (* Copyright (c) 2008, Adam Chlipala
2 * All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * - Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * - Redistributions in binary form must reproduce the above copyright notice,
10 * this list of conditions and the following disclaimer in the documentation
11 * and/or other materials provided with the distribution.
12 * - The names of contributors may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 *)
27
28 structure ListUtil :> LIST_UTIL = struct
29
30 fun mapfoldl f i =
31 let
32 fun mf s ls' ls =
33 case ls of
34 nil => (s, rev ls')
35 | h :: t =>
36 let
37 val (s, h') = f (h, s)
38 in
39 mf s (h' :: ls') t
40 end
41 in
42 mf i []
43 end
44
45 end